Fiducial Marker Tracking
APIs for the Marker Tracking system. More...
Classes
| Name | |
|---|---|
| struct | MLMarkerTrackerDecodedTypedData Structure type selector. |
| struct | MLMarkerTrackerDecodedArucoData Aruco decoded data. |
| struct | MLMarkerTrackerDecodedBinaryData Binary decoded data. |
| struct | MLMarkerTrackerDecodedData Represents the decoded data. |
| struct | MLMarkerTrackerResult Represents the result for a single marker. |
| struct | MLMarkerTrackerResultArray An array of all the marker results from the Marker Tracker. |
| struct | MLMarkerTrackerCustomProfile Marker Tracker Custom Profile. |
| struct | MLMarkerTrackerSettings Marker Tracker Settings. |
Types
Enums
Functions
| Name | |
|---|---|
| MLResult | MLMarkerTrackerResultArrayInit(MLMarkerTrackerResultArray * inout_result_array) Initializes default values for MLMarkerTrackerResultArray. |
| MLResult | MLMarkerTrackerSettingsInit(MLMarkerTrackerSettings * inout_settings) Initializes default values for MLMarkerTrackerSettings. |
| MLResult | MLMarkerTrackerCreate(const MLMarkerTrackerSettings settings, MLHandle out_handle) Create a Marker Tracker. |
| MLResult | MLMarkerTrackerUpdateSettings(MLHandle tracker_handle, const MLMarkerTrackerSettings * tracker_settings) Update the Marker Tracker with new settings. |
| MLResult | MLMarkerTrackerDestroy(MLHandle tracker_handle) Destroy an Marker Tracker. |
| MLResult | MLMarkerTrackerGetResult(MLHandle tracker_handle, MLMarkerTrackerResultArray * out_data) Get the results for Marker Tracking. |
| MLResult | MLMarkerTrackerReleaseResult(MLMarkerTrackerResultArray * data) Release the resources for the results array. |
Detailed Description
APIs for the Marker Tracking system.
This API can be used to track fiducial markers like QR codes, April tags and Aruco markers. For fiducial markers, this API provides 6DOF poses, and the encoded information.
The scanner supports up to 16 markers. Identical QR codes will be treated as separate targets and reported individually, identical Aruco markers or April tags will lead to a collision and won't be reported separately.
List of supported, trackable markers (with pose info):
Aruco markers.
AprilTag v2.
QR codes (model 1 & 2). List of supported, detectable markers (no pose info):
EAN-13 (experimental).
UPC-A (experimental).
Code 128 (experimental). Starting at API level 28 all ArUco marker, QR code and April tag poses reported from this API are consistently following the convention below.
Marker axes convention: The marker has its own coordinate system (which in the case of a marker coplanar with the image plane and facing the camera means a 180° rotation around the vertical axis).
In RUB coordinates, this means that we will have:
y ^
__|___
| | |
x <--|--+ |
|_____|
Z-axis pointing backwards away from the camera.
THIS API IS DEPRECATED IN FAVOR OF OPENXR XR_ML_marker_understanding EXTENSION: https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#XR_ML_marker_understanding
Shared Object:
- perception.magicleap*
Enums Documentation
MLMarkerTrackerDetectorType
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerDetectorType_None | 0 | Represents no marker type. |
| MLMarkerTrackerDetectorType_QR | 1 << 0 | QR code. |
| MLMarkerTrackerDetectorType_Aruco | 1 << 1 | Aruco and AprilTag. |
| MLMarkerTrackerDetectorType_EAN_13 | 1 << 2 | EAN-13 (experimental). |
| MLMarkerTrackerDetectorType_UPC_A | 1 << 3 | UPC-A (experimental). |
| MLMarkerTrackerDetectorType_Code_128 | 1 << 4 | Code 128 decoded data (experimental). |
| MLMarkerTrackerDetectorType_All | 0x3FFFFFFF | All supported marker types. |
| MLMarkerTrackerDetectorType_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Represents the different detector types supported by the API.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerProfile
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerProfile_Default | 0 | Generic tracker profile. Tracker profile that covers standard use cases. If this does not suite the needs of the application try the other profiles listed below. |
| MLMarkerTrackerProfile_Custom | 1 | Customer Tracker Profile. Application can define a custom traker profiler. See MLMarkerTrackerCustomProfile for more details. |
| MLMarkerTrackerProfile_Speed | 2 | Optimized for speed. Use this profile to reduce the compute load and increase detection/tracker speed. This can result poor poses. |
| MLMarkerTrackerProfile_Accuracy | 3 | Optimized for accuracy. Use this profile to optimize for accurate marker poses. This can cause increased load on the compute. |
| MLMarkerTrackerProfile_SmallTargets | 4 | Optimized for small targets. Use this profile to optimize for markers that are small or for larger markers that need to detected from far. |
| MLMarkerTrackerProfile_Large_FoV | 6 | Optimized for FoV. Use this profile to be able to detect markers across a larger FoV. Marker Tracker system will attempt to use multiple cameras to detect the markers. |
| MLMarkerTrackerProfile_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Represents the different tracker profiles.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 21
MLMarkerTrackingFpsHint
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackingFpsHint_Low | 0 | Low FPS. |
| MLMarkerTrackingFpsHint_Medium | 1 | Medium FPS. |
| MLMarkerTrackingFpsHint_High | 2 | High FPS. |
| MLMarkerTrackingFpsHint_Max | 3 | Max possible FPS. |
| MLMarkerTrackingFpsHint_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Marker tracker FPS hint.
