CMPUT610 Hand-Eye Coordination and Visual Interaction Martin Jagersand Department of Computing Science University of Alberta

MexVision

This version of MexVision is installed in /usr/vis/research/XVision/MexVision. You need to add this to your matlab path to use it.

To get started try the GUI: In Matlab type "xvui". Other useful commands are "grabimage" and YUVtoRGB.

MexVision Commands

• 'init': initialize using a ieee1394 camera as the video source
  preconditions: video has not already been created
  
  
• 'window': create a window to display the video, and use for interactive tracker initialization
  preconditions: video has been created
  parameters: window title
  
  
• 'edge': create an edge tracker and have the user initialize it
  preconditions: window has been created
  returns: id of the tracker
  
  
• 'ssd1' create a translation only ssd Tracker and have the user initialize it
  preconditions: window has been created
  returns: id of the tracker
  
  
• 'ssd2'
  create a translating/rotating/scaling ssd tracker and have the user initialize it
  preconditions: window has been created
  returns: id of the tracker
  
  
• 'blob'
  create a color blob tracker and have the user initialize it
  preconditions: window has been created
  returns: id of the tracker
  
  
• 'frame'
  grab a frame from the video
  returns: matrix containing the image (in YUV422 format)
  note: use grabimage to get image in YUV format
  
  
• 'framerate': get the current tracking framerate
  preconditions: video has been created
  returns: the tracking framerate
  
  
• 'image': get the transformed image associated with a tracker
  preconditions: the tracker exists and is of type ssd2
  parameters: the id of the tracker returns: grayscale image for the tracker
  
  
• 'get': get the state of a tracker
  preconditions: the tracker exists
  parameters: the id of the tracker returns: vector containing the state of the tracker. Given no parameters returns all tracked points sorted first after tracker type (SSD1, SSD2), then tracker number.
  
  Note: Line and color tracker coordinate acess not yet implemented.
  
  
• 'delete': remove a tracker
  preconditions: the tracker exists
  parameters: the id of the tracker
  
  
• 'quit': End MexVision
  

Using MexVision to capture images:

• Initialize MexVision:
  >> MexVision('init');
  
  
• Capture YUV images with
  >> im=grabimage;
  Convert to RGB with
  >> im2=YUVtoRGB(im);
  or
  >> im2=YUVtoRGB(grabimage);
  
  
• Quit MexVision:
  >> MexVision('quit');