Photo Mode - Ricoh B291 Service Manual

IMAGE PROCESSING

Photo Mode

Photo mode emphasizes grayscale processing to achieve the best possible
reproduction of photographs and eliminate moiré by using the highest density and γ
coefficient in the reproduction of grayscales and dithering. Print Photo performs
smoothing and dithering for photos copied from magazines, newspapers, etc. The
Normal selection uses a higher resolution setting and employs error diffusion but
does not use smoothing to improve the appearance of text in photographs. Glossy
photo paper employs MTF filter processing and error diffusion to copy glossy or
matte photographs and achieves a low incidence of moiré, thus reproducing copies
of photographs of high resolution.
For photo mode, the features used depend on which type of gray scale processing
has been selected for Photo mode (either 'dithering and smoothing' or 'error
diffusion and MTF'); this depends on the setting of SP 4904 001. Details are
explained later in this section.
Image Processing Flow
Scanner Image
Correction
Pre-Filter
Processing
Pre-Filter Smoothing
Magnification Main Scan Direction
Filter
Processing
Density Control
Grayscale Dither/Error Diffusion
Processing
NOTE: An SP code number and name set in bold italic denotes an SSP (Special
Service Program) mode. To access an SSP, enter the SP mode: press and
hold down " on the 10-key pad then "Copy SP" on the touch-screen.
B291/B295/B296/B297
CÓPIA NÃO CONTROLADA
Shading Correction
!
Background Erase
!
!
!
Smoothing/MTF
Correction
!
γ Coefficient
!
CÓPIA NÃO CONTROLADA
Related SP Modes
SP4903 66 (Background Erase Level: Photo
Mode)
SP4903 12 (Pre-Filter: Photo Mode)
SP2909 1 (Main Scan Magnification)
SP4904 024 Photo (General Quality) (!pg. 6-35)
SP4904 2 (Quality Photo Mode)
6-26 SM