IMAGE CODING METHOD, IMAGE DECODING METHOD, MAXIMUM/MINIMUM CODING MEANS, AND MAXIMUM/MINIMUM VALUE DECODING MEANS

摘要

The amount of data is reduced without marring the quality of image so that image signals can be efficiently tramsmitted or stored. A maximum detector (2) detects the maximum MAX of each block of input signals (1) and a minimum detector (6) simultaneously detects the minimum MIN of each block. Comparators (4 and 8) compare the maximum and minimum with the maximum and minimum of the preceding block and output the results of comparison to a maximum coder (5) and a minimum value coder (9), respectively. When the result of the comparison of the comparator (4) does not show the coincidence of the two maximums, the coder (5) codes the maximum. When the result of comparison of the comparator (9) does not show the coincidence of the two minimums, the coder (9) codes the minimum. A normalizing device (10) calculates (input signal-MIN)/(MAX-MIN) and a normalized value coder (11) codes and outputs the result of calculation by the device (10).