Multi-Lens Imaging Distortion Correction for Component Mounting
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Solution Overview
Problem
Existing component mounting machines face challenges in accurately recognizing the positions of both components and fiducial marks due to combined distortion from different lenses, leading to inaccurate image recognition and mounting.
Innovation Solution
The method involves configuring an imaging system with a first imaging region using a first lens and a second imaging region using both the first and second lenses, where distortion values for each region are measured and stored, allowing for correction of images captured in both regions to suppress distortion and improve accuracy in recognizing the holding state of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a second lens with smaller diameter is installed in the visual field of the first lens to focus on fiducial marks at different height, then both the component and fiducial marks can be imaged at the same time, but combined distortion arises due to different distortion characteristics of each lens causing complex distortion in the captured image
Solution Approach 1:
The imaging system is divided into two separate imaging systems: a first imaging system using only the first lens for imaging the component, and a second imaging system using both the first and second lenses for imaging the fiducial marks. This segmentation allows each imaging system to be optimized independently, avoiding the combined distortion problem while maintaining the ability to image both components and fiducial marks simultaneously.
Solution Approach 2:
The patent introduces an intermediary processing step that captures images from both imaging systems, detects the position of fiducial marks through the second imaging system, and uses this information to correct the position data of components captured by the first imaging system. This intermediary position correction mechanism resolves the distortion issue by separating the imaging paths while maintaining coordinated position recognition.
2Device complexity
If a single lens is used to image both the component and fiducial marks, then the imaging system is simpler, but it is not possible to focus on both objects at different heights simultaneously
Solution Approach 1:
The imaging system is segmented into two independent imaging paths: the first imaging system focuses on the component plane using the first lens, while the second imaging system focuses on the fiducial marks plane using both lenses. This segmentation enables simultaneous imaging of objects at different heights without requiring a complex variable-focus lens system.
Solution Approach 2:
The first lens serves a dual function by being part of both the first imaging system (for component imaging) and the second imaging system (for fiducial mark imaging). This multi-functionality allows the system to achieve simultaneous imaging capability without proportionally increasing the total number of lenses required.
3Productivity
If distortion correction is not performed in multi-lens systems, then the processing is simpler and faster, but the position recognition of both component and fiducial marks becomes inaccurate
Solution Approach 1:
The patent performs preliminary distortion correction by capturing images of a distortion measurement object through both imaging systems, calculating distortion characteristics in advance, and storing correction data. This preliminary action allows the actual component imaging to proceed with pre-computed correction parameters, maintaining both speed and accuracy.
Solution Approach 2:
The system implements feedback-based distortion correction where the position of fiducial marks detected through the second imaging system is used to verify and refine the distortion correction applied to component images from the first imaging system. This feedback mechanism ensures accurate position recognition while maintaining efficient processing through iterative optimization.
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 more accurate recognition and correction of images, leading to improved component mounting precision and reduced mounting faults by effectively addressing distortion issues in multi-lens systems.
Implementation Method 1
an imaging means which is configured to have a first imaging region in which an object forms an image on an image sensor through a first lens and a second imaging region in which an object forms an image on the image sensor through the first lens and a second lens
Data Source
AI summary
A component mounting machine includes a part camera in which a suction nozzle for sucking a component P and a fiducial mark are provided on a head, a sub-lens is installed in a visual field of a lens, the component is imaged through a main lens, and it is possible to image the fiducial mark through the lens and the sub-lens. Distortion correction values of the main lens portion are measured, distortion correction values of the sub-lens portion are measured, and the distortion correction values are stored in advance as a distortion correction table. During component mounting, when the component P which is sucked by the suction nozzle and the fiducial mark are imaged at the same time by the part camera, the obtained image is corrected using the distortion correction table, and a suction state of the component P is detected based on the corrected image.