3D Measurement Layout for Brightness-Based Background Removal
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Solution Overview
Problem
Existing three-dimensional measurement systems face inaccuracies in background removal due to variations in imaging conditions, leading to reduced precision in calculating three-dimensional coordinates.
Innovation Solution
The system employs a light receiving device positioned to avoid brightness levels outside a specified range, either below a lower limit or above an upper limit, to exclude background light reflections, using reflective or diffusing members to control light paths, and incorporates a data acquisition unit to acquire and calculate coordinates within defined brightness thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light receiving device is positioned to receive reflected light from the mounting surface, then the background can be captured for removal processing, but the brightness variations due to imaging timing differences reduce the accuracy of background removal
Solution Approach 1:
The patent extracts and removes the mounting surface from the measurement data by identifying and excluding regions with brightness above a predetermined threshold. This separates the background (mounting surface) from the object of interest, eliminating the problem of background removal inaccuracies while preserving measurement precision for the actual object.
Solution Approach 2:
The patent changes the brightness parameter threshold to distinguish between the mounting surface and the measured object. By setting a predetermined brightness threshold and excluding regions exceeding it, the system adapts to different imaging conditions and maintains reliable measurements regardless of lighting variations or timing differences.
2Loss of information
If the light receiving device captures all reflected light including background reflections, then more complete imaging data is obtained, but the measurement accuracy decreases due to background light interference
Solution Approach 1:
The patent applies different quality criteria to different regions of the imaging data. Regions with brightness below the threshold are processed for three-dimensional coordinate calculation, while regions above the threshold are excluded. This local differentiation maintains measurement precision by focusing computational resources on valid object regions while preserving the overall imaging data structure.
Solution Approach 2:
The patent extracts only the relevant portions of imaging data (regions with brightness below the threshold) for three-dimensional coordinate calculation. This extraction process removes background interference while retaining complete object information, resolving the contradiction between data completeness and measurement accuracy.
3Ease of manufacture
If background removal is performed by calculating difference with background image, then background can be removed, but slight errors occur due to variations in current flowing through the camera during imaging
Solution Approach 1:
The patent changes from temporal difference calculation to spatial threshold-based separation. Instead of comparing images taken at different times (which suffers from camera current variations), the method uses brightness thresholding on a single image to separate background from object, eliminating timing-related errors while maintaining implementation simplicity.
Solution Approach 2:
The patent performs preliminary identification of background regions using brightness thresholding before three-dimensional coordinate calculation. This preliminary action separates valid measurement regions from background regions in advance, preventing propagation of background errors into the final measurement results while keeping the process efficient.
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 enhances the accuracy of three-dimensional point cloud measurement by minimizing the influence of background light, allowing precise removal of background components and reducing processing load, thereby improving measurement precision.
Implementation Method 1
a light receiving device for receiving reflected light
Implementation Method 2
a light projecting device for projecting light onto a measuring object
Data Source
AI summary
A three dimensional measurement system has a measurement unit that images the measuring object and that has a light projecting device projecting projected light onto the measuring object and a light receiving device receiving the reflected light. The system has a specular reflection member that forms a mounting surface for mounting the measuring object and reflects projected light at a specific angle. The system has a data acquisition unit that acquires imaging data and a coordinate calculation unit that calculates three dimensional coordinates for the part of the imaging data whose brightness is higher than the lower limit brightness and does not calculate three dimensional coordinates for the part whose brightness is lower than the lower limit brightness. The light receiving device is arranged at a position where the brightness of the part where the specular reflection member is imaged is lower than the lower limit brightness.