• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.319-320
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• 2006

In this paper, we propose a vision based system employing two cameras to provide effective touch screen function. The two main processes - determining touch (or no-touch) and contact location of screen plane - are essential for enabling touch screen function. First region of interest is found by using color characteristic and histogram for determining the contact mode. Second, if the hand touches the mirror, the fingertip point in image is found using the correlation coefficient based on the mirror attribute. Subsequently, the fingertip coordinate in image is transformed to the location in mirror plane by using four predefined points (termed as four-point method) and bilinear transform. Representative experimental results show that the proposed system is suited to touch screen.

• ETRI Journal
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• v.36 no.6
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• pp.979-987
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• 2014

This paper describes new tactile feedback patterns and the effect of their input performance for a button GUI activated by a tap gesture on mobile touch devices. Based on an analysis of touch interaction and informal user tests, several tactile feedback patterns were designed. Using these patterns, three user experiments were performed to investigate appropriate tactile feedback patterns and their input performance during interaction with a touch button. The results showed that a tactile pattern responding to each touch and release gesture with a rapid response time and short falling time provides the feeling of physically clicking a button. The suggested tactile feedback pattern has a significantly positive effect on the number of typing errors and typing task completion time compared to the performance when no feedback is provided.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.35-42
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• 2016

Various events of stop, playback, capture, and zoom-in/out in playing video is available in the monitor of a small size such as smart phones. However, if the size of the display increases, then the cost of the touch recognition is increased, thus provision of a touch event is not possible in practice. In this paper, we propose a video event control system that recognizes a touch inexpensively from the depth information, then provides the variety of events of the toggle, the pinch-in / out by the single or multi-touch. The proposed method finds a touch location and the touch path by the depth information from a depth camera, and determines the touch gesture type. This touch interface algorithm is implemented in a small single-board system, and can control the video event by sending the gesture information through the UART communication. Simulation results show that the proposed depth touch method can control the various events in a large screen.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.50-61
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• 2011

The Infrared touch method is generally used for a mid and large-size touch screen. But this method has several problems, such as difficulty with installation of a touch-object recognition device, limited application and coordinate error in multi-point touch system. Since we can take advantages of both color and local information when we use general cameras for a touch screen, a touch screen using general camera is more efficient than infrared one. It also has an advantage of easy installation of a touch-object device. However, it did not much appeal in a market because of several problems, such as color sensitivity, illumination and reflected light. In this paper, we study a method for a touch screen using a general camera and image processing method to recognize touch objects and coordinate calculation method to single and multi-point touch screen. It has the same recognition performance as an infrared touch screen for single-point method. And it does not have ghost point problem by using distance information of touch object and camera in multi-point touch system. But recognition performances of multi-point touch screen are less than single-point. If we improve execution time, this method can replace an infrared method for a single point touch screen, according to result of experience.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.2
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• pp.80-88
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• 2012

This paper focuses on small touch key size and spacing that affect the usability of the smart phones. The experiments examined thirty-six different touch key designs, combinations of four touch key sizes (width (mm) ${\times}$height (mm); $4{\times}4$, $4{\times}7$, $7{\times}4$, and $7{\times}7$), and nine spacings (horizontal (mm)${\times}$vertical (mm); $0{\times}0$, $0{\times}1$, $0{\times}3$, $1{\times}0$, $1{\times}1$, $1{\times}3$, $3{\times}0$, $3{\times}1$, and $3{\times}3$). Forty participants volunteered in the experiment. The completion time, error rate, identification discomfort, and control discomfort were measured. The results revealed that the touch key sizes of $7{\times}7$ and $7{\times}4$ provide the best performance in terms of the error rate measure, while the touch key size of $7{\times}7$ provides the best results for other measures. In addition, touch key spacings of $1{\times}1$, $1{\times}3$ and $3{\times}1$ are regarded as the best for all the measures. The results of this study suggest a practical approach for the small touch key design for the smart phones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.875-877
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• 2011

This paper introduces a touch screen panel driver using modified charge pump circuit. The touch screen panel driver is composed of an analog circuit part which senses a touch and a digital circuit which analyse the sensed signal. To verify the functions the touch screen panel driver, a mixed-mode circuit was built and simulated using Cadence Spectre. The digital circuits were modeled with Verilog-A in order to interface with the analog circuits and verify the functionalities of the driver with less simulation time. From the simulation results, we can verify the reliable operations of the simple structured touch screen panel driver which does not include an ADC.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1235-1244
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• 2010

Most emerging smart phones support capacitive touch sensors. It renders existing gesture-based interfaces not suitable since they were developed for the resistive touch sensors and pen-based input. Unlike the flick gestures from the existing gesture interfaces, the finger flick gesture used in this paper reduces the workload about half by selecting the target and the command to perform on the target at a single touch input. With the combination with multi-touch interface, it supports various menu commands without having to learn complex gestures, and is suitable for the touch-based devices hence it minimizes input error. This research designs and implements the multi-touch and flick interface to provide an effective file management system on the smart phones with capacitive touch input. The evaluation proves that the suggested interface is superior to the existing methods on the capacitive touch input devices.

• Journal of Broadcast Engineering
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• v.20 no.4
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• pp.568-579
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• 2015

Recently, mobile devices with touch display panel are widely used. Accuracy and reaction speed of touch signal are very important in touch devices. Therefore, we need to develop an effective algorithm to reduce touch noise quickly and accurately. This paper proposes a touch noise reduction algorithm using Kalman filtering in consideration of signal motion. First, a specific pre-emphasis processing is applied to an input signal so as to maximize the effect of Kalman filtering. In other words, a pure signal in the touch signal increases but noise in the touch signal decreases. Next, motion of the signal is detected. Motion estimation is performed only if motion is detected. If we detect motion by using the only neighborhood of the signal, we can reduce about 75% of the computation in comparison with examining the entire area. Finally, Kalman filtering using the previous state of current signal is performed. Experimental results show that the proposed algorithm suppresses touch noise sufficiently without degradation of the pure signal

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1933-1939
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• 2011

The former people who made musical instruments used touch devices for sound control. As the first multi-touch system appeared in 1982, the performance of the system has been improved rapidly by many researches. In spite of such performance improvement, the popularization of multi-touch interface was looked difficult. However, in 2007, multi-touch interfaces have become popular with Apple Iphone and people have been able to experience easily multi-touch interface using smart phones. In this paper we propose a general-purpose multi-touch interaction system for multi-touch content producer and market invigoration of multi-touch interface. We show by real field tests that the proposed method has benefits in the aspects of price and performance compared with other techniques.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.723-728
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• 2015

In the conventional hot rolling process, the defects of products such as scratches occur due to impact and friction. Impact occurs as a result of the contact of between rollers and the slab. Also, friction occurs in the rolling process. To improve these defects, a variety of processes were developed. The flying touch method is also one of the processes to reduce defects and uses a movable upper roller. To use this unfixed roller, the impact and frictions between rollers and the slab should be minimized. This paper proposes a hot rolling process simulator to verify and test the efficiency of the flying touch method. The simulator was designed to verify the method. This paper also proposes a new impact reducing method and velocity synchronization method which are simulated to realize the method.