Adaptive Blurring Filter for Image Noise Reduction

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Solution Overview

Problem

Small digital cameras, especially those with low-cost and portable devices, face challenges in noise reduction due to their limited image sensor capabilities, which affects image quality, especially in low-light conditions and requires processor-intensive methods that are not efficient for real-time noise identification and removal.

Innovation Solution

An intelligent blurring filter that uses pixel information from a single frame to reduce noise, employing a non-linear function and median filters to determine per-pixel blurring radii, balancing noise reduction with the preservation of fine image details, and operates without the need for multiple frames or significant processing resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If accurate noise determination methods are used, then noise identification accuracy is improved, but processing speed deteriorates due to processor-intensive operations

Engineering Contradiction:
Improvenoise identification accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent employs a disposable, single-frame de-noising approach that processes each image independently without requiring multiple frames or complex temporal analysis. This single-use processing method reduces computational overhead while maintaining effective noise removal through localized gradient analysis and adaptive blurring.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention applies local quality by computing gradient magnitudes and applying adaptive blurring radii on a per-pixel basis rather than uniformly across the entire image. This localized processing allows accurate noise determination in each region while reducing overall computational complexity through parallelizable operations.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If blurring is applied to remove noise, then noise reduction is improved, but image detail preservation deteriorates

Engineering Contradiction:
Improvenoise reductionVSAvoidimage detail preservation
Core Design Contradiction:
Object-generated harmful factorsVSLoss of information

Solution Approach 1:

The patent implements dynamic adaptive blurring where the blur radius varies per pixel based on local gradient magnitude. Pixels with high gradients (edges and details) receive minimal or no blurring, while pixels with low gradients (smooth regions with noise) receive stronger blurring. This dynamic adaptation preserves image details while effectively reducing noise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different blurring strengths are applied to different regions of the image based on local characteristics. The gradient magnitude computation identifies regions requiring preservation (edges) versus regions suitable for noise reduction (smooth areas), enabling selective processing that maintains overall image quality.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple frames are used for noise identification, then noise determination accuracy is improved, but processing complexity and resource requirements deteriorate

Engineering Contradiction:
Improvenoise determination accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention uses a single-frame disposable approach where each image is processed independently without requiring frame buffering or temporal comparison. This eliminates the complexity of multi-frame processing pipelines while maintaining practical noise removal effectiveness through spatial gradient analysis.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The de-noising algorithm is self-sufficient, using only the information present in the single input frame to determine and remove noise. It does not require external reference frames or complex temporal analysis, making the processing simpler and more suitable for real-time applications on resource-constrained devices.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS10262397B2Image de-noising using an equalized gradient space
Publication Date: 2019.04.16 INTEL CORP
  • US10262397B2 patent drawing
  • US10262397B2 patent drawing
  • US10262397B2 patent drawing

AI summary

Image de-noising is described using an equalized gradient space. In one example, a method of de-noising an image includes determining an intensity gradient magnitude for an image, determining blurring radii for a plurality of pixels of the image using the intensity gradient, and blurring the image at each of the plurality of pixels using the blurring radii.