ar

Includes:

<stdio.h>
<stdlib.h>
<stdint.h>
<AR/config.h>
<AR/arConfig.h>
<AR/matrix.h>
<AR/icp.h>
<AR/param.h>
<AR/arImageProc.h>

Introduction

ARToolKit core routines.

Discussion

This header declares essential types and API for the entire ARToolKit SDK.

For compile-time per-machine configuration, see <AR/config.h>.
For compile-time ARToolKit configuration, see <AR/arConfig.h>.

Groups

"Utility".

Group members:

arUtilPrintMtx16: Prints a 4x4 row-major matrix via ARLOG(...).
arUtilPrintTransMat: Prints a transformation matrix via ARLOG(...).

"Square detection".

Group members:

arCreateHandle: Create a handle to hold settings for an ARToolKit tracker instance.
arDeleteHandle: Delete a handle which holds settings for an ARToolKit tracker instance.
arDetectMarker: Detect markers in a video frame.
arGetBorderSize: Get the border size.
arGetDebugMode: Find out whether ARToolKit's debug mode is enabled.
arGetImageProcMode: Get the image processing mode.
arGetLabelingMode: Enquire whether detection is looking for black markers or white markers.
arGetLabelingThresh: Get the current labeling threshold.
arGetLabelingThreshMode: Get the labeling threshold mode (auto/manual).
arGetLabelingThreshModeAutoInterval: Get the number of frames between auto-threshold calculations.
arGetMarker: Get information on the markers detected in a video frame.
arGetMarkerExtractionMode: Get the marker extraction mode
arGetMarkerInfo: Examine a set of detected squares for match with known markers.
arGetMarkerNum: Get the number of markers detected in a video frame.
arGetMatrixCodeType: Get the size and ECC algorithm being used for matrix code (2D barcode) marker detection.
arGetPatternDetectionMode: Get the pattern detection mode
arGetPattRatio: Get the width/height of the marker pattern space, as a proportion of marker width/height.
arGetPixelFormat: Get the expected pixel format for video frames being passed to arDetectMarker
arSetBorderSize: Set the border size.
arSetDebugMode: Enable or disable ARToolKit's debug mode.
arSetImageProcMode: Set the image processing mode.
arSetLabelingMode: Select between detection of black markers and white markers.
arSetLabelingThresh: Set the labeling threshhold.
arSetLabelingThreshMode: Set the labeling threshold mode (auto/manual).
arSetLabelingThreshModeAutoInterval: Set the number of frames between auto-threshold calculations.
arSetMarkerExtractionMode: Set the marker extraction mode
arSetMatrixCodeType: Set the size and ECC algorithm to be used for matrix code (2D barcode) marker detection.
arSetPatternDetectionMode: Set the pattern detection mode
arSetPattRatio: Set the width/height of the marker pattern space, as a proportion of marker width/height.
arSetPixelFormat: Set the expected pixel format for video frames being passed to arDetectMarker

"3D calculation by Stereo".

"Pattern identification".

Group members:

arPattActivate: Activate a previously deactivated pattern.
arPattAttach: Associate a set of patterns with an ARHandle.
arPattCreateHandle: Allocate a pattern handle.
arPattDeactivate: Deactivate a previously activated pattern.
arPattDeleteHandle: Free all loaded patterns and pattern handle.
arPattDetach: Reset an ARHandle to no pattern association.
arPattFree: Frees (unloads) a pattern file from memory.
arPattGetID2: Match the interior of a detected square against known patterns.
arPattGetIDGlobal: Match the interior of a detected square against known patterns with variable border width.
arPattGetImage2: Extract the image (i.e. locate and unwarp) of the pattern-space portion of a detected square.
arPattGetImage3: Extract the image (i.e. locate and unwarp) of an arbitrary portion of a detected square.
arPattLoad: Load a pattern file into a pattern handle.
arPattSave: Save a pattern to a pattern file.

"3D calculation".

Group members:

ar3DChangeCpara: (description)
ar3DChangeLoopBreakThresh: (description)
ar3DChangeLoopBreakThreshRatio: (description)
ar3DChangeMaxLoopCount: (description)
ar3DCreateHandle: Create handle used for 3D calculation from calibrated camera parameters.
ar3DCreateHandle2: Create handle used for 3D calculation from an intrinsic parameters matrix.
ar3DDeleteHandle: Delete handle used for 3D calculation.
arGetTransMat: (description)
arGetTransMatRobust: (description)
arGetTransMatSquare: (description)
arGetTransMatSquareCont: (description)

Functions

ar3DChangeCpara: (description)
ar3DChangeLoopBreakThresh: (description)
ar3DChangeLoopBreakThreshRatio: (description)
ar3DChangeMaxLoopCount: (description)
ar3DCreateHandle: Create handle used for 3D calculation from calibrated camera parameters.
ar3DCreateHandle2: Create handle used for 3D calculation from an intrinsic parameters matrix.
ar3DDeleteHandle: Delete handle used for 3D calculation.
arCreateHandle: Create a handle to hold settings for an ARToolKit tracker instance.
arDeleteHandle: Delete a handle which holds settings for an ARToolKit tracker instance.
arDetectMarker: Detect markers in a video frame.
arGetBorderSize: Get the border size.
arGetDebugMode: Find out whether ARToolKit's debug mode is enabled.
arGetImageProcMode: Get the image processing mode.
arGetLabelingMode: Enquire whether detection is looking for black markers or white markers.
arGetLabelingThresh: Get the current labeling threshold.
arGetLabelingThreshMode: Get the labeling threshold mode (auto/manual).
arGetLabelingThreshModeAutoInterval: Get the number of frames between auto-threshold calculations.
arGetMarker: Get information on the markers detected in a video frame.
arGetMarkerExtractionMode: Get the marker extraction mode
arGetMarkerInfo: Examine a set of detected squares for match with known markers.
arGetMarkerNum: Get the number of markers detected in a video frame.
arGetMatrixCodeType: Get the size and ECC algorithm being used for matrix code (2D barcode) marker detection.
arGetPatternDetectionMode: Get the pattern detection mode
arGetPattRatio: Get the width/height of the marker pattern space, as a proportion of marker width/height.
arGetPixelFormat: Get the expected pixel format for video frames being passed to arDetectMarker
arGetTransMat: (description)
arGetTransMatRobust: (description)
arGetTransMatSquare: (description)
arGetTransMatSquareCont: (description)
arGetVersion: Get the ARToolKit version information in numberic and string format.
arPattActivate: Activate a previously deactivated pattern.
arPattAttach: Associate a set of patterns with an ARHandle.
arPattCreateHandle: Allocate a pattern handle.
arPattDeactivate: Deactivate a previously activated pattern.
arPattDeleteHandle: Free all loaded patterns and pattern handle.
arPattDetach: Reset an ARHandle to no pattern association.
arPattFree: Frees (unloads) a pattern file from memory.
arPattGetID2: Match the interior of a detected square against known patterns.
arPattGetIDGlobal: Match the interior of a detected square against known patterns with variable border width.
arPattGetImage2: Extract the image (i.e. locate and unwarp) of the pattern-space portion of a detected square.
arPattGetImage3: Extract the image (i.e. locate and unwarp) of an arbitrary portion of a detected square.
arPattLoad: Load a pattern file into a pattern handle.
arPattSave: Save a pattern to a pattern file.
arSetBorderSize: Set the border size.
arSetDebugMode: Enable or disable ARToolKit's debug mode.
arSetImageProcMode: Set the image processing mode.
arSetLabelingMode: Select between detection of black markers and white markers.
arSetLabelingThresh: Set the labeling threshhold.
arSetLabelingThreshMode: Set the labeling threshold mode (auto/manual).
arSetLabelingThreshModeAutoInterval: Set the number of frames between auto-threshold calculations.
arSetMarkerExtractionMode: Set the marker extraction mode
arSetMatrixCodeType: Set the size and ECC algorithm to be used for matrix code (2D barcode) marker detection.
arSetPatternDetectionMode: Set the pattern detection mode
arSetPattRatio: Set the width/height of the marker pattern space, as a proportion of marker width/height.
arSetPixelFormat: Set the expected pixel format for video frames being passed to arDetectMarker
arUtilChangeToResourcesDirectory: Change to the resources directory using the specified behavior.
arUtilGetFileBasenameFromPath: Get file base name from a path.
arUtilGetFileExtensionFromPath: Get file extension from a path.
arUtilGetFileURI: Get a path as a file URI.
arUtilGetPixelFormatName: Get a string holding a descriptive name for a given pixel format enumeration.
arUtilGetPixelSize: Get the size in bytes of a single pixel for a given pixel format.
arUtilGetResourcesDirectoryPath: Get the path to the resources directory using the specified behavior.
arUtilPrintMtx16: Prints a 4x4 row-major matrix via ARLOG(...).
arUtilPrintTransMat: Prints a transformation matrix via ARLOG(...).
arUtilSleep: Relinquish CPU to the system for specified number of milliseconds.

