Efficient Filtering of Image Data

A filter circuit for filtering image data, comprising:

• a memory for storing a portion of the image data;
• coefficient logic configured to determine a filter coefficient to be applied to a reference pixel in a sub-matrix of the image data, the coefficient logic includes a register array to store a plurality of filter coefficients, the register array further includes data representing a filter type associated with each register in the register array, wherein the filter coefficients are numbers that can be represented in a 2M form;
• First In First Out (FIFO) logic to retrieve portions of the image data from the memory;
• and
• filter logic configured to calculate an average of multiplications of pixel values and corresponding coefficients, the filter logic including sum logic to calculate a sum of numbers, multiplication logic to multiply a pixel value by a corresponding coefficient value through a bit shift operation, and division logic to divide the sum of numbers by a number of pixels in the sub-matrix, wherein the number of pixels in the sub-matrix being capable of being represented in a 2N form.

A method of efficiently applying a filter to image data, comprising:

• identifying a filter having a filter size to filter the image data;
• reducing a number of pixel positions within the filter, the number of pixel positions selected from different concentric rings of the filter;
• and
• applying the filter with the reduced number of pixel positions to the image data, wherein the number of pixel positions is selected to reduce the filter size to a number that can be represented in a 2N form to enable use of bit shift operations for multiplication and division.