| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize compression and expansion processing of a high quality image even in an edge part of a high frequency. SOLUTION: Image data are stored in a 4×4 buffer 1, an LDMIN and LDMAX calculating device 2 calculated the LMAX value and the LMIN value of the image data, and LD calculating device 3 performs a GBTC operation by using the LMAX value, the LMIN value and the image data to calculate and LD value, an LD histogram calculating device 4 divides the LD value into several parts and prepares a histogram by counting up the sections belonging to respective sections. An edge boundary value calculating device 5 calculates the code length of a plurality of allocated patterns in order to allocate the code length to the 2/8, 3/8 and 4/8 GBTCs, etc., of each section from histogram values, compares the code length with the code length limitation of a line and allocates the code length on the basis of a priority with high image quality. A GBTC encoding device 6 decides which BGTC processing is to be carried out according to an edge boundary value and performs encoding.</p> |