The MLMarkerTrackingFpsHint enum values are used to hint to the back-end the max frames per second that should be analyzed. This is set in the MLMarkerTrackerCustomProfile structure and this setting applies to all enabled trackers.
CPU load is a combination of enabled detector types, FpsHint and ResolutionHint. More detectors and a higher fps and resolution hints will result in a higher CPU load. High CPU load can affect the performance of your system.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackingResolutionHint
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackingResolutionHint_Low | 0 | Low Resolution. |
| MLMarkerTrackingResolutionHint_Medium | 1 | Medium Resolution. |
| MLMarkerTrackingResolutionHint_High | 2 | High Resolution. |
| MLMarkerTrackingResolutionHint_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Marker tracker resolution hint.
The MLMarkerTrackingResolutionHint enum values are used to hint to the back-end the resolution that should be used. This is set in the MLMarkerTrackerCustomProfile structure and this setting currently only applies to the QR, UPC and EAN detectors.
CPU load is a combination of enabled detector types, FpsHint and ResolutionHint. More detectors and a higher fps and resolution hints will result in a higher CPU load. High CPU load can affect the performance of your system.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerCameraHint
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerCameraHint_RGB_Camera | 0 | Single RGB camera. |
| MLMarkerTrackerCameraHint_World_Cameras | 1 | One or more world cameras. |
| MLMarkerTrackerCameraHint_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Marker tracker camera hint.
The MLMarkerTrackerCameraHint enum values are used to hint to the camera that should be used. This is set in the MLMarkerTrackerCustomProfile structure and this setting currently only applies to the aruco detectors.
RGB camera has higher resolution than world cameras and are better suited for use cases where the target to be tracked is small or needs to be detected from far.
World cameras make use of multiple world cameras to improve accuracy and increase the FoV for detection.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 21
MLMarkerTrackerCornerRefineMethod
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerCornerRefineMethod_None | 0 | No refinement. Inaccurate corners. |
| MLMarkerTrackerCornerRefineMethod_Subpix | 1 | Subpixel refinement. Corners have subpixel coordinates. High detection rate, very fast, reasonable accuracy. |
| MLMarkerTrackerCornerRefineMethod_Contour | 2 | Contour refinement. High detection rate, fast, reasonable accuracy. |
| MLMarkerTrackerCornerRefineMethod_AprilTag | 3 | AprilTag refinement. Reasonable detection rate, slowest, but very accurate. |
| MLMarkerTrackerCornerRefineMethod_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Corner Refinement Method.
The Aruco/April tag detector comes with several corner refinement methods. Choosing the right corner refinement method has an impact on the accuracy and speed trade-off that comes with each detection pipeline.
Deprecated since 1.6.0. Scheduled for removal.
Corner refinement only applies to Aruco and April tags, not QR codes.
API Level:
- 20
MLMarkerTrackerFullAnalysisIntervalHint
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerFullAnalysisIntervalHint_Max | 0 | Detector analyzes every frame fully. |
| MLMarkerTrackerFullAnalysisIntervalHint_Fast | 1 | Detector analyzes frame fully very often. |
| MLMarkerTrackerFullAnalysisIntervalHint_Medium | 2 | Detector analyzes frame fully a few times per second. |
| MLMarkerTrackerFullAnalysisIntervalHint_Slow | 3 | Detector analyzes frame fully about every second. |
| MLMarkerTrackerFullAnalysisIntervalHint_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Full Frame Analysis Time Interval.