ar3DChangeCpara

(description)

int ar3DChangeCpara(
    AR3DHandle *handle,
    ARdouble cpara[3][4] );

Parameters

handle: (description)
cpara: (description)

Return Value

(description)

Discussion

(description)

ar3DChangeLoopBreakThresh

(description)

int ar3DChangeLoopBreakThresh(
    AR3DHandle *handle,
    ARdouble loopBreakThresh );

Parameters

handle: (description)
loopBreakThresh: (description)

Return Value

(description)

Discussion

(description)

ar3DChangeLoopBreakThreshRatio

(description)

int ar3DChangeLoopBreakThreshRatio(
    AR3DHandle *handle,
    ARdouble loopBreakThreshRatio );

Parameters

handle: (description)
loopBreakThreshRatio: (description)

Return Value

(description)

Discussion

(description)

ar3DChangeMaxLoopCount

(description)

int ar3DChangeMaxLoopCount(
    AR3DHandle *handle,
    int maxLoopCount );

Parameters

handle: (description)
maxLoopCount: (description)

Return Value

(description)

Discussion

(description)

ar3DCreateHandle

Create handle used for 3D calculation from calibrated camera parameters.

AR3DHandle *ar3DCreateHandle(
    ARParam *arParam);

Parameters

arParam: (description)

Return Value

The handle. When no more ar3D*() functions need be called, the handle should be deleted by calling ar3DDeleteHandle().

Discussion

An AR3DHandle holds data structures used in calculating the 3D pose of a marker from the 2D location of its corners (i.e. pose estimation).

See Also

ar3DCreateHandle2
ar3DDeleteHandle

ar3DCreateHandle2

Create handle used for 3D calculation from an intrinsic parameters matrix.

AR3DHandle *ar3DCreateHandle2(
    ARdouble cpara[3][4]);

Parameters

cpara: (description)

Return Value

The handle. When no more ar3D*() functions need be called, the handle should be deleted by calling ar3DDeleteHandle().

Discussion

An AR3DHandle holds data structures used in calculating the 3D pose of a marker from the 2D location of its corners (i.e. pose estimation).

See Also

ar3DCreateHandle
ar3DDeleteHandle

ar3DDeleteHandle

Delete handle used for 3D calculation.

int ar3DDeleteHandle(
    AR3DHandle **handle );

Parameters

handle: A pointer to the 3D handle. On success, the contents of this location will be set to NULL.

Return Value

0 if the handle was successfully deleted, -1 otherwise.

Discussion

When no more ar3D*() functions need be called, the handle should be deleted by calling ar3DDeleteHandle().

See Also

ar3DDeleteHandle

arCreateHandle

Create a handle to hold settings for an ARToolKit tracker instance.

ARHandle *arCreateHandle(
    ARParamLT *paramLT );

Parameters

paramLT: The created handle will hold a pointer to the calibrated camera parameters specified by this parameter. This parameter uses the new lookup-table based form of the camera parameters introduced in ARToolKit v5. An ARParamLT structure may be created from an ARParam structure via the call: ARParamLT *paramLT = arParamLTCreate(&param, AR_PARAM_LT_DEFAULT_OFFSET);

Return Value

An ARHandle which should be passed to other functions which deal with the operations of the ARToolKit tracker.

Discussion

ARHandle is the primary structure holding the settings for a single ARToolKit square marker tracking instance. Settings include expected video stream image size and pixel format, tracking modes, loaded markers and more.

Expected video stream image size is taken directly from the supplied ARParamLT structure's xsize and ysize fields. Video stream image pixel format defaults to AR_DEFAULT_PIXEL_FORMAT, which is platform and video-module dependent. Usually a call to arSetPixelFormat() is advisable to set the correct format.

After creation of the ARHandle, tracking settings should be set via appropriate calls to other arSet*() functions.

The ARHandle should be disposed of via a call to arDeleteHandle when tracking with this instance is complete.

See Also

arSetPixelFormat
arDeleteHandle

arDeleteHandle

Delete a handle which holds settings for an ARToolKit tracker instance.

int arDeleteHandle(
    ARHandle *handle );

Parameters

handle: The handle to delete, as created by arCreateHandle();

Return Value

0 if no error occured.

Discussion

The calibrated camera parameters pointed to by the handle are NOT deleted by this operation.

See Also

arCreateHandle

arDetectMarker

Detect markers in a video frame.

int arDetectMarker(
    ARHandle *arHandle,
    ARUint8 *dataPtr );

Parameters

arHandle: Handle to initialised settings, including camera parameters, incoming video image size and pixel format, markers, detection modes and other information.
dataPtr: Pointer to the first byte of a block of memory containing pixel data for an image which is to be processed for marker detection. The format of pixels in this image is specified by arSetPixelFormat(). The width and height of the image are specified by the xsize and ysize parameters of the camera parameters held in arHandle.

Return Value

0 if the function proceeded without error, or a value less than 0 in case of error. A result of 0 does not however, imply any markers were detected.

Discussion

This is the core ARToolKit marker detection function. It calls through to a set of internal functions to perform the key marker detection steps of binarization and labelling, contour extraction, and template matching and/or matrix code extraction.

Typically, the resulting set of detected markers is retrieved by calling arGetMarkerNum to get the number of markers detected and arGetMarker to get an array of ARMarkerInfo structures with information on each detected marker, followed by a step in which detected markers are possibly examined for some measure of goodness of match (e.g. by examining the match confidence value) and pose extraction.

See Also

arCreateHandle
arGetMarkerNum
arGetMarker

arGetBorderSize

Get the border size.

int arGetBorderSize(
    ARHandle *handle,
    ARdouble *borderSize );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its border size.
borderSize: Pointer into which will be placed the value representing the border size. The default border size for newly-created ARHandle structures is AR_BORDER_SIZE_DEFAULT.

Return Value

0 if no error occured.

Discussion

N.B. Deprecated in favour of arGetPattRatio(), but retained for backwards compatibility.

arGetDebugMode

Find out whether ARToolKit's debug mode is enabled.

int arGetDebugMode(
    ARHandle *handle,
    int *mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its mode.
mode: Pointer into which will be placed the value representing the mode.

Return Value

0 if no error occured.

Discussion

See arSetDebugMode() for more info.

arGetImageProcMode

Get the image processing mode.

int arGetImageProcMode(
    ARHandle *handle,
    int *mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its mode.
mode: Pointer into which will be placed the value representing the current image processing mode.

Return Value

0 if no error occured.

Discussion

See arSetImageProcMode() for a complete description.

arGetLabelingMode

Enquire whether detection is looking for black markers or white markers.

int arGetLabelingMode(
    ARHandle *handle,
    int *mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its labeling mode.
mode: Pointer into which will be placed the value representing the mode.

Return Value

0 if no error occured.

Discussion

See discussion for arSetLabelingMode.

arGetLabelingThresh

Get the current labeling threshold.

int arGetLabelingThresh(
    ARHandle *handle,
    int *thresh );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its labeling threshold value.
thresh: Pointer into which will be placed the value of the labeling threshhold. An integer in the range [0,255] (inclusive)

Return Value

0 if no error occured.

Discussion

This function queries the current labeling threshold. For, AR_LABELING_THRESH_MODE_AUTO_MEDIAN and AR_LABELING_THRESH_MODE_AUTO_OTSU, the threshold value is only valid until the next auto-update. The current threshold mode is not affected by this call. The threshold value is not relevant if threshold mode is AR_LABELING_THRESH_MODE_AUTO_ADAPTIVE.

See Also

arSetLabelingThresh

arGetLabelingThreshMode

Get the labeling threshold mode (auto/manual).

int arGetLabelingThreshMode(
    const ARHandle *handle,
    AR_LABELING_THRESH_MODE *mode_p);

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its labeling threshold value.
mode_p: Pointer into which will be placed the value of the labeling threshold mode, one of: AR_LABELING_THRESH_MODE_MANUAL, AR_LABELING_THRESH_MODE_AUTO_MEDIAN, AR_LABELING_THRESH_MODE_AUTO_OTSU, AR_LABELING_THRESH_MODE_AUTO_ADAPTIVE

Return Value

0 if no error occured.

