3D Depth Sensor Distance Measurement Using Multi-Frequency Optical Shutter
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Solution Overview
Problem
Current 3D depth sensors using a single frequency for distance measurement face limitations in maximum measurable distance and accuracy, with increased frequency enhancing accuracy but reducing measurable distance, and methods using multiple frequencies require more frames for updates, prolonging information update time.
Innovation Solution
A method utilizing two or more frequencies to measure frames, with a maximum of four frames for distance updates, calculating phases based on equations to determine accurate distances, and controlling the optical shutter's amplitude and offset to simplify computations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single frequency is used for distance measurement, then the measurement process is simple and fast, but the measurable distance is limited and accuracy is reduced
Solution Approach 1:
The measurement process is segmented into multiple frequency components. Instead of using a single frequency, the patent divides the measurement into measurements at different frequencies (first frequency and second frequency), where each frequency provides complementary information. This segmentation allows the system to overcome the limitations of single-frequency measurement while maintaining manageable complexity through structured processing of each frequency component.
Solution Approach 2:
The patent changes the frequency parameter during the measurement process. By performing measurements at multiple frequencies and combining the results, the system achieves both extended measurable distance and maintained accuracy. The frequency parameter is varied systematically to resolve the contradiction between measurement simplicity and measurement performance.
2Measurement precision
If multiple frequencies are used to increase measurable distance and accuracy, then measurement precision improves, but the number of frames required increases, prolonging information update time
Solution Approach 1:
The patent merges measurements from multiple frequencies into a unified distance calculation. By combining the results from first frequency measurements and second frequency measurements through a unified calculation process, the system achieves accurate distance measurement without requiring separate processing sequences for each frequency, thereby reducing the total time required for information updates.
Solution Approach 2:
The patent implements a dynamic measurement strategy where the number of frames measured at each frequency can be adjusted. The system measures m frames at the first frequency and n frames at the second frequency, where m and n are positive integers that can be optimized based on specific application requirements. This dynamic approach allows flexibility in balancing measurement accuracy against update time, resolving the contradiction by adapting to different operational needs.
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
This approach maintains the time for updating distance information while increasing measurable distance and accuracy, reducing depth error to 1.25% compared to 2.11% with single-frequency methods.
Implementation Method 1
measuring m number of frames using light modulated at a first frequency to determine a first tentative distance
Implementation Method 2
measuring a time of flight (TOF) method. The 3D depth sensor measures a distance to an object by measuring a time for light that is emitted from a light source and is reflected by the object to return thereto
Data Source
AI summary
A method of measuring a distance by using a 3-dimensional (3D) depth sensor is provided. The method may include: measuring m number of frames using light modulated at a first frequency to determine a first tentative distance from a viewpoint to an object at the first frequency, m being a positive integer; measuring n number of frames using light modulated at a second frequency to determine a second tentative distance from the viewpoint to the object at the second frequency, n being a positive integer, a sum of m and n being four; and determining a resulting distance to the object based on the first distance and the second distance.