Optical Measuring Device for 3D Shape Detection
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Solution Overview
Problem
Existing optical measuring devices using the light section method struggle to accurately determine the three-dimensional shape of objects when the transport medium is uncontrolled, leading to measurement errors due to uncertainty in object movement and lack of information about the transport route between height profiles.
Innovation Solution
The optical measuring device captures images of the object surface during movement, determines shifts in features, and uses a combination of depth information from height profiles and 2D image sensor data to derive object movement between profiles, allowing for accurate displacement detection without distortion from slippage or uncontrolled transport media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If incremental encoders are used to convert belt movement into signals for constant distance, then measurement precision is improved, but reliability deteriorates due to slippage between the assumed object movement and actual object movement
Solution Approach 1:
The patent introduces an optical intermediary system (light section sensor projecting a light line onto the object surface) as a mediator to directly measure object position and movement. Instead of relying on belt encoders that can slip, the system projects a light line onto the object itself and tracks its position, creating a direct measurement link between the object and sensor that eliminates slippage errors.
Solution Approach 2:
The patent replaces the mechanical encoder system (which converts belt movement into electrical signals) with an optical measurement system. The light section sensor uses optical projection and imaging to directly capture object position and movement, substituting mechanical measurement with optical measurement to eliminate mechanical slippage and improve reliability.
2Measurement precision
If the sensor is moved over the object at constant speed, then measurement precision is improved, but device complexity increases due to the requirement for controlled transport
Solution Approach 1:
The patent inverts the traditional measurement approach by making the sensor stationary and the object move beneath it. Instead of moving the sensor over a stationary object (which requires complex positioning systems), the object is conveyed past the fixed sensor, simplifying the device while maintaining measurement precision through the object's natural movement.
Solution Approach 2:
The patent creates a measurement system that works with various transport methods (conveyor belts, slides, roller conveyors, free fall sections) without requiring controlled or constant speed transport. The universal design allows the same stationary sensor setup to measure objects regardless of how they are transported, eliminating the need for complex speed control mechanisms.
3Device complexity
If uncontrolled transport methods like slides or roller conveyors are used, then device complexity is reduced, but measurement precision deteriorates due to lack of information about transport path
Solution Approach 1:
The patent implements feedback by continuously capturing images of the light line projected onto the moving object and using correlation analysis to determine actual object position and displacement. The system compares consecutive images to calculate movement, providing real-time feedback on object position regardless of transport method, thereby maintaining measurement precision with simple transport mechanisms.
Solution Approach 2:
The patent uses the light line projected onto the object surface as an intermediary marker to track object movement. This optical marker serves as a reference that remains attached to the object throughout transport, allowing the stationary sensor to accurately measure object position and displacement even with uncontrolled transport methods like slides or free fall sections.
4Measurement precision
If correlation analysis is performed on consecutive images to detect displacement, then measurement precision is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent creates optical copies (images) of the light line pattern on the object surface at different positions and times. By comparing these copied images through correlation analysis, the system determines object displacement with high precision. The copying approach allows digital processing of position information without adding mechanical complexity to the measurement system.
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 enables precise detection of the object's actual displacement path within the light section sensor area, even with uncontrolled transport methods like slides or roller conveyors, by adapting lens and lighting settings to changing distances and surface structures, ensuring accurate correlation analysis and reduced measurement uncertainty.
Implementation Method 1
an illumination unit (5) designed to project a linear marking (L) onto the object (3)
Implementation Method 2
at least one image recording unit (6) for capturing the linear marking projected onto the object (3)
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an optical measuring device (1) for ascertaining the three-dimensional shape of an object (3), having a light section sensor (4), which has an illuminating unit (5) designed to project a linear marking (L) onto the object (3) and at least one image capturing unit (6) for capturing the linear marking (L) projected onto the object (3), and an advancement detection unit, which is designed to detect the advancement distance of the object (3) moving under the light section sensor (4) over time (t). The optical measuring device (1) is designed to determine spacing profiles of the object (3) from the linear marking (L). The optical measuring device (1) is also designed to capture images of the surface of the object (3) captured during the movement of the object (3), determine a movement of features in the captured images of the object surface during an integral of time, and ascertain a movement of the object (3) in the interval of time from the determined movement of the features in the images of the object surface and a scale of the captured images of the object surface, said scale being derived from the spacing profile of the object (3).