See Also

arSetLabelingThresh

arGetLabelingThreshModeAutoInterval

Get the number of frames between auto-threshold calculations.

int arGetLabelingThreshModeAutoInterval(
    const ARHandle *handle,
    int *interval_p);

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its labeling threshold auto interval value.
interval_p: Pointer into which will be placed the value of the labeling threshhold auto interval. An integer in the range [0,INT_MAX] (inclusive)

Return Value

0 if no error occured.

Discussion

This is the number of frames BETWEEN calculations, meaning that the calculation occurs every (interval + 1) frames.

See Also

arSetLabelingThreshModeAutoInterval

arGetMarker

Get information on the markers detected in a video frame.

ARMarkerInfo *arGetMarker(
    ARHandle *arHandle );

Parameters

arHandle: Handle upon which arDetectMarker has been called.

Return Value

An array (of length arGetMarkerNum(arHandle)) of ARMarkerInfo structs. A better name for this function would be arGetDetectedMarkerInfo, but the current name lives on for historical reasons.

See Also

arGetMarkerNum
ARMarkerInfo
arDetectMarker

arGetMarkerExtractionMode

Get the marker extraction mode

int arGetMarkerExtractionMode(
    ARHandle *handle,
    int *mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its mode.
mode: Pointer into which will be placed the value representing the mode.

Return Value

0 if no error occured.

Discussion

(description)

arGetMarkerInfo

Examine a set of detected squares for match with known markers.

int arGetMarkerInfo(
    ARUint8 *image,
    int xsize,
    int ysize,
    int pixelFormat, 
    ARMarkerInfo2 *markerInfo2,
    int marker2_num, 
    ARPattHandle *pattHandle,
    int imageProcMode,
    int pattDetectMode,
    ARParamLTf *arParamLTf,
    ARdouble pattRatio, 
    ARMarkerInfo *markerInfo,
    int *marker_num, 
    const AR_MATRIX_CODE_TYPE matrixCodeType );

Parameters

image: Image in which squares were detected.
xsize: Horizontal dimension of image, in pixels.
ysize: Vertical dimension of image, in pixels.
pixelFormat: Format of pixels in image. See <AR/config.h> for values.
markerInfo2: Pointer to an array of ARMarkerInfo2 structures holding information on detected squares which are candidates for marker matching.
marker2_num: Size of markerInfo2 array.
pattHandle: Handle to loaded patterns for template matching against detected squares.
imageProcMode: Indicates whether square detection was performed treating the image as a frame or a field.
pattDetectMode: Whether to perform color/mono template matching, matrix code detection, or both.
arParamLTf: Lookup table for the camera parameters for the optical source from which the image was acquired. See arParamLTCreate.
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
markerInfo: Output: Pointer to an array of ARMarkerInfo structures holding information on successful matches.
marker_num: Output: Size of markerInfo array.
matrixCodeType: When matrix code pattern detection mode is active, indicates the type of matrix code to detect.

Return Value

0 in case of no error, or -1 otherwise.

Discussion

Performs the intermediate marker-detection stage of taking detected squares in a processed image, and matching the interior of these squares against known marker templates, or extracting matrix codes from the interior of the square.

See Also

arParamLTCreate

arGetMarkerNum

Get the number of markers detected in a video frame.

int arGetMarkerNum(
    ARHandle *arHandle );

Parameters

arHandle: Handle upon which arDetectMarker has been called.

Return Value

The number of detected markers in the most recent image passed to arDetectMarker. Note that this is actually a count, not an index. A better name for this function would be arGetDetectedMarkerCount, but the current name lives on for historical reasons.

See Also

arGetMarker
ARMarkerInfo
arDetectMarker

arGetMatrixCodeType

Get the size and ECC algorithm being used for matrix code (2D barcode) marker detection.

int arGetMatrixCodeType(
    ARHandle *handle,
    AR_MATRIX_CODE_TYPE *type_p);

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its mode.
type_p: Pointer into which will be placed the value representing the mode.

Return Value

0 if no error occured.

Discussion

See the description for arSetMatrixCodeType().

See Also

arGetPatternDetectionMode
arSetMatrixCodeType

arGetPatternDetectionMode

Get the pattern detection mode

int arGetPatternDetectionMode(
    ARHandle *handle,
    int *mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its mode.
mode: Pointer into which will be placed the value representing the mode.

Return Value

0 if no error occured.

Discussion

See arSetPatternDetectionMode() for a complete description.

arGetPattRatio

Get the width/height of the marker pattern space, as a proportion of marker width/height.

int arGetPattRatio(
    ARHandle *handle,
    ARdouble *pattRatio );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried.
pattRatio: Pointer into which will be placed the value representing the width/height of the marker pattern space, as a proportion of marker width/height. The default border size for newly-created ARHandle structures is AR_PATT_RATIO.

Return Value

0 if no error occured.

Discussion

N.B. Supercedes arGetBorderSize().

arGetPixelFormat

Get the expected pixel format for video frames being passed to arDetectMarker

int arGetPixelFormat(
    ARHandle *handle,
    AR_PIXEL_FORMAT *pixFormat );

Parameters

handle: Handle to AR settings structure from which to retrieve the pixel format.
pixFormat: Pointer into which will be placed the value representing the format of pixels being processed by the ARToolKit detection routines. See AR_PIXEL_FORMAT reference for more information.

Return Value

0 if no error occured.

Discussion

See discussion for arSetPixelFormat().

See Also

arSetPixelFormat
arCreateHandle
arDetectMarker

arGetTransMat

(description)

ARdouble arGetTransMat(
    AR3DHandle *handle,
    ARdouble initConv[3][4], 
    ARdouble pos2d[][2],
    ARdouble pos3d[][3],
    int num, 
    ARdouble conv[3][4] );

Parameters

handle

(description)

initConv

(description)

pos2d

(description)

pos3d

(description)

num

(description)

conv

(description)

Return Value

(description)

Discussion

(description)

arGetTransMatRobust

(description)

ARdouble arGetTransMatRobust(
    AR3DHandle *handle,
    ARdouble initConv[3][4], 
    ARdouble pos2d[][2],
    ARdouble pos3d[][3],
    int num, 
    ARdouble conv[3][4] );

Parameters

handle: (description)
initConv: (description)
pos2d: (description)
pos3d: (description)
num: (description)
conv: (description)

Return Value

(description)

Discussion

(description)

arGetTransMatSquare

(description)

ARdouble arGetTransMatSquare(
    AR3DHandle *handle,
    ARMarkerInfo *marker_info, 
    ARdouble width,
    ARdouble conv[3][4] );

Parameters

handle: (description)
marker_info: (description)
width: (description)
conv: (description)

Return Value

(description)

Discussion

(description)

arGetTransMatSquareCont

(description)

ARdouble arGetTransMatSquareCont(
    AR3DHandle *handle,
    ARMarkerInfo *marker_info, 
    ARdouble initConv[3][4], 
    ARdouble width,
    ARdouble conv[3][4] );

Parameters

handle: (description)
marker_info: (description)
initConv: (description)
width: (description)
conv: (description)

Return Value

(description)

Discussion

(description)

arGetVersion

Get the ARToolKit version information in numberic and string format.

ARUint32 arGetVersion(
    char **versionStringRef);

Parameters

versionStringRef: If non-NULL, the location pointed to will be filled with a pointer to a string containing the version information. Fields in the version string are separated by spaces. As of version 2.72.0, there is only one field implemented, and this field contains the major, minor and tiny version numbers in dotted-decimal format. The string is guaranteed to contain at least this field in all future versions of the toolkit. Later versions of the toolkit may add other fields to this string to report other types of version information. The storage for the string is malloc'ed inside the function. The caller is responsible for free'ing the string.

Return Value

Returns the full version number of the ARToolKit in binary coded decimal (BCD) format. BCD format allows simple tests of version number in the caller e.g. if ((arGetVersion(NULL) >> 16) > 0x0272) printf("This release is later than 2.72\n"); The major version number is encoded in the most-significant byte (bits 31-24), the minor version number in the second-most-significant byte (bits 23-16), the tiny version number in the third-most-significant byte (bits 15-8), and the build version number in the least-significant byte (bits 7-0).

