Algorithm 2 extracts histogram features from BMP images. It begins by taking an image as input and converts it to grayscale if necessary. The image is divided into tiles, and histograms are calculated for each tile. These histograms are stored in a 2D array, representing the result. The algorithm iterates through tiles, extracting sub-images, calculating histograms, and storing them in the result array. Finally, the resulting array of numerical values defining the histogram is returned, providing essential feature extraction for subsequent analysis in video stream matching.
