1. A method for classifying an object in an image, the method comprising the steps of: defining an image area located within the object in the image, decomposing the image area into an array of subareas, defining an array of aggregated pixel values by calculating, for each of the subareas, an aggregated pixel value of the respective subarea, calculating a gradient array depending on differences between the aggregated pixel values of adjacent subareas, analyzing the gradient array, identifying, depending on a result of the analyzing step, the object as belonging to a class of a predefined set of classes.