3D Measurement Device Exposure Time Adjustment
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Solution Overview
Problem
Conventional three-dimensional measurement apparatuses often require excessively long exposure times to maximize the number of three-dimensional point groups, which can limit the time interval for measuring moving targets, such as those on a manufacturing line, due to the lack of efficient exposure time adjustment.
Innovation Solution
A three-dimensional measurement apparatus that determines the exposure time to ensure a minimum threshold of feature points or points in the three-dimensional point group is met while reducing the exposure time below the maximum, using a calculation unit to estimate and adjust the exposure time based on the relationship between exposure time and the number of points, allowing for shorter measurement times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the exposure time is extended to maximize the number of three-dimensional point groups, then the measurement precision is improved, but the measurement time increases and productivity decreases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the exposure time based on the reflectivity characteristics of the measurement target. The system calculates a reflectivity index from the captured image and determines the optimal exposure time accordingly, allowing it to use shorter exposure times for highly reflective surfaces while maintaining sufficient point group density, thus resolving the contradiction between measurement precision and productivity
2Measurement precision
If the exposure time is extended to capture more feature points, then the measurement precision is improved, but the time interval for measuring moving targets decreases
Solution Approach 1:
The system changes the exposure time parameter dynamically based on the reflectivity index calculation. By analyzing the relationship between exposure time and captured point density, the system determines the minimum sufficient exposure time for each measurement target, thereby reducing unnecessary time intervals while maintaining measurement precision for moving targets
3Measurement precision
If the exposure time is set to maximize point group calculation, then the measurement precision is improved, but the measurement efficiency for successive measurements decreases
Solution Approach 1:
The patent implements parameter changes by calculating the reflectivity index from captured images and using this information to determine the optimal exposure time for subsequent measurements. This allows the system to adaptively adjust exposure time based on target characteristics, maintaining sufficient point group density while improving measurement efficiency for successive measurements on manufacturing lines or other dynamic environments
4Device complexity
If a fixed exposure time is used manually, then the device complexity is reduced, but the adaptability to varying ambient conditions decreases
Solution Approach 1:
The system applies self-service by automatically calculating the reflectivity index from captured images and determining the optimal exposure time without manual intervention. The apparatus serves itself by using its own captured data to adjust measurement parameters, thereby maintaining simplicity in operation while achieving high adaptability to varying ambient conditions and different measurement targets
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 allows for a decrease in exposure time without significantly reducing the number of points captured, thereby shortening the time required to measure three-dimensional shapes and improving measurement efficiency for moving targets.
Implementation Method 1
capture an image of the measurement target onto which the patterned light is projected
Data Source
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AI summary
Provided are a three-dimensional measurement device, etc., capable of shortening the amount of time required to measure a three-dimensional geometry of a measurement target by shortening the exposure time of an imaging unit. This three-dimensional measurement device is provided with: a projection unit which projects patterned light onto a measurement target; an imaging unit which captures, in a prescribed exposure time, images of the measurement target onto which the patterned light has been projected; a calculation unit which calculates, on the basis of a plurality of feature points included in each of the images, the positions of a group of three-dimensional points representing the three-dimensional geometry of the measurement target; and a determination unit which determines the exposure time so that the number of feature points and/or the number of three-dimensional points in the group is equal to or greater than a threshold established on the basis of the maximal value of one of the two numbers, and that the exposure time becomes shorter than an exposure time corresponding to the maximal value.