Multi-camera Surface Topography System for Blind Hole Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current non-contact three-dimensional measurement technologies in Automatic Optical Inspection (AOI) are limited by their narrow field of view and mechanical motion range, making it time-consuming to measure deep or large structures like blind holes, and they do not provide 2D color images of the surface.
Innovation Solution
A surface topography optical measuring system with multiple image capture modules, each equipped with an electronically controlled focal length tunable lens and optical assembly, captures images at different heights, allowing for simultaneous measurement of height differences across the surface, including deep or large structures, while providing 2D color images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-point three-dimensional measurement technologies are used, then accurate depth measurements are obtained, but no two dimensional image of the surface is provided and time-consuming two dimensional scanning is required
Solution Approach 1:
The system divides the measurement task into multiple parallel operations by using a multi-camera array, where each camera captures depth information for a specific region simultaneously, eliminating the need for sequential scanning while maintaining measurement accuracy
Solution Approach 2:
The system transitions from single-point depth measurement to multi-point simultaneous measurement by adding spatial dimensionality through multiple cameras arranged in an array, capturing both 2D surface images and 3D depth information in parallel
2Loss of information
If focus based three-dimensional measurement approaches are used, then two dimensional images and spectral information are provided, but the field of view and mechanical motion range are limited
Solution Approach 1:
The measurement field is segmented into multiple regions, each captured by a dedicated camera in the array, allowing the system to cover a large overall area while each individual camera maintains its optimal field of view and focuses on its assigned region
Solution Approach 2:
The system merges the capabilities of multiple cameras into a unified measurement system, combining their individual fields of view to achieve a large overall coverage area while preserving the spectral information and focusing capabilities of each camera
3Area of stationary object
If scanning is performed to measure structures larger than the system's field of view, then complete surface coverage is achieved, but the measurement process becomes time consuming
Solution Approach 1:
The large surface area is segmented into multiple smaller regions, each captured simultaneously by a different camera in the array, eliminating the need for time-consuming sequential scanning while achieving complete surface coverage
Solution Approach 2:
The system performs continuous simultaneous measurement across the entire surface area using multiple cameras operating in parallel, maintaining continuous useful action without the interruptions and time delays associated with sequential scanning
4Length of stationary object
If long range motion along the Z axis is implemented to measure deep structures, then the full depth range is covered, but the system complexity and measurement time increase
Solution Approach 1:
The depth measurement range is segmented across multiple cameras positioned at different heights, with each camera responsible for measuring a specific depth range, thereby extending the overall measurement capability without requiring any single camera to perform long-range motion
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
Enables fast and accurate three-dimensional measurements of complex structures, including those beyond the traditional field of view, by capturing images within focusing ranges of individual modules, reducing measurement time and improving surface topography analysis.
Implementation Method 1
Each of the plurality of image capture modules includes an electronically controlled focal length tunable lens
Data Source
AI summary
A surface topography optical measuring system including image capture modules, a control module and a computation module is provided. Each image capture module includes an electronically controlled focal length tunable lens, an optical assembly and an image sensor, wherein the image capture modules respectively capture images at different heights between a lowest and a highest surfaces of an object. The control module is coupled to the image capture modules to independently control the image capture modules. The computation module is coupled to the control module and the image sensor of each image capture module, wherein the computation module perform calibration of the surface topography optical measuring system and assesses in-focused pixels in the captured images to measure a height difference between a highest and a lowest surfaces of the object or between any surfaces of interest of the object. A surface topography optical measuring method is also provided.