Binary Processing - Ricoh C226 Service Manual

OPTICS/IMAGE PROCESSING

2.1.3 Binary Processing

In the halftone processing chip, the 6-bit digital signal data is generated in the
A/D conversion circuit and is sent to the binary processing circuit. At that time
the data is inverted to match the binary processing circuit. Therefore, the
white peak level becomes 0, and the black level becomes 63.
In the binary processing circuit, the 6-bit data is converted into 1-bit data for
either black or white pixels. The binary process for the letter mode is different
from that for the photo mode and the letter/photo mode as follows:
Letter Mode: MTF (Modulation Transfer Function) Correction
Photo Mode: Error Diffusion Processing
Data Compensation Processing
In this process, the 6-bit data is converted based on a compensation curve (γ
curve) which corresponds to selected image settings. For example, if a
darker image is selected, a compensation curve which converts each pixel
value to a higher number is selected. The output data is also 6-bit.
C226 2-12 SM