Image Pickup Apparatus Driving Method for Color Noise Reduction

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Solution Overview

Problem

Image pickup apparatuses with RGB pixels struggle to reduce color noise effectively, which affects image quality due to the presence of white pixels that increase random and photo shot noise.

Innovation Solution

The method involves processing color data from multiple frames using noise reduction techniques such as averaging and interpolation, combining resolution data from white pixels with color data from RGB pixels to generate images with reduced noise and improved responsiveness to motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If white pixels are added to increase luminance sensitivity, then luminance sensitivity is improved, but color noise increases

Engineering Contradiction:
Improveluminance sensitivityVSAvoidcolor noise
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the pixel array into distinct color pixels (R, G, B) and white pixels (W), allowing each type to be optimized for its specific function. Color pixels are dedicated to capturing color information while white pixels capture luminance, enabling independent optimization without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces green pixels (G) as intermediary elements between red and blue pixels in the color filter array. These green pixels serve as mediators that capture green wavelength components, enabling more accurate color reconstruction and reducing color noise through the additional chrominance information.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If color filters are arranged in Bayer array, then color image capture is enabled, but color noise is increased

Engineering Contradiction:
Improvecolor image capture capabilityVSAvoidcolor noise
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent creates a composite pixel array structure combining multiple pixel types (R, G, B, W) with different optical characteristics. This composite approach integrates the color-capturing capability of RGB pixels with the luminance sensitivity of white pixels, achieving both color image capture and noise reduction.

Inventive Principle:
Principle #40Composite materials

3Object-generated harmful factors

If multiple frames are processed for noise reduction, then color noise is reduced, but responsiveness to motion decreases

Engineering Contradiction:
Improvecolor noiseVSAvoidmotion responsiveness
Core Design Contradiction:
Object-generated harmful factorsVSSpeed

Solution Approach 1:

The patent performs preliminary separation of luminance and chrominance components from the captured frames before noise reduction processing. By pre-processing the signal into Y (luminance) and C (chrominance) components, the system can apply different processing strategies to each, preserving motion detail in luminance while reducing noise in chrominance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the noise reduction strength applied to different color components based on their characteristics. Luminance components undergo lighter processing to preserve motion sharpness, while chrominance components receive stronger noise reduction, creating a dynamic, adaptive processing approach.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces color noise and afterimages in images generated by the image pickup apparatus, improving image quality while maintaining responsiveness to object motion.

Implementation Method 1

color filters (which may be denoted by CFs) each configured to transmit light of a specific wavelength component, such as light of red, green, or blue color

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentEP3240289B1Image pickup apparatus driving method
Publication Date: 2021.07.21 CANON KK
  • EP3240289B1 patent drawingFigure 1
  • EP3240289B1 patent drawingFigure 2
  • EP3240289B1 patent drawingFigure 3(a)~3(b)

AI summary

An object is to provide a technique for generating an image with reduced color noise in at least an image pickup apparatus having R, G, and B pixels. A method for driving an image pickup apparatus is a method that generates image data using signals output by R, G, and B pixels contained in n frames, where n is an integer greater than or equal to two, and a signal or signals output by a W pixel contained in m frame or frames, where m is smaller than n, or that generates image data using signals output by R and B pixels contained in n frames and a signal or signals output by a G pixel contained in m frame or frames.