KLT Feature Tracker

Runs KLT Feature tracking on a sequence of frames. More...

Data Structures
struct	VPIKLTFeatureTrackerCreationParams
	Creation parameters of KLT Feature Tracker. More...
struct	VPIKLTFeatureTrackerParams
	Structure that defines the parameters for vpiCreateKLTFeatureTracker. More...
struct	VPIKLTTrackedBoundingBox
	Stores a bounding box that is being tracked by KLT Tracker. More...

Enumerations
enum	VPIKLTFeatureTrackerType
	KLT Feature Tracker algorithm type. More...

Functions
VPIStatus	vpiInitKLTFeatureTrackerCreationParams (VPIKLTFeatureTrackerCreationParams *params)
	Initialize VPIKLTFeatureTrackerCreationParams with default values. More...
VPIStatus	vpiCreateKLTFeatureTracker (uint32_t backends, int32_t imageWidth, int32_t imageHeight, VPIImageFormat imageFormat, const VPIKLTFeatureTrackerCreationParams *params, VPIPayload *payload)
	Creates payload for vpiSubmitKLTFeatureTracker. More...
VPIStatus	vpiInitKLTFeatureTrackerParams (VPIKLTFeatureTrackerParams *params)
	Initialize VPIKLTFeatureTrackerParams with default values. More...
VPIStatus	vpiSubmitKLTFeatureTracker (VPIStream stream, uint32_t backend, VPIPayload payload, VPIImage templateImage, VPIArray inputBoxList, VPIArray inputPredictionList, VPIImage referenceImage, VPIArray outputBoxList, VPIArray outputEstimationList, const VPIKLTFeatureTrackerParams *params)
	Runs KLT Feature Tracker on two frames. More...

Detailed Description

Runs KLT Feature tracking on a sequence of frames.

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Data Structure Documentation

VPIKLTFeatureTrackerCreationParams

struct VPIKLTFeatureTrackerCreationParams

Creation parameters of KLT Feature Tracker.

Definition at line 79 of file KLTFeatureTracker.h.

Collaboration diagram for VPIKLTFeatureTrackerCreationParams:

Data Fields
int32_t	maxTemplateCount	Maximum number of templates to be tracked.
int32_t	maxTemplateHeight	Maximum height of each tracked templates.
int32_t	maxTemplateWidth	Maximum width of each tracked template.

VPIKLTFeatureTrackerParams

struct VPIKLTFeatureTrackerParams

Structure that defines the parameters for vpiCreateKLTFeatureTracker.

Definition at line 137 of file KLTFeatureTracker.h.

Collaboration diagram for VPIKLTFeatureTrackerParams:

Data Fields
float	maxScaleChange	Maximum relative scale change. Scale changes larger than this will make KLT consider that tracking was lost.
float	maxTranslationChange	Maximum relative translation change. Translation changes larger than this will make KLT consider that tracking was lost.
float	nccThresholdKill	Threshold to consider template tracking was lost. Must be a value between 0 and 1.
float	nccThresholdStop	Threshold to stop estimating.
float	nccThresholdUpdate	Threshold for requiring template update. Must be a value between 0 and 1.
int32_t	numberOfIterationsScaling	Number of Inverse compositional iterations of scale estimations.
VPIKLTFeatureTrackerType	trackingType	Type of KLT tracking that will be performed.

VPIKLTTrackedBoundingBox

struct VPIKLTTrackedBoundingBox

Stores a bounding box that is being tracked by KLT Tracker.

Definition at line 334 of file Types.h.

Collaboration diagram for VPIKLTTrackedBoundingBox:

Data Fields
VPIBoundingBox	bbox	Bounding box being tracked.
uint8_t	reserved1	Reserved for future use.
uint8_t	reserved2	Reserved for future use.
int8_t	templateStatus	Status of the template related to this bounding box. Accepted values: 1 template needs updating. 0 existing template still can be used for tracking, it doesn't need to be updated.
int8_t	trackingStatus	Tracking status of this bounding box. Accepted values: 1 tracking information is invalid and shouldn't be relied upon. 0 tracking information is valid.

Enumeration Type Documentation

VPIKLTFeatureTrackerType

enum VPIKLTFeatureTrackerType

#include <vpi/algo/KLTFeatureTracker.h>

KLT Feature Tracker algorithm type.

