Calculating the amount of blurriness on glass image

Hello all. I need a help regarding the calculation of blurriness on the glass. Actually, I have to estimate the amount of fog present on the glass in a gray image which in otherwords called as blurriness. For this I have two images out of which one is with fog on glass and the other is without fog on glass.

I tried image subtraction method but it does not seem to give the difference image perfectly. Please help me in the methods or steps that I should follow in order to get the image showing the difference in intensity pixels and also in calculating the amount of fog or blurriness present in the image.

Thanks in advance.

Answer 1

[Selva Karna]

you go to use image fusing techniques

[nithin birudurat]

Thank you for your answer. But could you please also suggest me which fusion technique suits this application better. For example, PCA fusion, highpass filtering or discrete wavelet transform. This would help me alot for the next steps.

Thanks in advance.

Answer 2

[Image Analyst]

You're asking for us to give image analysis advice on an image but you didn't show us the image. But I don't have the crystal Ball Toolbox, so I don't know what your image looks like and can only give very general advice, which is to use a texture filter like stdfilt(), threshold it, and compute the area fraction. The SD image will be dark in blurry areas and bright in detailed areas.

sdImage = stdfilt(grayImage, true(5));
binaryImage = sdImage < somethresholdValue; % Whatever works, like 5 or 20 or whatever.
blurAreaFraction = nnz(binaryImage) / numel(binaryImage);

[nithin birudurat]

Thank you for the answer with clear explanation. To let you know in detail about the image, I am attaching an RGB image with the fog on glass. I have to visualize the difference between the normal glass and the glass with fog (attached image). Meaning that the fog covered on the glass should be clearly visible in the resulting image.

And also I need to calculate the amount of fog present on the glass. Please suggest the method that I have to follow to achieve the desired result.

[Image Analyst]

I don't know what a fog free glass looks like. If the glass is transparent, I suggest you use scattered light (darkfield, light coming in from a high angle and scattering off the glass into the lens). I ought to know - I image glass in my job (among dozens of other things).

[nithin birudurat]

The fog free glass looks almost similar to this but without fog on it. The only difference you can see here is just a layer of fog on the glass as shown in the attached image. And the images which I have at present are with the same light effect on the glass lenses.