Bit-reversing method and system for linear image scaling

摘要

A bit-reversing method and system are disclosed for linearly scaling an image frame horizontally, vertically or both. The system includes a counter circuit for outputting the current frame-column number of the currently scanned pixel and the current frame-row number of the currently scanned frame-row. The numbers are bit reversed in a converter circuit. The bit-reversed current frame-column number is compared in a comparator circuit to a horizontal scaling constant which equals the number of pixels to be discarded in each frame-row of the image frame. The bit-reversed current frame-row number is compared in the comparator circuit to a vertical scaling constant which equals the number of frame-rows of the image frame to be discarded. If the bit-reversed current frame-row number is greater than the vertical scaling constant then the comparator circuit outputs appropriate signals to a scaling controller and an address generator for storing the currently scanned frame-row in a frame buffer. Otherwise, the comparator circuit outputs appropriate signals for discarding the currently scanned frame-row. Likewise, if the bit-reversed current column number is greater than the horizontal scaling constant, the comparator circuit outputs appropriate signals to the scaling controller and address generator for storing the currently scanned pixel in the frame buffer. Otherwise, the comparator circuit outputs appropriate signals for discarding the currently scanned pixel.