Position Input Device Head-Tracking Coordinate Transformation
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Solution Overview
Problem
Existing non-contact position input devices face challenges in accurately detecting the intended position while maintaining good operability, often leading to deterioration due to the detection of unintended movements.
Innovation Solution
A position input device that includes a coordinate system setting unit, transformation matrix calculation unit, transformation matrix update unit, and indication straight line calculation unit, which sets a second coordinate system based on the operator's head position, calculates and updates a transformation matrix, and determines whether to update it based on the fingertip's position relative to the operator's line of sight, to accurately detect the pointed position without unnecessary movement detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position input device continuously detects and responds to fingertip movements, then the measurement precision of position input is improved, but the operability deteriorates due to detection of unintended movements
Solution Approach 1:
The patent changes the parameter of transformation matrix update based on the spatial relationship between the fingertip and the operator's line of sight. By calculating whether the fingertip is within a predetermined angle range from the line of sight, the system dynamically adjusts whether to update the transformation matrix, thereby filtering out unintended movements while preserving intentional input accuracy
Solution Approach 2:
The patent introduces an intermediary judgment mechanism (the angle range check) between the raw fingertip position detection and the transformation matrix update. This intermediary step acts as a filter that determines whether a detected movement should trigger a transformation matrix update, preventing direct response to unintended movements while maintaining response to intentional input
2Adaptability or versatility
If the transformation matrix is updated frequently to track head movements, then the adaptability to operator position changes is improved, but the reliability deteriorates due to false detection of movements
Solution Approach 1:
The patent changes the update condition of the transformation matrix from continuous to conditional based on the angle parameter. By checking whether the fingertip falls within a predetermined angle range from the line of sight, the system selectively updates the transformation matrix only when the movement is likely intentional, thereby improving reliability while maintaining adaptability
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the spatial relationship between the fingertip and the line of sight, and uses this feedback information to control the transformation matrix update. This feedback loop ensures that updates occur only when justified by the operator's intentional movement, preventing false detection
Data Source
AI summary
A position input device includes a coordinate system setting unit that uses position and orientation of the head of an operator in a first coordinate system to set a second coordinate system in a space including the operator, where a position on the face of the operator is designated as an origin, a transformation matrix calculation unit that calculates a transformation matrix from the first to the second coordinate system, a transformation matrix update unit that updates the transformation matrix according to a result obtained by transforming a coordinate indicating a position of the fingertip of the operator in the first coordinate system with the transformation matrix, and an indication straight line calculation unit that calculates a straight line passing through the origin of the second coordinate system and the position of the fingertip based on the transformation matrix and the position of the fingertip in the first coordinate system.