1. A method comprising: dividing a digital image into tiles; determining a degree of local contrast in each of the tiles; selecting a first plurality of the tiles that exhibits a greatest degree of local contrast; determining an average color of each of the first plurality of tiles; dividing the first plurality of tiles into clusters of tiles with similar colors; selecting a learning tile from each cluster of tiles, wherein each learning tile has the greatest degree of local contrast from among the tiles of the cluster to which the learning tile belongs; segmenting the learning tiles into objects; classifying the objects into classes of objects; associating a color with each class of objects; determining characteristics of the objects that belong to distinct classes of objects; generating pixelwise descriptors that indicate the class of objects to which each pixel most probably belongs; generating a pixel heat map without again segmenting the digital image into objects by applying the pixelwise descriptors to each pixel of the digital image, wherein each pixel of the digital image is assigned the color associated with the class of objects to which that pixel most probably belongs; and displaying the pixel heat map on a graphical user interface.