Image Processing Device Tone Quantization Error Diffusion

The patent applies local quality by dividing the image processing into separate processing regions corresponding to different ejection ports. A pixel array is divided into multiple regions, each region corresponding to one ejection port, and error diffusion is performed independently within each region using dedicated error diffusion coefficients. This allows correction values specific to each ejection port's characteristics to be applied, compensating for variations in ink ejection amount while maintaining tone quantization accuracy.

The patent changes the parameters of error diffusion by using different error diffusion coefficients for different regions corresponding to different ejection ports. Instead of using uniform error diffusion coefficients across the entire image, the system adjusts the diffusion parameters locally to match the specific characteristics of each ejection port, thereby correcting density nonuniformity while preserving the quantization process.

The patent segments the pixel array into multiple regions, with each region corresponding to a specific ejection port. This segmentation allows the system to apply correction values tailored to each ejection port's characteristics. The segmentation is implemented in the image processing unit, which divides the incoming pixel data into region-specific groups and processes each group with appropriate error diffusion coefficients, thereby managing complexity through structured organization.

The patent performs preliminary action by pre-calculating and storing correction values for each ejection port before actual image recording. The correction values, which compensate for variations in ink ejection amount, are determined in advance and stored in memory. During image processing, these pre-computed correction values are directly applied without requiring real-time calculation, thus reducing processing complexity while maintaining density uniformity.