Touch Coordinate Inlier Filtering for Straight-Line Drawing

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Solution Overview

Problem

Existing touch sensing apparatuses experience decreased accuracy of predicted vectors and increased jitter during straight line drawing events due to noise in touch coordinates, particularly from outliers outside the reference range.

Innovation Solution

A touch sensing apparatus that processes touch panel data by detecting raw data, calculating touch coordinates, generating straight lines between any two coordinates, counting inlier touch coordinates within a reference range, and selecting a suitable straight line based on the number and distance of these inliers to predict the motion vector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If all touch coordinates are used for motion vector prediction, then more data is available for calculation, but accuracy decreases due to noise from outliers

Engineering Contradiction:
Improvenumber of touch coordinates usedVSAvoidaccuracy of predicted vector
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent extracts and removes outlier touch coordinates that fall outside the reference range from the set of all touch coordinates. By identifying coordinates that deviate significantly from the straight line pattern and excluding them, the system retains only the inlier coordinates that accurately represent the user's drawing intent, thereby improving prediction accuracy without sacrificing useful data.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different treatment to different regions of the touch coordinate data. Coordinates within the reference range (inliers) are treated as valid data for prediction, while coordinates outside the reference range (outliers) are treated as noise and excluded. This local differentiation based on spatial position relative to the straight line enables selective use of data quality.

Inventive Principle:
Principle #3Local quality

2Device complexity

If traditional motion vector prediction is used, then processing is simple, but straight line drawing jitter increases due to noise

Engineering Contradiction:
Improvecomplexity of prediction algorithmVSAvoidsmoothness of straight line drawing
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary classification of touch coordinates into inliers and outliers before the motion vector prediction step. By pre-identifying and separating valid coordinates from noisy ones using the reference range criterion, the system prepares clean input data for the prediction algorithm, thereby improving drawing stability without significantly increasing overall system complexity.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If outlier coordinates are included in prediction, then all available information is used, but inlier identification becomes difficult and accuracy decreases

Engineering Contradiction:
Improveinformation retention in predictionVSAvoidaccuracy of inlier identification
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent introduces a reference range parameter to distinguish between inlier and outlier coordinates. By defining a spatial threshold based on the straight line geometry, the system transforms the ambiguous task of identifying valid coordinates into a clear parameter-based classification, enabling accurate differentiation between useful and noisy data while retaining all inlier information.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4625121A1Touch sensing device and method
Publication Date: 2025.10.01 LX SEMICON CO LTD
  • EP4625121A1 patent drawingFigure 1
  • EP4625121A1 patent drawingFigure 2~4
  • EP4625121A1 patent drawingFigure 5~7

AI summary

The present disclosure relates to a touch sensing apparatus and method capable of reducing jitter occurring when drawing a straight line among touch drawing events, the touch sensing apparatus may include a sensing signal processor configured to detect raw data corresponding to a touch drawing event of the touch panel and a controller configured to generate touch data by predicting a motion vector of touch coordinates based on the detected raw data, wherein the controller may calculate touch coordinates of the raw data when the raw data is input, generate a straight line connecting any two touch coordinates among the calculated touch coordinates, count a number of inlier touch coordinates positioned within a reference range from the straight line, select a suitable straight line based on the number of inlier touch coordinates, and determine a touch coordinate closest to the selected suitable straight line as a predicted coordinate to predict the motion vector of the touch coordinates.