Discussion

As of version 2.72, ARToolKit now allows querying of the version number of the toolkit available at runtime. It is highly recommended that any calling program that depends on features in a certain ARToolKit version, check at runtime that it is linked to a version of ARToolKit that can supply those features. It is NOT sufficient to check the ARToolKit SDK header versions, since with ARToolKit implemented in dynamically-loaded libraries, there is no guarantee that the version of ARToolKit installed on the machine at run-time will be as recent as the version of the ARToolKit SDK which the host program was compiled against.

The version information is reported in binary-coded decimal format, and optionally in an ASCII string.

A increase in the major version number indicates the removal of functionality previously provided in the API. An increase in the minor version number indicates that new functionality has been added. A change in the tiny version number indicates changes (e.g. bug fixes) which do not affect the API. See the comments in the config.h header for more discussion of the definition of major, minor, tiny and build version numbers.

arPattActivate

Activate a previously deactivated pattern.

int arPattActivate(
    ARPattHandle *pattHandle,
    int patno );

Parameters

pattHandle: The handle holding the loaded pattern which is to be reactivated.
patno: The index into the pattern handle's array of patterns to the pattern to be reactivated.

Return Value

0 on success, or -1 if the pattern was already activated or no pattern was loaded.

Discussion

When a pattern is activated, is becomes available for recognition in a scene. This is the default state for a loaded pattern.

See Also

arPattDeactivate

arPattAttach

Associate a set of patterns with an ARHandle.

int arPattAttach(
    ARHandle *arHandle,
    ARPattHandle *pattHandle);

Parameters

arHandle: (description)
pattHandle: (description)

Return Value

Returns 0 in the case of success, or -1 if the specified ARHandle already has an ARPattHandle attached, or if arHandle is NULL.

Discussion

Associating a set of patterns with an ARHandle makes the patterns the set which will be searched when marker identification is performed on an image associated with the same ARHandle.

See Also

arPattDetach

arPattCreateHandle

Allocate a pattern handle.

ARPattHandle *arPattCreateHandle(
    void);

Return Value

The created pattern handle, or NULL in case of error.

Discussion

Allocates an empty pattern handle, into which patterns can be loaded by calling arPattLoad(). When the pattern handle is no longer needed, it should be freed by calling arPattDeleteHandle().

Note that a pattern handle is NOT required when using only matrix- code (2D barcode) markers.

See Also

arPattLoad
arPattDeleteHandle

arPattDeactivate

Deactivate a previously activated pattern.

int arPattDeactivate(
    ARPattHandle *pattHandle,
    int patno);

Parameters

pattHandle: The handle holding the loaded pattern which is to be deactivated.
patno: The index into the pattern handle's array of patterns to the pattern to be deactivated.

Return Value

0 on success, or -1 if the pattern was already deactivated or no pattern was loaded.

Discussion

When a pattern is activated, is becomes unavailable for recognition in a scene. Deactivating unused patterns can speed up recognition time and accuracy when there are multiple patterns in a scene, and it is also useful for controlling interactivity in a scene.

See Also

arPattActivate

arPattDeleteHandle

Free all loaded patterns and pattern handle.

int arPattDeleteHandle(
    ARPattHandle *pattHandle);

Parameters

pattHandle: The handle to free.

Return Value

0 on success, or -1 if trying to free a NULL handle.

Discussion

Frees a pattern handle, freeing (unloading) any patterns loaded into the handle in the process.

arPattDetach

Reset an ARHandle to no pattern association.

int arPattDetach(
    ARHandle *arHandle);

Parameters

arHandle: (description)

Return Value

Returns 0 in the case of success, or -1 if the specified ARHandle has no ARPattHandle attached, or if arHandle is NULL.

Discussion

See arPattAttach() for more information.

See Also

arPattAttach

arPattFree

Frees (unloads) a pattern file from memory.

int arPattFree(
    ARPattHandle *pattHandle,
    int patno );

Parameters

pattHandle: The pattern handle to unload from.
patno: The index into the pattern handle's array of patterns to the pattern to be unloaded.

Return Value

0 if the pattern was successfully unloaded, or -1 if there was no pattern loaded.

Discussion

Unloads a pattern from a pattern handle, freeing that slot for another pattern to be loaded, if necessary.

See Also

arPattLoad

arPattGetID2

Match the interior of a detected square against known patterns.

int arPattGetID2(
    ARPattHandle *pattHandle,
    int imageProcMode,
    int pattDetectMode, 
    ARUint8 *image,
    int xsize,
    int ysize,
    AR_PIXEL_FORMAT pixelFormat,
    ARParamLTf *arParamLTf,
    ARdouble vertex[4][2],
    ARdouble pattRatio, 
    int *codePatt,
    int *dirPatt,
    ARdouble *cfPatt,
    int *codeMatrix,
    int *dirMatrix,
    ARdouble *cfMatrix, 
    const AR_MATRIX_CODE_TYPE matrixCodeType );

Parameters

pattHandle: Handle contained details of known patterns, i.e. loaded templates, or valid barcode IDs.
imageProcMode: See discussion of arSetImageProcMode().
pattDetectMode: See discussion of arSetPatternDetectionMode().
image: Pointer to packed raw image data.
xsize: Horizontal pixel dimension of raw image data.
ysize: Vertical pixel dimension of raw image data.
pixelFormat: Pixel format of raw image data.
arParamLTf: Lookup table for the camera parameters for the optical source from which the image was acquired. See arParamLTCreate.
vertex: 4x2 array of points which correspond to the x and y locations of the corners of the detected marker square.
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
codePatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the ID of the pattern from pattHandle, or -1 if not identified.
dirPatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the direction (up, right, down, left) of the pattern from pattHandle.
cfPatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the confidence factor of the match (range [0.0 - 1.0]).
codeMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the ID of the pattern, or -1 if not identified.
dirMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the direction (up, right, down, left) of the pattern.
cfMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the confidence factor of the match (range [0.0 - 1.0]).
matrixCodeType: When matrix code pattern detection mode is active, indicates the type of matrix code to detect.

Return Value

0 if the function was able to correctly match, or -1 in case of error or no match.

See Also

arParamLTCreate

arPattGetIDGlobal

Match the interior of a detected square against known patterns with variable border width.

int arPattGetIDGlobal(
    ARPattHandle *pattHandle,
    int imageProcMode,
    int pattDetectMode, 
    ARUint8 *image,
    int xsize,
    int ysize,
    AR_PIXEL_FORMAT pixelFormat,
    ARParamLTf *arParamLTf,
    ARdouble vertex[4][2],
    ARdouble pattRatio, 
    int *codePatt,
    int *dirPatt,
    ARdouble *cfPatt,
    int *codeMatrix,
    int *dirMatrix,
    ARdouble *cfMatrix, 
    const AR_MATRIX_CODE_TYPE matrixCodeType,
    int *errorCorrected,
    uint64_t *codeGlobalID_p );

Parameters

pattHandle: Handle contained details of known patterns, i.e. loaded templates, or valid barcode IDs.
imageProcMode: See discussion of arSetImageProcMode().
pattDetectMode: See discussion of arSetPatternDetectionMode().
image: Pointer to packed raw image data.
xsize: Horizontal pixel dimension of raw image data.
ysize: Vertical pixel dimension of raw image data.
pixelFormat: Pixel format of raw image data.
arParamLTf: Lookup table for the camera parameters for the optical source from which the image was acquired. See arParamLTCreate.
vertex: 4x2 array of points which correspond to the x and y locations of the corners of the detected marker square.
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
codePatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the ID of the pattern from pattHandle, or -1 if not identified.
dirPatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the direction (up, right, down, left) of the pattern from pattHandle.
cfPatt: Where the pattern matching mode includes template (picture) matching, and a valid template is matched, the confidence factor of the match (range [0.0 - 1.0]).
codeMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the ID of the pattern, or -1 if not identified.
dirMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the direction (up, right, down, left) of the pattern.
cfMatrix: Where the pattern matching mode includes matrix (barcode) matching, and a valid matrix is matched, the confidence factor of the match (range [0.0 - 1.0]).
matrixCodeType: When matrix code pattern detection mode is active, indicates the type of matrix code to detect.
errorCorrected: Pointer to an integer which will be filled out with the number of errors detected and corrected during marker identification, or NULL if this information is not required.
codeGlobalID_p: Pointer to uint64_t which will be filled out with the global ID, or NULL if this value is not required.

Return Value

0 if the function was able to correctly match, or -1 in case of error or no match.

