Image segmentation based upon optical features

I have an image with some texture in a region shown in first image. I want to segment the image based upon this texture. For this I have extracted feature as shown with blue squares (second image). I want to extract the region bound to the rectangular distribution of the features (shown by red dotted line).

Can somebody help me by suggesting some methodology to pursue this problem. Thanks

Answer 1

[Image Analyst]

I'd make a binary image with a point where each blue spot is. Then I'd dilate it with imdilate(). Then use my Extract biggest blob function attached, to get the largest blob, which will be the region you want. You can call bwboundaries on it if you want a list of the (x,y) coordinates of the perimeter.