Systems (100) and methods (200, 1600) for generating a medical and/or dental diagnosis. The methods comprise: obtaining a true color image of a select part of a subject's body； converting the true color image to a grayscale intensity image； generating a histogram equalized image by adjusting the gray-scale intensity image's contrast； processing the histogram equalized image to generate first information useful for generating the medical and/or dental diagnosis, the first information comprising at least one of (a) a ratio of a disease region's pixel mean intensity value and a normal region's mean pixel intensity value and (b) an indicator indicating whether a periodontal ligament space has widened or broken； and generating the medical and/or dental diagnosis based at least on the first information.
