Digital Camera White Balance Correction for Mixed Strobe and Ambient Lighting
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Solution Overview
Problem
Conventional digital cameras struggle to maintain consistent white balance in scenes with partial strobe illumination, leading to discordant color tones in regions primarily illuminated by the strobe and ambient light sources of different color balances.
Innovation Solution
A method for generating a blended image by combining a first image and a second image, using correction factors and histogram factors to reconcile color divergence and intensity distribution, ensuring proper white balance across both types of illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital cameras use standard white balance processing, then color accuracy is maintained under uniform ambient lighting, but color consistency deteriorates in regions illuminated by strobe light with different color balance
Solution Approach 1:
The patent applies local quality by differentiating processing between strobe-illuminated regions and ambient-illuminated regions. The system identifies strobe regions and applies stroke-specific white balance correction factors to these regions, while maintaining standard processing for ambient regions. This localized approach ensures color accuracy within each region type while maintaining overall color consistency across the entire image.
Solution Approach 2:
The patent changes the white balance parameter (color correction factors) based on the illumination type detected in different regions. By adjusting the white balance parameters specifically for strobe-illuminated regions to match the ambient illumination color balance, the system resolves the color inconsistency without affecting the overall image processing pipeline.
2Area of stationary object
If the camera captures images with both strobe and ambient illumination, then complete scene coverage is achieved, but color divergence occurs between regions illuminated by different light sources
Solution Approach 1:
The system divides the image into strobe-illuminated regions and ambient-illuminated regions, applying different color correction strategies to each. This local differentiation allows the camera to maintain complete scene coverage while ensuring color uniformity within and across regions by treating each illumination type appropriately.
Solution Approach 2:
The patent uses an intermediary processing step that identifies strobe regions and applies a color correction mediator (white balance adjustment) to harmonize the color temperatures between strobe and ambient regions. This intermediary correction layer ensures that both regions contribute to a uniformly colored final image.
3Device complexity
If standard image processing is applied to blended strobe and ambient images, then processing simplicity is maintained, but color discordance appears in the final photograph
Solution Approach 1:
The patent performs preliminary action by identifying strobe-illuminated regions and applying color correction factors before the final image composition. This pre-processing step ensures that when strobe and ambient images are blended, the color discordance is already corrected, maintaining processing simplicity while achieving color accuracy.
Solution Approach 2:
The system changes the white balance parameters specifically for strobe regions during the blending process. By adjusting these parameters to match the ambient illumination characteristics, the patent achieves color accuracy without requiring completely separate processing pipelines, thus maintaining reasonable processing complexity.
Data Source
AI summary
A technique for generating a digital photograph comprises blending two related images, each sampled according to a different illumination environment. The two related images are blended according to a blend surface function that includes a height discontinuity separating two different blend weight regions. Color consistency between the two related images is achieved by spatial color correction prior to blending. The technique enables a digital camera to generate a strobe image having an appearance of consistent color despite discordant strobe and ambient scene illumination.