Image Processing Noise Reduction High-Frequency Preservation

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Solution Overview

Problem

Conventional noise reduction processing in images often results in a loss of high-frequency components, leading to a perceived reduction in image sharpness.

Innovation Solution

An image processing apparatus that performs noise reduction while preserving sharpness by emphasizing high-frequency components through demosaicing and correction using a high-frequency emphasized image, generated by extracting and enhancing the high-frequency components of the input image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If noise reduction processing is performed on an image, then noise is reduced, but high-frequency components are lost leading to reduced sharpness

Engineering Contradiction:
ImprovenoiseVSAvoidsharpness
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The image processing is segmented into distinct stages: demosaicing processing to generate a preliminary image, noise reduction processing on that preliminary image, and subsequent correction using high-frequency components extracted from the original image. This segmentation allows each processing stage to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

High-frequency components are extracted and preserved from the original image before noise reduction processing is applied. This preliminary extraction ensures that the sharpness information is saved and can be used to correct the noise-reduced image afterward, preventing permanent loss of high-frequency details.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If conventional noise reduction processing is applied, then noise is reduced, but image quality deteriorates due to loss of high-frequency components

Engineering Contradiction:
ImprovenoiseVSAvoidimage quality
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A correction image is generated as an intermediary by extracting high-frequency components from the original image and combining them with the noise-reduced image. This correction image acts as a mediator that transfers the sharpness information back to the noise-reduced image, thereby restoring image quality without reintroducing noise.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The final output image is a composite combining elements from multiple processing paths: the noise-reduced portions from the processed preliminary image and the high-frequency sharpness components from the correction image. This composite approach allows the final image to possess both low noise and high sharpness characteristics.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3826301B1Image processing apparatus, image processing method, and computer program
Publication Date: 2023.03.22 CANON KK
  • EP3826301B1 patent drawingFigure 1
  • EP3826301B1 patent drawingFigure 2
  • EP3826301B1 patent drawingFigure 3A~3B

AI summary

There is provided with an image processing apparatus. A noise reduction means (210) generates a noise-reduced image in which noise is reduced from an input image (220) in which a plurality of types of pixels that represent mutually different types of color information are arranged in one plane. An extraction means (220) generates a high-frequency emphasized image in which a high-frequency component of the input image (220) is emphasized. A demosaicing means (231) generates a demosaiced image having a plurality of planes that each represent one type of color information by demosaicing processing to the noise-reduced image. A generation means (232) generates an output image (290) by correcting the demosaiced image by using the high-frequency emphasized image.