Image Processing Apparatus Reducing Fixed-Pattern Noise

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Solution Overview

Problem

Existing image processing methods fail to effectively reduce fixed-pattern noise in image sensor data, particularly in out-of-focus image groups and moving image data, leading to deteriorated image quality, especially when image magnification and reduction are small, and are unable to accurately handle multiplicative noise.

Innovation Solution

An image processing method that uses iterative calculations to determine optimal brightness changes for each pixel across multiple images, ensuring common changes for corresponding pixels, thereby reducing fixed-pattern noise and improving overall image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If filter type methods are applied to an out-of-focus image group, then arbitrary viewpoint images or arbitrary out-of-focus images can be generated, but image quality deteriorates due to fixed-pattern noise

Engineering Contradiction:
Improveability to generate arbitrary viewpoint imagesVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing fixed-pattern noise reduction processing on the out-of-focus image group before generating arbitrary viewpoint images or arbitrary out-of-focus images. This preprocessing step removes fixed-pattern noise from the input images, ensuring that the subsequent filter type methods operate on cleaned data, thereby preventing noise-induced quality deterioration while maintaining the ability to generate diverse viewpoint images.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If image magnification and reduction are significantly small in an out-of-focus image group, then photography can be performed with a stable optical system, but fixed-pattern noise appears at approximately the same positions and becomes conspicuous

Engineering Contradiction:
Improveoptical system stabilityVSAvoidfixed-pattern noise visibility
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of fixed-pattern noise into a beneficial outcome by exploiting the fact that the noise appears at consistent positions across images with small magnification changes. This positional consistency allows the algorithm to effectively identify and remove the fixed-pattern noise through comparative analysis, transforming the stability that causes noise visibility into an advantage for noise detection and elimination.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If a simplified process is used to reduce fixed-pattern noise in moving images, then processing speed is improved, but estimation accuracy of fixed-pattern noise is low

Engineering Contradiction:
Improveprocessing speedVSAvoidfixed-pattern noise estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by adapting the fixed-pattern noise reduction approach based on the specific characteristics of the input data. For moving images, the system dynamically selects and adjusts processing parameters to balance speed and accuracy, while for out-of-focus image groups, it employs more rigorous processing. This dynamic adaptation allows the system to optimize processing speed without sacrificing necessary accuracy in different应用场景.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10419698B2Image processing apparatus and image processing method
Publication Date: 2019.09.17 CANON KK
  • US10419698B2 patent drawing
  • US10419698B2 patent drawing
  • US10419698B2 patent drawing

AI summary

An image processing method, includes: an input step in which a computer acquires data of a plurality of input images acquired by imaging performed using a same image sensor; and an optimization process step in which a computer determines an optimal solution of brightness change with respect to each input image by performing iterative calculations using an iterative method to improve overall image quality of the plurality of input images. In the optimization process step, an optimal solution of brightness change for each pixel of each input image is determined under a condition that common brightness change is performed with respect to pixels at a same position in respective input images.