• Journal of Korea Multimedia Society
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• v.16 no.1
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• pp.67-74
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• 2013

In this paper, we propose the pointing and correction algorithm for optimized performance based on Bluetooth communication. The error from the accelerometer sensor's output must be carefully managed as the accelerometer sensor is more sensitive to data change compared to that of the gyroscope sensor. Thus, we minimize the noise by applying the Kalman filter to data for each axis from the accelerometer. In addition, we can also obtain effect compensating the hand tremor by applying the Kalman filter to the data variation for x and y. In this study, we extract data through the Quaternion mapping process on data from the accelerometer and gyroscope. In turn, we can obtain a tilt compensation by applying a compensation algorithm with acceleration of the gravity of the extracted data. Moreover, in order to correct the inaccuracy on smart sensor due to the rapid movement of a device, we propose a adaptive pointing and correction algorithm using the genetic approach to generate the initial population depending on the user.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.6
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• pp.493-497
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• 2016

Infrared (IR) imaging is capable of detecting targets that are not visible at night, thus it has been widely used for the security and defense system. However, the quality of the IR image is often degraded by low resolution and noise corruption. This paper addresses target segmentation with the IR image. Multiple regions of interest (ROI) are extracted by the multi-level segmentation and targets are segmented from the individual ROI. Each level of the multi-level segmentation is composed of a k-means clustering algorithm an expectation-maximization (EM) algorithm, and a decision process. The k-means clustering algorithm initializes the parameters of the Gaussian mixture model (GMM) and the EM algorithm iteratively estimates those parameters. Each pixel is assigned to one of clusters during the decision. This paper proposes the selection and the merging of the extracted ROIs. ROI regions are selectively merged in order to include the overlapped ROI windows. In the experiments, the proposed method is tested on an IR image capturing two pedestrians at night. The performance is compared with conventional methods showing that the proposed method outperforms others.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.808-814
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• 2007

In this paper, the measurement system of crane moving range is concerned with range recognition technology using phase and magnitude of radio wave. By the proposed technology, we design the radio transmitter and receiver and realize the measurement system, and save the data in disk that is earned from 900Mhz RF signal, middle frequency 450khz of analog signal. As a result of RF measurement, we got 9.3 dBm of RF output and 96 dBc@10khz of phase noise. Range information is earned the data through digital signal processing of IF signal. For the estimation of range measured, we analyze the difference between real range and measurement range, and also suggest the method to remove the measurement error using average processing and amplitude properties. A result is 0.12 and 0.00422 deviation in l0mn-30m and within 5m respectively, and then 2.4E-04 deviation in 4m by using compensation of level characteristics lately.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.608-618
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• 2007

Image binarization is an important preprocessing to identify the object of interest by dividing pixels into the background and object. We proposes efficient binarization method and a stroke reconstruction method of the low quality character image for an effective character recognition. First, the character image is binarized by using the both advantages of local and global thresholding method and then the noise elimination around the character stroke and the hole filling on the stoke by the analysis of the binarized stroke image are performed to enhance the quality of the character stroke. Proposed binarization algorithm for character image achieved an efficiency of both processing speed and performance by the adaptive threshold selection. Moreover, We could get a high qualify binary image by a stroke reconstruction of the step-by-step denoising process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1162-1169
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• 2007

In this paper, we proposed a container identifier recognition method for containers used in harbors. After converting a real container image to a gray image, edges are detected from the gray image applying Prewitt mask and candidate identifier area is extracted using morphological features of individual identifier for identifying containers. Because noises are included in the extracted candidate identifier area, noises are eliminated and each identifier is separated using 4-directional edge tracking algorithm and Grassfire algorithm. Each identifier in the noise-free candidate identifier area is recognized using FCM-based row RBF network for discriminating containers. We used 300 real container images for experiment to evaluate the performance of the proposed method, and we could verify the proposed method is better than a conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2158-2165
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• 2007

