• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.278-284
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• 1986

There are considerabel interests in the use of acoustical lengths for characterization of scattered data required in diffraction tomography. In this paper, we present two new methods, calculation of acoustical lengths by Hibert transform and estimate on of integrated values on the scan lines from calcualted vales. These techniques offer insight into the acquisition of projection data in diffraction tomography. The validity of the proposed methods has bee confirmed by computer simulation.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.467-475
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• 2016

Ultrasonic propagation imaging (UPI) has shown great potential for detection of impairments in complex structures and can be used in wide range of non-destructive evaluation and structural health monitoring applications. The software implementation of such algorithms showed a tendency in time-consumption with increment in scan area because the processor shares its resources with a number of programs running at the same time. This issue was addressed by using field programmable gate arrays (FPGA) that is a dedicated processing solution and used for high speed signal processing algorithms. For this purpose, we need an independent and flexible block of logic which can be used with continuously evolvable hardware based on FPGA. In this paper, we developed an FPGA-based ultrasonic propagation imaging system, where FPGA functions for both data acquisition system and real-time ultrasonic signal processing. The developed UPI system using FPGA board provides better cost-effectiveness and resolution than digitizers, and much faster signal processing time than CPU which was tested using basic ultrasonic propagation algorithms such as ultrasonic wave propagation imaging and multi-directional adjacent wave subtraction. Finally, a comparison of results for processing time between a CPU-based UPI system and the novel FPGA-based system were presented to justify the objective of this research.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.151-154
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• 2001

In this Paper, a new harmonic imaging technique is proposed and evaluated experimentally. In the proposed method, a weighted chin signal with a hanning window is transmitted. The RF samples obtained on each array element are individually compressed by correlating with the reference signal defined as the 2nd harmonic (2f0) component of a transmitted chirp signal generated in a square-law system. The proposed method uses the compressed 2f0 component to form an image, for which the crosscorrelation term with f0 component should be suppressed below at least -60dB. After experiment, the 6dB pulse width and peak sidelobe level of the compressed 2f0 component were 0.7us and -60dB, respectively. This result shows that the proposed method can successfully eliminate the f0 component with a single transmit-receive event and therefore is more efficient than the conventional pulse inversion (PI) method in terms of frame rate. We also observed that the 2nd harmonic compont starts to decrease for source pressure higher than 210kPa in water, which implies that SNR of the 2nd harmonic imaging using short pulses cnanot be incresed beyond a certain limit.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.79.4-79
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• 2002

Our goal is the development of a system that estimates the location of interested point in a room with accuracy and low cost. Non-contacting position estimating method is widely used in various areas. Among these methods, acoustic signal-based method is the cheapest and provides reasonably accurate estimation as a result of many research efforts. Most of the acoustic-signal-based three-dimensional location estimators such as 3D sonic digitizer are using the ultrasound, and are organized with two procedures; time-of-flight (TOF) estimation and localization estimation. Since the errors in estimating the TOF could be accumulated with that of localization estimate, accuracy of TOF estimate is as...

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.79-82
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• 1991

Digital FHR monitoring system based on the personal computer combined wi th the digital signal processing (DSP) board was implemented. The DSP board acquires and digitally processes ultrasound fetal Doppler signal for digital rectification, envelope detection, autocorrealtion function calculation and its peak position detection. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data taransmission and on-line analysis of fetal heart rate change including on-line warning system, base-line estmation, acceleration, deceleration and variability. The advantages of PC-DSP based system can be summarized as follows: 1) Minimum hardware realization. 2) Increased flexibility. 3) Total care system.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.559-562
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• 1997

In this paper, we propose the method that reduce the grating lobe in the ultrasound synthetic focusing images. synthetic focusing images have more larger and closer grating lobe than conventional phased array images and more lower signal to noise ratio. so, we represent the method that reduce the grating lobe by using multi element receive focusing. experimental results are showed that the proposed multi element receiving method reduce the grating lobe and increase the signal to noise ratio.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.213-214
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• 1998

The important role of the ultrasonic Doppler system in the modem clinical medicine is to provide the clinical information of the vascular system. The ultrasonic pulsed wave(PW) Doppler system, a kind of the ultrasound Doppler system, is more available than the ultrasonic continuous wave(CW) Doppler system because it can evaluate the velocity and the direction of blood flow as well as the depth of vessel. However, the ultrasonic PW Doppler system has the disadvantage that the range of evaluating velocity of blood flow is limited(Nyquist limit). In order to solve this limit, we propose the algorithm for eliminating this aliasing in this paper. In addition, we propose the efficient signal processing algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.82-88
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• 2003

The nondestructive internal quality evaluation of agricultural products has been strongly required from the needs for individual inspection. Recently, the ultrasonic wave has been considered as a solution fur this problem, and an ultrasonic system was constructed for the ultrasonic NDE of fruits and vegetables in our previous work. In this paper, the practical applicability of our ultrasonic system is tested fur the inspection of internal defects (central cavity) in Atlantic potato. Sound speed and RMS of transmitted ultrasonic wave signal were measured and classification algorithm using 2 dimensional stochastic analysis. was presented. Experimental results showed greater value of sound speed and RMS (root mean square) of transmitted signal in normal samples than in abnormal samples with cavity. Also a stochastic method to distinguish normal and abnormal showed fault detection rate less than 5%.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.2
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• pp.70-77
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• 2019

Breast ultrasound readings are very important to diagnose early breast cancer. In Ultrasonic inspection, it shows a significant difference in image quality depending on the ultrasonic equipment, and there is a large difference in diagnosis depending on the experience and skill of the inspector. Therefore, objective criteria are needed for accurate diagnosis and treatment. In this study, we analyzed texture characteristics by applying GLCM (Gray Level Co-occurrence Matrix) algorithm and extracted characteristic parameters and diagnosed breast cancer using neural network classifier. Breast ultrasound images were classified into normal, benign and malignant tumors and six texture parameters were extracted. Fourteen cases of normal, malignant and benign tumor diagnosed by mammography were studied by using the extracted six parameters and learning by multi - layer perceptron neural network back propagation learning method. As a result of classification using 51 normal images, 62 benign tumor images, and 74 malignant tumor images of the learned model, the classification rate was 95.2%.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.4
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• pp.290-298
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• 2014

Ultrasonic thickness measurement is a non-destructive method to measure the local thickness of a solid element, based on the time taken for an ultrasound wave to return to the surface. When an element is very thin, it is difficult to measure thickness with the conventional ultrasonic thickness method. This is because the method measures the time delay by using the peak of a pulse, and the pulses overlap. To solve this problem, we propose a method for measuring thickness by using the power cepstrum and the minimum variance cepstrum. Because the cepstrums processing can divides the ultrasound into an impulse train and transfer function, where the period of the impulse train is the traversal time, the thickness can be measured exactly. To verify the proposed method, we performed experiments with steel and, acrylic plates of variable thickness. The conventional method is not able to estimate the thickness, because of the overlapping pulses. However, the cepstrum ultrasonic signal processing that divides a pulse into an impulse and a transfer function can measure the thickness exactly.