Histogramming of image dataset (datafile)
H = IM_HIST(A,N)
For every object in the dataset A the set of feature values (for images pixels)is mapped into a histogram, specifying for each bin the number of features having a value as specified for that bin. If H is converted to a dataset it has a feature size equal to the number of bins times the number of bands in the image. So color images return a histogram for every band.
Use HISTM if the bin positions have to be determined automatically is a 'training' stage from some images.