Edge Enhancement Control Using Whiteness Degrees

Solution Overview

Problem

Conventional edge enhancement processing often results in unnatural outlines, particularly when applied to images with white backgrounds, as it excessively enhances edges that should not be emphasized, leading to a trade-off between sufficient enhancement and avoiding harmful effects on image quality.

Innovation Solution

An image processing apparatus that calculates whiteness degrees around a target pixel and adjusts the edge enhancement processing intensity using a correction value, thereby suppressing unnatural outlining by reducing enhancement near white backgrounds while maintaining sufficient sharpness where needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If general edge enhancement processing is applied to all edges in the image, then the sharpness and readability of image edges are improved, but unnatural outlines appear on edges bordering white backgrounds

Engineering Contradiction:

Improveedge sharpnessVSAvoidunnatural outlines

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies different edge enhancement intensities to different regions of the image based on local characteristics. Specifically, it calculates a whiteness degree for each pixel and uses this information to determine the appropriate enhancement level, thereby applying strong enhancement only where needed (non-white backgrounds) and suppressing enhancement where it would cause harm (white backgrounds).

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the edge enhancement parameter (enhancement intensity) based on the whiteness degree of pixels. By changing the enhancement parameter according to local image characteristics, it achieves optimal enhancement without producing unnatural outlines on white backgrounds.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If edge enhancement is suppressed to avoid unnatural outlines on white backgrounds, then harmful effects are reduced, but sufficient enhancement cannot be achieved for images that need it

Engineering Contradiction:

Improveunnatural outlinesVSAvoidedge sharpness

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different edge enhancement intensities to different regions of the image based on local characteristics. Specifically, it calculates a whiteness degree for each pixel and uses this information to determine the appropriate enhancement level, thereby applying strong enhancement only where needed (non-white backgrounds) and suppressing enhancement where it would cause harm (white backgrounds).

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the edge enhancement parameter (enhancement intensity) based on the whiteness degree of pixels. By changing the enhancement parameter according to local image characteristics, it achieves optimal enhancement without producing unnatural outlines on white backgrounds.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9646367B2Image processing apparatus and image processing method each with a function of applying edge enhancement to input image data

Publication Date: 2017.05.09 CANON KK

AI summary

Edge enhancement processing is executed by obtaining a sum of whiteness degrees around a target pixel, to which edge enhancement is to be applied, and by adjusting the amount of edge enhancement such that the degree of edge enhancement decreases as the sum of whiteness degrees increases, and the degree of edge enhancement increases as the sum of whiteness degrees decreases. A whiteness degree is a value indicating the extent to which a pixel is close to white, and a sum of whiteness degrees indicates the extent to which the color around the target pixel is whitish.