Camera Self-Calibration via Mirror Reflection
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Solution Overview
Problem
Current methods for absolute length measurement in images, such as using monocular or stereo cameras, require calibration objects or pre-calibrated setups, which can be cumbersome and limit user-friendly, self-controlled measurements, especially for applications like body measurement where precise calibration is needed without external aids.
Innovation Solution
A method using a single monocular camera device that calibrates absolute length by leveraging its own dimensions, such as lens diameter or screen size, and optional angular information from built-in sensors like gyroscopes, allowing seamless calibration without external objects or user input, by projecting the camera's characteristics onto the image and calculating pixel size adjustments based on metadata and image analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external calibration objects or pre-calibrated setups are used for absolute length measurement, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The camera device performs self-calibration by capturing an image of itself in a mirror and automatically determining its dimensions and characteristics from the captured image, eliminating the need for external calibration objects or pre-calibrated setups. The device uses its own reflected image as the calibration reference.
Solution Approach 2:
The camera device creates a copy of itself through mirror reflection and uses this optical copy as the calibration object. The reflected image serves as a self-generated reference that contains all necessary dimensional information for calibration, replacing traditional external calibration artifacts.
2Measurement precision
If external calibration objects are required for absolute length measurement, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The system automatically captures the camera's reflected image and performs calibration without requiring user intervention to position or register external calibration objects. The calibration process is initiated and completed autonomously by the camera device itself.
Solution Approach 2:
The calibration function is extracted from the traditional external calibration object framework and integrated directly into the camera device's self-calibration process. The device extracts its own dimensional information from its reflected image, eliminating the need for separate calibration artifacts.
3Measurement precision
If traditional monocular or stereo calibration methods are used, then absolute length measurement capability is achieved, but adaptability deteriorates due to requirement of calibration objects
Solution Approach 1:
The self-calibration mechanism using mirror reflection is a universal approach that can be applied to any camera device regardless of its specific application. The same calibration method works for body measurement, object measurement, and other applications without requiring application-specific calibration objects or procedures.
Solution Approach 2:
The camera device autonomously performs calibration for any measurement application it encounters, adapting to different scenarios without requiring external calibration aids. The self-service calibration makes the system versatile across multiple applications including body measurement, object measurement, and spatial mapping.
Data Source
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AI summary
The invention relates to a method of performing an absolute length calibration for an object (20) located with or covered by a camera device (15) in a mirror (10), the method comprising the steps of determining dimensions of the camera device (15) based on the type of the camera device (15), capturing an image of the camera device (15) with an image of the object (20) with the camera device (15), measuring a length on the image of the object (20) and measuring dimensions of the camera device (15) from the captured image, and using the determined dimensions of the camera device (15), the measured length of the image of the object (20) and the measured dimensions of the camera device (15) to calibrate the length of the object (20).