Luminance Mapping for AR Displays
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Solution Overview
Problem
Existing augmented reality systems fail to adequately account for the background physical environment and human perception, leading to suboptimal image presentation as the background luminance combines with displayed image luminance, altering the appearance in a non-linear manner that is not accurately represented by simple luminance adjustments.
Innovation Solution
The method involves adjusting luminance values of images based on a non-linear relationship between luminance and perception, using a luminance-to-lightness curve, and accounting for background luminance to display images on augmented reality devices in a way that mimics the intended appearance without background luminance, by determining first and second luminance values and perceptual values to accurately represent luminance differences as perceived by humans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple luminance shifting is used to adjust image content for background luminance, then the adjustment process is simple and fast, but the image appearance does not accurately match human perception because human perception of lightness is not linearly correlated with luminance changes
Solution Approach 1:
The patent transforms the luminance adjustment problem from a simple linear shift to a non-linear transformation based on perceptual modeling. It introduces a luminance-to-lightness curve that maps physical luminance values to perceived lightness values, allowing the system to adjust images in a way that matches human perception rather than just physical light measurements. This resolves the contradiction by changing the adjustment parameter from linear luminance to non-linear perceptual lightness.
2Device complexity
If luminance values are adjusted without accounting for human perception, then the computational complexity is low, but the image appearance is suboptimal because the non-linear relationship between luminance and perception is not addressed
Solution Approach 1:
The patent introduces an intermediary perceptual model (luminance-to-lightness curve) that sits between the physical luminance values and the final displayed image. This intermediary layer transforms physical measurements into perceptually relevant values, allowing the system to achieve high visual quality without directly manipulating complex perceptual parameters. The curve acts as a pre-computed lookup table that simplifies the transformation process while maintaining perceptual accuracy.
3Productivity
If background luminance is not considered in image adjustment, then the processing is faster and simpler, but the image appearance is altered because background luminance combines with displayed image luminance in a non-linear manner
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the background luminance environment and incorporating its effects into the luminance adjustment process before image display. By measuring or estimating the background luminance and using it to adjust the image luminance values in advance, the system compensates for the non-linear combination that would otherwise occur during display. This ensures consistent image appearance across different background conditions without requiring real-time adjustments.
Data Source
AI summary
Various implementations disclosed herein adjust the luminance values of an image to improve the appearance of the image on an augmented reality device. In some implementations, the luminance values of an image are adjusted so that the image can be displayed on an augmented reality device (e.g., with background luminance) such that the image will be perceived more similarly to how the image would be perceived otherwise (e.g., on a device without background luminance). In some implementations, an image is adjusted based on an estimate of human perception of luminance that is not linear.