Camera-Based Multi-Touch Illumination Using Fan-Shaped Light Beams
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Solution Overview
Problem
Current camera-based multi-touch interactive systems face challenges in accurately detecting finger or pen touching, hovering, and posture recognition, especially in diverse lighting conditions and across various display technologies, with a need for high precision and adaptability to different interaction surfaces and formats.
Innovation Solution
A camera-based multi-touch interaction system utilizing planar fan-shaped light beams of visible and/or near-infrared light, combined with a camera arrangement and computational unit, to enhance position and posture determination by ensuring constant light intensity and reducing sensitivity to ambient light, allowing for dual-mode finger and pen input, and capturing gestures on various interactive surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional camera-based tracking systems are used to detect finger or pen touching, then the system can capture basic position information, but the detection precision is insufficient under diverse lighting conditions and across various display technologies
Solution Approach 1:
The system changes the wavelength parameter of light by using near-infrared illumination instead of visible light. This parameter change allows the system to operate independently of ambient visible lighting conditions and works across different display technologies, thereby improving both detection precision and adaptability simultaneously
Solution Approach 2:
The patent introduces an intermediary near-infrared illumination system between the camera and the interaction surface. This intermediary provides controlled lighting that enables precise detection without being affected by ambient light variations, resolving the contradiction between precision and adaptability
2Reliability
If multiple camera viewpoints are used to reduce occlusion susceptibility and improve robust tracking, then the measurement reliability improves, but the device complexity increases
Solution Approach 1:
The patent transitions from two-dimensional planar illumination to three-dimensional volumetric illumination using focused fan-shaped light beams. This dimensional change allows single-camera detection to achieve reliability previously requiring multiple cameras, as the volumetric illumination provides depth information and reduces occlusion effects
Solution Approach 2:
The system replaces the mechanical approach of using multiple physical cameras with an optical field approach using focused volumetric illumination and single-camera detection. This substitution achieves similar or superior reliability with reduced device complexity
3Measurement precision
If feature extraction methods are used to determine finger posture and touch detection, then the system can provide basic interaction capability, but the precision in distinguishing between hovering and touching states is insufficient
Solution Approach 1:
The system uses near-infrared wavelength illumination to change the optical parameter, enabling precise detection of interaction states. The wavelength-specific illumination provides consistent contrast between hovering and touching states regardless of ambient lighting, improving both precision and response accuracy
Solution Approach 2:
The illumination system operates in periodic pulses synchronized with the camera frame rate. This periodic action allows for precise timing measurements that can distinguish between hovering and touching states based on light reflection timing, enhancing detection precision and interaction response 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 system achieves accurate and robust detection of touch and hover conditions, as well as posture recognition, with improved precision and adaptability to different lighting conditions and display technologies, enabling advanced multi-modal human-computer interaction across various surfaces and formats.
Implementation Method 1
an illuminant arrangement for generating one or more planar fan-shaped light beams of visible and/or near-infrared light radiation
Implementation Method 2
a camera arrangement for sensing the interaction surface within the camera's field-of-view to generate corresponding signals
Data Source
AI summary
A method, system and apparatus is provided for controlling and interacting within an interaction volume and/or surface of a computer. The method, apparatus and system is optionally employed together with, or even be integrated into, data projectors of all types and its fixtures/stands, and used together with flat screens (LCD, plasma, OLED, rear-projection screen and so forth) to render such display systems interactive. The apparatus incorporates a camera covering the interaction area from either a very short distance or from a larger distance to determine the lateral positions (X, Y) and even capturing the pose of the finger(s), hand(s) or other interacting object(s), which optionally include the determination of “touch” and “hovering”.