Adaptive Noise Reduction for CCD Image Edge Preservation

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Solution Overview

Problem

Existing image capturing systems face challenges in effectively reducing noise in image signals, particularly due to fixed pattern and random noise components, which affect the quality of captured images.

Innovation Solution

An image capturing system that includes local region extraction, adaptive noise reduction processing, noise estimation, and subsequent noise reduction processing to optimize noise reduction based on the target pixel and its neighboring pixels, using a combination of noise reduction units and noise estimation units to calculate and apply weighting factors for effective noise suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If noise reduction processing is applied to image signals, then noise components are suppressed, but edge details may be degraded

Engineering Contradiction:
Improvenoise componentsVSAvoidedge details
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different processing strategies to different regions of the image. Edge regions are identified and processed differently from non-edge regions, preserving edge sharpness while reducing noise in smooth areas. This is achieved through edge detection and adaptive filtering that adjusts its strength based on local image characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The noise reduction processing is made adaptive and dynamic rather than uniform. The filtering strength and parameters are adjusted based on local image properties such as edge presence, noise level estimation, and signal strength. This allows the system to optimize noise reduction while preserving important image features in different regions.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If adaptive noise reduction processing is performed on target pixels, then noise is reduced, but processing complexity increases

Engineering Contradiction:
ImprovenoiseVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The image processing is divided into distinct stages: edge detection, noise level estimation, adaptive parameter selection, and filtering. Each stage processes specific aspects independently, making the overall complex system manageable and efficient. Local regions are segmented and processed with appropriate parameters based on their characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions such as edge detection and noise level estimation before applying the main noise reduction filtering. This allows the filtering parameters to be pre-determined based on local image properties, making the actual filtering operation more efficient and adaptive without requiring complex real-time adjustments during processing.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If noise amount estimation is performed based on target pixel values, then noise reduction accuracy is improved, but processing time increases

Engineering Contradiction:
Improvenoise amount estimation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs noise amount estimation selectively rather than uniformly across all pixels. Full estimation is performed on target pixels and their neighbors, while other areas use simplified approaches or inherit parameters from adjacent regions. This partial processing approach maintains accuracy where needed while reducing overall processing time.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS8488026B2Image capturing system and computer readable recording medium for recording image processing program
Publication Date: 2013.07.16 OLYMPUS CORPORATION(JP)
  • US8488026B2 patent drawing
  • US8488026B2 patent drawing
  • US8488026B2 patent drawing

AI summary

An image capturing system includes: a first noise reduction unit which roughly removes the effects of an edge component by performing edge-preserving adaptive noise reduction processing on a target pixel within a local region including the target pixel and the neighboring pixels extracted from an image signal acquired from a CCD; a noise estimation unit which dynamically estimates the noise amount with respect to the target pixel based upon the target pixel value thus subjected to the noise reduction processing by the first noise reduction unit; and a second noise reduction unit which performs noise reduction processing on the target pixel based upon the target pixel value thus subjected to the noise reduction processing by the first noise reduction unit and the noise amount thus estimated by the noise estimation unit.