In order to improve performance, the detectors don't always run on the full frame. Full frame analysis is however necessary to detect new markers that weren't detected before. Use this option to control how often the detector may detect new markers and its impact on tracking performance.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerArucoDictionaryName
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackerArucoDictionaryName_NotInitialized | -1 | Default value. Nothing will be detected. |
| MLMarkerTrackerArucoDictionaryName_DICT_4X4_50 | 0 | 4 by 4 pixel Aruco marker dictionary with 50 IDs. |
| MLMarkerTrackerArucoDictionaryName_DICT_4X4_100 | 4 by 4 pixel Aruco marker dictionary with 100 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_4X4_250 | 4 by 4 pixel Aruco marker dictionary with 250 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_4X4_1000 | 4 by 4 pixel Aruco marker dictionary with 1000 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_5X5_50 | 5 by 5 pixel Aruco marker dictionary with 50 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_5X5_100 | 5 by 5 pixel Aruco marker dictionary with 100 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_5X5_250 | 5 by 5 pixel Aruco marker dictionary with 250 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_5X5_1000 | 5 by 5 pixel Aruco marker dictionary with 1000 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_6X6_50 | 6 by 6 pixel Aruco marker dictionary with 50 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_6X6_100 | 6 by 6 pixel Aruco marker dictionary with 100 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_6X6_250 | 6 by 6 pixel Aruco marker dictionary with 250 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_6X6_1000 | 6 by 6 pixel Aruco marker dictionary with 1000 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_7X7_50 | 7 by 7 pixel Aruco marker dictionary with 50 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_7X7_100 | 7 by 7 pixel Aruco marker dictionary with 100 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_7X7_250 | 7 by 7 pixel Aruco marker dictionary with 250 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_7X7_1000 | 7 by 7 pixel Aruco marker dictionary with 1000 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_ARUCO_ORIGINAL | 5 by 5 pixel Aruco marker dictionary with 1024 IDs. | |
| MLMarkerTrackerArucoDictionaryName_DICT_APRILTAG_16h5 | 4 by 4 bits, minimum hamming distance between any two codes = 5, 30 codes. | |
| MLMarkerTrackerArucoDictionaryName_DICT_APRILTAG_25h9 | 5 by 5 bits, minimum hamming distance between any two codes = 9, 35 codes. | |
| MLMarkerTrackerArucoDictionaryName_DICT_APRILTAG_36h10 | 6 by 6 bits, minimum hamming distance between any two codes = 10, 2320 codes. | |
| MLMarkerTrackerArucoDictionaryName_DICT_APRILTAG_36h11 | 6 by 6 bits, minimum hamming distance between any two codes = 11, 587 codes. | |
| MLMarkerTrackerArucoDictionaryName_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Supported pre-defined Aruco dictionary and AprilTags.
Marker Tracker supports pre-defined Aruco dictionary and AprilTags. Aruco dictionaries can be looked up and markers can be generated for them here: [http://chev.me/arucogen/]
Deprecated since 1.6.0. Scheduled for removal.
: Due to the 4X4 and the 'Aruco Original' dictionaries suffering from frequent false detections, we discourage their use.
API Level:
- 20
MLMarkerTrackingDecodedDataType
| Enumerator | Value | Description |
|---|---|---|
| MLMarkerTrackingDecodedDataType_None | 0 | Represents no decoded data. |
| MLMarkerTrackingDecodedDataType_Aruco | 1 | Aruco and AprilTag decoded data. |
| MLMarkerTrackingDecodedDataType_QR | 2 | QR decoded data. |
| MLMarkerTrackingDecodedDataType_EAN_13 | 3 | EAN-13 decoded data. |
| MLMarkerTrackingDecodedDataType_UPC_A | 4 | UPC-A decoded data. |
| MLMarkerTrackingDecodedDataType_Code_128 | 5 | Code 128 decoded data. |
| MLMarkerTrackingDecodedDataType_Ensure32Bits | 0x7FFFFFFF | Ensure enum is represented as 32 bits. |
Decoded Data Type enumeration.
Each decoder may output different types of decoded data structures. The type field of #MLMarkerTrackingDecodedTypedData holds this enum and can be used to cast #MLMarkerTrackingDecodedTypedData to the correct sub type.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
Types Documentation
MLMarkerTrackerDecodedTypedData
typedef struct MLMarkerTrackerDecodedTypedData MLMarkerTrackerDecodedTypedData;
Structure type selector.
