PDL Color Conversion Switching for Monochrome Print Accuracy

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Solution Overview

Problem

Existing methods for printing monochrome representations of color data, such as discriminability reproducing color conversion, can result in improper drawing when color synthesis or transparency operations are involved, particularly when performed on raster data, leading to loss of discriminability and processing inefficiencies.

Innovation Solution

An image processing apparatus that analyzes draw commands and switches between discriminability reproducing color conversion and all-color uniform color conversion based on specific print job settings, ensuring efficient processing and preventing improper drawing by canceling discriminability reproducing color conversion when color changes are specified, such as in ROP or α-blending operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If discriminability reproducing color conversion is performed on raster data after rasterizing, then processing efficiency is improved, but improper drawing occurs in regions with color synthesis or transparency

Engineering Contradiction:

Improveprocessing efficiencyVSAvoiddrawing accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent dynamically switches between two color conversion methods based on the presence of color synthesis or transparency operations. When such operations are detected in the print job, the system uses all-color uniform color conversion; otherwise, it employs discriminability reproducing color conversion. This dynamic adaptation resolves the contradiction by selecting the appropriate method for each specific case.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of color conversion method selection based on the characteristics of the print job. By detecting whether color synthesis or transparency operations are specified, the system adjusts the color conversion approach to maintain both processing efficiency and drawing accuracy under different conditions.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If discriminability reproducing color conversion is performed before rasterizing, then processing efficiency is improved, but improper drawing occurs due to color synthesis or transparency operations

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidcolor value accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically determines the timing and method of color conversion based on the print job characteristics. By detecting color synthesis or transparency operations, the system adapts its processing approach to prevent improper drawing while maintaining efficiency where possible.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary detection of color synthesis or transparency operations in the PDL data to prevent improper drawing before it occurs. By identifying these operations in advance, the system can select the appropriate color conversion method to avoid the harmful effects of improper drawing.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If all-color uniform color conversion is used, then processing is simple and efficient, but discriminability is lost because different RGB values may be converted to the same color value

Engineering Contradiction:

Improveconversion method simplicityVSAvoidcolor discriminability

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent applies different color conversion methods to different regions or cases based on the original image characteristics. For images requiring discriminability, it uses discriminability reproducing color conversion; for others, it uses simpler all-color uniform color conversion. This local differentiation resolves the contradiction between simplicity and information preservation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the color conversion parameter based on the number of colors in the original image and the presence of color synthesis or transparency operations. This adaptive parameter selection allows the system to maintain discriminability when needed while keeping processing simple when appropriate.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11831839B1Image processing apparatus, method, and program product for printing based on PDL data in print job for printing monochrome representation of color data

Publication Date: 2023.11.28 CANON KK

AI summary

The technique of the present disclosure can achieve processing efficiency and prevention of improper drawing in printing a monochrome representation of color data. In performing discriminability reproducing color conversion processing, a PDL analysis unit determines whether processing involving color change that changes the original color is specified in operator information on a target object for the discriminability reproducing color conversion processing. In a case where processing that changes the original color, such as ROP or α-blending, is specified for the target object, the discriminability reproducing color conversion processing for the page is canceled and switched to all-color uniform color conversion processing. This enables both of efficient discriminability reproducing color conversion and prevention of improper drawing.