Multi-Pointer Gesture Recognition via Touch Point Clustering

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Solution Overview

Problem

Interactive input systems employing two imaging devices face challenges in accurately locating and tracking multiple pointers, leading to pointer ambiguity issues, especially when the pointers do not have distinctive markings, which complicates the recognition of gestures made using multiple pointers.

Innovation Solution

A gesture recognition method that captures images across an input region, processes them to identify clusters of touch points, recognizes gestures based on the motion of these clusters, and updates the display accordingly, using at least one imaging sensor and processing structure to analyze image data and determine the location of touch points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple pointers are tracked using triangulation with two imaging devices, then pointer location can be determined, but pointer ambiguity issues occur when pointers lack distinctive markings

Engineering Contradiction:
Improvepointer location accuracyVSAvoidgesture recognition reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the set of all detected touch points into multiple clusters, where each cluster corresponds to a single pointer. This is achieved by analyzing spatial relationships and grouping touch points that belong together based on their relative positions and motion patterns, thereby resolving the ambiguity of which touch points belong to which pointer

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces cluster centers as intermediary representations that simplify pointer identification. Instead of directly tracking individual touch points which may be ambiguous, the system computes cluster centers from grouped touch points and tracks these centers, providing a stable intermediary representation that resolves pointer ambiguity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If cluster analysis is performed to resolve pointer ambiguity, then gesture recognition accuracy improves, but processing complexity increases

Engineering Contradiction:
Improvegesture recognition accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the processing task into distinct stages: first detecting all touch points, then segmenting them into clusters based on spatial relationships, computing cluster centers, and finally tracking gesture motion. This segmentation of processing steps makes the complex task more manageable and efficient

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies clustering and center computation only to the necessary subset of touch points that form actual pointers, rather than processing all detected points equally. This partial action approach reduces unnecessary computation while maintaining gesture recognition accuracy

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9262016B2Gesture recognition method and interactive input system employing same
Publication Date: 2016.02.16 SMART TECH INC (CA)
  • US9262016B2 patent drawing
  • US9262016B2 patent drawing
  • US9262016B2 patent drawing

AI summary

A gesture recognition method comprises capturing images, processing the images to identify at least two clusters of touch points associated with at least two pointers, recognizing a gesture based on motion of the clusters, and updating a display in accordance with the recognized gesture.