Feature Extraction of Each Object

Main Sheet Configuration

• Required Modules
  • CvfdWebcam
  • LOOP0 (This appears after you create iterator sheet.)

 

CvfdWebcam

All description is available at Image I/O.

 

LOOP0

All description is available at Image I/O.

 

 Iterator Sheet Configuration

• Required Modules
  • CvfdQueryFrame
  • CvfdhCondensation
  • CvfdhDrawSrcRoi
  • CvfdhShowImage
  • CvfdhCalcOpticalFlow
  • SaveFeatures

 

CvfdQueryFrame

All description is available at Image I/O.

 

CvfdhCondensation

All description is available at Image-based Segmentation and Object Tracking.

 

CvfdhDrawSrcRoi

All description is available at Image-based Segmentation and Object Tracking.

 

CvfdhShowImage

All description is available at Image I/O.

 

CvfdhCalcOpticalFlow

• Module Description

This module calculates optical flow vector of each segmented image and outputs the direction and length of each vector as the image feature.
If you want to use other image features, you can replace this module with a module in the following category.

Node list > FDOPENCV_HARK:Feature

• Module Location

Node list > FDOPENCV_HARK:Feature > CvfdhCalcOpticalFlow

 

• Property settings

Name	Type	Value	Explanation
OPTICAL_FLOW_TYPE	string	PyrLK	Optical flow type you want to apply

You can select one of BM/HS/LK/PyrLK for your preference.

 

SaveFeatures

This is a HARK standard module.
Therefore, all description is available at HARK document.

• Property settings

Name	Type	Value	Explanation
BASENAME	string	sep_	Prefix of file name when saving.

 

 Examining the network file

Save the network file before closing [e.g.) cvOpticalFlowAfterSegmentation.n ] Connect your camera supported by OpenCV [e.g.) USB camera] Go to the terminal and run the HARK network file

./cvOpticalFlowAfterSegmentation.n

 

You’ll see the video stream in BaseImage window with a segment window.
After the execution, you will see that sep_*.spec is saved to your current directory, which is the raw-formatted feature file.
The asterisk means the tracked object index.