Different Marker Decoders will produce different data. Use this structure to find what the data structure is.
switch ( data->type ) {
case MLMarkerTrackingDecodedDataType_Aruco:
MLMarkerTrackerDecodedArucoData * aruco = reinterpret_cast<MLMarkerTrackerDecodedArucoData*>(data);
MLog(Verbose, "Received Aruco Code %u", aruco->id);
break;
default:
MLog(Verbose, "Unhandled type received");
}
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedArucoData
typedef struct MLMarkerTrackerDecodedArucoData MLMarkerTrackerDecodedArucoData;
Aruco decoded data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedBinaryData
typedef struct MLMarkerTrackerDecodedBinaryData MLMarkerTrackerDecodedBinaryData;
Binary decoded data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedQRData
typedef MLMarkerTrackerDecodedBinaryData MLMarkerTrackerDecodedQRData;
QR Code data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedEAN13Data
typedef MLMarkerTrackerDecodedBinaryData MLMarkerTrackerDecodedEAN13Data;
EAN-13 data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedUPCAData
typedef MLMarkerTrackerDecodedBinaryData MLMarkerTrackerDecodedUPCAData;
UPC-A data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerDecodedCode128Data
typedef MLMarkerTrackerDecodedBinaryData MLMarkerTrackerDecodedCode128Data;
Code 128 data.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 25
MLMarkerTrackerDecodedData
typedef struct MLMarkerTrackerDecodedData MLMarkerTrackerDecodedData;
Represents the decoded data.
The different detectors will have different decoded outputs. See MLMarkerTrackerDecodedTypedData for details on the output formats supported.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerResult
typedef struct MLMarkerTrackerResult MLMarkerTrackerResult;
Represents the result for a single marker.
A list of these detections will be returned by the Marker Tracker, after processing a camera frame succesfully.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerResultArray
typedef struct MLMarkerTrackerResultArray MLMarkerTrackerResultArray;
An array of all the marker results from the Marker Tracker.
Free this array with MLMarkerTrackerReleaseResult.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerCustomProfile
typedef struct MLMarkerTrackerCustomProfile MLMarkerTrackerCustomProfile;
Marker Tracker Custom Profile.
Marker Tracker system provides a set of standard tracking profiles (see MLMarkerTrackerProfile) to configure the tracker settings. If this does not meet the application's needs then the application can choose to define a custom tracker profile using MLMarkerTrackerCustomProfile.
Deprecated since 1.6.0. Scheduled for removal.
MLMarkerTrackerSettings
typedef struct MLMarkerTrackerSettings MLMarkerTrackerSettings;
Marker Tracker Settings.
When creating a Marker Tracker, this list of settings needs to be passed to configure the tracker properly. The tracker will only output detections of markers that belong to the defined dictionary and the estimated poses will only be correct if the marker length has been set correctly.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 21
Functions Documentation
MLMarkerTrackerResultArrayInit
static inline MLResult MLMarkerTrackerResultArrayInit(
MLMarkerTrackerResultArray * inout_result_array
)
Initializes default values for MLMarkerTrackerResultArray.
Parameters
| MLMarkerTrackerResultArray * | inout_result_array | The object to initialize to an empty result array. |
Returns
| MLResult | MLResult_InvalidParam | Failed to init result array due to pointer being NULL. |
| MLResult | MLResult_Ok | Successfully initialized the marker tracking result array. |
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerSettingsInit
static inline MLResult MLMarkerTrackerSettingsInit(
MLMarkerTrackerSettings * inout_settings
)
Initializes default values for MLMarkerTrackerSettings.
Parameters
| MLMarkerTrackerSettings * | inout_settings | The object to initialize with default settings. |
Returns
| MLResult | MLResult_InvalidParam | Failed to init settings array due to pointer being NULL. |
| MLResult | MLResult_Ok | Successfully initialized the marker tracking settings array. |
This call initializes a setting struct with default values. Default values will not start any tracking as the API user needs to add which detector types should be enabled and in case of Aruco/April tag tracking also the corresponding dictionary.
Default marker size is 10cm, but smaller or larger sizes are supported as long as they are detectable with the camera.
Default corner refinement method is 'Contour'. Edge refinement is deactivated.
Max time between fully analyzed frames is 1s.
