Binocular Telecentric Crystal Sizing Under Refraction Constraints
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Solution Overview
Problem
Existing calibration methods for telecentric systems in glass crystallizers fail to accurately account for lens distortion and refraction effects, leading to ambiguity in external parameters and limited accuracy in three-dimensional crystal size measurement.
Innovation Solution
A method using a non-contact high-resolution backlit calibration pole with a checkerboard pattern and binocular telecentric cameras for in situ calibration, combined with a two-step stereo imaging calibration model and simplified epipolar rectification, enables precise three-dimensional length and width measurement of crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing calibration methods for telecentric systems are used in glass crystallizers, then the calibration process can be performed, but measurement precision deteriorates due to unaccounted lens distortion and refraction effects
Solution Approach 1:
The patent introduces a calibration rod with a reflective surface as an intermediary object placed inside the glass crystallizer. This calibration rod serves as a mediator that accounts for both lens distortion and refraction effects by providing known geometric features (reflection points) that can be used to calculate and correct measurement errors in the telecentric imaging system
Solution Approach 2:
The patent changes the calibration approach by incorporating refraction index parameters and lens distortion parameters into the calibration model. By adjusting and optimizing these parameters through the calibration rod measurements, the system achieves accurate compensation for optical distortions and refraction effects in the glass crystallizer environment
2Measurement precision
If complex calibration methods are used to account for lens distortion and refraction, then measurement precision improves, but device complexity increases
Solution Approach 1:
The calibration rod is designed to be self-contained with integrated reflective surfaces and known geometric features. The system performs self-calibration by using the calibration rod's inherent geometric properties to automatically determine and correct for lens distortion and refraction parameters without requiring external complex calibration equipment or manual intervention
Solution Approach 2:
The patent extracts the calibration functionality into a separate, removable calibration rod that can be independently placed and removed from the crystallizer. This extraction allows the complex calibration process to be isolated from the main measurement system, simplifying the overall device while maintaining high measurement precision through dedicated calibration hardware
3Ease of manufacture
If traditional calibration methods are used, then the calibration process is simpler, but measurement precision deteriorates due to ambiguity in external parameters
Solution Approach 1:
The patent transitions from traditional two-dimensional planar calibration patterns to a three-dimensional calibration rod with reflective surfaces. This dimensional change provides additional geometric constraints and measurement information that resolve external parameter ambiguity while maintaining calibration simplicity through the rod's straightforward placement and measurement protocol
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
Achieves rapid, accurate, and automated three-dimensional size measurement of crystals in glass crystallizers, overcoming refraction errors and simplifying the calibration process for industrial applications.
Implementation Method 1
the influence of refraction generated by propagation in a cross-medium optical system, such as a glass crystallizer filled with solution
Implementation Method 2
the influence of refraction generated by propagation in a cross-medium optical system, such as a glass crystallizer filled with solution
Data Source
AI summary
A method for real-time detection of length and width size distribution of a crystal population in a glass crystallizer by binocular telecentric cameras. A calibration pole that can extend into an in-situ environment (reactor/glass tube) is designed; a binocular telecentric stereo vision imaging model is established; a simple calibration method of a rotating calibration pole suitable for an in-situ limited space and a calibration plate design solution are proposed. A simplified telecentric stereo epipolar rectification method is also provided to ensure the accurate matching of in situ snapshot image pairs. A three-dimensional reconstruction method by ray intersection based on analytical solutions is provided to measure the three-dimensional postures of particles in a crystallizer. Finally, the three-dimensional length and width are quantitatively evaluated through the statistical data of the Euclidean distances of length and width feature point pairs of crystals.