• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.77-80
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• 2000

In this paper, we propose a method of detecting the distance between two vehicles by computing the disparity of the close-rang vehicle stereo image using two digital cameras. The boundary(or edge) of the object considered the vehicle is obtained by using the modified wavelet transform which has multi-resolution characteristics. We analyze the histogram using the coarse-to-fine method considering a whole feature and increase the resolution to obtain the exact disparity. From the results, the distance of the close-range vehicle is detected effectively by using our proposed method.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.2
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• pp.128-133
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• 1998

In this paper, we present a parallel framework for tracking moving objects. Parallel framework consists largely of two parts:Search Space Reduction(SSR) and Tracking(TR). SSR is further composed of fuzzy clustering and prediction based on Kalman filter. TR is done by boundarymatching using the Hausdorff distance based on distance transform.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.643-650
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• 2013

In this paper, we propose a novel method for enhancing the detection speed and rate by reducing the computation in Hough Circle Transform on real-time iris detection of smartphone camera image. First of all, we find a face and eyes from input image to detect iris and normalize the iris region into fixed size to prevent variation of size for iris region according to distance from camera lens. Moreover, we carry out histogram equalization to get regular image in bright and dark illumination from smartphone and calculate minimal iris range that contains iris with the distance between corner of the left eye and corner of the right eye on the image. Subsequently, we can minimize the computation of iris detection by applying Hough Circle Transform on the range including the iris only. The experiment is carried out in two case with bright and dark illumination. Our proposed method represents that detection speed is 40% faster and detection rate is 14% better than existing methods.

• Geophysics and Geophysical Exploration
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• v.14 no.3
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• pp.185-190
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• 2011

In marine controlled-source electromagnetic (CSEM) modeling, it may be difficult to evaluate primary fields accurately using conventional linear filters because they decay very rapidly with distance. However, since there exists a closed-form solution to the Hankel transform in TM mode for a homogeneous half space, we can assess the accuracy of linear filters for evaluating the Hankel transform. As a result, only nine out of 36 source-receiver pairs show that EM fields decrease linearly in semi-log scale with an increase of source-receiver distance, while EM fields are either 0 or not reduced significantly due to an effect of the air layer. There also exist closed-form solutions for the nine pairs, and the others can be evaluated accurately with a relatively short filter. This paper proposes a method which uses closed-form solutions for TM-mode Hankel transforms and a filter with 61 coefficients for TE-mode ones.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1943-1952
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• 2011

Rail vehicle brakes partly or completely transform the kinetic energy of moving vehicles into other forms of energy, in order to reduce the speed, and if necessary to bring them to a halt. To fulfil these requirements, the effect of a certain brake force is necessary and especially it is considered that the brake force is a important device to rail vehicles as a mass transit. The brake distance is a criterion for measuring brake force. The brake force is measured via dozens of brake distance test before its service operation. The brake distance is influenced by cars and rail conditions; weight of cars, speed on the verge of braking, temperature of brake disk and condition of the upper side of rail, etc. Therefore we will study how the these factors impact with the brake distance via a real test results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1024-1031
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• 2012

In this paper, FMCW type radar level transmitter using correlation analysis method is implemented for precise distance measurement of cargo tank. FMCW type radar level transmitter is the device for distance measurement which calculates the distance by analyzing the beat frequency, that is, the frequency difference between Tx and RX signal from radar antenna using Fast Fourier Transform(FFT), but compensated algorithm like Zoom FFT is needed for the improvement of the frequency precision because the frequency precision of FFT is limited depending on sampling frequency and the number of sampling data. In case of Zoom FFT, the number of sampling data and noisy signal are the main factor influencing the measurement accuracy of Zoom FFT like FFT. Therefore, in order to overcome the limited environment and achieve the precise measurement, correlation coefficient is used for the distance measurement and the errors of measurement are verified to be in the range of ${\pm}1mm$.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.764-776
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• 2008

