I would like to automate process of creating thumbnails / contact sheets for videos. They are usually m x n matrixes of pictures, eg 6x11 or 8x12 etc. Randomly selected pictures are sometimes bad quality: contains movement (blurry image), camera spans (blurry too), too dark or completely black, or completely white, no details, etc. Currently I am using the jpg image file size for image metric: bigger file size -> more details on the picture. Combined with number of colors (can be determined with ImageMagick "identify -format %k" command). I normalize both to 0.0-1.0 interval by dividing with the largest value in the group of the pictures and then I compute the following metric:
gamma*number_of_colors^2+(1-gamma)*file_size^2
Where gamma is a weighting parameter and can be in interval 0.0-1.0. What other approaches, image metrics can be used for this purpose?
