1. A computer implemented method for determining a color score for at least a portion of a biological tissue, the method comprising: obtaining a digital image of the biological tissue; receiving a selection of a portion of the image as an evaluation area; for each of a plurality of pixels within the evaluation area: determining a plurality of color components that are based on a Cartesian color space, determining, from the color components, a hue value in a polar coordinate based color space, and determining a color value based on the hue value; and assigning a color score to the evaluation area based on an average of the color values of the plurality of pixels.