How to find the color space of an image

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I am trying to do diffrent colorspace conversion on images (rgb2lab,rgb2ntsc..etc) in opencv using c++. After the conversion I just compare my output image with Matlab output image. Comparison is just done by normal vision. but I know that in the case of images normal vision comparison is not accurate. How can I find which colorspace(rgb,ntsc,lab,xyz) my image belong to?. Any standard method or technique for finding the colorspace of a image?

I am totally new in image processing domain.So please give proper guidance in image processing using openCV...