Camera Module Alignment via Optical Parameter Matrices
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Solution Overview
Problem
Conventional camera module aligning methods for portable electronic devices are inaccurate due to mechanical surface tolerances and rely on non-quantitative trial-and-error processes, failing to ensure precise installation position and posture for high-resolution and wide-angle imaging.
Innovation Solution
A camera module aligning method that uses internal and external parameter matrices to determine the correct installation position and posture by shooting a reference chart with characteristic points, employing mathematical formulas to establish a standard relationship between image and chart coordinates, allowing for precise calibration through maximum likelihood estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional automated optical inspection (AOI) with third-party camera module is used for identification, then the aligning process can be automated, but the accuracy is insufficient due to mechanical surface tolerance
Solution Approach 1:
The patent replaces the conventional mechanical surface-based AOI alignment method with an optical parameter-based alignment method. By using intrinsic optical parameters (focal length, principal point) and extrinsic parameters (rotation and translation) of the camera module, the system achieves precise alignment without relying on mechanical surface tolerances. The alignment is accomplished through mathematical calculation of coordinate transformations between the reference chart and captured image, substituting mechanical measurement with optical-mathematical computation.
2Ease of manufacture
If non-quantitative trial-and-error alignment method is used, then the process is simpler to implement, but the alignment precision is insufficient for high-resolution imaging
Solution Approach 1:
The patent transforms the alignment process from a qualitative trial-and-error method to a quantitative parameter-based method. By introducing internal parameters (focal length f, principal point coordinates u0, v0) and external parameters (rotation matrix R, translation matrix T), the system enables precise calculation of the camera module's installation position and posture. The coordinate transformation formula q=K[R|T]Q provides a mathematical framework that directly computes the correct alignment parameters, replacing iterative trial-and-error with direct calculation.
3Reliability
If repeated trial-and-error procedures are performed to complete alignment, then the alignment can be achieved, but the production time is increased
Solution Approach 1:
The patent performs preliminary calibration to obtain the camera module's intrinsic optical parameters before the actual alignment process. By pre-determining the focal length, principal point, and other optical characteristics through calibration shots of a reference chart, the system eliminates the need for repeated trial-and-error during production. The pre-established parameter matrices enable direct calculation of alignment position and posture, significantly reducing production time while maintaining high accuracy.
Data Source
AI summary
A camera module aligning method includes the following steps. Firstly, a reference chart having plural chart characteristic points is provided. Then, a camera module is used to shoot the reference chart, and an installation position and an installation posture of the camera module are acquired according to an internal parameter matrix and an external parameter matrix. When the camera module shoots the reference chart and an image is formed on an imaging plane of the camera module, a relationship between at least one image characteristic point of the image and the corresponding chart characteristic point complies with a standard relationship. The standard relationship is defined by the internal parameter matrix and the external parameter matrix.