See Also

arParamLTCreate

arPattGetImage2

Extract the image (i.e. locate and unwarp) of the pattern-space portion of a detected square.

int arPattGetImage2(
    int imageProcMode,
    int pattDetectMode,
    int patt_size,
    int sample_size, 
    ARUint8 *image,
    int xsize,
    int ysize,
    AR_PIXEL_FORMAT pixelFormat,
    ARParamLTf *arParamLTf, 
    ARdouble vertex[4][2],
    ARdouble pattRatio,
    ARUint8 *ext_patt );

Parameters

imageProcMode: See discussion of arSetImageProcMode().
pattDetectMode: See discussion of arSetPatternDetectionMode().
patt_size: The number of horizontal and vertical units to subdivide the pattern-space into.
sample_size: At present, must always be the square of patt_size.
image: Pointer to packed raw image data.
xsize: Horizontal pixel dimension of raw image data.
ysize: Vertical pixel dimension of raw image data.
pixelFormat: Pixel format of raw image data.
arParamLTf: Lookup table for the camera parameters for the optical source from which the image was acquired. See arParamLTCreate.
vertex: 4x2 array of points which correspond to the x and y locations of the corners of the detected marker square.
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
ext_patt: Pointer to an array of appropriate size (i.e. patt_size*patt_size*3), which will be filled with the extracted image. Where a colour image is available, it will be supplied in BGR byte order.

Return Value

0 if the function was able to correctly get the image, or -1 in case of error or no match.

See Also

arParamLTCreate

arPattGetImage3

Extract the image (i.e. locate and unwarp) of an arbitrary portion of a detected square.

int arPattGetImage3(
    ARHandle *arHandle,
    int markerNo,
    ARUint8 *image,
    ARPattRectInfo *rect,
    int xsize,
    int ysize, 
    int overSampleScale,
    ARUint8 *outImage );

Parameters

arHandle: The ARHandle structure associated with the current tracking data.
markerNo: The marker number (in range 0 to arHandle->marker_num - 1, inclusive) from which to extract the pattern.
image: The source video image.
rect: Pointer to an ARPattRectInfo structure which defines the portion of the marker image to extract.
xsize: Width of the output image, in pixels.
ysize: Height of the output image, in pixels.
overSampleScale: Number of samples to acquire per destination pixel, e.g. 2.
outImage: Pointer to a buffer, at least xsize*ysize*arUtilGetPixelSize(arHandle->arPixelFormat) bytes in size, which will be filled out with the marker image.

Return Value

0 if the function was able to correctly get the image, or -1 in case of error or no match.

Discussion

Use this function to obtain an image of the marker pattern space for display to the user.

See Also

ARPattRectInfo

arPattLoad

Load a pattern file into a pattern handle.

int arPattLoad(
    ARPattHandle *pattHandle,
    const char *filename );

Parameters

pattHandle: Pattern handle, as generated by arPattCreateHandle(), into which the pattern file infomation will be loaded.
filename: Pathname of pattern file to load. The pattern file is typically generated by the make_patt program. The pathname is relative to the current working directory, which is operating system- specific.

Return Value

Returns the index number of the loaded pattern, in the range [0, AR_PATT_NUM_MAX - 1], or -1 if the pattern could not be loaded because the maximum number of patterns (AR_PATT_NUM_MAX) has already been loaded already into this handle.

Discussion

This function loads a pattern template from a file on disk, and attaches it to the given ARPattHandle so making it available for future pattern-matching. Additional patterns can be loaded by calling again with the same ARPattHandle (however no more than AR_PATT_NUM_MAX patterns can be attached to a single ARPattHandle). Patterns are initially loaded in an active state.

Note that matrix-code (2D barcode) markers do not have any associated pattern file and do not need to be loaded.

See Also

arPattCreateHandle
arPattActivate
arPattDeactivate
arPattFree

arPattSave

Save a pattern to a pattern file.

int arPattSave(
    ARUint8 *image,
    int xsize,
    int ysize,
    int pixelFormat,
    ARParamLTf *paramLTf, 
    int imageProcMode,
    ARMarkerInfo *marker_info,
    ARdouble pattRatio,
    int pattSize,
    const char *filename );

Parameters

image: (description)
xsize: (description)
ysize: (description)
pixelFormat: (description)
paramLTf: (description)
imageProcMode: (description)
marker_info: (description)
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
pattSize: The number of rows and columns to create in the pattern. Normally AR_PATT_SIZE1.
filename: (description)

Return Value

(description)

Discussion

This function is used by the make_patt utility. See the sourcecode to mk_patt for usage.

arSetBorderSize

Set the border size.

int arSetBorderSize(
    ARHandle *handle,
    const ARdouble borderSize );

Parameters

handle: An ARHandle referring to the current AR tracker to have its border size set.
borderSize: The border size. To set the default, pass (1.0 - 2*AR_PATT_RATIO). If compatibility with ARToolKit verions 1.0 through 4.4 is required, this value must be 0.25.

Return Value

0 if no error occured.

Discussion

N.B. Deprecated in favour of arSetPattRatio(), but retained for backwards compatibility.

arSetDebugMode

Enable or disable ARToolKit's debug mode.

int arSetDebugMode(
    ARHandle *handle,
    int mode );

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its debug mode.
mode: Options for this field are: AR_DEBUG_DISABLE AR_DEBUG_ENABLE The default mode is AR_DEBUG_DISABLE.

Return Value

0 if no error occured.

Discussion

In debug mode, ARToolKit offers additional error reporting. Use this function to enable or disable debug mode at runtime.

Additionally, in debug mode, ARToolKit creates a mono (8-bit grayscale) image of the thresholded video input, and makes this available through the field ARHandle->labelInfo.bwImage.

arSetImageProcMode

Set the image processing mode.

int arSetImageProcMode(
    ARHandle *handle,
    int mode );

Parameters

handle: An ARHandle referring to the current AR tracker to have its mode set.
mode: Options for this field are: AR_IMAGE_PROC_FRAME_IMAGE AR_IMAGE_PROC_FIELD_IMAGE The default mode is AR_IMAGE_PROC_FRAME_IMAGE.

Return Value

0 if no error occured.

Discussion

When ARthe image processing mode is AR_IMAGE_PROC_FRAME_IMAGE, ARToolKit processes all pixels in each incoming image to locate markers. When the mode is AR_IMAGE_PROC_FIELD_IMAGE, ARToolKit processes pixels in only every second pixel row and column. This is useful both for handling images from interlaced video sources (where alternate lines are assembled from alternate fields and thus have one field time-difference, resulting in a "comb" effect) such as Digital Video cameras. The effective reduction by 75% in the pixels processed also has utility in accelerating tracking by effectively reducing the image size to one quarter size, at the cost of pose accuraccy.

arSetLabelingMode

Select between detection of black markers and white markers.

int arSetLabelingMode(
    ARHandle *handle,
    int mode );

Parameters

handle: An ARHandle referring to the current AR tracker to have its labeling mode set.
mode: Options for this field are: AR_LABELING_WHITE_REGION AR_LABELING_BLACK_REGION The default mode is AR_LABELING_BLACK_REGION.

Return Value

0 if no error occured.

Discussion

ARToolKit's labelling algorithm can work with both black-bordered markers on a white background (AR_LABELING_BLACK_REGION) or white-bordered markers on a black background (AR_LABELING_WHITE_REGION). This function allows you to specify the type of markers to look for. Note that this does not affect the pattern-detection algorith which works on the interior of the marker.

arSetLabelingThresh

Set the labeling threshhold.

int arSetLabelingThresh(
    ARHandle *handle,
    int thresh );

Parameters

handle: An ARHandle referring to the current AR tracker to have its labeling threshold value set.
thresh: An integer in the range [0,255] (inclusive).

Return Value

0 if no error occured.

Discussion

This function forces the labeling threshold mode to AR_LABELING_THRESH_MODE_MANUAL and sets the threshold value. The default value is AR_DEFAULT_LABELING_THRESHm which is 100, unless edited in arConfig.h.

Background: The labeling threshold is the value which the AR library uses to differentiate between black and white portions of an ARToolKit marker. Since the actual brightness, contrast, and gamma of incoming images can vary signficantly between different cameras and lighting conditions, this value typically needs to be adjusted dynamically to a suitable midpoint between the observed values for black and white portions of the markers in the image.

arSetLabelingThreshMode

Set the labeling threshold mode (auto/manual).

int arSetLabelingThreshMode(
    ARHandle *handle,
    const AR_LABELING_THRESH_MODE mode);

Parameters

handle: An ARHandle referring to the current AR tracker to be queried for its labeling threshold mode.
mode: An integer specifying the mode. One of: AR_LABELING_THRESH_MODE_MANUAL, AR_LABELING_THRESH_MODE_AUTO_MEDIAN, AR_LABELING_THRESH_MODE_AUTO_OTSU, AR_LABELING_THRESH_MODE_AUTO_ADAPTIVE

Return Value

0 if no error occured.

