Video Latency Measurement Using Reflected Light Signals

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Solution Overview

Problem

Current multimedia installations face challenges in synchronizing video and audio signals from independent equipment, with existing methods being either poorly implemented, costly, or complex, particularly in measuring and adjusting for video latency.

Innovation Solution

A method utilizing a photosensitive sensor integrated into the decoder equipment to measure video latency by emitting test light signals and analyzing reflected light, allowing for automatic and cost-effective synchronization without requiring user interaction or external equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external audio/video acquisition equipment is used to measure video latency, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvevideo latency measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The decoder equipment uses its own integrated photosensitive sensor to measure video latency, eliminating the need for external measurement equipment. The system performs self-diagnosis by emitting test light signals through the video reproduction equipment and capturing the reflected light with its built-in sensor, thereby achieving precise measurement without adding external devices.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The photosensitive sensor integrated in the decoder equipment serves multiple functions: it is used for both capturing video content during normal operation and for measuring video latency through emitted test light signals. This multi-functionality eliminates the need for dedicated external measurement equipment while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If external audio/video acquisition equipment is used to measure video latency, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvevideo latency measurement precisionVSAvoidmeasurement process simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The measurement process is fully automated through the decoder equipment's self-service capability. The system automatically emits test light signals, captures the reflected light with the integrated photosensitive sensor, processes the captured signals, and calculates video latency without requiring user installation of applications or manual audio capture operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The measurement function is extracted and integrated into the decoder equipment itself, removing the need for external measurement tools and complex user operations. The system extracts only the necessary test light emission and capture functions needed for latency measurement, simplifying the overall operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the photosensitive sensor captures reflected light from the environment, then ease of operation is improved, but measurement precision may worsen

Engineering Contradiction:
Improvesensor positioning flexibilityVSAvoidlight signal capture accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system emits test light signals in periodic flashes with specific temporal patterns. By using periodic emission rather than continuous light, the system creates distinct, time-separated signals that are easier to detect and measure accurately, even when captured indirectly through environmental reflection.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The test light signals use specific color characteristics that can be distinguished from ambient environmental light. By utilizing particular wavelength ranges or color patterns for the test signals, the system maintains measurement precision even when the sensor captures reflected light from the environment rather than direct light.

Inventive Principle:
Principle #32Color changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simple, automatic, and cost-effective measurement of video latency, facilitating synchronization between video and audio reproduction equipment without additional hardware or user complexity, improving the multimedia experience.

Implementation Method 1

acquiring, using the photosensitive sensor, captured light signals comprising test light signals received which result from a reflection of the test light signals emitted

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

captured light signals comprising test light signals received which result from a reflection of the test light signals emitted on at least one surface of an environment of the video reproduction equipment

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3823277B1Measuring method for a video latency
Publication Date: 2022.12.28 SAGEMCOM BROADBAND SAS
  • EP3823277B1 patent drawingFigure 1
  • EP3823277B1 patent drawingFigure 2
  • EP3823277B1 patent drawing

AI summary

A method for measuring video latency induced by a video playback device (2) connected to a decoder device (1) in which a photosensitive sensor (8) is integrated, comprising the steps of: - generating test light signals from a screen of the video playback device (2); - acquiring, using the photosensitive sensor (8), captured light signals including received test light signals resulting from a reflection of the emitted test light signals on at least one surface of an environment of the video playback device (2); - acquiring measurement signals produced by the photosensitive sensor (8) from the captured light signals, and analyzing the measurement signals to obtain a video latency measurement.