Image Processing Apparatus Using Manhattan Distance for Natural Color Replacement

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Solution Overview

Problem

Existing image processing methods struggle to effectively replace pixel colors with representative colors without altering the chroma, leading to unnatural color changes and potential strangeness in limited color images.

Innovation Solution

An image processing apparatus that extracts representative colors, calculates color differences, adjusts the brightness component based on chroma, and selects the representative color to replace pixel colors, minimizing chroma changes and unnatural appearances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pixel colors are replaced by representative colors using conventional methods, then the number of colors is limited to several representative colors, but the chroma is altered and colors become unnatural and strange

Engineering Contradiction:

Improvecolor representation accuracyVSAvoidchroma preservation

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the parameter used for color difference calculation from Euclidean distance to Manhattan distance in the L*a*b* color space. This parameter change allows the replacement process to preserve chroma better while still limiting colors to representative colors, resolving the contradiction between color representation and chroma preservation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the color replacement process into distinct steps: extracting representative colors, calculating color differences using Manhattan distance, selecting the closest representative color, and replacing pixel colors. This segmentation allows each step to be optimized independently, maintaining chroma while achieving limited color representation

Inventive Principle:

Principle #1Segmentation

2Productivity

If conventional color replacement methods are used, then processing is simple and fast, but the resulting image has unnatural color transitions and strange appearances

Engineering Contradiction:

Improveprocessing speedVSAvoidnatural appearance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

By changing from Euclidean distance to Manhattan distance calculation, the patent maintains computational efficiency (keeping processing speed high) while significantly improving color replacement accuracy and natural appearance. The Manhattan distance formula involves simpler operations that are computationally efficient

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the conventional Euclidean distance metric with Manhattan distance metric in the color space. This substitution maintains the simplicity and speed of the replacement process while dramatically improving the quality and naturalness of the resulting limited color image

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8744179B2Image processing apparatus, image processing method, and non-transitory computer readable medium that utilizes representative colors

Publication Date: 2014.06.03 FUJIFILM BUSINESS INNOVATION CORP

AI summary

Provided is an image processing apparatus including an extraction unit that extracts representative colors from a target image, a color difference calculation unit that calculates a color difference between the representative color and a pixel of interest of the target image, a change unit that changes a brightness component of the color difference depending on chroma of the representative colors, and a replacement unit that selects the representative color depending on the color difference changed in the change unit to replace a color of the pixel of interest by the representative color.