how can i draw small circles on several specific pixels and count all the pixels inside these circles

I have a road map and i am trying to put circles on each road pixel (which defined the accessibility from the road) and then count all the pixels inside these circles. Can someone help me with this

thanks Mojtaba

Answer 1

[Image Analyst]

You can use viscircles() to draw circles in the overlay above the image. From the radius, you know how many complete pixels and partial pixels will be in a circle of that radius.

[Mojtaba Houballah]

Hello,

I dont know if i was clear in my question.

The first problem that I had is sepcifying the center of the circles with the black pixels(the roads), so specifying the coordinates of the pixels.

The second problem is counting the pixels inside these circles (I tried using inpolygon function).

can you give me a small example of how to do that?.

Many thanks in advance Mojtaba

[Image Analyst]

I see blue, red, and white pixels. No black pixels. To find centroids of blobs, use regionprops(). See my Image Segmentation Tutuorial. http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862&sort=downloads_desc