Frame memory device and method with subsampling and read-out of stored signals at lower resolution than that of received image signals

Abstract

A frame memory device is employed in a digital camera, for example, to output raster-scanned digital color image signals at lower resolution than that of original image signals. The order of sequentially received original raster-scanned digital color image signals is rearranged, and the rearranged signals are sequentially stored in a memory having a two-dimensional address structure such that vertical addresses represent the order of entry of respective scan lines that constitute the image signals and horizontal addresses represent the order of entry of respective signals that belong to each of the scan lines. The stored rearranged signals are subsampled and read out while skipping horizontal and vertical addresses of the memory at regular intervals. The image signals may comprise YCCcolor signals having a sampling ratio of 4:2:2. Sequentially received C signals in the order of C→C→C→C, for example, are rearranged in the order of C→C→C→C. Scanning frequencies of image signals generated in the raster-scan scheme can be made equal to those of NTSC or PAL television signals for convenient display of image signals on a television monitor.