Virtual Image Marker Calibration for Touch Panel Coordinate Accuracy
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Solution Overview
Problem
Existing spatial coordinate input devices require large-scale instruments and complex device configurations for calibration, which can lead to measurement errors and distorted positional relationships of markers.
Innovation Solution
A reference position setting method and operation detection device that display at least three markers on an operation surface, acquire and transform coordinate values using a sensor and coordinate transformation units, performing rotation, parallel movement, and scaling to simplify the device configuration and ensure accurate calibration without additional measurement instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed using optical measurement device with grid plate and pointer, then coordinate correspondence is corrected, but device complexity increases and large-scale instruments are required
Solution Approach 1:
The patent uses a virtual image of the operation surface displayed on a display unit as a copy of the actual operation surface. Markers are displayed on this virtual image, and the sensor detects positions in the virtual space. Coordinate transformation units then map these virtual coordinates to the actual touch panel coordinates, eliminating the need for physical grid plates and optical measurement devices while maintaining calibration accuracy.
Solution Approach 2:
The patent replaces the mechanical/optical calibration system (grid plate, pointer, TV cameras) with an electronic/software-based system. The coordinate transformation units perform mathematical transformations to convert sensor coordinates to screen coordinates, substituting physical measurement instruments with computational methods that achieve the same calibration function with reduced complexity.
2Measurement precision
If optical measurement device with multiple TV cameras is used for calibration, then coordinate transformation is achieved, but device complexity and instrument scale increase
Solution Approach 1:
The display unit serves multiple functions: it displays the operation surface, displays markers for calibration, and provides the virtual image space for sensor detection. The coordinate transformation units perform multiple coordinate system conversions (sensor coordinates to temporary coordinates to screen coordinates). This multi-functionality eliminates the need for separate dedicated calibration instruments.
Solution Approach 2:
The patent creates a virtual copy of the operation surface on the display unit with markers positioned at known locations. The sensor detects marker positions in this virtual space, and through coordinate transformation, these detections are mapped to the actual touch panel. This copying approach replaces complex optical measurement systems with a software-based virtual environment.
3Adaptability or versatility
If large-scaled calibration instruments are provided, then coordinate system transformation is possible, but device configuration becomes complex and space-consuming
Solution Approach 1:
The patent introduces a virtual dimension by displaying the operation surface and markers as a virtual image on the display unit. The sensor operates in this virtual space, and coordinate transformation units bridge the virtual dimension with the physical touch panel dimension. This dimensional approach allows calibration without physical grid plates in real space.
Solution Approach 2:
The coordinate transformation units act as intermediaries that convert coordinates between different reference systems. They transform sensor-detected coordinates in the virtual space to screen coordinates on the touch panel through mathematical transformations, eliminating the need for direct physical measurement instruments.
Data Source
AI summary
A reference position setting method includes: a process of displaying at least three markers on an operation surface; a process of acquiring coordinate values of a sensor coordinate system; a process of transforming the acquired coordinate value into coordinate values of a temporary coordinate system; and a process of transforming the transformed coordinate values into coordinate values of a screen coordinate system. At least one of parallel movement and rotation is performed with respect to the sensor coordinate system to transform the sensor coordinate system into the temporary coordinate system. Movement of the temporary coordinate system in a direction parallel to a plane including a second X-axis and a second Y-axis, and enlargement or reduction of the temporary coordinate system are performed to transform the temporary coordinate system into the screen coordinate system.