3D Scanner Sensor Layout for Non-Coded Pattern Correspondence
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Solution Overview
Problem
Existing 3D scanners using non-coded structured light struggle with disambiguating imaged elements, particularly lines, due to the lack of unique identifying characteristics, necessitating improved methods for correspondence determination between projected and reflected patterns.
Innovation Solution
A 3D scanner design with overlapping fields of view using multiple cameras and a projector, where the cameras' optical axes are parallel and sensors are displaced to enhance image overlap, allowing for improved correspondence identification through triangulation algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-coded elements are used in structured light projection, then the manufacturing complexity is reduced, but the ability to disambiguate imaged elements deteriorates
Solution Approach 1:
The patent introduces a computational intermediary (disambiguation algorithm) that processes images from multiple cameras to resolve element correspondence. The algorithm uses the known geometric relationship between cameras and the projected pattern, along with triangulation mathematics, to compute which imaged elements correspond to which projected elements, thereby mediating between the simple non-coded projection and accurate measurement.
Solution Approach 2:
The patent transitions from two-dimensional image data to three-dimensional spatial information by introducing a third dimension (depth) through triangulation. By using multiple cameras viewing the object from different angles and applying triangulation mathematics, the system resolves element correspondence in 3D space, adding a dimensional perspective that enables disambiguation without coded elements.
2Area of stationary object
If multiple cameras are used to improve measurement coverage, then the measurement area is increased, but the device complexity increases
Solution Approach 1:
The patent divides the measurement task into segments handled by multiple cameras, each responsible for capturing a specific portion of the projected pattern from a different viewpoint. This segmentation of the imaging function across multiple cameras increases the overall measurement area while maintaining manageable complexity through modular camera units.
Solution Approach 2:
The patent makes each camera multi-functional by designing them to perform the same imaging function simultaneously from different positions. Each camera serves as a universal imaging unit that can capture any portion of the projected pattern within its field of view, allowing the system to scale measurement area by adding identical functional units rather than requiring specialized components.
3Measurement precision
If sensors are displaced from optical axes to maximize field of view overlap, then the measurement precision is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates feedback through the disambiguation algorithm that uses the known sensor displacements and camera geometries to compute correct element correspondences. The system feeds back the geometric relationships and uses them to correct for any positioning variations, allowing the algorithm to compensate for manufacturing tolerances and maintain measurement precision.
Solution Approach 2:
The patent deliberately changes the positioning parameters of sensors from their conventional locations (centered on optical axes) to displaced positions that maximize field of view overlap. This parameter change improves measurement precision by ensuring that corresponding points appear in both camera images, and the known displacement values are incorporated into the triangulation calculations.
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
Enhances the accuracy and efficiency of 3D scanning by maximizing the measurement area and reducing ambiguity in element correspondence, facilitating sharper 3D model reconstruction.
Implementation Method 1
a projector configured to project a plurality of non-coded elements onto an object
Implementation Method 2
The first lens focusses a reflection of a first portion of the plurality of non-coded elements onto the first sensor
Implementation Method 3
The first lens focusses a reflection of a first portion of the plurality of non-coded elements onto the first sensor
Data Source
AI summary
A system includes a projector configured to project a plurality of non-coded elements onto an object, the projector having a first optical axis. The system includes a first camera having a first lens and a first sensor. The first lens defines a second optical axis. The system includes a second camera having a second lens and a second sensor. The second lens defines a third optical axis. The projector, the first camera, and the second camera are disposed on a substantially straight line in a first direction. The first optical axis is substantially parallel to the second optical axis, which is substantially parallel to the third optical axis. A center of the first sensor is displaced along the first direction away from the second optical axis, and a center of the second sensor is displaced along the first direction away from the third optical axis.