Image Processing Apparatus Adaptive Edge Emphasis

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Solution Overview

Problem

Conventional image processing techniques fail to accurately adjust image processes based on image attributes, leading to deterioration when processes are switched between text and halftone areas, particularly due to incorrect determination of attributes and lack of transition states.

Innovation Solution

An image processing method and apparatus that adaptively defines adjusting levels based on variation and variation time count, using edge emphasis and smoothing processes to enhance sharpness and prevent moiré, by calculating luminance and derivative values within a 7x7 pixel area and applying filter coefficients to adjust edge emphasis amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If edge emphasis process is applied to text area, then sharpness is enhanced, but image deteriorates when switching occurs during one character

Engineering Contradiction:
ImprovesharpnessVSAvoidimage quality consistency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from static binary switching (text area/halftone area) to dynamic continuous adjustment. The edge emphasis amount is adjusted continuously based on the degree of match between image signal characteristics and reference waveforms, allowing smooth transitions without abrupt switching during character rendering.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of edge emphasis amount from a binary on/off state to a continuous variable. By comparing image signal waveforms with reference waveforms and calculating match degrees, the system dynamically adjusts the edge emphasis parameter to optimize sharpness while preventing deterioration at transition boundaries.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If smoothing process is applied to halftone area, then moiré is reduced, but image deteriorates when switching occurs within the area

Engineering Contradiction:
Improvemoiré reductionVSAvoidimage quality consistency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies dynamics by implementing continuous adjustment of smoothing process intensity based on waveform comparison. Instead of binary switching, the smoothing amount is dynamically modified according to the degree of match between image signal and reference waveform, enabling smooth transitions within halftone areas and preventing image deterioration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the smoothing parameter from a fixed binary state to a continuously adjustable parameter. By calculating match degrees between image signals and reference waveforms, the system dynamically modifies the smoothing amount to effectively reduce moiré while maintaining image quality consistency throughout the halftone area.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If binary switching of adjusting processes is used, then processing is simple, but no transition state exists causing image deterioration

Engineering Contradiction:
Improveprocess control simplicityVSAvoidimage quality at transition
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces static binary switching with dynamic continuous adjustment. By introducing waveform comparison and match degree calculation, the system creates transition states that smoothly connect different processing regions, eliminating abrupt boundaries that cause image deterioration while maintaining reasonable computational complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1874032B1Image processing apparatus and image processing method
Publication Date: 2017.08.09 CANON KK
  • EP1874032B1 patent drawingFigure 1A
  • EP1874032B1 patent drawingFigure 1B
  • EP1874032B1 patent drawingFigure 2

AI summary

There is disclosed an image processing apparatus which applies an adjusting process to an image that includes a pixel to be processed. The image processing apparatus extracts (S701) an image area with a predetermined size including the pixel to be processed. The apparatus calculates (S705) a variation associated with the pixel to be processed from signal values of pixels included in the image area. The apparatus calculates (S706) a variation time count in the image area from the signal values of the pixels included in the image area. The apparatus calculates (S707, S708, S709) adjusting levels Fz1, Fz2, and Fe from the variation time count and the variation using a definition unit which defines correspondence among the variation time count, the variation, and the adjusting levels, and applies an adjusting process to a signal value of the pixel to be processed by the calculated adjusting levels.