what does this code mean?

1/(mean(mean(I1(xy_index(2)+(-7:7),xy_index(1)+(-7:7),1)))/mean(mean(I2(xy_index(2)+(-7:7),xy_index(1)+(-7:7),1))))

Answer 1

Thanks Roberson

Answer 2

It appears to be finding the ratio of the mean values of two 15 element square subarrays, each from a different array.

actually I was interested in color calibration for the imaging system by using different intensity images. by using this command i got the value between 0 to 1 for different group of images. is it the pixel value for gray scale image transformed from digital image or something else?

the whole command for the first set of image was as follow

I1 = imread('E:\allergen-data\20120823\folder 3\3.BMP');
subplot(211)
imshow(I1)
I2 = imread('E:\allergen-data\20120823\folder 2\14.BMP');
subplot(212)
imshow(I2)
I1 = rgb2gray(I1);
I2 = rgb2gray(I2);
xy_index = [310 820];
1/(mean(mean(I1(xy_index(2)+(-7:7),xy_index(1)+(-7:7),1)))/mean(mean(I2(xy_index(2)+(-7:7),xy_index(1)+(-7:7),1))))

it displays ans in the value between 0 to 1. could you help what is it actually?

It is not a gray scale value. It is "something else".

It does not produce a value between 0 and 1: it can produce infinity in some cases.

The expression is of the form 1 / (A / B) . That could be rewritten as B/A, which makes it clearer that what it produces is a ratio of the grayscale intensities of the mean color of the respective two blocks.

Thanks Roberson