Quasi-3D Tracking with Angled 2D Optical Sensors
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Solution Overview
Problem
User input devices, such as trackballs, are deficient in tracking rotational components of motion, particularly polar rotations and azimuthal rotations, due to limitations in detecting speckle pattern translations or imaging correlations, which result in 'blind spots' in motion detection.
Innovation Solution
The implementation of multiple 2D sensor apparatus positioned strategically, either in a full quasi 3D configuration or with a single sensor at an angle, to effectively track changes in spherical coordinates, including polar and azimuthal rotations, by combining measurements from multiple sensors or restricting user-accessible areas to enhance detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single 2D optical motion sensor is used, then the device structure is simple, but it cannot detect rotational components (polar and azimuthal rotations) resulting in blind spots in motion detection
Solution Approach 1:
The patent divides the sensing function into multiple 2D optical motion sensors positioned at different locations or orientations. Each sensor detects specific motion components, and together they cover all rotational degrees of freedom, eliminating blind spots while maintaining the simplicity of individual 2D sensors
Solution Approach 2:
The patent transitions from a single 2D sensor plane to a multi-sensor spatial arrangement that effectively creates 3D motion detection capability. By positioning sensors at different angles or locations, the system detects rotational components that would be invisible to a single 2D sensor, achieving quasi-3D tracking without requiring a fundamentally different sensing approach
2Measurement precision
If multiple 2D sensor apparatus are positioned strategically, then rotational components can be detected accurately, but the device complexity increases
Solution Approach 1:
The patent makes each 2D sensor apparatus multi-functional by strategically positioning them so that each sensor contributes to detecting multiple motion components. The sensors are arranged to detect both translational and rotational movements, allowing the system to achieve comprehensive motion tracking with relatively simple individual sensor units
Solution Approach 2:
The patent combines measurements from multiple 2D sensors to achieve accurate 3D motion tracking. By merging the detection data from sensors positioned at different locations or orientations, the system reconstructs full motion information including rotational components, achieving high measurement precision through data integration rather than through complex individual sensors
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
Enables accurate tracking of full quasi 3D motions, eliminating motion blind zones and improving overall tracking accuracy by detecting previously undetectable rotational components, thereby enhancing user input device performance.
Implementation Method 1
tracking a certain rotational component of any arbitrary motion by a user. This limitation is discussed as follows in relation to FIGS. 1 and 2... tracking either a reflected or a scattered optical signal from the moving surface, which carries the motion information... tracking any speckle pattern translation, or imaging correlation change, or laser frequency Doppler shift
Implementation Method 2
detect either a reflected or a scattered optical signal from the moving surface
Implementation Method 3
The 2D sensor apparatus 204 may include an optical device to generate an optical beam which creates an image spot 206 of radius r′ on the tracking ball
Data Source
AI summary
One embodiment relates to a user input device for tracking motion. The device includes a tracking ball and a user-accessible touching area for user manipulation of the tracking ball. First and second two-dimensional sensors are positioned at tracking heights away from the tracking ball. The first two-dimensional sensor may be positioned across the tracking ball and opposite to the user-accessible touching area. The second two-dimensional sensor may be positioned at an angle with respect to a z-axis defined as extending from the user-accessible touching area through a center of the tracking ball to the first two-dimensional sensor. Other embodiments, aspects and features are also disclosed.