Event-Based Shape Measurement for Secondary Reflection Filtering
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Solution Overview
Problem
Existing shape measuring devices using the light-section method face challenges in accurately measuring objects with large irregularities due to secondary reflected light interfering with regular reflected light, leading to incorrect shape measurements.
Innovation Solution
A shape measuring system utilizing an event-based vision sensor (EVS) with a light source part and light receiving part that captures regular reflected light through waveform control, wavelength division, polarization switching, or dispersion to distinguish and remove unwanted signals, ensuring accurate three-dimensional data capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a non-scanning imaging device is used to capture reflected light for shape measurement, then high-speed measurement is achieved, but measurement precision deteriorates due to secondary reflected light interference
Solution Approach 1:
The patent segments the measurement process by dividing the captured light signals into different categories based on their temporal characteristics. The signal processing unit separates regular reflected light (first light) from secondary reflected light (second light) by analyzing the timing and intensity patterns of detected photons, allowing high-speed capture while maintaining precision through digital signal segmentation.
Solution Approach 2:
The patent extracts only the useful signal components from the total detected light. By using the event-based vision sensor to detect photon arrival times and applying signal processing algorithms, the system extracts regular reflected light information while filtering out secondary reflected light and ambient light interference, achieving both high speed and high precision.
2Quantity of substance
If ambient light and secondary reflected light are present during measurement, then the light receiving part captures more light signals, but measurement precision deteriorates due to unwanted signal interference
Solution Approach 1:
The patent implements feedback-based signal validation by comparing detected light signals against expected temporal and intensity patterns. The signal processing unit uses feedback from the event-based vision sensor's precise timing data to identify and reject signals that do not conform to the characteristics of regular reflected light, thereby maintaining precision while utilizing all available light signals.
Solution Approach 2:
The patent changes the detection parameters by using an event-based vision sensor that operates in photon-counting mode with precise timestamp recording. This parameter change allows the system to distinguish between useful and unwanted light signals based on their arrival time distributions and intensity patterns, enabling accurate separation of signal from noise.
3Quantity of substance
If multiple detection values are obtained from secondary reflected light and regular reflected light, then more data is captured, but measurement precision deteriorates due to conflicting shape information
Solution Approach 1:
The patent extracts only the valid shape information from the multiple detection values by identifying which signals correspond to regular reflected light. The signal processing unit uses temporal analysis and intensity thresholding to extract genuine shape data while discarding conflicting information from secondary reflected light, maintaining precision despite increased data quantity.
Solution Approach 2:
The patent introduces an intermediary signal processing layer that mediates between the raw detection data and the final shape measurement. This intermediary processing stage applies algorithms to resolve conflicts between multiple detection values, using the precise timing information from the event-based vision sensor to determine which signals represent the true object shape.
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 system enables high-speed and accurate shape measurement by distinguishing between regular and secondary reflected light, providing unique data values for each point on the object's surface, thereby suppressing erroneous measurements.
Implementation Method 1
a light source part that emits measurement light to a measurement target; a light receiving part that receives reflected light that is the measurement light reflected from the measurement target
Implementation Method 2
a non-scanning imaging device called event-based vision sensor (EVS) is known as opposed to a scanning (synchronous) imaging device that performs imaging in synchronization with a synchronization signal
Data Source
AI summary
Shape measuring systems are disclosed. In one example, a shape measuring system includes a light source part with a light source, a waveform control lens, and a scan mechanism. It also includes light receiving parts that each include a light receiving lens on which reflected light reflected by the measurement target among measurement light from the light source part is incident, an EVS, which is an asynchronous imaging device that is a light receiving element, an event issuing part that detects an event on the basis of output data from the EVS and outputs event data, and a transmitting part that outputs the event data to the signal processing part. A signal processing part includes an unwanted signal removing part that removes an unwanted signal resulting from incidence of secondary reflected light, and a three-dimensional calculating part that calculates a three-dimensional shape of the measurement target.