Hybrid Scalar-Vector Dithering for Display Quantization Error Reduction
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Solution Overview
Problem
Display apparatus employing time division gray scale suffer from image quality degradation due to quantization errors, which can be mitigated but result in dither noise when using traditional dithering processes.
Innovation Solution
A hybrid scalar-vector dithering process is employed, where scalar dithering is applied to a composite color subfield and vector dithering is applied across component color subfields, using identical dither masks to reduce quantization errors and dither noise, and controlling light energy output based on image saturation parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional dithering processes are used to mitigate quantization errors, then quantization errors are reduced, but dither noise is introduced
Solution Approach 1:
The patent segments the dithering process into two distinct components: scalar dithering applied to individual color subfields and vector dithering applied across multiple color subfields. This segmentation allows each dithering type to address specific aspects of quantization errors while minimizing their respective noise contributions, thereby resolving the contradiction between error reduction and noise introduction.
Solution Approach 2:
The patent applies different dithering strategies to different color subfields based on local image characteristics. Scalar dithering is applied to luminance-critical subfields where precision is paramount, while vector dithering is applied to chrominance subfields where color accuracy is prioritized. This local differentiation optimizes the balance between quantization error reduction and dither noise minimization for each subfield type.
2Measurement precision
If more subframes per color subfield are used, then image quality improves, but processing complexity and display time increase
Solution Approach 1:
The patent employs partial dithering actions by selectively applying scalar and vector dithering only to specific color subfields rather than uniformly to all subframes. This selective application reduces the overall processing complexity and computational burden while maintaining image quality in the most critical subfields, thereby resolving the contradiction between quality improvement and complexity increase.
Solution Approach 2:
The patent changes the dithering parameters (mask patterns, application regions, and intensity) based on image saturation characteristics. For saturated regions, vector dithering is emphasized to preserve color accuracy, while for unsaturated regions, scalar dithering dominates to maintain luminance precision. This dynamic parameter adjustment optimizes image quality without requiring increased subframe counts or processing complexity.
3Measurement precision
If scalar dithering is applied to composite color subfields, then luminance precision improves, but color accuracy may be compromised
Solution Approach 1:
The patent merges scalar dithering and vector dithering into a hybrid approach where both operations are applied to the same set of color subfields. Scalar dithering ensures luminance precision by processing individual subfields, while vector dithering simultaneously preserves color accuracy by processing multiple subfields together. This merging allows both luminance and color precision to be maintained without compromise.
Solution Approach 2:
The patent applies preliminary scalar dithering to composite color subfields to establish luminance precision before subsequent vector dithering is applied to refine color accuracy. This sequential preliminary action ensures that luminance precision is first established, then color accuracy is optimized without disrupting the luminance precision already achieved, thereby resolving the contradiction between the two precision requirements.
Data Source
AI summary
This disclosure provides systems, methods, and apparatus for generating images on a display using a hybrid scalar-vector dithering process. The hybrid scalar-vector dithering process includes a combination of a scalar dithering process and a vector dithering process. In the scalar dithering process, at least one color subfield is dithered based on the data within just that color subfield. In the vector dithering process, data across multiple color subfields is dithered together. In some implementations, the color subfield processed by the scalar dithering process is a composite color subfield, such as white (W), yellow (Y), cyan (C) and magenta (M). The color subfields processed by the vector dithering process can be component color subfields, such as red (R), green (G), and blue (B) color subfields. In some implementations, an identical dither mask is applied in both the vector and scalar portions of the hybrid scalar-vector dithering process.