Ambient-Light Histogram Remapping for Low-Gray Display Visibility
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Solution Overview
Problem
Existing automatic luminance control methods in automotive displays enhance upper gray shades but compromise the visibility of lower gray shades, especially under varying ambient lighting conditions.
Innovation Solution
An image enhancement system that includes an ambient light sensor, a circuit, and a processor to dynamically remap gray shades based on ambient light levels, compressing one region and stretching another to improve visibility of both maximum and minimum gray shades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If automatic luminance control methods are used to maintain visibility of peak-white gray shades, then visibility of high gray shades is improved, but visibility of lower gray shades is compromised
Solution Approach 1:
The patent divides the gray shade range into multiple regions (e.g., first region for lower gray shades, second region for higher gray shades) and applies different processing to each region. The histogram is segmented to identify different gray shade regions, and the lookup table applies different mapping transformations to different regions, allowing lower gray shades to be enhanced without compromising higher gray shades.
Solution Approach 2:
The patent applies different luminance enhancement strategies to different parts of the gray shade spectrum. Instead of uniformly increasing display luminance across all gray shades, the system selectively enhances specific gray shade regions based on histogram analysis, applying local quality adjustments to preserve both low and high gray shade visibility.
2Illumination intensity
If display luminance is increased to maintain visibility under high ambient light, then visibility is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic luminance control that adapts to ambient lighting conditions through an ambient light sensor. The system dynamically adjusts display luminance based on real-time ambient light measurements, using lookup tables that are selected or modified based on ambient light levels, thereby optimizing visibility while minimizing power consumption in varying lighting environments.
Solution Approach 2:
The system uses feedback from ambient light sensors to continuously monitor ambient lighting conditions and adjusts display luminance accordingly. The histogram analysis provides feedback on the content being displayed, allowing the system to optimize luminance settings based on both environmental conditions and image content, reducing power consumption while maintaining visibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances visibility of both high and low gray shades by adjusting the display luminance and image enhancement dynamically, maintaining visibility and reducing artifacts under different ambient lighting conditions.
Implementation Method 1
An ambient light sensor is provided to measure an ambient light level
Data Source
AI summary
An image enhancement system includes an ambient light sensor, a circuit and a processor. The ambient light sensor is operational to measure an ambient light level. The circuit is operational to: generate a histogram based on an input video signal; export the histogram; receive a gray shade look up table; and generate an output video signal by converting multiple gray shades in the input video signal based on the gray shade look up table. The processor is operational to: receive the histogram; develop the gray shade look up table based on the histogram and the ambient light level; dynamically remap the gray shades in the gray shade look up table in response to the ambient light level to compress a first region of the gray shades and stretch a second region of the gray shades; and transfer the gray shade look up table to the circuit.