Auto White Balance Adjustment via Light-Source Box Mapping
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Solution Overview
Problem
Conventional digital image processing systems face challenges in achieving optimal auto white balance (AWB) performance due to varying color temperatures based on location and time of photography, leading to unstable color changes and reduced image quality.
Innovation Solution
An adaptable AWB adjustment system that uses a map-setting unit to select light-source boxes, count white pixels, and calculate red and blue gains based on a mapping value, allowing for accurate color balance indoors and outdoors, and applying gains according to user preferences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same AWB algorithm based on standard scene and chart is used throughout the world, then mass production efficiency is improved, but AWB performance deteriorates when photographing at locations different from the standard scene and chart
Solution Approach 1:
The patent implements dynamic AWB adjustment by enabling the system to switch between fixed AWB parameters (for mass production consistency) and adaptive AWB parameters (for location-specific optimization). The controller dynamically selects or adjusts AWB parameters based on detected photographing conditions, allowing the system to adapt to different environments while maintaining production efficiency.
Solution Approach 2:
The patent changes AWB parameters (such as white balance temperature and tint values) based on detected photographing conditions including location type and time of day. By adjusting these parameters dynamically rather than using fixed values, the system achieves both mass production efficiency and location-adaptive AWB performance.
2Device complexity
If conventional AWB integration is performed over the whole image, then processing simplicity is improved, but color accuracy deteriorates due to saturation or distortion from brightest and darkest portions
Solution Approach 1:
The patent extracts and excludes the brightest and darkest portions of the image from the AWB integration process. By removing these problematic regions that cause saturation and distortion, the system performs integration only on the remaining mid-tone portions, thereby improving color accuracy without significantly complicating the processing workflow.
Solution Approach 2:
The patent applies different processing strategies to different regions of the image: excluding extreme bright and dark regions from integration, while potentially applying different integration weights or methods to various zones. This local differentiation improves overall color accuracy by treating problematic regions differently from normal regions.
3Reliability
If AWB parameters are fixed for mass production, then manufacturing consistency is improved, but adaptability to different locations and times deteriorates
Solution Approach 1:
The patent implements dynamic AWB adjustment by enabling the system to switch between fixed AWB parameters (for mass production consistency) and adaptive AWB parameters (for location-specific optimization). The controller dynamically selects or adjusts AWB parameters based on detected photographing conditions, allowing the system to adapt to different environments while maintaining production efficiency.
Solution Approach 2:
The patent incorporates feedback mechanisms that detect photographing conditions (location type, time of day, lighting characteristics) and use this information to adjust AWB parameters accordingly. This feedback loop enables the system to maintain manufacturing consistency through fixed parameters when appropriate, while adapting to different locations and times when needed.
Data Source
AI summary
Techniques, systems and apparatus are described for adjusting auto white balance (AWB). An AWB adjusting device includes a map setting unit to perform map-setting on a number of light-source boxes that is at least M times greater than a number of registers by performing map-switching. M is an integer greater than or equal to 2. The AWB adjusting device includes a pixel counting unit for counting a number of white pixels of a standard image contained in each light-source box with map-setting. The AWB adjusting device includes a light-source selection unit to select a light source based on a maximum light-source box selected from the number of light-source boxes having a greatest number of the white pixels. The AWB adjusting device includes a balance gain applying unit to calculate a red gain and a blue gain based on a mapping value of the maximum light-source box to adjust AWB.