HumTouch: Localization of Touch on Semi-Conductive Surfaces by Sensing Human Body Antenna Signal

Abstract

HumTouch is a touch sensing technology utilizing the environmental electromagnetic wave. The method can be realized using conductive and semi-conductive materials by simply attaching electrodes to the object’s surface. In this study, we compared three methods for localizing a touch on 20×16cm2 and 40×36cm2 papers, on which four or eight electrodes were attached to record the voltages leaked from the human fingertip. The number and positions of the electrodes and the data processing of the voltages differed according to the localization methods. By constructing a kernel regression analysis model between the electrode outputs and the actual physical locations, the touched locations were estimated. Each of the three methods was tested via leave-one-out cross validation. Out of the three methods discussed, two exhibited superior performances in terms of the estimation errors. Of these two methods, one simply uses the voltages recorded by the four electrodes attached on the middle of paper edges as inputs to the regression system. The other uses differential outputs of electrode pairs as the inputs. The smallest mean location errors were 0.31 cm on 20×16cm2 paper and 0.27 cm on 40×36cm2 paper, which are smaller than the size of a fingertip.

One-touch calibration of hum-noise-based touch sensor for unknown users utilizing models trained by different users

“…These currents can be detected using voltage acquisition devices attached to the surface of the object. HumTouch sensing technology uses these currents for touch localization on papers [35,37], woods [36], and in water [38] and gesture recognition [34].…”

“…In their experiment, the hum-noise in the wall was detected through human skin when a person touched the wall. The hum-noise-based sensing method employed in this study is called HumTouch [34][35][36][37], which uses the environmental noise leaking from human fingers onto the surfaces of conductive or semiconductive objects. Touch or finger localization is achieved based on the voltages recorded at multiple electrodes attached to the surface [35][36][37].…”

“…The hum-noise-based sensing method employed in this study is called HumTouch [34][35][36][37], which uses the environmental noise leaking from human fingers onto the surfaces of conductive or semiconductive objects. Touch or finger localization is achieved based on the voltages recorded at multiple electrodes attached to the surface [35][36][37]. In previous studies on hum-noise-based touch sensors, calibration for localization was performed for individual users, using machine learning or statistical approaches comprising support vector machines and regression analysis [27][28][29][30][35][36][37].…”

“…Touch or finger localization is achieved based on the voltages recorded at multiple electrodes attached to the surface [35][36][37]. In previous studies on hum-noise-based touch sensors, calibration for localization was performed for individual users, using machine learning or statistical approaches comprising support vector machines and regression analysis [27][28][29][30][35][36][37]. Because of the individual differences in human bodies, the voltages recorded on material surfaces differ among users, leading to inaccurate localization of touch.…”

“…It does not require any resistive or capacitive materials and layers installed on the surface as long as the surface material is semiconductive. Hence, HumTouch may allow us to turn wooden products [36], such as furniture, and those covered with paper [35,37] or cloth into touch-sensitive interfaces. Furthermore, HumTouch can localize a human body in water [38].…”