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 28
MLMarkerTrackerCreate
MLResult MLMarkerTrackerCreate(
const MLMarkerTrackerSettings * settings,
MLHandle * out_handle
)
Create a Marker Tracker.
Parameters
| const MLMarkerTrackerSettings * | settings | List of settings of type MLMarkerTrackerSettings that configure the tracker. |
| MLHandle * | out_handle | A pointer to an MLHandle to the newly created Marker Tracker. If this operation fails, out_handle will be ML_INVALID_HANDLE. |
Returns
| MLResult | MLResult_InvalidParam | Failed to create Marker Tracker due to invalid out_handle. |
| MLResult | MLResult_Ok | Successfully created Marker Tracker. |
| MLResult | MLResult_PerceptionSystemNotStarted | Perception System has not been started. |
| MLResult | MLResult_PermissionDenied | Failed to create tracker due to lack of permission(s). |
| MLResult | MLResult_UnspecifiedFailure | Failed to create the Marker Tracker due to an internal error. |
Required Permissions:
- com.magicleap.permission.MARKER_TRACKING (protection level: normal)
Deprecated since 1.6.0. Scheduled for removal.
Only one marker tracker is allowed per app/session. This call will fail when called multiple times. Use MLMarkerTrackerUpdateSettings and update values if you want to change the detector.
API Level:
- 21
MLMarkerTrackerUpdateSettings
MLResult MLMarkerTrackerUpdateSettings(
MLHandle tracker_handle,
const MLMarkerTrackerSettings * tracker_settings
)
Update the Marker Tracker with new settings.
Parameters
| MLHandle | tracker_handle | MLHandle to the Marker Tracker created by MLMarkerTrackerCreate(). |
| const MLMarkerTrackerSettings * | tracker_settings | List of new Marker Tracker settings. |
Returns
| MLResult | MLResult_InvalidParam | Failed to update the settings due to invalid tracker_settings. |
| MLResult | MLResult_Ok | Successfully updated the Marker Tracker settings. |
| MLResult | MLResult_PerceptionSystemNotStarted | Perception System has not been started. |
| MLResult | MLResult_UnspecifiedFailure | Failed to update the settings due to an internal error. |
Required Permissions:
- None
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 21
MLMarkerTrackerDestroy
MLResult MLMarkerTrackerDestroy(
MLHandle tracker_handle
)
Destroy an Marker Tracker.
Parameters
| MLHandle | tracker_handle | MLHandle to the Marker Tracker created by MLMarkerTrackerCreate(). |
Returns
| MLResult | MLResult_Ok | Successfully destroyed the Marker Tracker. |
| MLResult | MLResult_PerceptionSystemNotStarted | Perception System has not been started. |
| MLResult | MLResult_UnspecifiedFailure | Failed to destroy the tracker due to an internal error. |
Required Permissions:
- None
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerGetResult
MLResult MLMarkerTrackerGetResult(
MLHandle tracker_handle,
MLMarkerTrackerResultArray * out_data
)
Get the results for Marker Tracking.
Parameters
| MLHandle | tracker_handle | MLHandle to the Marker Tracker created by MLMarkerTrackerCreate(). |
| MLMarkerTrackerResultArray * | out_data | Pointer to an array of pointers to MLMarkerTrackerResult. The content will be freed by the MLMarkerTrackerReleaseResult. |
Returns
| MLResult | MLResult_InvalidParam | Failed to return detection data due to invalid out_data. |
| MLResult | MLResult_Ok | Successfully fetched and returned all detections. |
| MLResult | MLResult_PerceptionSystemNotStarted | Perception System has not been started. |
| MLResult | MLResult_UnspecifiedFailure | Failed to return detections due to an internal error. |
Required Permissions:
- None
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20
MLMarkerTrackerReleaseResult
MLResult MLMarkerTrackerReleaseResult(
MLMarkerTrackerResultArray * data
)
Release the resources for the results array.
Parameters
| MLMarkerTrackerResultArray * | data | The list of detections to be freed. |
Returns
| MLResult | MLResult_InvaldParam | Failed to free structure due to invalid data. |
| MLResult | MLResult_Ok | Successfully freed data structure. |
| MLResult | MLResult_PerceptionSystemNotStarted | Perception System has not been started. |
| MLResult | MLResult_UnspecifiedFailure | Failed to free data due to an internal error. |
Required Permissions:
- None
Deprecated since 1.6.0. Scheduled for removal.
API Level:
- 20