Method and apparatus for converting image data

Abstract

A method and apparatus for converting input image data in line-scan format into block-scan format, and for converting input image data in block-scan format into line-scan format. The apparatus can be implemented as a single integrated circuit which includes a memory and control logic for implementing format conversion, but no external address lines. The apparatus includes an address generator which automatically generates an address sequence for each strip of input data. Each input data strip comprises N lines of image data words, with L vectors in each line, where each vector comprises M image data words. The apparatus converts a line-scan format input data strip into blocks each consisting of N vectors. Each input data strip is processed efficiently, by automatically generating a sequence of addresses for the vectors of the strip. During each iteration of a format conversion operation, one address is generated, one vector is read out of a memory location identified by that address, and one input vector is written into the memory location. The address generator preferably generates addresses for B input data strips which comprise an image by performing a sequence of iterations during each of B cycles, where each iteration includes the step of 'modulo k' addition by an increment F, where F has a different value during each cycle. The increment F for each of the cycles following the first cycle is stored as it becomes available during performance of a previous one of the cycles.