Selective Image Smoothing for Bleed-Through Reduction

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Solution Overview

Problem

Bleed-through noise in scanned images of double-sided documents reduces visual quality and compressibility, increasing storage and transmission costs.

Innovation Solution

A method of selective smoothing in digital image processing that generates upper and lower bounds for each pixel, using a weighted average of these bounds and the original pixel intensity to reduce bleed-through while preserving image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional smoothing methods are applied to reduce bleed-through, then noise reduction is achieved, but image sharpness and contrast are compromised

Engineering Contradiction:
Improvebleed-through noiseVSAvoidimage sharpness and contrast
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different processing treatments to different regions of the image based on local characteristics. By analyzing pixel intensity variations and identifying regions with bleed-through patterns versus regions with genuine image content, the method selectively smooths only the affected areas while preserving the sharpness and contrast of important features. This local differentiation resolves the contradiction by making the smoothing effect spatially variable rather than uniform.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts smoothing parameters based on local image characteristics. By computing metrics such as intensity gradients, neighborhood variance, and bleed-through detection scores for different regions, the method adapts the smoothing strength and kernel size to match local requirements. This parameter adaptation allows aggressive smoothing in bleed-through regions while maintaining conservative processing in feature-rich areas, thus resolving the contradiction between noise reduction and detail preservation.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If aggressive smoothing is applied to remove bleed-through, then noise reduction is improved, but compressibility deteriorates due to loss of image detail

Engineering Contradiction:
Improvebleed-through noiseVSAvoidimage compressibility
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent applies smoothing selectively only to regions identified as containing bleed-through noise, rather than uniformly across the entire image. By preserving genuine image details and edges in non-affected regions, the method maintains higher frequency content that contributes to compressibility. This localized approach ensures that information loss is minimized while still achieving noise reduction where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs a controlled, gradual smoothing approach analogous to fluid dynamics, where the smoothing influence propagates selectively through the image based on local conditions. By using adaptive kernel sizes and intensity-weighted averaging that respects image structure, the method removes noise without creating artificial artifacts that would degrade compressibility. The smoothing operation is modulated to follow natural image gradients rather than imposing uniform blurring.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Data Source

PatentUS7636492B2Selective smoothing including bleed-through reduction
Publication Date: 2009.12.22 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • US7636492B2 patent drawing
  • US7636492B2 patent drawing
  • US7636492B2 patent drawing

AI summary

A group of pixels of a digital image is processed to reduce bleed-through. The processing includes generating an upper bound for each pixel of the group; and taking a weighted average of the upper bound and original pixel intensity for each pixel of the group.