Correlation coefficient for image pixels

I want to calculate the correlation coefficient for my image pixel(binary)and after that for my encrypted image. I know corr2 is for calculating the correlation coefficient for two images.

But is there a function for calculating the correlation coefficient for one image in matlab?Actually I want a number not a matrix

Answer 1

[Nitin]

Hello, I am pretty sure corr2 returns a value , http://www.mathworks.com.au/help/images/ref/corr2.html

You need to compare with something to get a correlation coefficient, either with other images or other parts of your image

[sa za]

Hi.corr2 returns a value but between two image but for one image what should i do?i know i should choose random pixels from my image and calculating the correlation coefficient between them but how? may be i should split the image into two parts and used for corr2 parameters?

[Image Analyst]

If it's encrypted, wouldn't the correlation be about 0? If not, it's not encrypted very well.

[sa za]

hi.yes.correlation should be about 0.but how can I get this correlation ?

[Image Analyst]

I thought you were using corr2(). What's wrong with that?

Answer 2

[sa za]

I can not use corr2 because corr2 working for two image but I want to get correlation coefficient for one image could I divide my image in 2 parts and then use corr2?