White Balance Correction Across Different Sensor Color Filter Arrays

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Solution Overview

Problem

Existing image sensors using certain color filter arrays, such as RCCG, face issues with unsuitable white balance correction methods, leading to color casts in corrected images.

Innovation Solution

A method involving a reference image sensor with a type 2 color filter array and a target image sensor with a type 1 color filter array, utilizing a target matrix and white balance Planckian curves to determine a compensation parameter for effective white balance correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard white balance correction method is applied to image sensors with type 1 color filter arrays (e.g., RCCG), then the correction process can be completed, but color casts appear in the corrected images due to mismatched quantum efficiency characteristics

Engineering Contradiction:
Improvewhite balance correction accuracyVSAvoidcolor cast in corrected images
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent transforms the white balance correction approach by changing from direct correction of raw images to correction based on quantum efficiency response curves. By converting the problem into parameter space (quantum efficiency curves) and back, the method adapts the correction parameters to match the specific characteristics of type 1 color filter arrays, eliminating color casts while maintaining correction accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces quantum efficiency response curves as an intermediary between the image sensor's color filter array characteristics and the white balance correction process. These curves serve as a mediator that translates the physical characteristics of the sensor into correction parameters, enabling accurate white balance adjustment for type 1 color filter arrays without introducing color casts

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a white balance correction method designed for type 2 color filter arrays (e.g., RGGB) is directly applied to type 1 color filter arrays, then the correction process is simple, but the method is unsuitable and produces poor correction effects

Engineering Contradiction:
Improvewhite balance correction process simplicityVSAvoidcompatibility with different color filter arrays
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal white balance correction framework that can handle multiple color filter array types (both type 1 and type 2) through a common quantum efficiency-based approach. By establishing correction methods based on fundamental quantum efficiency characteristics rather than array-specific algorithms, the system achieves both simplicity and broad compatibility across different sensor types

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4718861A1White balance correction method and apparatus for images, storage medium, and electronic device
Publication Date: 2026.04.01 BEIJING HORIZON ROBOTICS TECH RES & DEV CO LTD
  • EP4718861A1 patent drawingFigure 1
  • EP4718861A1 patent drawingFigure 2~3
  • EP4718861A1 patent drawingFigure 4~5

AI summary

Disclosed are a white balance correction method and apparatus for images, a storage medium, and an electronic device. The method includes: determining a first quantum efficiency response curve for a reference image sensor; determining a second quantum efficiency response curve for a target image sensor, where a color filter array of the target image sensor is different from that of the reference image sensor; determining a target matrix for conversion between the second quantum efficiency response curve and the first quantum efficiency response curve; determining a first white balance Planckian curve for the target image sensor; determining a white balance compensation parameter adaptable to the target image sensor based on the target matrix, the first white balance Planckian curve, and a first image collected by the target image sensor; performing, based on the white balance compensation parameter, white balance correction on a second image collected by the target image sensor.