PURPOSE: To erase a black frame image and the black stripe of a fold by detecting a shade part of a book original through a line sensor, and operating a specific shade removing means selectively.
CONSTITUTION: The line sensor 25 of 512-bit ×2 constitution is provided behind a half-mirror 21 to make an X-directional scan by the movement of an optical system and an Y-directional scan with the clock of the sensor 21, and a video output is obtained and converted from analog to digital in sequence. The book type original is thick, so shade parts are formed at an edge part and a center part. This shade trails on the line sensor 21 as shown by Δt2 in figure. The shade part is detected by knowing the gradient of its density. For the purpose, blank exposure is performed by detecting the shade part during pre-scanning operation. and then the black frame image and black stripe of a fold are eliminated to obtain a clear image.
HASEGAWA SHIZUO
SAITOU TAKASHI
| JPS5611466A | 1981-02-04 | |||
| JPS55164844A | 1980-12-22 | |||
| JPS55138736A | 1980-10-29 | |||
| JPS55130269A | 1980-10-08 | |||
| JPS5754956A | 1982-04-01 |