detecting object in Homogeneous Intensity image.

I have image of Tiger's Pugmark (footprint impression) on mud. I want to detect the boundary of the pugmark but the image is uniform in intensity that is foreground and background cannot be distinguished based on intensity variations. What can i do to distinguish between the pugmark and the background.

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers

[Walter Roberson]

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Answer 1

[Image Analyst]

Try thresholding and texture filters, like entropyfilt() and stdfilt(). It will be tough, particularly where the pawprint is not very well outlined. I can imagine you could have some parts that don't have a clear and distinct outline - it just kind fades away.

[Suvidha]

Thank you . I am going to try it on the imaage. I also tried the 'neon' effect in picasa on this image and it outlined the pugmark impression. But i could not find algorithm for neon filtering. if you know anything about it please share it here. Here's what it looks like after neon effect

[Image Analyst]

Looks like a Sobel filter to me. You can do that with conv2() or imgradient().