Host-Based Touch Processing Center of Mass Estimation

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Solution Overview

Problem

Conventional touch processing algorithms face issues with suboptimal determination, aliasing, and low processing power, leading to biased and jittery touch location estimation and inaccurate shape parameter calculation due to treating capacitive panel measurements as point masses and low pixel density.

Innovation Solution

The implementation of a parallel processing system that receives touch input data points, determines a center of mass estimate, and performs downsampling to differentiate between coarse and fine objects, using maximum likelihood estimation to improve touch point positioning and shape estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If center of mass estimation is used for touch location determination, then the processing is computationally simple, but the estimation is suboptimal and subject to aliasing causing bias and high jitter

Engineering Contradiction:
Improveprocessing speedVSAvoidtouch location accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the touch processing into multiple stages: initial center of mass estimation, followed by iterative refinement using the measured capacitance values and kernel function matching. This segmentation allows the system to start with a simple computational approach and progressively improve accuracy through additional processing steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary center of mass estimation to obtain an initial touch location estimate, which then serves as the starting point for subsequent refinement iterations. This preliminary action provides a good initial guess that reduces the computational burden of the more complex refinement algorithms.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If low pixel density is used in capacitive touch panel, then the device complexity is reduced, but the shape parameter estimation becomes inaccurate

Engineering Contradiction:
Improvepixel densityVSAvoidshape parameter accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the processing parameters by applying kernel function matching and iterative optimization algorithms that can extract accurate shape parameters from low-density pixel data. Instead of relying on high pixel density, the system transforms the problem through mathematical modeling and parameter optimization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the mechanical approach of increasing pixel density with a computational approach using kernel function matching and capacitance distribution analysis. This replaces the need for finer physical sampling with sophisticated signal processing and mathematical modeling.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If conventional touch processing algorithms are used, then the processing power requirement is low, but the determination is suboptimal leading to biased results

Engineering Contradiction:
Improvepower consumptionVSAvoidtouch determination accuracy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements dynamic processing where the level of computational effort can be adjusted based on the specific touch event characteristics. The system starts with simple center of mass calculation and only performs more computationally intensive kernel matching and iterative refinement when necessary to achieve the desired accuracy level.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces kernel function matching as an intermediary step between simple center of mass estimation and final touch determination. This intermediary process uses the measured capacitance values and a modeled kernel function to bridge the gap between crude initial estimation and accurate final results, improving reliability without requiring full computational power from the start.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS9310933B2Optimization for host based touch processing
Publication Date: 2016.04.12 QUALCOMM INC
  • US9310933B2 patent drawing
  • US9310933B2 patent drawing
  • US9310933B2 patent drawing

AI summary

Systems and methods are disclosed for determining a touch position from data received from a touch panel. In one implementation, an apparatus for processing a touch input signal includes a processor that may be configured for parallel processing, a touch device, a memory, operably connected to the processor, and configured to store processor instructions. The processor instructions can configure the processor to receive a plurality of data points corresponding to a plurality of touch events on the touch device, determine a center of mass estimate from the plurality of data points, determine a search radius of center of mass estimate, and determine an optimal touch point position based on the center of mass estimate and the search radius using the processor.