An Economical Touch Panel Using SAW Absorption

Adler, R.; Desmares, P.

doi:10.1109/freq.1986.200948

Cited by 7 publications

(7 citation statements)

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“…Similarly, Equation (3) is the magnitude of change of D x , where D x denotes the absolute values of change of position in the x-axis. Equation (4) represents summation of A x and A y and Equation (5) is its average value, where N refers to the last sampling point. Additionally, S(k), which denotes the magnitudes of change of trajectory velocity without direction, is defined as trajectory smoothness in order to represent the amount of noise or zigzag degree.…”

Section: A Signal Preprocessingmentioning

confidence: 99%

Position Estimation and Smooth Tracking With a Fuzzy-Logic-Based Adaptive Strong Tracking Kalman Filter for Capacitive Touch Panels

Lin

Chang

Hung

et al. 2015

IEEE Trans. Ind. Electron.

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This work presents a novel 7-inch capacitive touch panel (CTP) system with a smooth tracking algorithm that accurately estimates the position where the panel is touched and tracks the trajectory of touch. The proposed CTP system consists of a micro-controller unit, sensor IC, and interface board. When a user draws at different speeds, the measurement noise caused by the sensor IC induces an error in the touched position and zigzag trajectory, especially when the motion is slow. The fuzzy logic-based adaptive strong tracking Kalman filter (FLASTKF) method is implemented in a CTP system to mitigate the effect of measurement noise and provide a smooth tracking trajectory at different speeds. Moreover, the approach effectively measures and quantifies the "smoothness" of the touched trajectory. Experimental results indicate that the proposed method reduces the measurement noise and decreases the mean tracking error by 85.4% over that achieved using the moving average filter (MAF).Index Terms-Capacitive touch panel, Kalman filter, fuzzy logic system, strong tracking Kalman filter.

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Section: A Signal Preprocessingmentioning

confidence: 99%

Position Estimation and Smooth Tracking With a Fuzzy-Logic-Based Adaptive Strong Tracking Kalman Filter for Capacitive Touch Panels

Lin

Chang

Hung

et al. 2015

IEEE Trans. Ind. Electron.

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“…These involve interaction of a tactile object such as a human finger with a solid surface in either passive [1]- [3] or active [4]- [6] forms. Plates are strongly confined along the thickness.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of ultrasonic touchscreen

Firouzi

Nikoozadeh

Khuri‐Yakub

2014

2014 IEEE International Ultrasonics Symposium

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Transient Lamb waves induced by finite piezoelectric transducers have been widely used in ultrasonic touch systems, where a tactile object is localized through its interaction with the Lamb waves. However, this problem has not been looked in-depth theoretically, which is essential for development of robust systems. The two-dimensional theory often fails to provide a true picture as the diffraction effects are of great significance in these technologies. Reduced order models such as the plate theories, on the other hand, can support diffraction. However, they fail to support mid to higher spectrum of the Lamb modes. Moreover, many introduce errors in the range of the supported modes. Hence, for many problems, the design confidence level is only achieved upon a three-dimensional theory. We present the mathematical modeling of piezoelectrically induced elastic waves propagating through homogeneous plates subjected to a tactile object. We use a finite element method to solve the model problem. The model is validated against the experimental data.

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“…have become commonplace in everyday life. Several touch sensing mechanisms have been developed including resistive membrane [6], surface acoustic wave [7], piezoelectric [8], capacitive [9] and optical [10], [11] sensing techniques. However, utilizing such interfaces in MRI is still a challenge.…”

Section: Introductionmentioning

confidence: 99%

Design of an fMRI-compatible optical touch stripe based on frustrated total internal reflection

Jarrahi

Wanek

2014

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Previously we developed a low-cost, multi-configurable handheld response system, using a reflective-type intensity modulated fiber-optic sensor (FOS) to accurately gather participants' behavioral responses during functional magnetic resonance imaging (fMRI). Inspired by the popularity and omnipresence of the fingertip-based touch sensing user interface devices, in this paper we present the design of a prototype fMRI-compatible optical touch stripe (OTS) as an alternative configuration. The prototype device takes advantage of a proven frustrated total internal reflection (FTIR) technique. By using a custom-built wedge-shaped optically transparent acrylic prism as an optical waveguide, and a plano-concave lens to provide the required light beam profile, the position of a fingertip touching the surface of the wedge prism can be determined from the deflected light beams that become trapped within the prism by total internal reflection. To achieve maximum sensitivity, the optical design of the wedge prism and lens were optimized through a series of light beam simulations using WinLens 3D Basic software suite. Furthermore, OTS performance and MRI-compatibility were assessed on a 3.0 Tesla MRI scanner running echo planar imaging (EPI) sequences. The results show that the OTS can detect a touch signal at high spatial resolution (about 0.5 cm), and is well suited for use within the MRI environment with average time-variant signal-to-noise ratio (tSNR) loss < 3%.

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An Economical Touch Panel Using SAW Absorption

Cited by 7 publications

References 0 publications

Position Estimation and Smooth Tracking With a Fuzzy-Logic-Based Adaptive Strong Tracking Kalman Filter for Capacitive Touch Panels

Position Estimation and Smooth Tracking With a Fuzzy-Logic-Based Adaptive Strong Tracking Kalman Filter for Capacitive Touch Panels

Numerical modeling of ultrasonic touchscreen

Design of an fMRI-compatible optical touch stripe based on frustrated total internal reflection

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