Projector Calibration via Harmonic Analysis for Manufacturing
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Solution Overview
Problem
Manufacturing processes require optimal and rapid focusing and squaring of projected images, which is challenging due to the need for minimal human interaction and efficient image processing in manufacturing environments, particularly for sophisticated parts like ceramic devices.
Innovation Solution
A system for automatic projector calibration that includes a projector, an image sensor positioned at a specified angle, an aperture, and a processing subsystem. The system uses a test pattern to iteratively adjust focus and skew settings by analyzing harmonic frequencies to maximize image focus and square the projected image, utilizing a controller to optimize projector settings automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automatic calibration is implemented to reduce human interaction, then productivity improves, but measurement precision may deteriorate
Solution Approach 1:
The system captures images of the projected test pattern using an imaging device and automatically analyzes them to determine focus and squareness metrics. The controller uses this feedback to iteratively adjust projector settings, achieving both high automation and measurement precision through closed-loop control
Solution Approach 2:
The system replaces manual mechanical adjustment of projector focus and geometry with automated image processing and control algorithms. Software-based analysis of test pattern images substitutes for human visual inspection and manual knob adjustments, maintaining precision while enabling full automation
2Manufacturing precision
If complex image processing is used to achieve optimal focus and squareness, then manufacturing precision improves, but loss of time increases
Solution Approach 1:
The system projects a predefined test pattern with known geometric features before actual manufacturing. This preliminary projection establishes reference information that simplifies subsequent focus and squareness measurements, enabling rapid automated calibration without complex real-time analysis during production
Solution Approach 2:
The system automatically adjusts key projector parameters including focus distance, horizontal shift, vertical shift, and rotation angle based on test pattern analysis. By directly modifying these critical parameters through automated feedback, the system achieves high manufacturing precision efficiently without time-consuming manual optimization
Data Source
AI summary
A system is disclosed including an image sensor positioned at a first specified angle relative to a projected image plane. The system includes a projector that projects a test pattern onto the projected image plane. A controller is structured to iteratively adjust the projector focus until an image focus index is maximized, where the image focus index is a function of an amplitude of at least one harmonic frequency of a scan of the test pattern. The controller is further structured to determine a skew indicator value and adjust a projector skew adjustment. The controller is further structured to compare a current zoom level to a target zoom level and adjust a projector zoom. The projected image plane is a manufacturing surface, where the projected image is utilized in a manufacturing process.