White Balance Adjustment Using Exposure Parameters and Pixel Color Data

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Solution Overview

Problem

Traditional image processing technologies fail to effectively compensate for color differences in images captured across various lighting environments, leading to suboptimal image quality.

Innovation Solution

A white balance adjustment method that determines a first white balance gain based on environmental illumination modes, calculated using exposure time, exposure gain, and aperture values, and adjusts the white balance gain using a second gain derived from pixel three-primary-color values, combining environmental and pixel data for improved compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If white balance gain is determined only by three-primary-color values of pixel points, then the calculation process is simple, but the color difference compensation in different lighting environments is insufficient

Engineering Contradiction:
Improvecalculation simplicityVSAvoidcolor difference compensation accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent combines two white balance determination methods: (1) traditional three-primary-color value analysis, and (2) new method using brightness value plus exposure parameters (exposure time, exposure gain, aperture value). These two approaches are merged to calculate a comprehensive white balance gain that leverages both pixel color data and environmental illumination data, thereby improving color compensation accuracy while maintaining computational feasibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary variable - the environmental illumination mode - which is determined by mapping the calculated illumination value (derived from brightness and exposure parameters) to predefined illumination modes. This intermediary serves as a bridge between raw sensor data and the final white balance adjustment, enabling the system to adapt to different lighting conditions (sunny, cloudy, indoor, artificial light) more effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If traditional three-primary-color value method is used, then the processing speed is fast, but the adaptability to different lighting environments is poor

Engineering Contradiction:
Improveprocessing speedVSAvoidlighting environment adaptability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary calculation of the illumination value using the formula: illumination value = brightness value × exposure time × exposure gain × aperture value. This pre-computed illumination value is then mapped to environmental illumination modes before the final white balance adjustment. By preparing this environmental context information in advance, the system can quickly adapt to different lighting conditions without adding significant processing overhead during image capture.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3648459B1White balance adjustment method and apparatus, camera and medium
Publication Date: 2024.02.28 HANGZHOU HIKVISION DIGITAL TECHNOLOGY CO LTD
  • EP3648459B1 patent drawingFigure 1A~1B
  • EP3648459B1 patent drawingFigure 2~3
  • EP3648459B1 patent drawingFigure 4

AI summary

The application provides a white balance adjustment method, apparatus, camera, and medium. This method includes: obtaining a current image taken by the camera; determining a brightness value of the image and the acquisition parameter values with which the image is captured by the camera, in which the acquisition parameter values includes the exposure time, the exposure gain and the aperture value with which the image is captured by the camera; determining the first white balance gain, according to brightness value, exposure time, exposure gain and aperture value; calculating a second white balance gain with which the image is captured by the camera, according to the three-primary-color values of the pixel points of the image; adjusting the white balance gain of the camera according to the first white balance gain and the second white balance gain. The white balance gain determined by the embodiment of this application may better compensate for the color difference of the image taken by the camera.