Image Processing Apparatus Watercolor Effect Generation

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Solution Overview

Problem

Existing image processing methods struggle to authentically depict the rough line drawing and color bleeding effects of watercolor paintings while maintaining the atmosphere of the input image, as they either lose color information or fuse boundaries, making it difficult to express the desired artistic effects.

Innovation Solution

An image processing apparatus and method that mix an edge component extracted from the input image with a gradated blurring component, using a combination of small and large blurring images and gradation correction to retain natural gradation and low-frequency components, allowing for the reproduction of watercolor-like effects with the input image's color as a basic color.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If all color information is lost before coloring to express watercolor taste with small number of colors, then the watercolor painting taste is expressed, but the atmosphere of the input image cannot be retained

Engineering Contradiction:
Improvewatercolor painting taste expressionVSAvoidcolor information loss
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The image processing is divided into multiple stages: edge component extraction, blurring image generation with different radii, and selective color application. This segmentation allows different parts of the image to be processed differently, preserving atmospheric information while achieving watercolor effects through controlled color loss in specific regions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different blur radii are applied to different regions based on edge detection results. Edge portions use smaller blur radii to preserve sharpness and atmospheric information, while non-edge portions use larger blur radii to achieve watercolor bleeding effects. This local quality approach ensures color information is selectively retained where needed

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If color subtraction is performed in spatially grouped images to express limited paint taste, then the watercolor painting taste is expressed, but boundaries between groups are fused making it difficult to express rough line drawing effect

Engineering Contradiction:
Improvelimited paint taste expressionVSAvoidboundary sharpness
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The blur radius is dynamically adjusted based on the local edge strength detected in the image. Regions with strong edges maintain sharper boundaries with smaller blur radii, while regions with weak edges allow more blending with larger blur radii. This dynamic adjustment preserves the rough line drawing effect while achieving watercolor painting taste

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The blur radius parameter is changed according to the spatial location and edge characteristics of different image regions. By varying this parameter dynamically, the system achieves different levels of boundary sharpness in different areas, allowing both rough line drawings and watercolor effects to coexist

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If colored area is moved in random direction to express color bleeding feeling, then the color bleeding feeling is expressed, but the atmosphere of the input image is lost due to color difference

Engineering Contradiction:
Improvecolor bleeding feelingVSAvoidinput image atmosphere
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

A blurring operation with controlled radius acts as an intermediary between the original color information and the final watercolor effect. This intermediary process allows color to spread and bleed in a controlled manner while preserving the underlying atmospheric information from the input image, avoiding the harsh color replacement approach

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2672691B1Image processing apparatus and image processing method
Publication Date: 2018.11.07 CANON KK
  • EP2672691B1 patent drawingFigure 1A
  • EP2672691B1 patent drawingFigure 1B
  • EP2672691B1 patent drawingFigure 2A~2G

AI summary

An image processing apparatus (1) uses an edge component of an input image in which a little low-frequency component of a dark part is retained as a luminance signal, synthesizes a large blurring component generated from the input image as a color component, and realizes a taste of natural watercolor paintings in which gradation is not inverted from a bright part to the dark part when a color is placed on a rough line drawing in watercolor-like processing.