Adaptive Transfer Functions for Display Code Allocation
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Solution Overview
Problem
Current display technologies struggle to maintain optimal image rendering across varying ambient conditions, leading to issues like color banding, crushed shadows, and unintended color casts, due to their fixed transfer functions and inefficient allocation of display codes, which result in poor performance and increased resource demands.
Innovation Solution
The use of perceptually-aware dynamic display adjustment techniques, involving optical and non-optical sensors to collect environmental data, which a processor utilizes to evaluate a perceptual model. This model adjusts the display's transfer function, including gamma, black point, and white point, to ensure the image appears as intended by the author, regardless of the viewing environment, by determining the viewer's adaptation levels and mapping the display's output to match the viewer's perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed transfer function is used for display, then the display device is simple to implement, but it cannot maintain optimal image rendering across varying ambient conditions
Solution Approach 1:
The patent implements dynamic adjustment of the display transfer function by continuously monitoring ambient light conditions through optical sensors and adapting the gamma, black point, and white point parameters in real-time. This transforms the static transfer function into a dynamic system that automatically responds to changing viewing environments, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The system employs feedback mechanisms where optical sensors detect ambient light levels and spectral characteristics, which are then processed to determine appropriate transfer function adjustments. This closed-loop feedback system enables the display to self-adjust to ambient conditions without requiring complex manual configuration, achieving adaptability while managing system complexity.
2Manufacturing precision
If display codes are allocated uniformly across the brightness range, then the encoding is simple, but it results in color banding in dark ranges and wasted codes in bright ranges
Solution Approach 1:
The patent applies local quality by allocating display codes non-uniformly across the brightness range, concentrating more codes in the dark ranges where human visual acuity is most sensitive to brightness differences. This perceptually-driven code allocation strategy optimizes brightness differentiation precision in critical regions while reducing code usage in less sensitive bright ranges, eliminating color banding without requiring uniformly high precision across all brightness levels.
3Adaptability or versatility
If content is viewed in an environment different from its intended viewing environment, then the viewer can access the content anywhere, but the image appearance deteriorates with crushed shadows and incorrect tonality
Solution Approach 1:
The patent dynamically changes key transfer function parameters (gamma, black point, white point) based on detected ambient light conditions to maintain accurate image appearance across different viewing environments. By adjusting these parameters in response to ambient illumination levels and spectral characteristics, the system preserves the intended tonality and shadow detail whether viewing content in dark theaters or bright outdoor environments, thus maintaining manufacturing precision while enabling viewing flexibility.
4Manufacturing precision
If more display codes are allocated to represent the full dynamic range of human vision, then the brightness representation is more accurate, but the resource consumption increases
Solution Approach 1:
The patent applies partial action by allocating display codes selectively based on perceptual needs rather than uniformly across the entire brightness range. By concentrating code allocation in the dark ranges where human visual acuity is highest and reducing allocation in bright ranges where differentiation is less critical, the system achieves accurate brightness representation in perceptually important regions while minimizing overall resource consumption for code storage and processing.
Data Source
AI summary
The disclosed techniques use a display device, optionally including optical and/or non-optical sensors providing information about the ambient environment of the display device—along with knowledge of the content that is being displayed—to predict a viewer of the display device's current visual adaptation. Using the viewer's predicted adaptation, the content displayed on the display device may be more optimally encoded. This encoding may be accomplished at encode time and may be performed in a display pipeline or, preferably, in the transfer function of the display itself—thereby reducing the precision required in the display pipeline. For example, in well-controlled scenarios where the viewer's adaptation may be fully characterized, e.g., a viewer wearing a head-mounted display (HMD) device, the full dynamic range of the viewer's perception may be encoded in 8 or 9 bits that are intelligently mapped to only the relevant display codes, given the viewer's current predicted adaptation.