IMAGE COMPRESSOR/EXPANDER, IMAGE INFORMATION DISPLAY DEVICE, AND NAVIGATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To reduce the memory capacity of a memory means which is necessary in performing scroll display. SOLUTION: When map display data of another part of areas is made necessary by high-speed scrolling, a data input receptacle 4 inputs the display data and a drawing device 16 develops the display data read into a buffer region 22a to a drawing region 22b. A compressor 17 compresses the display data and writes the data into a memory 18 for display. An expander 19 reads the display data out of the memory 18 for display, expands the data and outputs the data to a display controller 20. The compression is performed by sampling the luminance data (y) of respective pixels and color data (u) and (v) for one pixel component with four pixels per each of longitudinal and lateral two pieces as a unit after performing RGB-YUV conversion relating to the respective pixels. COPYRIGHT: (C)2004,JPO