shrink ROI

[aveo]

Hi Bruce,

Your suggestion worked. I am able to shrink the ROI using erode function and looping it until the required area percentage is reached. 

Thanks a ton.

Regards

Aveo

[SimonAldred]

If you had a large image (>20MB) and the amount of erosion needed was taking too much time, is there another way? I've tried shrinking an ROI with respect to the centroid, which is fast, but this doesn't always maintain the overall shape in the way that erosion does. In other words I need a fast erosion. Is there a mathematical routine that does this somehow? 

[AmitShachaf]

You could select erosion kernel that is proportion to the size of the image. 

That will make the erosion faster.