Phase-Based Distance Sensing With Triangulation Range Extension
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Solution Overview
Problem
Existing distance measuring devices using Indirect Time of Flight (Indirect ToF) schemes are limited by the repetition period of the phase difference, leading to size constraints due to the need for different optical systems.
Innovation Solution
A distance measuring device that includes a distance measuring sensor, a first distance generation unit, a phase generation unit, and a second distance generation unit, which generate distance measurement values based on phase differences and repetition periods, using pattern light with varying luminance to enhance accuracy and reduce device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a different optical system is provided to obtain repetition period, then distance measurement range is improved, but device size increases
Solution Approach 1:
The patent combines two different optical systems (triangulation system and Indirect ToF system) into a single integrated device. The triangulation unit and phase difference unit share the same housing and optical path, allowing the device to obtain both the repetition period and phase difference information without requiring separate standalone systems, thus avoiding an increase in overall device size.
Solution Approach 2:
The distance measuring device is designed to perform multiple functions using a single integrated system. It can simultaneously execute triangulation-based distance measurement and Indirect ToF-based phase difference measurement, making the device universal enough to handle various measurement scenarios without requiring additional separate optical systems.
2Measurement precision
If pattern light is emitted at high intensity, then signal detection is improved, but saturation occurs reducing measurement accuracy
Solution Approach 1:
The light source device dynamically adjusts the emission intensity of pattern light based on the measured distance to the object. When the object is far away, higher intensity is used to ensure sufficient signal strength for phase difference detection. When the object is close, lower intensity is used to prevent saturation of the photodetector, thereby maintaining measurement accuracy across different distance ranges.
Solution Approach 2:
The patent changes the parameter of light emission intensity dynamically. By adjusting the intensity parameter of pattern light based on distance information, the system optimizes the balance between signal strength and saturation prevention, improving both signal detection quality and measurement reliability under different operating conditions.
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
The solution allows for accurate distance measurement across varying ranges while maintaining a compact device size by combining triangulation and ToF methods, improving measurement accuracy and reducing saturation issues.
Implementation Method 1
a distance measuring sensor that receives reflected light that is pattern light emitted from a light source device, reflected by an object, and returned
Implementation Method 2
a phase generation unit that generates, as a phase difference, a time from when the pattern light is emitted to when the pattern light is received as the reflected light
Data Source
AI summary
The present disclosure provides a light receiving device, a control method, and a distance measuring system capable of suppressing an increase in size of a device that generates a distance measurement value on the basis of a phase difference.According to the present disclosure, provided is a distance measuring device including: a distance measuring sensor that receives reflected light that is pattern light emitted from a light source device, reflected by an object, and returned; a first distance generation unit that generates a first distance measurement value that is a distance to the object on the basis of a position of the pattern light received by the distance measuring sensor; a phase generation unit that generates, as a phase difference, a time from when the pattern light is emitted to when the pattern light is received as the reflected light; and a second distance generation unit that generates a second distance measurement value that is a distance to the object, according to: the phase difference; and a repetition period of the phase difference based on the first distance measurement value.