how to find a specific color in a image through matlab

[karmax]

hi ... i have an image of red lines whose junction is blue as you can see in pic. actually i want to find out all the cordinates of blue point with respect to any point.image size always be 420 X 720.i attached one of the sample pic.please help me out.
thanks

[fiflak666]

what's the problem?
you just have to move from one corner (0,0) of the image to the other (dim_x,dim_y) and with every piksel check if its RGB values say that it's blue (assuming that it's 8-bit color depth it's gonna be something around RED 0, GREEN 0 BLUE 255)

if so, you've found blue point - remember its coordinates and go along with your checking

[karmax]

i want to thin this image so line contains in single pixel instead of 2 pixel in left and right.i applied sobel on this image an i got underattached image.please help out.

[awally88]

Quick question, you're not using jpeg for the actual analysis are you? Because otherwise everything will die because of the lossy compression algorithm that jpeg uses.

I don't know much about imaging algorithms but isn't sorbel mainly used for edge finding complicated pictures? I don't know how it will go thinning pixels from an image. Do you have some code you can attach so we can check it out?

[karmax]

i need to first find out the nearest cordinate from center of the pic.then i need to find all the cordinates taking nearest point as center.so i am attaching that code.here is the link from you can download the code:http://www.ziddu.com/download/5239973/find_near.rar.html