See Also

arSetLabelingThresh

arSetLabelingThreshModeAutoInterval

Set the number of frames between auto-threshold calculations.

int arSetLabelingThreshModeAutoInterval(
    ARHandle *handle,
    const int interval);

Parameters

handle: An ARHandle referring to the current AR tracker for which the labeling threshold auto interval will be set.
interval: The interval, specifying the number of frames between automatic updates to the threshold. An integer in the range [0,INT_MAX] (inclusive). Default value is AR_LABELING_THRESH_AUTO_INTERVAL_DEFAULT.

Return Value

0 if no error occured.

Discussion

This is the number of frames BETWEEN calculations, meaning that the calculation occurs every (interval + 1) frames.

See Also

arGetLabelingThreshModeAutoInterval

arSetMarkerExtractionMode

Set the marker extraction mode

int arSetMarkerExtractionMode(
    ARHandle *handle,
    int mode );

Parameters

handle: An ARHandle referring to the current AR tracker to have its mode set.
mode: Options for this field are: AR_USE_TRACKING_HISTORY AR_NOUSE_TRACKING_HISTORY AR_USE_TRACKING_HISTORY_V2 The default mode is AR_USE_TRACKING_HISTORY_V2.

Return Value

0 if no error occured.

Discussion

(description)

arSetMatrixCodeType

Set the size and ECC algorithm to be used for matrix code (2D barcode) marker detection.

int arSetMatrixCodeType(
    ARHandle *handle,
    const AR_MATRIX_CODE_TYPE type);

Parameters

handle: An ARHandle referring to the current AR tracker to have its mode set.
type: The type of matrix code (2D barcode) in use. Options include: AR_MATRIX_CODE_3x3 AR_MATRIX_CODE_3x3_HAMMING63 AR_MATRIX_CODE_3x3_PARITY65 AR_MATRIX_CODE_4x4 AR_MATRIX_CODE_4x4_BCH_13_9_3 AR_MATRIX_CODE_4x4_BCH_13_5_5 The default mode is AR_MATRIX_CODE_3x3.

Return Value

0 if no error occured.

Discussion

When matrix-code (2D barcode) marker detection is enabled (see arSetPatternDetectionMode) then the size of the barcode pattern and the type of error checking and correction (ECC) with which the markers were produced can be set via this function.

This setting is global to a given ARHandle; It is not possible to have two different matrix code types in use at once.

See Also

arSetPatternDetectionMode
arGetMatrixCodeType

arSetPatternDetectionMode

Set the pattern detection mode

int arSetPatternDetectionMode(
    ARHandle *handle,
    int mode );

Parameters

handle: An ARHandle referring to the current AR tracker to have its mode set.
mode: Options for this field are: AR_TEMPLATE_MATCHING_COLOR AR_TEMPLATE_MATCHING_MONO AR_MATRIX_CODE_DETECTION AR_TEMPLATE_MATCHING_COLOR_AND_MATRIX AR_TEMPLATE_MATCHING_MONO_AND_MATRIX The default mode is AR_TEMPLATE_MATCHING_COLOR.

Return Value

0 if no error occured.

Discussion

The pattern detection determines the method by which ARToolKit matches detected squares in the video image to marker templates and/or IDs. ARToolKit v4.x can match against pictorial "template" markers, whose pattern files are created with the mk_patt utility, in either colour or mono, and additionally can match against 2D-barcode-type "matrix" markers, which have an embedded marker ID. Two different two-pass modes are also available, in which a matrix-detection pass is made first, followed by a template-matching pass.

arSetPattRatio

Set the width/height of the marker pattern space, as a proportion of marker width/height.

int arSetPattRatio(
    ARHandle *handle,
    const ARdouble pattRatio );

Parameters

handle: An ARHandle referring to the current AR tracker to be modified.
pattRatio: The the width/height of the marker pattern space, as a proportion of marker width/height. To set the default, pass AR_PATT_RATIO. If compatibility with ARToolKit verions 1.0 through 4.4 is required, this value must be 0.5.

Return Value

0 if no error occured.

Discussion

N.B. Supercedes arSetBorderSize().

arSetPixelFormat

Set the expected pixel format for video frames being passed to arDetectMarker

int arSetPixelFormat(
    ARHandle *handle,
    AR_PIXEL_FORMAT pixFormat );

Parameters

handle: Handle to settings structure in which to set the pixel format.
pixFormat: Value representing the format of pixels to be processed by the ARToolKit detection routines. See AR_PIXEL_FORMAT reference for more information.

Return Value

0 if no error occured.

Discussion

This function should be used at least once after creation of an ARHandle, to set the pixel format with which images will be passed to arDetectMarker(). If not called, the default value AR_DEFAULT_PIXEL_FORMAT will be used. Note that AR_DEFAULT_PIXEL_FORMAT varies depending on platform and video module. If the pixel format of incoming video images changes, this value must also be changed.

See Also

arGetPixelFormat
arCreateHandle
arDetectMarker

arUtilChangeToResourcesDirectory

Change to the resources directory using the specified behavior.

#ifdef ANDROID 
int arUtilChangeToResourcesDirectory(
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR behavior,
    const char *path,
    jobject instanceOfAndroidContext);  
#else 
int arUtilChangeToResourcesDirectory(
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR behavior,
    const char *path);  
#endif

Parameters

behavior: See AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR type for allowed values.
path: When behavior is AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_SUPPLIED_PATH, the path to change to (absolute or relative to current working directory). In all other cases, if this parameter is non-NULL, it will be taken as a subdirectory of the desired path and to which the working directory should be changed.

Return Value

-1 in the case of error, or 0 otherwise.

Discussion

ARToolKit uses relative paths to locate several types of resources, including camera parameter files, pattern files, multimarker files and others. This function provides the convenience of setting the current process working directory to the appropriate value for your application.

On Android only, the function has an optional parameter 'instanceOfAndroidContext'. If behavior is AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_APP_CACHE_DIR, this parameter must be an instance of a class derived from android/content/Context. In all other cases, pass NULL for this parameter.

Availability: Not available on Windows Runtime (WinRT).

arUtilGetFileBasenameFromPath

Get file base name from a path.

char *arUtilGetFileBasenameFromPath(
    const char *path,
    const int convertToLowercase);

Parameters

path: Full or partial pathname.
convertToLowercase: If convertToLowercase is TRUE, uppercase ASCII characters in the basename will be converted to lowercase.

Return Value

A string with the basename portion of path. NB: The returned string must be freed by the caller.

Discussion

Given a full or partial pathname passed in string path, returns a string with the base name portion of path, i.e. the text between the rightmost path separator and the the rightmost '.' character, if any. If the filename contains no '.', returns the filename.

arUtilGetFileExtensionFromPath

Get file extension from a path.

char *arUtilGetFileExtensionFromPath(
    const char *path,
    const int convertToLowercase);

Parameters

path: Full or partial pathname.
convertToLowercase: If convertToLowercase is TRUE, uppercase ASCII characters in the extension will be converted to lowercase.

Return Value

A string with the extension portion of path. NB: The returned string must be freed by the caller.

Discussion

Given a full or partial pathname passed in string path, returns a string with the extension portion of path, i.e. the text after the rightmost '.' character, if any. If the filename contains no '.', NULL is returned.

arUtilGetFileURI

Get a path as a file URI.

char *arUtilGetFileURI(
    const char *path);

Parameters

path

Full or partial pathname.

On Windows, both partial pathnames, full pathnames including the drive letter, or UNC pathnames (beginning with "\\" are all OK.

Return Value

A string with the the file URI for that path, or NULL in the case of error. NB: The returned string must be freed by the caller (by calling free() once its use is complete).

Discussion

Given a full or partial pathname passed in string path, returns a string with the file URI for that path.

Partial pathnames are handled by concatening with the process's current working directory.

arUtilGetPixelFormatName

Get a string holding a descriptive name for a given pixel format enumeration.

const char *arUtilGetPixelFormatName(
    const AR_PIXEL_FORMAT arPixelFormat);

Parameters

arPixelFormat: Enumerated pixel format number for which to retrieve a name.

