Dynamic Color to Gray Conversion for Print Distinguishability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing color conversion methods for printing RGB data to grayscale formats, such as NTSC conversion, lose color information, leading to reduced distinguishability, especially for images with overlapping colors and individuals with color blindness.

Innovation Solution

An image processing apparatus that acquires the number of colors used in a page and determines between two gray data conversion methods: one assigning different gray values to colors and another combining color components at a predetermined ratio, allowing for automatic switching based on the number of colors and drawing tendencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If all-color conversion is used to convert RGB values into gray scale values at a predetermined ratio, then the conversion process is simple and effective for documents requiring gradation, but color information is lost and distinguishability between different colors deteriorates

Engineering Contradiction:

Improveconversion process simplicityVSAvoidcolor information loss

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The patent dynamically switches between all-color conversion and number-of-colors-based conversion depending on the document characteristics. The determination unit analyzes whether the document contains regions where color distinguishability is critical, and automatically selects the appropriate conversion method, making the system adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the conversion parameter from a fixed predetermined ratio (all-color conversion) to a variable approach where gray values are assigned based on the number of colors detected in the document. This allows the conversion method to adapt its parameters based on the specific content being converted.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If all-color conversion is used to convert RGB values into gray scale values, then the conversion is performed at a predetermined ratio, but boundaries between overlapping or contacting colors disappear and distinguishability deteriorates

Engineering Contradiction:

Improveconversion efficiencyVSAvoidboundary definition precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the conversion approach based on document analysis. When boundaries between colors are critical (such as in pie charts or overlapping regions), the system switches to number-of-colors-based conversion that preserves boundary definition, otherwise using efficient all-color conversion.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If color conversion is performed without considering the number of colors used, then the conversion process is straightforward, but visually-recognizable density difference cannot be ensured for distinguishability

Engineering Contradiction:

Improveconversion process complexityVSAvoidvisual distinguishability information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent performs preliminary analysis of the document to count the number of colors used before performing conversion. This preliminary action enables the system to select the appropriate conversion method in advance, ensuring that visual distinguishability is preserved without adding complexity to the actual conversion process.

Inventive Principle:

Principle #10Preliminary action

4Loss of information

If the number of colors is analyzed and gray values are assigned based on the number of colors, then visually-recognizable density difference is achieved, but the conversion process becomes more complex

Engineering Contradiction:

Improvecolor distinguishability preservationVSAvoidconversion process complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent makes the conversion process dynamic by switching between two methods based on document characteristics. The determination unit analyzes whether the document benefits from number-of-colors-based conversion, and only applies the more complex method when necessary, thereby balancing complexity with distinguishability preservation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11438483B2Color to gray data conversion determined between assigning gray values based on number of colors and combining color components at predetermined ratio

Publication Date: 2022.09.06 CANON KK

AI summary

In a case where a user manually selects an image to be converted into a monochrome image with distinguishability, the user is to take labor and may select an image unsuitable for conversion into a monochrome image with distinguishability. An attribute in a page of print data is analyzed for each page, and based on the attribute of the page, a distinguishability improvement method that performs conversion into gray data by using density difference or outline emphasis is switched.