Digital Gamma Curve Scaling via Virtual Tap Points

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Solution Overview

Problem

Conventional gamma correction methods in digital display systems are inadequate as they rely on analog manipulation, which is not suitable for modern digital displays, leading to issues with contrast enhancement and nonlinear luminance reproduction.

Innovation Solution

A method and system for digitally scaling a gamma curve in a linear and ratiometric fashion, using virtual tap points to generate a modified gamma curve that provides smooth, continuous, and monotonic contrast enhancement, equivalent to a digital equivalent of a voltage tap-based analog resistor ladder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If analog manipulation of voltages is used for gamma correction, then contrast enhancement is achieved, but the method is not appropriate for modern digital display systems

Engineering Contradiction:

Improvecompatibility with digital display systemsVSAvoidcontrast enhancement performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the analog voltage manipulation system with a digital lookup table system. The analog contrast enhancement block that manipulated continuous voltages is substituted with digital LUTs that store pre-calculated gamma correction values, enabling gamma correction to be performed through digital memory access and interpolation rather than analog circuit manipulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters from continuous analog voltages to discrete digital values stored in lookup tables. By pre-calculating and storing gamma correction values for various luminance codes in digital memory, the system transforms the gamma correction process from analog voltage manipulation to digital parameter retrieval and interpolation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If digital lookup tables are used for gamma correction, then digital compatibility is achieved, but visual artifacts may appear due to discontinuous gamma curves

Engineering Contradiction:

Improvedigital system compatibilityVSAvoidvisual artifacts

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic interpolation between discrete lookup table entries based on the actual luminance code value. Rather than simply retrieving fixed values from the LUT, the system calculates intermediate values by interpolating between adjacent table entries, creating a smooth continuous gamma curve that adapts to any input luminance code without producing visual artifacts.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces linear interpolation as an intermediary process between the discrete lookup table values and the final gamma-corrected output. This intermediary calculation smooths the transitions between discrete LUT entries, eliminating the discontinuities that would otherwise cause visible artifacts in the displayed image.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Extent of automation

If conventional digital gamma correction is implemented, then digital processing is achieved, but the gamma curve may not be smooth or continuous

Engineering Contradiction:

Improvedigital processing capabilityVSAvoidsmoothness and continuity of gamma curve

Core Design Contradiction:

Extent of automationVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent ensures continuous gamma correction by implementing linear interpolation that operates for every possible luminance code value. This continuous interpolation process fills in the gaps between discrete LUT entries, maintaining the smoothness and continuity of the gamma curve across the entire luminance range without interruption or discontinuity.

Inventive Principle:

Principle #20Continuity of useful action

4Ease of operation

If analog resistor ladder is used, then voltage tap control is achieved, but the system lacks digital precision and scalability

Engineering Contradiction:

Improvevoltage control capabilityVSAvoidluminance code accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7783105B2Method and system for digitally scaling a gamma curve

Publication Date: 2010.08.24 NAT SEMICON CORP

AI summary

A method and system for digitally scaling a waveform. A method is described performing a linear waveform transformation and translation of a curve in a smooth and continuous fashion. Another method is described for scaling a waveform in which the available accuracy and resolution is manipulated for a given waveform. Specifically, by strategically placing virtual tap points of a waveform, as well as changing the scaling factors used for calculating points on the waveform provides for adjusting the accuracy and resolution in one or more regions of a waveform. These scaling methods provide a digital equivalent of a voltage tap-based analog resistor ladder used for digital-to-analog conversion. The digital virtual tap points represent the analog voltage tap points, and the vertical translation of the curve acts in a smooth, monotonic, and continuous fashion.