Position Detection Device Using Dual-Wavelength Imaging
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Solution Overview
Problem
Existing interactive projectors face challenges in accurately detecting the position of a pointing unit due to the difficulty in distinguishing the shadow of the pointing unit from the unit itself, leading to inaccurate position detection when their boundaries overlap.
Innovation Solution
The use of a position detection device with a first illumination device casting first light and a second illumination device casting second light of different wavelengths, combined with a first image pickup device sensitive to the first light and a second image pickup device sensitive to the second light, positioned differently to detect the object's contact with the operation surface by ensuring their specified positions are within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image pickup device is used to detect the pointing unit, then the device complexity is reduced, but the measurement precision of the pointing unit position deteriorates due to shadow interference
Solution Approach 1:
The system divides the detection task into two separate image pickup devices, each capturing images from different positions. The first image pickup device captures the pointing unit without shadow interference, while the second captures the shadow. By segmenting the detection function, the system eliminates the trade-off between device simplicity and measurement precision.
Solution Approach 2:
The solution transitions from a single viewpoint detection to multi-viewpoint detection by positioning image pickup devices at different locations. This dimensional change in observation perspective allows simultaneous acquisition of both the pointing unit and its shadow, enabling precise position determination through spatial relationship analysis.
2Illumination intensity
If the shadow of the pointing unit is used for detection, then the illumination requirement is simplified, but the measurement precision deteriorates due to difficulty in discriminating the shadow from the pointing unit
Solution Approach 1:
The system segments the detection targets by using two image pickup devices positioned at different locations. One device is optimized for capturing the pointing unit while the other captures the shadow, allowing clear discrimination between the two without complex illumination schemes.
Solution Approach 2:
The system introduces a spatial relationship as an intermediary for detection. By analyzing the positional relationship between the pointing unit and its shadow across multiple viewpoints, the system can accurately determine contact state without relying solely on shadow intensity or boundary detection.
3Device complexity
If a single viewpoint detection is used, then the device complexity is reduced, but the reliability of contact detection deteriorates when the pointing unit overlaps with its shadow
Solution Approach 1:
The detection function is segmented into multiple viewpoint observations. By capturing images from different positions, the system can distinguish between cases where the pointing unit overlaps with its shadow versus cases where they are separated, significantly improving contact detection reliability.
Solution Approach 2:
The system merges information from multiple image pickup devices to achieve reliable contact detection. By combining the detection results from different viewpoints, the system overcomes the limitations of single-viewpoint detection and maintains high reliability even when the pointing unit overlaps with its shadow.
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
This configuration enhances the accuracy of detecting the position of the pointing unit and its contact with the operation surface by eliminating shadows from the images captured by each device, thereby improving interaction precision.
Implementation Method 1
a first image pickup device picking up an image of the operation surface and the object and having a higher sensitivity to the first light than to the second light
Implementation Method 2
a second image pickup device picking up an image of the operation surface and the object and arranged at a different position from the first image pickup device, the second image pickup device having a higher sensitivity to the second light than to the first light
Data Source
AI summary
A projector includes: an illumination device casting one detection light and another detection light onto an operation surface; a first image pickup device having a higher sensitivity to the one detection light than to the another detection light; a second image pickup device different from the position of the first image pickup device, the second image pickup device having a higher sensitivity to the another detection light than to the one detection light; and a detection device detecting that an object is in contact with the operation surface when a position of a pointing unit specified based on a first picked-up image picked up using the first image pickup device and a position of the pointing unit specified based on a second picked-up image picked up using the second image pickup device are within a predetermined range.