Patent Document ID: 9197789
Application ID: 14233968
Patent Status: 1

Claim One:
1. A method for removing fog from images and/or videos comprising: (a) carrying out a histogram equalization such that a foggy image is equalized to increase contrast; (b) estimating an airlight map by providing an initial airlight map A of the foggy image and/or video, the estimation is based on minimum intensity across red, green and blue channel of observed image intensity at pixel (x,y) and refining the airlight map A involving anisotropic diffusion or bilateral filtering; (c) restoring the foggy image based on the refined airlight map A by carrying out restoration of each color component of de-foggy image involving I 0 ⁡ ( x , y , c ) = ( I ⁡ ( x , y , c ) - A ) ( 1 - A I ∞ ⁡ ( c ) ) q based on the refined airlight map involving a restoration process having wherein cε(r,g,b), I 0 (x,y,c) is image intensity in absence of the fog, I(x,y,c) is the observed image intensity at the pixel (x,y) and I α (c) is global atmospheric constant or sky intensity, q=k 1 /k 2 , k 1 is extinction co-efficient for attenuation, k 2 is extinction co-efficient for the airlight, with said involvement of k1 and k2 providing flexibility to focus on quality of the image at a required depth by involving different extinction co-efficient for the attenuation and the airlight in factor q to favour control of visual quality of the restored image whereby for a lower value of the factor q(q<1), objects in at a lower depth are more enhanced, and for a higher value of the factor q(q>1), the images at a further end are more enhanced, and performing a histogram stretching of the restored image if the restored image has low contrast.