Return Value

A constant c-string holding a descriptive name for the pixel format. The string returned matches the constants used in the definition of the type AR_PIXEL_FORMAT, e.g. "AR_PIXEL_FORMAT_RGB".

Discussion

On occasions it can be useful to display to the user the format of the pixels which ARToolKit is processing. This funtion converts a pixel-format number into a human-readable string description.

arUtilGetPixelSize

Get the size in bytes of a single pixel for a given pixel format.

int arUtilGetPixelSize(
    const AR_PIXEL_FORMAT arPixelFormat );

Parameters

arPixelFormat: The pixel type whose size is to be measured.

Return Value

Number of bytes required to store 1 pixel of the given type.

Discussion

Different pixel formats have different sizes in bytes, and therefore different storage requirements per row of pixels. Use this function to calculate the number of bytes required to store a single pixel of the given type.

arUtilGetResourcesDirectoryPath

Get the path to the resources directory using the specified behavior.

#ifdef ANDROID 
char *arUtilGetResourcesDirectoryPath(
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR behavior,
    jobject instanceOfAndroidContext);  
#else 
char *arUtilGetResourcesDirectoryPath(
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR behavior);  
#endif

Parameters

behavior: See AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR type for allowed values.

Return Value

NULL in the case of error, or the path otherwise. Must be free()d by the caller.

Discussion

arUtilPrintMtx16

Prints a 4x4 row-major matrix via ARLOG(...).

void arUtilPrintMtx16(
    const ARdouble mtx16[16]);

Parameters

mtx16: The matrix to print.

arUtilPrintTransMat

Prints a transformation matrix via ARLOG(...).

void arUtilPrintTransMat(
    const ARdouble trans[3][4]);

Parameters

trans: The transformation matrix to print.

arUtilSleep

Relinquish CPU to the system for specified number of milliseconds.

void arUtilSleep(
    int msec );

Parameters

msec: Sleep time in milliseconds (thousandths of a second).

Discussion

This function calls the native system-provided sleep routine to relinquish CPU control to the system for the specified time.

Availability: Not available on Windows Runtime (WinRT).

Typedefs

AR3DHandle: (description)
AR3DStereoHandle: (description)
AR_MARKER_INFO_CUTOFF_PHASE: Result codes returned by arDetectMarker to report state of individual detected trapezoidal regions.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR: Options for controlling the behavior of arUtilGetResourcesDirectoryPath and arUtilChangeToResourcesDirectory.
ARHandle: (description)
ARLabelInfo: (description)
ARMarkerInfo: Describes a detected trapezoidal area (a candidate for a marker match).
ARMarkerInfo2: (description)
ARPattHandle: A structure which holds descriptions of trained patterns for template matching.
ARPattRectInfo: Defines a pattern rectangle as a sub-portion of a marker image.
ARTrackingHistory: (description)

AR3DHandle

(description)

typedef struct { 
    ICPHandleT *icpHandle; 
} AR3DHandle;

Fields

icpHandle: (description)

Discussion

(description)

AR3DStereoHandle

(description)

typedef struct { 
    ICPStereoHandleT *icpStereoHandle; 
} AR3DStereoHandle;

Fields

icpStereoHandle: (description)

Discussion

(description)

AR_MARKER_INFO_CUTOFF_PHASE

Result codes returned by arDetectMarker to report state of individual detected trapezoidal regions.

typedef enum { 
    AR_MARKER_INFO_CUTOFF_PHASE_NONE, 
    AR_MARKER_INFO_CUTOFF_PHASE_PATTERN_EXTRACTION, 
    AR_MARKER_INFO_CUTOFF_PHASE_MATCH_GENERIC, 
    AR_MARKER_INFO_CUTOFF_PHASE_MATCH_CONTRAST, 
    AR_MARKER_INFO_CUTOFF_PHASE_MATCH_BARCODE_NOT_FOUND, 
    AR_MARKER_INFO_CUTOFF_PHASE_MATCH_BARCODE_EDC_FAIL, 
    AR_MARKER_INFO_CUTOFF_PHASE_MATCH_CONFIDENCE, 
    AR_MARKER_INFO_CUTOFF_PHASE_POSE_ERROR, 
    AR_MARKER_INFO_CUTOFF_PHASE_POSE_ERROR_MULTI, 
    AR_MARKER_INFO_CUTOFF_PHASE_HEURISTIC_TROUBLESOME_MATRIX_CODES 
} AR_MARKER_INFO_CUTOFF_PHASE;

Constants

AR_MARKER_INFO_CUTOFF_PHASE_NONE: Marker OK.
AR_MARKER_INFO_CUTOFF_PHASE_PATTERN_EXTRACTION: Failure during pattern extraction.
AR_MARKER_INFO_CUTOFF_PHASE_MATCH_GENERIC: Generic error during matching phase.
AR_MARKER_INFO_CUTOFF_PHASE_MATCH_CONTRAST: Insufficient contrast during matching.
AR_MARKER_INFO_CUTOFF_PHASE_MATCH_BARCODE_NOT_FOUND: Barcode matching could not find correct barcode locator pattern.
AR_MARKER_INFO_CUTOFF_PHASE_MATCH_BARCODE_EDC_FAIL: Barcode matching error detection/correction found unrecoverable error.
AR_MARKER_INFO_CUTOFF_PHASE_MATCH_CONFIDENCE: Matching confidence cutoff value not reached.
AR_MARKER_INFO_CUTOFF_PHASE_POSE_ERROR: Maximum allowable pose error exceeded.
AR_MARKER_INFO_CUTOFF_PHASE_POSE_ERROR_MULTI: Multi-marker pose error value exceeded.
AR_MARKER_INFO_CUTOFF_PHASE_HEURISTIC_TROUBLESOME_MATRIX_CODES: Heuristic-based rejection of troublesome matrix code which is often generated in error.

Discussion

When detecting markers, all trapezoidal regions in the incoming image are considered for marker matching. Various heuristics are used to reject regions judged to be non-markers. The code will, as far as possible, report rejection by placing one of these constants into the ARMarkerInfo.cutoffPhase field of regions rejected during the arDetectMarker() call. Note that the ARMarkerInfo.id of such rejected regions will be -1.

AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR

Options for controlling the behavior of arUtilGetResourcesDirectoryPath and arUtilChangeToResourcesDirectory.

typedef enum { 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_BEST = 0, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_CWD, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_SUPPLIED_PATH, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_EXECUTABLE_DIR, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_BUNDLE_RESOURCES_DIR, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_USER_ROOT, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_APP_CACHE_DIR, 
    AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_APP_DATA_DIR 
} AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR;

Constants

AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_BEST: Use a platform-dependent recommended-best option. Note the this behavior is subject to change in future versions of ARToolKit. At present, on Mac OS X and iOS, this will change to the Apple-provided resources directory inside the application bundle. At present, on other platforms, this will change to the same directory as the executable.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_CWD: Use the current working directory. For arUtilChangeToResourcesDirectory, this will leave the current working directory unchanged.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_SUPPLIED_PATH: Change to the working directory specified.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_EXECUTABLE_DIR: Change to the same directory as the executable. On OS X and iOS, this corresponds to the directory of the binary executable inside the app bundle, not ythe directory containing the app bundle.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_USER_ROOT: Change to the root of the implementation-dependent user-writable root. On OS X and Linux, this is equivalent to the "~" user home. On Android, this is the root of the "external" storage (e.g. an SD card). On Windows, this is the user home directory, typically "C:\Documents and Settings\USERNAME".
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_APP_CACHE_DIR: Change to a writable cache directory, i.e. a directory which is not normally shown to the user, in which files which may be subject to deletion by the system or the user. On Android, change to the applications's (internal) cache directory, and a valid instance of Android/Context must be passed in the instanceofAndroidContext parameter.
AR_UTIL_RESOURCES_DIRECTORY_BEHAVIOR_USE_APP_DATA_DIR: Change to a writable data directory, i.e. a directory which is not normally shown to the user, but in which files are retained permanently.

