Shading correction system

Abstract

Abstract PURPOSE: To make accurate shading corrections in a broad dynamic range by storing a calibrating signal, generated by a white diffussing board, in a digital memory and then by dividing picture information from an image sensor by its output signal. CONSTITUTION: On an edge part on original table 7, standard white diffusion board 9 is arranged in parallel to original 3 and before a scan on original 3, information on board 9 is obtained by fixed image sensor 6 by scanning diffusing board 9 and used as a calibrating signal for a shading componet. During the scan on board 9, change-over switch 10 is connected to contact (a) to code the calibrating signal of sensor 6 by A/D converter 11 and the coded signal is stored in digital memory 12. During the scan on original 3, it is connected to contact (b) to input original information from sensor 6 to divider circuit 13. A signal in memory 12, on the other hand, is outputted synchronizing with every single read and circuit 13 divides the original information to output picture information with no shading component. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Masaaki Mori

Bibliographic Details