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);
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Parameters
| Name
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Type
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Description
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| previousImage
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CuviImage*
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The first image whose features are to be tracked
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| nextImage
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CuviImage*
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Second image, in which to look for features of first image
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| inputFeatures
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CuviPointValue2D*
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Feature of first image
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| trackedFeatures
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CuviPointValue2D**
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Output feature list containing the location of tracked features from first image onto second image
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| featureCount
|
Cuvi32s
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Number of features to track
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| criteria
|
CuviFeaturesCriteria
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A structure containing various parameters that affect feature tracking behavior
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| stream
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CuviStream*
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GPU stream ID for execution
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Image Type Support
| Input
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Output
|
| 8uC1
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CuviPointValue2D
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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);
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