Image memory system

An image memory system in which image data related to the respective pixels of an image composed of pixels arranged at positions specified by combination of a row specifying bit string of Ny bits in length and a column specifying bit string of Nx bits in length is stored in specific two memories, wherein;

• said two respective memories have 2b (where b is a positive integer) banks capable of being operated independently of each other, make it possible to consecutively access synchronously with a clock a specified number of pieces of data at consecutive addresses in the same row space on the basis of addresses specified by a row address bit string of Nr bits in length and a column address bit string of Nc (Nc=Nx+Ny−Nr−b−1) bits in length in a bank specified by a bank changeover bit (or a bank changeover bit string), and have a route selecting bit for specifying a memory to he accessed out of said two memories, and said image memory system comprises;
• a means for forming said column address bit string out of the lower L bits of said column specifying bit string and the lower (Nc−L) bits of said row specifying bit string,
• a means for forming said row address bit string out of the upper (Nx−L−Bx) bits of said column specifying bit string and the upper (Ny−Nc+L−By) bits of said row specifying bit string when Bx (>=1) and By (>=1) are arbitrary positive integers satisfying “Bx+By=b+1”, and
• a means for forming a route selecting bit and a bank changeover bit string by using a bit string of Bx bits from the (L+1)th bit to the (L+Bx)th bit of said column specifying bit string and a bit string of By bits from the (Nc−L+1)th bit to the (Nc−L+By)th bit of said row specifying bit string, wherein;
• said route selecting bit is formed out of the exclusive OR of the (L+1)th bit of said column specifying bit string and the (Nc−L+1)th bit of said row specifying bit string, and
• said bank changeover bit string is formed out of a bit string obtained by removing either one bit of the (L+1)th bit of said column specifying bit string or the (Nc−L+1)th bit of said row specifying bit string, which are used for forming said route selecting bit, from a bit string obtained by combining both of said bit strings and together.