Function:TrackFeatures

CUVI Feature tracker tracks input features from frame 1 onto frame 2. The function is ideal for tracking selected number of features through an image sequence or a video stream. This is a custom algorithm and does not use optical flows to estimate motion. Check out Motion Estimate section for more details on Optical Flow based motion tracking.

Function

CuviStatus trackFeatures(CuviImage* previousImage, CuviImage* nextImage, CuviPointValue2D* inputFeatures, CuviPointValue2D** trackedFeatures, Cuvi32s featureCount, CuviTrackingCriteria criteria, CuviStream* stream = NULL);

Parameters

Name	Type	Description
previousImage	CuviImage*	The first image whose features are to be tracked
nextImage	CuviImage*	Second image, in which to look for features of first image
inputFeatures	CuviPointValue2D*	Feature of first image
trackedFeatures	CuviPointValue2D**	Output feature list containing the location of tracked features from first image onto second image
featureCount	Cuvi32s	Number of features to track
criteria	CuviFeaturesCriteria	A structure containing various parameters that affect feature tracking behavior
stream	CuviStream*	GPU stream ID for execution

Image Type Support

Input	Output
8uC1	CuviPointValue2D

Samples

Example

//Image size CuviSize size = cuviSize(img1->width,img1->height); //Create two 8-bit Grays-scale CuviImage objects CuviImage* gimg1 = new CuviImage(size,img1->depth,img1->nChannels); CuviImage* gimg2 = new CuviImage(size,img1->depth,img1->nChannels); //Populate the GPU Images gimg1->upload(img1->imageData,img1->widthStep); gimg2->upload(img2->imageData,img2->widthStep); CuviPointValue2D* features1, *features2; //selection and tracking criteria CuviFeaturesCriteria fc = cuviFeaturesCriteria(CUVI_FEATURES_HARRIS,0.006f,22); CuviTrackingCriteria tc = cuviTrackingCriteria(2,cuviSize(12,12),15,10.0f); //ROI for selection CuviROI roi = cuviROI(0,0,img1->width,img1->height); int featureCount = 50; //Select Features cuvi::computerVision::goodFeaturesToTrack(gimg1,roi,&features1,&featureCount,fc); //Track the selected features from first frame onto second frame cuvi::computerVision::trackFeatures(gimg1,gimg2,features1,&features2,featureCount,tc);