Image processing device

Details Image processing device Image processing device

1995-05-24

1998-05-05

Coles, Sr., Edward L.

Image analysis

Image compression or coding

Quantization

382252, 382270, 358465, 358466, 358455, H04N 140

Patent

active

057487944

ABSTRACT:
An image processing apparatus and method which can be selectively used in a variable mode and a fixed mode. In the variable mode, the quantizing values and thresholds for converting high valued image gradation into low valued image gradation can be changed so as to vary the surface gray levels of a printable image at a fixed laser gradation value. In the fixed mode, constant thresholds and quantizing values are used. The use of selectable operation modes enables easy printing operation with increased quality. Also, constant quality of printable images despite environmental changes may be realized by sensing and comparing currently read reference data with initially stored reference data and subsequently correcting quantizing values and thresholds in accordance with the compared result.

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