How to Sampling Uniformly in an image?

hi I'm working in Action Recognition Project. Here the motion boundary is detected by sobel operator. Now I have the result of sobel operator, a binary image. I have to take 25% of pixels in motion boundary by uniformly sampling.

Thanks in advance

Answer 1

[Image Analyst]

Try interparc by John D'Errico: http://www.mathworks.com/matlabcentral/fileexchange/34874-interparc

[Berbia]

Thanks for ur reply...The concept of interparc is just what I needed. But how can I use it for a binary image(white color indicates the motion boundary, not a proper curve)? I have to plot points on white pixels.How to specify values for px,py..?

[Image Analyst]

You can use bwboundaries() to get the coordinates of the outer perimeter of the white objects in your binary image. Then pass those coordinates into interparc().