Latency Measurement Using Shared Clock and Optical Sensor
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Solution Overview
Problem
Existing methods for measuring and compensating end-to-end latency in human-computer interaction systems are cumbersome and lack precision, particularly in real-world applications, due to the difficulty in synchronizing clocks between input and output devices.
Innovation Solution
A system using a shared clock for the processing device and acquisition device, employing a two-dimensional periodic image with specific pixel patterns to measure latency, and a software development toolkit for real-time compensation of latency and jitter, utilizing an optical sensor to track the movement of a calibrated output on the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external acquisition device such as a camera is used to detect cursor movement for measuring latency, then measurement capability is achieved, but synchronization precision between the processing device and camera deteriorates
Solution Approach 1:
The patent merges the clock resources of the processing device and acquisition device by sharing a single clock between them. This eliminates the synchronization problems between separate clocks, allowing precise latency measurement through a unified time reference that both devices use simultaneously.
Solution Approach 2:
The shared clock serves multiple functions: it provides the time reference for the processing device, the time reference for the acquisition device, and enables precise synchronization between them. This single clock performs what would otherwise require multiple independent timekeeping systems.
2Measurement precision
If a shared clock is used between processing device and acquisition device, then clock synchronization precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the clock resources of the processing device and acquisition device by sharing a single clock between them. This eliminates the synchronization problems between separate clocks, allowing precise latency measurement through a unified time reference that both devices use simultaneously.
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 precise measurement and real-time compensation of latency and jitter, improving user experience by reducing system lag and variance, applicable to various input and output interfaces, including audio interfaces.
Implementation Method 1
utilizing an optical sensor to track the movement of a calibrated output on the screen
Data Source
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AI summary
The invention discloses a method to measure end-to-end and partial latency between an input interface and an output interface of a processing device. The invention uses a generator of a calibrated output to be output by the processing device through the output interface and a sensor configured to capture the calibrated output and send it to a processing unit of the processing device through the input interface. An advantageous arrangement of a calibrated output is a specific texture to be output by a screen and captured by an optical sensor. A specific texture comprises elementary patterns which have a defined number of pixels and a defined proportion and location of dark and light pixels. According to certain aspects of the invention, a calibration of latency is performed based on a number of parameters defining the hardware and/or software configuration of the processing device, and/or its conditions of operation. In specific embodiments, a calibration routine and/or a compensation routine of latency of the processing device may be performed in real time.