3D Measurement Without Calibration Using Feature Amounts
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Solution Overview
Problem
Conventional three-dimensional measurement methods require camera and projector calibration, leading to large device sizes and maintenance challenges, especially in environments with vibrations, and lack precision due to systematic errors and the need for recalibration with focus or view angle adjustments.
Innovation Solution
A method using multiple feature amounts projected from various locations to establish a one-on-one correspondence with space coordinates, allowing for precise measurement without calibration, using a device with a projection unit, imaging unit, and memory unit to store and interpolate feature amounts and coordinates, enabling high-precision three-dimensional measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional stereo systems are used for three-dimensional measurement, then the device can perform basic measurement functions, but measurement precision deteriorates due to camera location shifts caused by vibrations
Solution Approach 1:
The patent changes the fundamental measurement parameters by using multiple feature amounts (phase values from different projection directions) instead of relying on stable camera-calibration parameters. This allows the system to maintain measurement precision even when camera position parameters shift due to vibrations, as the multiple feature amounts provide redundant information for accurate coordinate calculation
Solution Approach 2:
The patent performs preliminary measurement from multiple projection directions to acquire multiple feature amounts before final coordinate calculation. This preliminary acquisition of multiple perspectives creates a robust data foundation that compensates for any subsequent camera position shifts, ensuring measurement reliability without requiring stabilization
2Measurement precision
If camera and projector calibration is performed to achieve high measurement precision, then measurement accuracy improves, but device size increases and maintenance becomes difficult
Solution Approach 1:
The patent extracts and eliminates the calibration step from the measurement system. Instead of requiring calibrated camera and projector parameters, the system directly measures multiple feature amounts from the object and calculates coordinates without needing to know the precise optical parameters of the measurement devices, thereby simplifying the device structure
Solution Approach 2:
The patent introduces multiple feature amounts as intermediaries between the projection system and the coordinate calculation. These feature amounts (phase values from different directions) serve as mediators that bridge the measurement process without requiring direct calibration of the optical systems, reducing device complexity while maintaining precision
3Measurement precision
If calibration is performed to eliminate systematic errors, then measurement precision improves, but the process becomes time-consuming and requires stable optical systems
Solution Approach 1:
The patent performs preliminary measurements from multiple projection directions to acquire multiple feature amounts. This preliminary multi-directional measurement eliminates the need for time-consuming calibration procedures, as the multiple perspectives provide sufficient information for accurate coordinate calculation without systematic errors
Solution Approach 2:
The measurement system serves itself by using the measured feature amounts from multiple directions to automatically compensate for and eliminate systematic errors. The system does not require external calibration procedures or stable optical mounting, as the multi-directional feature amount acquisition inherently corrects for errors
4Adaptability or versatility
If the camera position is adjusted or focus is changed to adapt to different measurement scenarios, then measurement versatility improves, but precision deteriorates due to loss of calibration
Solution Approach 1:
The patent performs preliminary acquisition of multiple feature amounts from different projection directions before any camera adjustments. This preliminary multi-perspective data collection creates a robust measurement foundation that remains valid even after camera position or focus changes, maintaining precision while enabling versatility
Solution Approach 2:
The patent changes from relying on fixed calibration parameters to using multiple measurable feature amounts that can be重新acquired after any camera adjustment. This parameter change allows the system to adapt to different measurement scenarios without precision loss, as the feature amounts can be remeasured from the new camera position
Data Source
AI summary
The relationship between space coordinates and a plurality of feature amounts gained from at least a pattern or a change in the pattern that has been projected from a plurality of projection units is found in advance, and the relationship between the feature amounts and the space coordinates is used in order to find the space coordinates of the surface of an object from the feature amounts that have been gained from a pattern or a change in the pattern projected from the plurality of projection units onto the surface of the object.