Gamut Mapping for LED Signboards Using Chromaticity Lookup Tables

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Solution Overview

Problem

LED-based signboards face challenges in maintaining reliability and efficiency due to issues like LED failures, limited color gamut utilization, and color perception changes under varying ambient light conditions, which affect image quality and require extensive data handling and maintenance.

Innovation Solution

A method that maps colors from a smaller gamut to a larger one using chromaticity diagrams and interpolation functions to preserve hue and increase saturation, while also dynamically adjusting LED intensities to circumvent faults and compensate for ambient light, utilizing look-up tables and redundant LED drivers for fault tolerance and gamut expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If colors are mapped from a smaller gamut to a larger gamut using chromaticity diagrams and interpolation functions, then color richness and saturation are improved, but device complexity and data handling requirements increase

Engineering Contradiction:

Improvecolor saturationVSAvoiddata handling complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores mapping relationships between smaller and larger color gamuts in look-up tables before operation. This preliminary action allows the system to quickly retrieve color mapping data during runtime without performing complex real-time calculations, thereby improving color saturation while reducing the computational burden and data handling complexity during actual display operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified representation of color mapping relationships by generating look-up tables that copy the essential chromaticity transformation data. Instead of storing or processing complete chromaticity diagram information, the system uses condensed lookup tables that contain pre-computed mapping values, reducing memory requirements and processing complexity while maintaining color accuracy

Inventive Principle:

Principle #26Copying

2Reliability

If redundant LED drivers and fault detection mechanisms are implemented, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveoperation continuityVSAvoiddriver circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements fault detection mechanisms that monitor LED status before complete failure occurs. By detecting potential failures early through current sensing and status monitoring circuits, the system can take preventive actions or switch to backup drivers before the failure impacts display operation, thereby improving reliability while using relatively simple monitoring circuits rather than complex active redundancy

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent enables the LED display system to automatically detect and respond to LED failures without external intervention. The fault detection circuit continuously monitors LED status and can dynamically adjust drive currents or switch between redundant drivers autonomously, improving reliability through self-diagnosis and self-correction while minimizing the need for complex external control systems

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If LED intensity is dynamically adjusted to compensate for ambient light, then color perception consistency is improved, but energy consumption increases

Engineering Contradiction:

Improvecolor perception consistencyVSAvoidenergy consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent implements ambient light sensing that provides feedback to the LED drive system. The sensor detects ambient light conditions and automatically adjusts LED drive currents to maintain consistent color perception across different lighting environments. This feedback mechanism allows the system to optimize energy consumption by increasing LED intensity only when and where needed to compensate for ambient light, rather than maintaining constant high intensity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies different intensity compensation strategies to different regions of the display based on local ambient light conditions. By using ambient light sensors positioned at various locations and adjusting LED intensity locally rather than globally, the system maintains color consistency in each region while minimizing overall energy consumption by only increasing intensity where ambient light interference occurs

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8243090B2Method for mapping a color specified using a smaller color gamut to a larger color gamut

Publication Date: 2012.08.14 LANDMARK SCREENS LLC

AI summary

A method maps a color specified using a smaller color gamut to a larger color gamut. Under that method, a map in a chromaticity diagram is constructed that provides a direction and a magnitude for a unit change in chroma for a specified pixel value in the chromaticity diagram. Using the magnitude and direction in the map, the specified color is mapped to a new pixel value corresponding to a predetermined shift in chromaticity. Preferably, the new pixel value preserves the hue of the specified color, and its luminance related to that of the specified color. Also, the new pixel value preferably has a greater color saturation than the specified pixel value.