1. A method of quantifying a feature represented by image data, comprising: receiving image data; determining an operator for quantifying a feature of an image described by image data, wherein the operator includes a plurality of blocks, wherein the blocks include a primary block, encompassing a primary location, and outer blocks, wherein the outer blocks surround the primary block, wherein each of the blocks is sized to cover an odd number of pixels greater than one and each of the blocks covers an identical number of pixels, wherein each of the blocks is centered on a center of a pixel, wherein the blocks are arranged such that an external pixel of the image lies between the primary block and each of the outer blocks, wherein the external pixel does not contribute to a value indicative of an average intensity of any of the blocks; determining a gradient direction, about the primary location, of intensity of the image data near the primary location; rotating the operator about the primary location based on the gradient direction, wherein the rotated operator includes a rotated primary block and repositioned outer blocks, wherein rotating the operator includes determining locations of the repositioned outer blocks surrounding the primary block; and determining a value indicative of an average intensity of the rotated primary block and each of the repositioned outer blocks of the rotated operator; comparing the value indicative of the average intensity of the rotated primary block to each value indicative of the average intensity of each of the repositioned outer blocks; and quantifying a feature represented by the image data by generating a characteristic number based on the comparison.