Joon-Kee Cho

Magic wand: a hand-drawn gesture input device in 3-D space with inertial sensors

This paper presents a gesture input device, magic wand, with which a user can input gestures in 3-D space, inertial sensors embedded in it generate acceleration and angular velocity signals according to a users hand movement. A trajectory estimation algorithm is employed to convert them into a trajectory on 2-D plane. The recognition algorithm based on Bayesian networks finds the gesture model with the maximum likelihood from it. The recognition performance of the proposed system is quite promising; the writer-independent recognition rate was 99.2% on average for the database of 15 writers and 13 gesture classes.

Inertial sensor based recognition of 3-D character gestures with an ensemble classifiers

We present a 3-D input medium based on inertial sensors for on-line character recognition and an ensemble classification scheme for the recognition task. The system allows user to write a character in the air as a gesture, with a sensor-embedded device held in hand. The kinds of sensors used are 3-axis accelerometer and 3-axis gyroscope generating acceleration and angular velocity signals respectively. For character recognition, we used the technique of FDA (Fisher discriminant analysis). We tried different combinations of sensor signals to test the recognition performance. It is also possible to estimate a 2-D handwriting trajectory from the sensor signals. The best recognition rate of 93.23%, in case we use only raw sensor signals, was attained when all 6 sensor signals were combined. The recognition rate of 92.22% was reached if the estimated trajectory was used as input. Finally we tested the ensemble method and the generalization rate of 95.04% was attained on the ensemble recognizer consisting of 3 FDA recognizers based on acceleration-only, angular-velocity-only and handwriting trajectory respectively.

A novel hand gesture input device based on inertial sensing technique

In this paper, we present a novel gesture-based input device by using inertial sensing technique. The trajectories of users hand-drawn gestures in 3D space are captured and recognized by this device to fulfill user interaction task. The proposed device employs gyro-free inertial measurement unit (IMU) to track hand motions without requiring any external reference sensors or signals. Since the unbounded growing error of trajectory estimation, as a major drawback of IMU-based motion tracking technology, is carefully solved by using zero velocity compensation. Here, a deliberately-designed motion detection scheme is proposed to capture accurate hand motion period. Finally, the recognition algorithm based on Bayesian networks takes estimated trajectories and finds the corresponding gesture model with the maximum probability. Because the IMU provides outstanding capability of self-contained positioning, the proposed device is extraordinary simple and effective, comparing with the devices using other tracking technologies such as vision-based system. Experimental results also show its effectiveness and feasibility. Currently, after employing the trajectory estimation method provided in this paper, the recognition rate of 95.51% for 14 gestures has been achieved when this device is implemented as a TV remote controller. It can be used as a powerful, flexible interface for ubiquitous computing device.

A method of remote control for home appliance using free hand gesture

We propose a method of robust and fully automated remote control for home appliance using free hand gesture. The performance of the proposed system is verified with a hardware embedded in an air conditioner.

Noninvasive ultrasound temperature imaging with fusion algorithm

There is a great demand for a noninvasive temperature imaging to commercialize the US guided HIFU system. Echo shift is currently the most technologically developed method, but it cannot give an exact temperature over roughly 43°C since the relation between temperature and speed of sound is irregular depending on the temperature range and tissue type. CBE (Change in Backscattered Energy) has wider temperature range but has the severe artifact that appears behind heated region on ultrasound beam pathway. The object of this paper was to develop a temperature imaging method over the full temperature range by remedying these shortcomings. We present analysis for characteristics of echo shift and CBE up to 60°C through experiments and a fusion approach probabilistically combining echo shift and CBE for more exact temperature imaging over wider temperature range. They can be modeled based on the previous fusion temperature images and the current temperature images by each method. Then the current fusion temperature image can be obtained by combining the two temperature images with optimal weights calculated from the two error covariance maps. The possibility of this method was verified through in-vitro experiments.

Detection and localization of people in living room using a new background subtraction method

We propose a new block-based background subtraction and a sophisticated background update algorithm for illumination invariance and reliable performance. The proposed method is employed and verified for an air conditioner using an embedded hardware.