See Also

arUtilGetResourcesDirectoryPath
arUtilChangeToResourcesDirectory

ARHandle

(description)

typedef struct { 
    int arDebug; 
    AR_PIXEL_FORMAT arPixelFormat; 
    int arPixelSize; 
    int arLabelingMode; 
    int arLabelingThresh; 
    int arImageProcMode; 
    int arPatternDetectionMode; 
    int arMarkerExtractionMode; 
    ARParamLT *arParamLT; 
    int xsize; 
    int ysize; 
    int marker_num; 
    ARMarkerInfo markerInfo[AR_SQUARE_MAX]; 
    int marker2_num; 
    ARMarkerInfo2 markerInfo2[AR_SQUARE_MAX]; 
    int history_num; 
    ARTrackingHistory history[AR_SQUARE_MAX]; 
    ARLabelInfo labelInfo; 
    ARPattHandle *pattHandle; 
    AR_LABELING_THRESH_MODE arLabelingThreshMode; 
    int arLabelingThreshAutoInterval; 
    int arLabelingThreshAutoIntervalTTL; 
    ARImageProcInfo *arImageProcInfo; 
    ARdouble pattRatio; 
    AR_MATRIX_CODE_TYPE matrixCodeType; 
} ARHandle;

Fields

arDebug: (description)
arPixelFormat: (description)
arPixelSize: (description)
arLabelingMode: (description)
arLabelingThresh: (description)
arImageProcMode: To query this value, call arGetImageProcMode(). To set this value, call arSetImageProcMode().
arPatternDetectionMode: (description)
arMarkerExtractionMode: (description)
arParamLT: (description)
marker_num: (description)
markerInfo: (description)
marker2_num: (description)
markerInfo2: (description)
history_num: (description)
history: (description)
labelInfo: (description)
pattHandle: (description)
pattRatio: A value between 0.0 and 1.0, representing the proportion of the marker width which constitutes the pattern. In earlier versions, this value was fixed at 0.5.
matrixCodeType: When matrix code pattern detection mode is active, indicates the type of matrix code to detect.

Discussion

(description)

ARLabelInfo

(description)

typedef struct { 
    AR_LABELING_LABEL_TYPE *labelImage; 
    #if !AR_DISABLE_LABELING_DEBUG_MODE 
    ARUint8 *bwImage; 
    #endif  
    int label_num; 
    int area[AR_LABELING_WORK_SIZE]; 
    int clip[AR_LABELING_WORK_SIZE][4]; 
    ARdouble pos[AR_LABELING_WORK_SIZE][2]; 
    int work[AR_LABELING_WORK_SIZE]; 
    int work2[AR_LABELING_WORK_SIZE*7]; // area, pos[2], clip[4]. 
} ARLabelInfo;

Fields

labelImage: (description)
bwImage: (description)
label_num: (description)
area: (description)
clip: (description)
pos: (description)
work: (description)
work2: (description)

Discussion

(description)

ARMarkerInfo

Describes a detected trapezoidal area (a candidate for a marker match).

typedef struct { 
    int area; 
    int id; 
    int idPatt; 
    int idMatrix; 
    int dir; 
    int dirPatt; 
    int dirMatrix; 
    ARdouble cf; 
    ARdouble cfPatt; 
    ARdouble cfMatrix; 
    ARdouble pos[2]; 
    ARdouble line[4][3]; 
    ARdouble vertex[4][2]; 
    ARMarkerInfo2 *markerInfo2Ptr; 
    AR_MARKER_INFO_CUTOFF_PHASE cutoffPhase; 
    int errorCorrected; 
    uint64_t globalID; 
} ARMarkerInfo;

Fields

area: Area in pixels of the largest connected region, comprising the marker border and regions connected to it. Note that this is not the same as the actual onscreen area inside the marker border.
id: If pattern detection mode is either pattern mode OR matrix but not both, will be marker ID (>= 0) if marker is valid, or -1 if invalid.
idPatt: If pattern detection mode includes a pattern mode, will be marker ID (>= 0) if marker is valid, or -1 if invalid.
idMatrix: If pattern detection mode includes a matrix mode, will be marker ID (>= 0) if marker is valid, or -1 if invalid.
dir: If pattern detection mode is either pattern mode OR matrix but not both, and id != -1, will be marker direction (range 0 to 3, inclusive).
dirPatt: If pattern detection mode includes a pattern mode, and id != -1, will be marker direction (range 0 to 3, inclusive).
dirMatrix: If pattern detection mode includes a matrix mode, and id != -1, will be marker direction (range 0 to 3, inclusive).
cf: If pattern detection mode is either pattern mode OR matrix but not both, will be marker matching confidence (range 0.0 to 1.0 inclusive) if marker is valid, or -1.0 if marker is invalid.
cfPatt: If pattern detection mode includes a pattern mode, will be marker matching confidence (range 0.0 to 1.0 inclusive) if marker is valid, or -1.0 if marker is invalid.
cfMatrix: If pattern detection mode includes a matrix mode, will be marker matching confidence (range 0.0 to 1.0 inclusive) if marker is valid, or -1.0 if marker is invalid.
pos: 2D position (in camera image coordinates, origin at top-left) of the centre of the marker.
line: Line equations for the 4 sides of the marker.
vertex: 2D positions (in camera image coordinates, origin at top-left) of the corners of the marker. vertex[(4 - dir)%4][] is the top-left corner of the marker. Other vertices proceed clockwise from this. These are idealised coordinates (i.e. the onscreen position aligns correctly with the undistorted camera image.)
markerInfo2Ptr: (description)
cutoffPhase: If a trapezoidal region is detected, but is eliminated from the candidates for tracking, this field is filled out with the tracking phase at which the marker was cut off. An English-language description of the phase can be obtained by indexing into the C-string array arMarkerInfoCutoffPhaseDescriptions[].
globalID: If arPattDetectionMode is a matrix mode, matrixCodeType is AR_MATRIX_CODE_GLOBAL_ID, and idMatrix >= 0, will contain the globalID.

Discussion

After marker detection, a number of trapezoidal areas in the camera image will have been identified. An ARMarkerInfo struct is returned for each area so matched. Trapezoidal areas which have been matched with marker images (in pattern mode) or barcodes (in matrix mode) will have valid values assigned to the appropriate id field.

ARMarkerInfo2

(description)

typedef struct { 
    int area; 
    ARdouble pos[2]; 
    int coord_num; 
    int x_coord[AR_CHAIN_MAX]; 
    int y_coord[AR_CHAIN_MAX]; 
    int vertex[5]; 
} ARMarkerInfo2;

Fields

area: (description)
pos: (description)
coord_num: (description)
x_coord: (description)
y_coord: (description)
vertex: (description)

Discussion

(description)

ARPattHandle

A structure which holds descriptions of trained patterns for template matching.

typedef struct { 
    int patt_num; 
    int patt_num_max; 
    int *pattf; 
    int **patt; 
    ARdouble *pattpow; 
    int **pattBW; 
    ARdouble *pattpowBW; 
    //ARdouble        pattRatio; 
    int pattSize; 
} ARPattHandle;

Fields

patt_num: Number of valid patterns in the structure.
pattf: Flag: 0 = no pattern loaded at this position. 1 = pattern loaded and activated. 2 = pattern loaded but deactivated.
patt: Array of 4 different orientations of each pattern's colour values, in 1-byte per component BGR order.
pattpow: Root-mean-square of the pattern intensities.
pattBW: Array of 4 different orientations of each pattern's 1-byte luminosity values.
pattpowBW: Root-mean-square of the pattern intensities.

Discussion

Template (picture)-based pattern matching requires details of the pattern to be supplied to the matching functions. This structure holds such details. It is generally setup by loading pattern files from disk.

ARPattRectInfo

Defines a pattern rectangle as a sub-portion of a marker image.

typedef struct { 
    float topLeftX; 
    float topLeftY; 
    float bottomRightX; 
    float bottomRightY; 
} ARPattRectInfo;

Fields

topLeftX: Horizontal coordinate of the top left corner of the pattern space, in range 0.0f-1.0f.
topLeftY: Vertical coordinate of the top left corner of the pattern space, in range 0.0f-1.0f.
bottomRightX: Horizontal coordinate of the bottom right corner of the pattern space, in range 0.0f-1.0f.
bottomRightY: Vertical coordinate of the bottom right corner of the pattern space, in range 0.0f-1.0f.

Discussion

A complete marker image has coordinates {0.0f, 0.0f, 1.0f, 1.0f}. A standard ARToolKit marker with a pattern ratio of 0.5 has coordinates {0.25f, 0.25f, 0.75f, 0.75f}.

ARTrackingHistory

(description)

typedef struct { 
    ARMarkerInfo marker; 
    int count; 
} ARTrackingHistory;

Fields

marker: (description)
count: (description)

Discussion

(description)

Last Updated: Monday, May 11, 2015