how to remove background image and get fore image

Question

there are two images

alt text http://bbs.shoucangshidai.com/attachments/month_1001/1001211535bd7a644e95187acd.jpg alt text http://bbs.shoucangshidai.com/attachments/

Answer 1

Low-pass filter (blur) the images before you subtract them. Then use that difference signal as a mask to select the pixels of interest. A wide-enough filter will ignore the too-small (high-frequency) features that end up carving out "awful" regions inside your object of interest. It'll also reduce the highlighting of pixel-level noise and misalignment (the highest-frequency information).

In addition, if you have more than two frames, introducing some time hysteresis will let you form more stable regions of interest over time too.