Fingertip Identification Using Relative Finger Position Analysis
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Solution Overview
Problem
Existing multi-touch input devices struggle to accurately differentiate between fingertip and non-fingertip contacts, such as joint parts, when multiple fingers are in contact with or proximity to the operation surface, leading to incorrect recognition of touch areas.
Innovation Solution
An information processing device and method that determines the presence of non-fingertips based on the relative positional relationships among three or more fingers, using threshold values for distance variations and evaluation of finger arrangement patterns to distinguish between fingertip and non-fingertip contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-touch detection is implemented to detect contact positions of multiple fingers, then input operation variety and convenience are improved, but erroneous recognition of non-fingertip contacts (such as joint parts) increases
Solution Approach 1:
The patent applies local quality by analyzing the characteristics of each detected contact point individually. It determines whether each contact is a fingertip or non-fingertip based on local properties such as contact area size, contact position, and spatial relationships with other contacts. This allows the system to maintain multi-touch functionality while accurately distinguishing between valid fingertip inputs and erroneous non-fingertip contacts.
Solution Approach 2:
The patent segments the detection process into multiple stages: first detecting all contact positions, then classifying each contact as fingertip or non-fingertip based on specific criteria (contact area, position, spatial relationships), and finally processing only the valid fingertip contacts. This segmentation allows the system to handle complex multi-contact scenarios while maintaining high recognition accuracy.
2Reliability
If contact area size is used to distinguish palm from fingertip, then palm contact misrecognition is reduced, but joint part contacts are incorrectly identified as valid fingertip touches
Solution Approach 1:
The patent adds another dimension to the analysis by considering not only the contact area size (one dimension) but also the spatial arrangement of multiple contacts and their relative positions (additional dimensions). When multiple contacts are detected, the system analyzes the geometric relationships between them to determine whether they form a natural fingertip configuration or represent a joint part contact, thereby resolving the ambiguity that arises when relying solely on contact area size.
Solution Approach 2:
The patent merges multiple detection criteria into a unified judgment system. It combines contact area analysis, spatial position evaluation, and relative positional relationship assessment to make a comprehensive determination about whether a contact is a valid fingertip touch. This merging of criteria allows the system to overcome the limitations of individual criteria and achieve more accurate recognition.
3Device complexity
If simple contact detection is used, then device complexity is reduced, but accurate differentiation between fingertip and non-fingertip contacts becomes difficult
Solution Approach 1:
The patent applies self-service by using the detection system's own output data (contact positions, contact areas, spatial relationships) to automatically classify contacts as fingertip or non-fingertip. The system processes its own detection results through algorithmic analysis, eliminating the need for external intervention or complex additional hardware. This self-service approach maintains system simplicity while achieving reliable differentiation.
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
Accurately identifies non-fingertip contacts, preventing misrecognition and ensuring correct operation identification even when joints or other parts of fingers unintentionally come into contact with the surface during single-finger operations.
Implementation Method 1
A multi-touch digitizer system that detects a contact position of a finger or the like using a two-dimensional sensor matrix that detects a change in capacitance between conductive lines orthogonal in a lattice form
Data Source
AI summary
When positions of three or more fingers are specified in a sensor unit, it is determined in a determination unit whether a non-fingertip is included in a group consisting of three or more fingers based on a relative position relationship among the three or more fingers. Also, when it is determined that the non-fingertip is included in the group consisting of the three or more fingers, an operation of one true fingertip included in the group consisting of the three or more fingers is identified by an operation identification unit.