Differentiating between clouds and fog using image processing

I am trying to separate different sky features like fog and clouds.The problem is that fog and clouds have the color and texture sometimes.Does anyone has a good suggestion about it

Answer 1

[Image Analyst]

Please attach an image that you say is fog and one that you say is clouds. In the meantime, search VisionBib: http://www.visionbib.com/bibliography/contents.html I know there are papers there on clouds and haze/fog but they are usually aiming to gauge cloud coverage percentage or to remove haze from images, not to discriminate/distinguish/classify a hazy image as to whether it's hazy because you're looking through a cloud or a fog bank.

[Haider Ali]

I have attached the foggy and the cloudy image.I have to detect the presence of fog.If the clouds are present behind the fog and only fog is detected than it is not a problem.But the clouds should not be confused with fog

[Image Analyst]

You forgot to attach the cloudy image. To me, that could be a cloud or fog. Why does it even matter which it is? To detect fog/clouds/haze you could take the HSV color space version of the image and compare the average Saturation value of the image. If there is fog/clouds/haze, the average saturation value will be less than that for the clear reference image (no clouds).

[Haider Ali]

Thanks alot for your help,i will apply this method and see how it works

[Image Analyst]

OK, though can you still answer the question "Why does it even matter which it is?" What is the "use case"?

Answer 2

[Sailaja G]

In an image which is degraded by fog.how can we calculate the percentage of fog in that image....???

[Image Analyst]

Compare the contrast and spatial frequency content to a non-foggy image of the same scene.

[aswathy pavithran]

Sir,

i have only foggy image as input.i want to remove haze and fog. Using clahe method ia am able to removehaze for an extent. But some distortions are happening like big rectangular patches.what should i do to correct it.