ToF Distance Measurement Using Dual-Range Light Detection
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Solution Overview
Problem
Existing electronic apparatuses for distance measurement face challenges in accurately determining distance due to the influence of object reflectivity and ambient light, which affects the accuracy of time of flight (ToF) measurements.
Innovation Solution
The electronic apparatus employs a method where pulsed light is emitted twice, with the first measurement determining a threshold value for reflected light and a second measurement range, allowing for the reduction of ambient light influence and improvement in ToF accuracy by calculating distance based on the second duration of the second reflected light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single measurement range is used for ToF measurement, then the measurement process is simple, but the accuracy is reduced due to ambient light interference and object reflectivity variations
Solution Approach 1:
The patent divides the measurement process into two distinct measurement ranges: a first measurement range used to determine threshold values and object reflectivity characteristics, and a second measurement range used for accurate ToF measurement. This segmentation allows the system to adapt to different lighting conditions and object properties, improving measurement accuracy while managing complexity through structured multi-stage measurement
Solution Approach 2:
The patent performs preliminary measurements in the first measurement range to determine threshold values and object reflectivity characteristics before conducting the actual ToF measurement in the second range. This preliminary action enables the system to adapt its measurement parameters based on initial observations, reducing the impact of ambient light and reflectivity variations on the final measurement accuracy
2Reliability
If threshold values are determined without preliminary measurement, then the measurement process is faster, but the reliability of reflected light detection decreases
Solution Approach 1:
The patent performs preliminary measurements in the first measurement range to determine reliable threshold values that account for ambient light conditions and object reflectivity characteristics. These pre-determined threshold values are then used in the second measurement range to reliably distinguish reflected light from ambient light, ensuring accurate ToF measurement without excessive measurement time
Solution Approach 2:
The patent changes the measurement parameters (threshold values, measurement range) based on results from the first measurement range. By adapting these parameters to the specific measurement conditions observed preliminarily, the system achieves reliable reflected light detection in the second range while minimizing the time penalty through efficient parameter optimization
3Adaptability or versatility
If fixed measurement ranges are used, then the device operation is simpler, but the adaptability to different measurement conditions is reduced
Solution Approach 1:
The patent implements dynamic measurement ranges where the first measurement range is used to characterize the measurement environment and object properties, and the second measurement range is optimized based on these characteristics. This dynamic adaptation allows the system to handle various measurement conditions (different ambient light levels, different object reflectivities) while maintaining relatively simple operation through automated parameter adjustment
Solution Approach 2:
The patent automatically changes measurement parameters (threshold values, measurement range boundaries) based on conditions observed in the first measurement range. This parameter adaptation enables the system to adapt to different measurement conditions without requiring manual configuration, balancing adaptability with ease of operation through automated parameter optimization
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 enhances the accuracy of distance measurement by minimizing the impact of ambient light and improving the reliability of ToF calculations, resulting in more precise distance determination.
Implementation Method 1
measuring, using a time from emission of light to reception of reflected light reflected by an object, a distance to the object
Implementation Method 2
reception of reflected light reflected by an object
Data Source
AI summary
An electronic apparatus capable of determining a distance to an object based on at least first reflected light provided by a reflection of first pulsed light on the object and second reflected light provided by a reflection of a second pulsed light on the object has an input terminal to receive an electrical signal of intensity of reception light, and processing circuitry to specify, based on the electrical signal, a first duration from when the first pulsed light is emitted until when the first reflected light is received within a first measurement range, and determine, based on the first duration, a second measurement range of the second reflected light, specify, a second duration from when the second pulsed light is emitted until when the second reflected light is received within the second measurement range, and determine the distance from the electronic apparatus to the object.