Position Detection Device Using Reflected Light Distance Correction
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Solution Overview
Problem
Existing position detection systems struggle to accurately detect the indication position of an indicator on an operation surface when using reflected light, as the detected position may not match the actual indication position due to positional relationships between the imaging unit and the operation surface.
Innovation Solution
A position detection device and method that includes an imaging unit to capture images of the operation surface, a detection unit to identify the indication position based on reflected light and the distance between the operation surface and the imaging unit, and a calibration control unit to generate distance data for accurate position correction, allowing for quick and precise detection of the indication position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If position detection is performed using reflected light from an indicator, then the detection method is simpler and can be used with various indicators, but the detected position does not match the actual indication position on the operation surface
Solution Approach 1:
The patent replaces direct mechanical/optical contact detection with a light field-based detection system. Detection light is emitted along the operation surface, and the imaging unit captures reflected light from the indicator to determine position, eliminating the need for direct contact between the imaging unit and the operation surface while maintaining detection accuracy through coordinate transformation.
Solution Approach 2:
The patent introduces a third dimension (distance from operation surface) to resolve the position detection problem. By detecting the distance between the imaging unit and the operation surface, and using coordinate transformation based on this distance, the system accurately maps the reflected light position to the corresponding position on the operation surface, solving the accuracy issue while maintaining versatility.
2Measurement precision
If the imaging unit is positioned close to the operation surface for accurate detection, then detection accuracy improves, but the device structure becomes more complex and installation becomes difficult
Solution Approach 1:
The patent replaces the mechanical constraint of close positioning with an optical-mathematical solution. The imaging unit can be positioned at any distance from the operation surface, and accurate position detection is achieved through coordinate transformation that incorporates the measured distance, eliminating installation complexity while maintaining detection accuracy.
Solution Approach 2:
The patent makes the detection system dynamic by allowing the imaging unit to be positioned flexibly at various distances from the operation surface. The system dynamically adjusts the coordinate transformation based on the measured distance, enabling accurate detection regardless of the imaging unit's position, thus reducing installation complexity.
3Measurement precision
If distance measurement and coordinate transformation are performed in real-time for each detection, then detection accuracy is maintained, but detection speed decreases
Solution Approach 1:
The patent performs preliminary measurement of the distance between the imaging unit and the operation surface, and pre-calculates the coordinate transformation parameters. This preliminary action allows subsequent position detections to use the pre-established transformation relationship, maintaining accuracy while significantly improving detection speed by avoiding repeated complex calculations.
Solution Approach 2:
The system establishes a self-service mechanism where the measured distance and coordinate transformation parameters are stored and reused for multiple detection operations. Once the transformation relationship is established, the system can quickly detect multiple positions without repeating the full measurement and transformation process, thereby improving detection speed while maintaining accuracy.
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
The solution enables accurate detection of the indication position by correcting for positional relationships, ensuring that the detected position aligns with the actual indication on the operation surface, even when the reflection position of detection light differs from the operation surface, thereby improving detection accuracy and speed.
Implementation Method 1
the detection unit detects reflected light of detection light reflected by the indicator from the captured image of the imaging unit
Data Source
AI summary
A projector includes an imaging unit which images a screen SC, and a position detection unit which detects an indication position of an indicator based on a captured image of the imaging unit. The position detection unit detects reflected light of detection light reflected by the indicator from the captured image of the imaging unit and obtains the indication position of the indicator based on the position of the reflected light detected from the captured image and the distance between the screen SC and the imaging unit.