3D ToF Reliability Mapping Using IR Intensity Correlation
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Solution Overview
Problem
The existing time-of-flight (ToF) method for range finding and three-dimensional information generation is prone to errors due to shot noise, incorrect reflection from materials that absorb or transmit infrared/ultraviolet light, and optical path differences, leading to inaccurate distance measurements and unreliable three-dimensional information.
Innovation Solution
A reliability calculation device and method that utilizes an imaging device with ToF, IR, and polarization sensors to acquire distance and light intensity data, employing a gray chart for correlation to calculate ideal light intensity and reliability, and a selection process to determine the degree of reliability for each pixel based on actual and ideal IR values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ToF method is used for range finding, then distance measurement can be performed, but measurement precision deteriorates due to shot noise and incorrect reflection from materials
Solution Approach 1:
The patent introduces an intermediary evaluation chart with known reflectance properties as a mediator between the ToF sensor and the subject. By measuring the evaluation chart's reflected light intensity and comparing it with the subject's reflected light intensity, the system can determine reliability without directly measuring the subject's distance accuracy. This intermediary approach allows reliability assessment while maintaining the simplicity of the ToF measurement process.
Solution Approach 2:
The patent implements feedback by using the evaluation chart measurement results to adjust and verify the distance measurement reliability. The system compares the actual light intensity received from the subject with the expected intensity based on the evaluation chart data, and uses this feedback to determine whether the distance measurement is reliable, thereby improving measurement precision through iterative verification.
2Measurement precision
If manual correction of abnormal values is performed, then measurement precision improves, but device complexity and operation time increase
Solution Approach 1:
The patent enables the system to perform self-service by automatically calculating and providing reliability information for each pixel without requiring manual intervention. The evaluation chart measurement and automated comparison processes allow the system to self-verify and self-correct, eliminating the need for manual correction while maintaining high measurement precision and reducing operational complexity.
3Manufacturing precision
If reliability calculation is performed for each pixel, then three-dimensional information quality improves, but calculation time and processing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing the evaluation chart data before actual distance measurement. By preparing the correlation data between distance and light intensity for the evaluation chart in advance, the system can quickly determine pixel reliability during the actual measurement process without time-consuming calculations, thereby improving three-dimensional information quality while minimizing processing time.
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 accurate calculation of the reliability of measured distance values, improving the quality and reliability of generated three-dimensional information by filtering out inaccurate data and correcting for material properties and optical reflections.
Implementation Method 1
a method of calculating the distance to an object by emitting range-finding light to an object, receiving reflected light reflected by the object, and measuring a time from emission of light to reception of light is known. This range finding method is widely known as a time-of-flight (ToF) method.
Implementation Method 2
an IR image acquiring unit configured to acquire an IR image including information which corresponds to the distance image and which is information on the light intensity of infrared light at each of coordinates in the distance image
Implementation Method 3
correlation data which is data obtained by measuring a correlation between the distance to an evaluation chart and a received light intensity using the evaluation chart having a specific reflectance in advance
Data Source
AI summary
A three-dimensional information processing device includes a first acquisition unit configured to acquire first point group data which is point group data of a subject acquired at a first zoom magnification by a first point group data acquisition device, a second acquisition unit configured to acquire second point group data which is point group data of the subject acquired at a second zoom magnification by a second point group data acquisition device acquiring point group data at an angle of view which at least partially overlaps the angle of view at which the first point group data is acquired by the first point group data acquisition device, and an identification unit configured to identify an overlapping portion out of point groups included in the first point group data and point groups included in the second point group data.