3D Optical Scanning With Event Timing Correction for Triangulation
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Solution Overview
Problem
Existing three-dimensional measurement techniques using event-based sensors face challenges in achieving high-speed and high-precision due to inconsistent event generation timing and difficulty in accurately determining the time point of slit light passage, leading to insufficient distance measurement accuracy.
Innovation Solution
A three-dimensional measurement device and program that utilize an event-based sensor to monitor luminance changes, select a designated number of events, and calculate the time point of reference light passage through pixels using triangulation, thereby mitigating timing errors and enhancing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an event-based sensor is used to speed up the light section method, then measurement speed is improved, but distance measurement accuracy deteriorates because the event generation timing is inconsistent and does not accurately reflect the maximum luminance point
Solution Approach 1:
The system uses feedback by comparing the actual event timing with the expected timing based on the known luminance distribution profile of the slit light. The timing correction is calculated by referencing the predetermined luminance distribution characteristics, creating a feedback loop that adjusts the measured time point to compensate for the threshold-based detection delay.
Solution Approach 2:
The invention changes the parameter interpretation by not treating the event time as the direct maximum luminance time, but rather as a correlated parameter that needs transformation. By introducing a timing correction parameter based on the luminance distribution model, the system transforms the raw event time into an accurate passage time, effectively changing how the time parameter is used in calculations.
2Measurement precision
If the slit light has a luminance distribution with maximum near the center, then the light section method achieves high distance measurement accuracy, but the event-based sensor cannot accurately detect the maximum luminance time point because events are generated based on luminance change thresholds rather than absolute luminance values
Solution Approach 1:
The invention introduces an intermediary computational model (the predetermined luminance distribution) that mediates between the sensor output and the desired measurement. This model acts as a translator that converts the threshold-based event timing into accurate passage timing by referencing the known relationship between position and luminance in the slit light profile.
Solution Approach 2:
The system performs preliminary action by pre-establishing the luminance distribution characteristics of the slit light before measurement. This predetermined model is prepared in advance and used to predict and correct the timing offset, allowing the system to compensate for detection delays without requiring real-time complex analysis of the luminance profile.
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 high-speed and high-precision optical scanning three-dimensional measurement by accurately calculating the time point of reference light passage, reducing errors, and allowing for dense distance image generation and parallel processing.
Implementation Method 1
an event-based image sensor... monitors each pixel independently and asynchronously from moment to moment, and then, when a change in luminance exceeding a predetermined threshold is detected
Implementation Method 2
calculate a time point of passage when the reference light passes the pixel... and calculate three-dimensional information of the object by triangulation
Data Source
AI summary
A three-dimensional measurement device includes a projector for scanning and projecting reference light onto an object, and a light receiver for receiving the reflected reference light by the object. The light receiver monitors a luminance change for each pixel and outputs an event when the luminance change meets or exceeds a preset threshold. Each event includes the pixel's position, the time of the luminance change, and a polarity indicating the direction of the luminance change. The device also includes a calculator that selects a group of events where polarity transitions from positive to negative, calculates a passage time of the reference light through each pixel based on the event's time and threshold luminance value, and calculates the object's three-dimensional information using triangulation from the passage times.