Dynamic Luminance Metadata for Video Tone Mapping

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Solution Overview

Problem

Conventional video display devices perform suboptimal tone mapping due to reliance on static metadata, leading to potential loss of luminance and tone information, especially in scenes with varying luminance levels.

Innovation Solution

A method for generating dynamic metadata that includes luminance characteristics for each frame, such as 99Y and DY100, to optimize tone mapping and ensure optimal display of videos by adjusting luminance compression based on dynamic luminance data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If static metadata is used for tone mapping, then device complexity is reduced, but luminance and tone information is lost

Engineering Contradiction:
Improveluminance and tone informationVSAvoidprocessing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from static metadata to dynamic metadata that changes per frame. The system calculates luminance characteristics (min, max, average luminance) for each frame and uses these dynamic values to adjust tone mapping parameters, ensuring luminance information is preserved while adapting to varying scene conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters from fixed static values to dynamic calculated values. Specifically, it computes frame-specific luminance parameters (minimum luminance, maximum luminance, average luminance) and uses these to dynamically adjust tone mapping curves, thereby preserving luminance information without requiring overly complex device architecture.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If dynamic metadata is generated for each frame, then video quality is improved, but processing time increases

Engineering Contradiction:
Improvevideo qualityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating luminance characteristics for each frame before tone mapping. The system computes minimum, maximum, and average luminance values in advance, storing them as dynamic metadata. This preparation allows the actual tone mapping process to use these pre-computed values directly, reducing real-time processing time while maintaining high video quality.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If luminance compression is applied, then display adaptability is improved, but luminance accuracy deteriorates

Engineering Contradiction:
Improvedisplay adaptabilityVSAvoidluminance accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by applying different compression strategies to different luminance regions. Using the dynamically calculated tone mapping curves based on frame-specific luminance characteristics, the system preserves luminance accuracy in critical regions (shadows and highlights) while applying compression only where necessary for display adaptation, thus maintaining both adaptability and precision.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4220541A1Luminance characteristics generation method
Publication Date: 2023.08.02 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4220541A1 patent drawingFigure 1
  • EP4220541A1 patent drawingFigure 2
  • EP4220541A1 patent drawingFigure 3A~3B

AI summary

A luminance characteristics generation method includes: determining (S32), for each of frames included in a video, a value as first luminance characteristics, the value being obtained by dividing the number of pixels having luminances less than or equal to a first luminance among all pixels included in the frame by the number of all the pixels included in the frame; and outputting (S33) the first luminance characteristics determined in the determining of the value.