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# what does this code mean?

on 20 Nov 2012

### satish thapaliya (view profile)

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))))

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on 20 Nov 2012

Thanks Roberson

### Matt Fig (view profile)

on 20 Nov 2012
Edited by Matt Fig

### Matt Fig (view profile)

on 20 Nov 2012

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

satish thapaliya

### satish thapaliya (view profile)

on 20 Nov 2012

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)
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?

Walter Roberson

### Walter Roberson (view profile)

on 20 Nov 2012

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.

satish thapaliya

on 20 Nov 2012

Thanks Roberson