Image identification is the process of checking whether the query image is the transformed version of the specific original image or not. In this paper, image identification method based on feature composition is proposed. Used features include color distance, texture information and average pixel intensity. We extract color characteristics using color distance and texture information by Modified Generalized Symmetry Transform as well as average intensity of each pixel as features. Individual feature is quantized adaptively to be used as bins of histogram. The histogram is normalized according to data type and it is used as the signature in comparing the query image with database images. In matching part, Manhattan distance is used for measuring distance between two signatures. To evaluate the performance of the proposed method, independent test and accuracy test are achieved. In independent test, 60,433 images are used to evaluate the ability of discrimination between different images. And 4,002 original images and its 29 transformed versions are used in accuracy test, which evaluate the ability that the proposed algorithm can find the original image correctly when some transforms was applied in original image. Experiment results show that the proposed identification method has good performance in accuracy test. And the proposed method is very useful in real environment because of its high accuracy and fast matching capacity.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.11-19
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• 2016

The size of a display is large, The form becoming various of that do not apply to previous methods of gaze tracking and if setup gaze-track-camera above display, can solve the problem of size or height of display. However, This method can not use of infrared illumination information of reflected cornea using previous methods. In this paper, Robust pupil detecting method for eye's occlusion, corner point of inner eye and center of pupil, and using the face pose information proposes a method for calculating the simply position of the gaze. In the proposed method, capture the frame for gaze tracking that according to position of person transform camera mode of wide or narrow angle. If detect the face exist in field of view(FOV) in wide mode of camera, transform narrow mode of camera calculating position of face. The frame captured in narrow mode of camera include gaze direction information of person in long distance. The method for calculating the gaze direction consist of face pose estimation and gaze direction calculating step. Face pose estimation is estimated by mapping between feature point of detected face and 3D model. To calculate gaze direction the first, perform ellipse detect using splitting from iris edge information of pupil and if occlusion of pupil, estimate position of pupil with deformable template. Then using center of pupil and corner point of inner eye, face pose information calculate gaze position at display. In the experiment, proposed gaze tracking algorithm in this paper solve the constraints that form of a display, to calculate effectively gaze direction of person in the long distance using single camera, demonstrate in experiments by distance.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.807-817
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• 2015

This paper is to propose an encryption method for only an allowed user to see the content for a digital hologram, that is a high value-added content. This paper uses a characteristic of Fresnel transform that the object region is concentrated to a relatively small part of the diffraction plane. By encrypting the concentrated part only the region to be encrypted and in turn the amount of data to be encrypted is reduced a lot, which results in an high efficiency with low encryption rate. As the methodology, a digital hologram is first Fresnel transformed for reconstruction and the result is secondly Fresnel transformed to concentrate the energy into the center of the diffraction plane to encrypt the concentrated region only. For the 2nd transform, energy concentration degree is determined by adjusting the diffraction distance and encryption strength is determined by adjusting the scaling factor. For this we analyze the optimal encryption area according to the diffraction distance and the scaling factor. When applying the proposed method with diffraction distance of 20m the object information was visually unrecognizable with the encryption ratio only 0.005% ~ 0.02%.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.504-511
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• 2012

In this paper, level instrument is implemented using beat frequency for distance measurement which means the difference between Tx and Rx signal frequency from FMCW Radar Level Transmitter. Beat frequency is analyzed through Fast Fourier Transform of which frequency precision can be improved by applying Zoom FFT. Distance precision is improved from 146.5[mm] to 5[mm] using the advantage of Zoom FFT which can raise the frequency precision without changing the sampling frequency or FFT point number to be fixed in the beginning of designing signal processing. Also, measurement error can be reduced within 2[mm] by incresing the FFT points using the method of Spline interpolation. For verifying the effectiveness of this Zoom FFT to FMCW Radar Level Transmitter, test bench is made to measure the distance for every 1[mm] between 700[mm] and 2000[mm] and measurement error can be checked in the range of ${\pm}2$[mm].