Minolta CF910 Service Manual page 43

6 Histogram Making: PWB-C
• The scanning area is divided into 256 blocks [512 (main-scanning) × 512 (sub-
scanning) dots].
• The image data of the original (excluding the edges) is sampled during the pres-
can after the shading correction (at a rate of every 4 dots both in the main- and
sub-scanning directions).
• A histogram is then generated of saturation and lightness of each block (256
blocks). [This generates a lightness histogram for AE processing. See 8. AE Pro-
cessing.]
• The histogram is used to determine whether each block on the original (excluding
the edges) is monochrome or colored.
• Based on the results of the color/monochrome evaluation made of each block, the
copier determines whether the entire original is colored or monochrome
Block Division
Edge
Edge
Original
Edge
a (16 blocks) × b (16 blocks) = Scanning area (256 blocks)
Histogram
Frequency
Monochrome
Low
7 Image Data Editing: PWB-C
• R, G, and B data are converted to V (value), Cr, and Cb (color component) for
color adjustments (Brightness, Saturation, and Hue).
• The data are also synthesized with the image data (V, CR, Cb) from an external
device (Editor) via an interface to carry out various types of image synthesis pro-
cessing.
Edge
b
Colored
Saturation High
1154M077AA
M-26
ACS: Auto Color Selection
Block Configuration
512 dots
a
1154M076AA
Frequency
Colored
Dark
(ACS)
512 dots
4 dots
each
4 dots each
1154M084AA
Monochrome
Lightness Light
1154M078AA
.