POST-PROCESSING GENERATION OF FOCUS/DEFOCUS EFFECTS FOR COMPUTER GRAPHICS IMAGES

摘要

A method and apparatus are described for post-processing a computer-generated image (10) of a three-dimensional object for display as a pixel image. A focus depth is specified either by a user or from within the system for each image frame. The image pixels are grouped into non-overlapping blocks (12) of adjoining image pixels with a single respective depth value pre-specified or calculated at run-time for each block. Each block is extracted in turn from the image and the pixels within a block are convolution filtered with a common set of filter coefficients. Padding may be applied to fill areas (18) where a full filter kernel cannot be formed. The technique has particular suitability for MPEG-coded image streams where the existing MPEG macroblock specification may be taken advantage of.