How to detect various colors in a image?

I want to detect various colours of a image accurtely. If there is a red colour in image with different intensities the code must able to detect the changes and must generate a separate plot for it.

[jgg]

The standard imread command ( http://www.mathworks.com/help/images/read-image-data-into-the-workspace.html ) will return you a map of your image with the colour channels seperated out. For instance, in a .jpeg, the red colour channel corresponds to im(:,:,1).

I'm not sure what you mean plot in this context. Can you give an example of what you're trying to do?

Answer 1

[Image Analyst]

See several color segmentation demos in my File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

In addition, see the attached zip file where I find the green parts of a Sharpie marker pen moving in a video.

Let me know if you have any problems, but only after you've read this.

Answer 2

[Image Analyst]

An alternative to my other answer is one that looks at a video and finds the mean intensities of the R, G, and B channels and plots them.