Enumerator
VPI_KLT_INVERSE_COMPOSITIONAL	Inverse compositional algorithm for KLT tracker. The inverse compositional algorithm is a reformulation of the classic Lucas-Kanade algorithm to make the steepest-descent images and Hessian constant. Ref: Simon Baker, Iain Matthew, "Lucas-Kanade 20 Years On: A Unified Framework". International Journal of Computer Vision, February 2004, Volume 56, issue 3, pp. 228-231.

Definition at line 120 of file KLTFeatureTracker.h.

Function Documentation

vpiCreateKLTFeatureTracker()

VPIStatus vpiCreateKLTFeatureTracker	(	uint32_t	backends,
		int32_t	imageWidth,
		int32_t	imageHeight,
		VPIImageFormat	imageFormat,
		const VPIKLTFeatureTrackerCreationParams *	params,
		VPIPayload *	payload
	)

#include <vpi/algo/KLTFeatureTracker.h>

Creates payload for vpiSubmitKLTFeatureTracker.

Parameters

[in]	backends	VPI backends that are eligible to execute the algorithm. Currently only one backend is accepted.
[in]	imageWidth,imageHeight	Input image dimensions.
[in]	imageFormat	Input image format.
[in]	params
[out]	payload	Pointer to memory where the created payload handle will be written to.

Returns

an error code on failure else VPI_SUCCESS.

vpiInitKLTFeatureTrackerCreationParams()

VPIStatus vpiInitKLTFeatureTrackerCreationParams

(

VPIKLTFeatureTrackerCreationParams *

params

)

#include <vpi/algo/KLTFeatureTracker.h>

Initialize VPIKLTFeatureTrackerCreationParams with default values.

Default values:

• maxTemplateCount: 64
• maxTemplateWidth: 64
• maxTemplateHeight: 64

Parameters

[out]

params

Structure to be filled with default values.

Returns

an error code on failure else VPI_SUCCESS.

vpiInitKLTFeatureTrackerParams()

VPIStatus vpiInitKLTFeatureTrackerParams

(

VPIKLTFeatureTrackerParams *

params

)

#include <vpi/algo/KLTFeatureTracker.h>

Initialize VPIKLTFeatureTrackerParams with default values.

Default values:

• numberOfIterationsScaling: 20
• nccThresholdUpdate: 0.8
• nccThresholdKill: 0.6
• nccThresholdStop: 1.0
• maxScaleChange: 0.2
• maxTranslationChange: 1.5
• trackingType: VPI_KLT_INVERSE_COMPOSITIONAL

Parameters

[out]

params

Structure to be filled with default values.

Returns

an error code on failure else VPI_SUCCESS.

vpiSubmitKLTFeatureTracker()

VPIStatus vpiSubmitKLTFeatureTracker	(	VPIStream	stream,
		uint32_t	backend,
		VPIPayload	payload,
		VPIImage	templateImage,
		VPIArray	inputBoxList,
		VPIArray	inputPredictionList,
		VPIImage	referenceImage,
		VPIArray	outputBoxList,
		VPIArray	outputEstimationList,
		const VPIKLTFeatureTrackerParams *	params
	)

#include <vpi/algo/KLTFeatureTracker.h>

Runs KLT Feature Tracker on two frames.

Outputs tracked bounding boxes and estimated transform array.

Parameters

[in]	stream	The stream where the operation will be queued in.
[in]	backend	Backend that will execute the algorithm. Must be one of the backends specified during payload creation. If 0, VPI will select one of the eligible backends from the payload that accepts the given parameters, usually the fastest one.
[in]	payload	payload created with vpiCreateKLTFeatureTracker
[in]	referenceImage	reference image
[in]	inputBoxList	Input bounding box array, must have type VPI_ARRAY_TYPE_KLT_TRACKED_BOUNDING_BOX
[in]	inputPredictionList	Input predicted transform array, must have type VPI_ARRAY_TYPE_HOMOGRAPHY_TRANSFORM_2D
[in]	templateImage	template image
[out]	outputBoxList	output Bounding box array, must have type VPI_ARRAY_TYPE_KLT_TRACKED_BOUNDING_BOX
[out]	outputEstimationList	Sstimated transform array, must have type VPI_ARRAY_TYPE_HOMOGRAPHY_TRANSFORM_2D
[in]	params	Control parameters of the KLT feature tracker algorithm.

Returns

an error code on failure else VPI_SUCCESS