Multi-Lens Module Alignment via Calibration Object
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Solution Overview
Problem
Precise alignment of optical axes and lens centers in multi-lens modules during manufacturing is challenging due to their invisible nature, making it difficult to ensure parallelism and perpendicularity, which is crucial for high-quality image capturing devices.
Innovation Solution
A method and system that utilize a calibration object and target object to generate calibration parameter sets for each lens, allowing for image processing to create rectified images, which are then used to adjust and align the lenses using a lens adjusting mechanism, ensuring precise alignment based on intrinsic and external parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional inspection methods are used to check optical axes and lens centers, then the inspection process is simple, but the alignment precision cannot be ensured because optical axes and lens centers are invisible
Solution Approach 1:
The patent introduces a calibration object with known geometric features (such as a plane with multiple markers at precise positions) as an intermediary medium. This calibration object serves as a mediator between the invisible optical parameters (optical axes, lens centers) and the visible measurement system. By capturing images of this calibration object with each lens and comparing the captured positions against the known positions, the system can calculate and determine the precise locations of optical axes and lens centers without directly observing them.
Solution Approach 2:
The patent creates a virtual copy or model of the calibration object's coordinate system in the image space. By establishing correspondence between the real-world calibration object coordinates and their captured image coordinates, the system constructs a mathematical model that allows indirect measurement of optical parameters. This copying approach transforms the invisible optical geometry into a visible and measurable coordinate transformation problem.
2Measurement precision
If visual inspection is used to determine optical axis parallelism and lens center perpendicularity, then the inspection method is simple, but the measurement precision is insufficient due to the invisible nature of these optical elements
Solution Approach 1:
The calibration object acts as a mediator that translates the invisible optical parameters into measurable quantities. By placing markers with known positions on the calibration object and capturing their images through each lens, the system can compute the optical axis positions and orientations mathematically. The calibration object bridges the gap between what cannot be seen (optical axes) and what can be measured (marker positions in images).
Solution Approach 2:
The patent replaces traditional mechanical alignment tools and visual inspection methods with an optical-mathematical measurement system. Instead of using physical alignment fixtures or subjective visual judgment, the system uses image capture, coordinate transformation, and mathematical calculation to precisely determine optical parameters. This substitution enables objective, quantitative, and high-precision measurement of previously inaccessible optical properties.
Data Source
AI summary
The disclosure provides a method and a system for multi-lens module alignment, adapted to perform alignment on a multi-lens module having at least a first lens and a second lens during its manufacturing stage, where the method includes the following steps. A calibration object is first captured by using the first lens and the second lens to accordingly generate intrinsic parameters and external parameters of the first lens and the second lens, where the external parameters of the first lens and the second lens are associated with a common reference coordinate system. A target object is next captured by using the first lens and the second lens, and captured images of the target object are processed by using the intrinsic parameters and the external parameters to generate rectified images. The first lens and the second lens are adjusted and aligned according to the rectified images.