“…Feature extraction is the process of obtaining distinctive features representing an object based on color, texture, size, shape, and location and is an essential step in training ML classifiers. 34,51 Here, image features are extracted based on color and texture information only, as it has been found to be adequate based on extensive experimentation. After the region of interest (ROI) was cropped, it was converted from RGB (red-green-blue) to HSV (hue-saturation-value) and L*a*b* (lightness, green-red, blue-yellow) for each concentration to obtain in R, G, B, H, S, V, L*, a*, and b* color channels separately as HSV is more robust towards external lighting changes, and L*a*b* is particularly useful for boosting colors in images due to the way it handles colors, which offers more distinguish features for the training of machine learning classifiers.…”