In this paper, a Modified Fuzzy C-Means algorithm with Gaussian Weights(MFCM_GW) is presented for nonlinear blind channel equalization. The proposed algorithm searches the optimal channel output states of a nonlinear channel from the received symbols, based on the Bayesian likelihood fitness function and Gaussian weighted partition matrix instead of a conventional Euclidean distance measure. Next, the desired channel states of a nonlinear channel are constructed with the elements of estimated channel output states, and placed at the center of a Radial Basis Function(RBF) equalizer to reconstruct transmitted symbols. In the simulations, binary signals are generated at random with Gaussian noise. The performance of the proposed method is compared with those of a simplex genetic algorithm(GA), a hybrid genetic algorithm(GA merged with simulated annealing(SA): GASA), and a previously developed version of MFCM. It is shown that a relatively high accuracy and fast search speed has been achieved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1456-1462
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• 2008

In general, it is known a single biometric-based personal authentication has limitation to improve recognition rate due to weakness of individual recognition scheme. The recognition rate of face recognition system can be reduced by environmental factor such as illumination, while speaker verification system does not perform well with added surrounding noise. In this paper, a multi-modal biometric system composed of face and voice recognition system is proposed in order to improve the performance of the individual authentication system. The proposed empirical weight sum rule based on the reliability of the individual authentication system is applied to improve the performance of multi-modal biometrics. Since the proposed system is implemented using JAVA applet with security function, it can be utilized in the field of user authentication on the generic Web.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.17-24
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• 2008

This paper deals with a millimeter wave source which is utilizing sub-harmonic injection-synchronization technique. A 8.7GHz oscillator with MES-FET is fabricated, and is driven as a harmonic output oscillator at 17.4GHz by means of sub-harmonic injection-synchronization. The oscillator operates as a multiplier as well as oscillator in this system. Adopting this technique, we can obtain a high stable, high frequency millimeter wave source even though self-oscillating frequency of an oscillator is relatively low. In the experiments, the range of injection-synchronization is about 26MHz and is proportional to the input sub-harmonic power. From the spectrum analysis of the 2nd harmonic output. we blow that the phase noise of the harmonic oscillator is remarkably decreased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.223-228
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• 2007

The Digital Frequency Synthesizer(DFS) that generates the wideband signal with high speed frequency hopping rate and high frequency resolution characteristics was designed and implemented in this paper The DFS was applied as local oscillator for direct frequency conversion IF modules of DVB-RCS, which directly generates the transmission immediate frequency signal by using DDS and wideband PLL technologies. The DDS technology provides high speed frequency hopping rate and high frequency resolution characteristics, which are also the DVB-RCS requirement. The wideband PLL technology also provides the wideband signal generation, which is a necessity for direct frequency conversion modules. The implemented DFS provides the spurious suppression characteristic of -50 dBc and less, frequency resolution of 0.233 Hz and frequency hopping rate of 125 ns, respectively. Also the DFS represents the amplitude flatness of 3 dB and less in the pass-band, and phase noise characteristic of -75 dBc/Hz at 1 kHz frequency offset.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.392-401
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• 2007

Wireless network has high BER characteristic because of path loss, fading, noise and interference. Many packet losses occur without any congestion in wireless network. Therefore, many wireless TCP algorithms have been proposed. SNOOP, one of wireless TCP algorithms, hides packet losses for Fixed Host and retransmits lost packets in wireless network. However, SNOOP has a weakness for bust errors in wireless network. This paper proposes the SACK-SNOOP to improve TCP performance based on SNOOP and Freeze-TCP that use ZWA messages in wireless network. This message makes FH stop sending packets to MH. BS could retransmit error packets to MH for this time. SACK-SNOOP use improved Selective ACK, thereby reducing the number of packet sequences according to error environment. This method reduces the processing time for generation, transmission, analysis of ACK. This time gain is enough to retransmit local burst errors in wireless link. Furthermore, SACK-SNOOP can manage the retransmitted error by extending delay time to FH. The simulation shows that our proposed protocol is more effective for packet losses in wireless networks.