Method and device for 90-degree rotation of picture

Abstract

Abstract PURPOSE:To rotate a picture by 90 degrees at high speed in a normal memory constitu tion by obtaining a transposition matrix of an original picture, obtaining a picture rotated clockwise by 90 degrees by changing the bit arranging order for each row of the transposition matrix, and then obtaining a picture rotated counterclockwise by 90 degrees by changing the bit arranging order of each column of the transposition matrix. CONSTITUTION:A CPU 1 is provided together with a main storage 2, a picture store area 3, the N-bit input latch circuits 4 - 6, a 2N-bit data exchange circuit 7, the N-bit output latch circuits 8 and 9, a latch data selection circuit 10, an N-bit exchange circuit 11, a row forward changing circuit 12, and an N-bit output latch circuit 13. A transposition matrix of an original picture is obtained, and a desired picture is obtained by exchanging the bit arrangements of each row of the transposition matrix at the symmetrical positions of bits with the center of a row defined as a symmetrical axis in regard of the 90-degree clockwise rotation. Meanwhile a desired picture is obtained by converting the bit arranging order of the transposition matrix into the arrangement of rows of the adverse order in regard of the 90-degree counterclockwise rotation. Thus a picture can be rotated by 90 degrees at a high speed with use of a normal memory.

Inventors

• 👤 Yutaka Ozaki
• 👤 豊 尾崎

Bibliographic Details