A method for estimating feature values from a digitized image includes
calculating a gradient of an image, defining a filter weighting function,
convolving the gradient with the filter weighting function, integrating
over a subdomain of the convolved gradient to calculate components of a
cost matrix .PHI., wherein the cost matrix minimizes a distance metric in
a frequency domain of the image, solving for the eigenvalues of the cost
matrix, and calculating one or more features from the cost matrix
eigenvalues. One or more predesigned bandpass filters can be applied to
the image, and cost matrix eigenvalues are analyzed to select one or more
appropriate bandpass filters to be applied to the image.