Pressing Input Detection Using Touch-Time Adaptive Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pressing operation detection systems inaccurately detect pressing operations due to electromagnetic noise or external vibrations, leading to false positives or negatives, particularly in tap operations and gradual pressure applications.
Innovation Solution
A pressing operation detection device that differentiates between short and long touch times, using a smoothing processor for gradual pressure detection and direct detection for short taps, with threshold adjustments based on touch duration to accurately determine pressing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low pass filter (LPF) such as a moving average filter (MAF) is used to smooth pressing amounts, then false detection due to noise is reduced, but tap operations (short-duration pressing) are not detected accurately
Solution Approach 1:
The patent applies dynamics by switching between two detection modes (smoothing mode and non-smoothing mode) based on the duration of the touch input. When the touch duration exceeds a threshold, smoothing is applied to filter noise; when the touch duration is short (tap operation), smoothing is bypassed to ensure accurate detection. This dynamic adaptation resolves the contradiction between noise filtering and tap operation detection.
Solution Approach 2:
The patent changes the parameter of signal processing (smoothing application) based on the touch duration parameter. By monitoring how long a touch persists, the system adjusts whether to apply the moving average filter, thereby adapting the detection sensitivity to match the operational context and resolving the contradiction between reliability and responsiveness.
2Reliability
If noise filtering is applied to all pressing detections, then electromagnetic noise and external vibration noise are reduced, but the detection system becomes less responsive to legitimate short-duration pressing operations
Solution Approach 1:
The system dynamically adjusts its noise filtering behavior based on the temporal characteristics of the input. For short-duration touches (taps), the system disables smoothing to maintain measurement precision. For long-duration touches, the system enables smoothing to improve noise resistance. This dynamic parameter adjustment resolves the contradiction between noise resistance and measurement precision.
3Ease of operation
If a threshold value is set for pressing amount detection, then pressing operations can be determined, but instantaneous increases due to noise cause false positive detections
Solution Approach 1:
The patent implements a dynamic threshold application strategy where the smoothing filter is conditionally applied based on touch duration. For brief touches that might be noise, the threshold is effectively raised through smoothing. For sustained touches that are likely intentional, the threshold remains accessible. This resolves the contradiction between ease of operation and detection accuracy.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention includes a touch time detection unit detecting a touch time on an operation unit and a determination controller changing content of a determination process to be performed by a pressing operation determination unit based on the touch time. Content of the determination process to be performed by the pressing operation determination unit based on a pressing amount is changed such that easiness of a detection of a pressing operation when a pressing amount is instantaneously changed in a short period of time is differentiated based on a touch time so that false detection of a pressing operation caused by an instantaneous change of a pressing amount due to noise in a pressing operation of gradually increasing pressure is avoided and a case where a pressing operation of performing a strong press in a short period of time is not detected is avoided.