Display Gamma DAC Dithering for Lower Bit-Depth Luminance Control
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Solution Overview
Problem
Current gamma digital-to-analog converter (DAC) systems face limitations in effectively utilizing higher resolution image data, leading to inefficiencies in display pixel luminance control and increased resource usage due to higher bit-depth requirements.
Innovation Solution
The implementation of DAC dither circuitry that dithers DAC data in the DAC code domain to reduce bit-depth while maintaining effective resolution, allowing for the use of lower bit-depth gamma generators and reducing resource consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If higher bit-depth DAC data is used to maintain effective resolution, then display luminance control precision is improved, but device footprint and manufacturing cost increase
Solution Approach 1:
A dither circuit is introduced as an intermediary component between the image processing pipeline and the gamma generator. This dither circuit adds controlled random noise to the DAC data, enabling bit-depth reduction while preserving perceived luminance precision through temporal dithering effects
Solution Approach 2:
The system changes the bit-depth parameter of the DAC data from high resolution to reduced resolution, while compensating for the loss of precision through dithering techniques that manipulate the statistical properties of the quantization error
2Manufacturing precision
If higher bit-depth gamma generator is used to process high resolution image data, then image enhancement quality is improved, but manufacturing cost and resource usage increase
Solution Approach 1:
The patent employs a lower bit-depth gamma generator that is cheaper and simpler to manufacture, compensating for the reduced precision through software-based dithering algorithms that simulate higher precision through temporal averaging
Solution Approach 2:
The patent replaces the need for high-precision hardware (high bit-depth gamma generator) with a combination of lower-precision hardware and software-based dithering algorithms, substituting mechanical precision requirements with computational techniques
3Volume of moving object
If DAC data bit-depth is reduced to match gamma generator input, then device footprint and data line size decrease, but effective resolution is lost
Solution Approach 1:
The dither circuit applies periodic or pseudo-random noise addition to the DAC data across multiple time samples, creating temporal variations that preserve perceived resolution through the temporal integration properties of the display system and human visual system
Solution Approach 2:
The patent transitions the problem from a spatial resolution domain to a temporal domain by introducing time-varying dither signals, allowing the system to preserve effective resolution through temporal averaging rather than spatial precision
Data Source
AI summary
An electronic device may include an electronic display having multiple display pixels to display an image based on analog voltage signals. The electronic device may also include optical calibration circuitry to generate digital-to-analog converter (DAC) data based on image data associated with the image and dither circuitry to reduce a bit-depth of the DAC data, generating dithered DAC data. Additionally, the electronic device may include a gamma generator having one or more DACs to generate the analog voltage signals based on the dithered DAC data, which may instruct the gamma generator to generate the analog voltage signals indicative of the image data.