Visual Processing Device Contrast Adjustment via Lookup Table
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Solution Overview
Problem
Conventional display devices experience timing discrepancies and delays in outputting luminance and color signals due to complex computation processes in contrast adjustment, leading to unnatural image output and synchronization issues.
Innovation Solution
A visual processing device with a gain-based correction system that outputs a first gain signal with predetermined characteristics, allowing for precise correction of image signals without direct grayscale adjustment, and includes a gain limit portion to prevent color saturation, using a two-dimensional lookup table for complex gain characteristics and spatial processing to adjust contrast without saturating bright regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contrast adjustment circuits perform division computation to obtain conversion ratio, then contrast adjustment precision is improved, but output timing discrepancy occurs between luminance signal and color signals
Solution Approach 1:
The patent pre-calculates and stores conversion ratios in a lookup table (LUT) before they are needed for contrast adjustment. When contrast adjustment is required, the system simply retrieves the pre-computed conversion ratio from the LUT based on the input luminance signal level, rather than performing division computation in real-time. This preliminary action eliminates the timing delay while maintaining precision.
Solution Approach 2:
The patent creates a copy of the conversion ratio data in the form of a lookup table, which stores pre-computed values that can be quickly retrieved. Instead of repeatedly performing the same division computation, the system uses this copied data structure to provide instant access to the required conversion ratios, resolving the timing discrepancy issue.
2Reliability
If conventional contrast adjustment circuits perform multiplication computation to amplify color signal, then color signal correspondence is improved, but device complexity increases
Solution Approach 1:
The patent introduces a lookup table as an intermediary between the luminance signal and the color signal adjustment process. The LUT stores pre-computed conversion ratios that mediate the relationship between luminance levels and the corresponding color signal amplification factors, eliminating the need for complex real-time multiplication circuits while maintaining color signal correspondence.
Solution Approach 2:
The patent replaces the mechanical computation system (division and multiplication circuits) with a data retrieval system (lookup table). Instead of using hardware circuits to perform complex arithmetic operations, the system uses pre-stored data to achieve the same effect with simpler hardware, reducing device complexity while maintaining reliability.
3Manufacturing precision
If conventional contrast adjustment increases luminance signal level, then image contrast is improved, but color saturation occurs
Solution Approach 1:
The patent applies different conversion ratios from the lookup table based on the local luminance signal level. By selecting conversion ratios that are specifically tailored to different luminance ranges, the system enhances contrast in each local region without causing color saturation, as each region receives an appropriately scaled adjustment factor.
Solution Approach 2:
The patent changes the conversion ratio parameter dynamically based on the luminance signal level. The lookup table provides different conversion ratio values for different luminance levels, allowing the system to adjust the color signal amplification factor according to the local brightness conditions, thereby improving contrast while preventing color saturation through parameter adaptation.
Data Source
AI summary
The invention achieves a visual processing device that can execute precise contrast adjustment on image signals that have been input and that does not cause discrepancies in the output timing of the image signals that are output. The visual processing device is provided with a gain-type visual processing portion that outputs a first gain signal having predetermined gain characteristics with respect to the input image signal, and a correction portion that corrects the input image signal based on the first gain signal.