Logarithmic Correction and BGR-to-YMC Conversion
a. Logarithmic Correction
The output of the CCD possesses linear characteristics in relation to the intensity of light
reflected by an original. The density as perceived by the eye, however, does not necessarily have
To compensate for the discrepancy, the copier performs level conversion as shown in Figure 4-
b. BGR-to-YMC Conversion
The intensity of light passing through each of the filters (B, G, R) of the CCD and the density
of (Y, M, C) of an original are in a complementary relationship, enabling level conversion (B to Y,
G to M, R to C) as shown in Figure 4-409 and generation of Y, M, and C signals.
Figure 4-408 Logarithmic Correction
COPYRIGHT © 1999 CANON INC.
CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE PROCESSING SYSTEM
(Y, M, C)
Input level (B, G, R)
Figure 4-409 BGR-to-YMC Conversion