Line Sensor Calibration Using Reference Plate Rotation
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Solution Overview
Problem
Conventional methods for calibrating two line sensors to measure the distance between a photoconductor and a developing roller in electrophotography are costly and difficult to perform, requiring a marker with absolute coordinates, which complicates the calibration process.
Innovation Solution
A data processing apparatus and method that aligns the coordinate planes of two line sensors by measuring a reference plane plate at multiple positions, calculating the angle and relative position between the sensors' coordinate axes, allowing for calibration on the same coordinate system without the need for absolute markers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a marker with absolute coordinates is used for calibration, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive, complex absolute coordinate markers with a simple, inexpensive planar reference object that has known geometric features. This reference object can be a simple plate or surface with identifiable features rather than requiring precision-manufactured markers with pre-defined absolute coordinates, significantly reducing cost and complexity while maintaining calibration accuracy
Solution Approach 2:
The patent creates a virtual model of the reference object's position and orientation by capturing images from multiple cameras at different positions. Instead of requiring physical absolute coordinate markers, the system copies the geometric relationships into a computational model that can be used for calibration, eliminating the need for expensive physical markers
2Measurement precision
If two line sensors are used to measure the distance between photoconductor and developing roller, then measurement capability is improved, but coordinate system alignment becomes complex
Solution Approach 1:
The patent introduces a common reference object that both line sensors can measure as an intermediary element. This reference object serves as a mediator to establish the spatial relationship between the two sensors' coordinate systems. By measuring the same reference object from different positions, the system can calculate transformation parameters without requiring direct complex alignment procedures
Solution Approach 2:
The patent moves the calibration problem from a 2D coordinate alignment challenge to a 3D spatial relationship problem. By taking measurements from multiple positions (adding the temporal/dimensional dimension of multiple viewpoints), the system can compute the relative orientation and position of the two line sensors through stereo-calibration-like calculations, simplifying the alignment process
3Ease of operation
If conventional laser width measurement method is used, then simplicity is maintained, but adaptability to multiple developing rollers is lost
Solution Approach 1:
The patent develops a universal measurement approach using line sensors and reference object calibration that can be applied to any number of developing rollers. The system measures the positions of multiple developing rollers and the photoconductor simultaneously by taking images from multiple positions and performing stereo-calibration calculations, making it adaptable to configurations with one, two, or more developing rollers without requiring different measurement methods
Data Source
AI summary
A data processing apparatus processes measured data obtained from a first line sensor and a second line sensor. The data processing apparatus includes a hardware processor. The hardware processor is configured to obtain measured data from the first line sensor and the second line sensor, and a reference plane plate is measured in two or more positions differed by rotation around an axis orthogonal to the first coordinate plane and the second coordinate plane. The hardware processor is configured to calculate an angle between the same coordinate axes in the first coordinate plane and the second coordinate plane and a relative position of an origin of the first coordinate plane and an origin of the second coordinate plane based on measured data obtained from the first line sensor and the second line sensor in the two or more positions of the reference plane plate.