1. A method of analyzing an image, the method comprising: receiving at least one source image; selecting a tonal filter kernel, wherein the tonal filter kernel is at least one derivative of a second tonal filter kernel having a low-pass filtering characteristic; generating offset-kernel images from the source image, wherein each of at least a portion of the offset-kernel images are based on applications of domain-shifted tonal filter kernels to the source image; selecting an image location; and applying a neighborhood filter to the offset-kernel images at offset-kernel image locations corresponding with the image location to determine sampled function values defining a sampled output function.