1. A method for computing properties of an image represented by pixel values arranged in an array, a method comprising steps of: scanning the array to determine the pixel values; segmenting the array into blocks of the pixel values; performing an associative operation on the pixel values of each block to determine properties of the each block; storing the properties of the each block in a table; providing a window defining a fixed size region of the image, the window having vertices and being configured such that a single vertice at most will be encompassed by any given block having portions within the fixed size region; determining which portions of which blocks are within the fixed size region; selecting a property for each portion of each block within the fixed size region from the table based on the determining of which portions of which blocks are within the fixed size region and locations of the vertices of the window; and, performing the associative operation on the selected properties to determine an overall property for the fixed size region