• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.7C
• /
• pp.601-609
• /
• 2012

In this paper, a limited-view CT image reconstruction method was studied to reduce the scan times and the X-ray dose for the patients. To reduce streak artifacts which is caused by insufficient number of views, we introduce a sinogram interpolation method based on image matching. Image matching is achieved using the characteristics of the neighboring views including intensity, gradient and distance between the pixels. Interpolation is performed using the image matching results.. A numerical phantom and Al-acryl phantom were used for evaluating the effectiveness of the proposed interpolation method. The results showed that streak artifacts were reduced in the reconstructed images while the details of the images were preserved. Moreover, maximum 5% improvements in terms of PSNR were observed.

• Journal of KIISE:Databases
• /
• v.36 no.4
• /
• pp.327-340
• /
• 2009

To achieve the noise reduction effect in boundary image matching, we use the moving average transform of time-series matching. Our motivation is based on an intuition that using the moving average transform we may exploit the noise reduction effect in boundary image matching as in time-series matching. To confirm this simple intuition, we first propose $\kappa$-order image matching, which applies the moving average transform to boundary image matching. A boundary image can be represented as a sequence in the time-series domain, and our $\kappa$-order image matching identifies similar images in this time-series domain by comparing the $\kappa$-moving average transformed sequences. Next, we propose an index-based matching method that efficiently performs $\kappa$-order image matching on a large volume of image databases, and formally prove the correctness of the index-based method. Moreover, we formally analyze the relationship between an order $\kappa$ and its matching result, and present a systematic way of controlling the noise reduction effect by changing the order $\kappa$. Experimental results show that our $\kappa$-order image matching exploits the noise reduction effect, and our index-based matching method outperforms the sequential scan by one or two orders of magnitude.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.101-105
• /
• 2002

In this paper we describe techniques for the automated creation of geometric correct 3-D models of the building using two 2-D laser scanners. One of the laser scanners is used for position estimation using a scan matching algorithm, while the other is used to build 3-D models of the facade of the buildings. Those models can be used for virtual reality, tele-presence, digital cinematography and urban planning applications. Results are shown for building models in our campus using real data acquired from two sensors.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.23-25
• /
• 2007

The partial distortion elimination (PDE) scheme is used to decrease the sum of absolute difference (SAD) computational complexity, since the SAD calculation has been taken much potion of the video compression. In motion estimation (ME) based on PDE, it is ideal that the initial value of SAD in summing performance has large value. The traditional scan order methods have many operation time and high operational complexity because these adopted the division or multiplication. In this paper, we introduce the new scan order and search order by using only adder. We define the average value which is called to rough average value (RAVR). Which is to reduce the computational complexity and increase the operational speed and then we can obtain the improvement of SAD performance. And also this RAVR is used to decide the search order sequence, since the difference RAVR between the current block and candidate block is small then this candidate block has high probability to suitable candidate. Thus, our proposed algorithm combines above two main concepts and suffers the improving SAD performance and the easy hardware implementation methods.

• Journal of KIBIM
• /
• v.10 no.1
• /
• pp.1-8
• /
• 2020

In managing building facilities, spatial information is the basic data for decision making. However, the method of acquiring spatial information is not easy. In many cases, the site and drawings are often different due to changes in facilities and time after construction. In this case, the site data should be scanned to obtain spatial information. The scan data actually contains spatial information, which is a great help in making space related decisions. However, to obtain scan data, an expensive LiDAR (Light Detection and Ranging) device must be purchased, and special software for processing data obtained from the device must be available.Recently, SLAM (Simultaneous localization and mapping), an advanced map generation technology, has been spreading in the field of robotics. Using SLAM, 3D spatial information can be obtained quickly in real time without a separate matching process. This study develops and tests whether SLAM technology can be used to obtain spatial information for facility management. This draws considerations for developing a SLAM device for real-time remote scanning for facility management. However, this study focuses on the system development method that acquires spatial information necessary for facility management through SLAM technology. To this end, we develop a prototype, analyze the pros and cons, and then suggest considerations for developing a SLAM system.

• Journal of Yeungnam Medical Science
• /
• v.24 no.2
• /
• pp.179-185
• /
• 2007

Backgroud : Urinary tract infection (UTI) is common in children. The available gold standard methods for diagnosis, Tc-99m dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) are invasive and expensive. This study was performed to assess the role of power Doppler ultrasound (PDU) for diagnosis of acute pyelonephritis (APN). Materials and Methods : A prospective study was conducted in 25 children with aged 2 weeks to 5 years who were hospitalized with the first episode of febrile UTI suggesting acute pyelonephritis. All children were examined in the first 3-5 days of admission by PDU and Tc-99m DMSA scan. The comparison between PDU and DMSA scan was performed on the basis of patients. Results : The sensitivity and specificity of PDU for the detection of affected kidneys were 38.1% and 50.0%, and the positive predictive value and negative predictive value were 61.9% and 50.0%, respectively. Vesicoureteral refluxes (VUR) were identified in 11 patients (44.4%) and 18 kidneys (36%). The PDU and DMSA scan showed a matching perfusion defect in 23.8% and 50.0% respectively. Conclusion : These data indicate the PDU has a relatively low sensitivity and specificity for differentiating APN from lower UTI but may be a complement tool to DMSA scan for the prediction of VUR in infants and children.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.9B
• /
• pp.914-922
• /
• 2009

In this paper, we propose a matrix based real-time pattern matching method, called MDPI, for real-time intrusion detection on several Gbps network traffic. Particularly, in order to minimize a kind of overhead caused by buffering, reordering, and reassembling under the circumstance where the incoming packet sequence is disrupted, MDPI adopts independent partial matching in the case dealing with pattern matching matrix. Consequently, we achieved the performance improvement of the amount of 61% and 50% with respect to TCAM method efficiency through several experiments where the average length of the Snort rule set was maintained as 9 bytes, and w=4 bytes and w=8bytes were assigned, respectively, Moreover, we observed the pattern scan speed of MDPI was 10.941Gbps and the consumption of hardware resource was 5.79LC/Char in the pattern classification of MDPI. This means that MDPI provides the optimal performance compared to hardware complexity. Therefore, by decreasing the hardware cost came from the increased TCAM memory efficiency, MDPI is proven the cost effective high performance intrusion detection technique.

• Journal of Trauma and Injury
• /
• v.28 no.3
• /
• pp.158-169
• /
• 2015

Purpose: Frostbite can affect still soldiers. Initial clinical manifestations are similar for superficial and deep frostbite, so early treatment is identical. It is under-estimated by physicians. We try to identify the challenges of managing these complex tissue injuries. Methods: A retrospective analysis of 84 patients hospitalized at AFCH from 2009 to 2015 was conducted. We investigated differences of epidemiological characteristics, identification of soft tissue injury, treatment and complications between superficial (SF: 43; 51.2%) and deep (DF: 41; 48.8%) frostbite. Results: The major (94.0%) developed frostbite in dry circumstances (89.3%). Wet circumstances (66.7%) were more susceptible to DF rather than dry (46.7%). The 38 (45.2%) arrived to specialist within 7days. Most prone sites were feet, followed by hands. Toes had more deep injuries. DF presented more increased levels of ALT, CPK, CKMB, CRP. The bone scan of W+S+ was 48.3%, 87.1% and W+S- was 20.7%, 12.9%, respectively. The treatment resulted in improved or normalized perfusion scan with matching clinical improvement. It was a good tool to assess treatment response. Eighteen normal and 8 stenotic type of PCR resulted in normal with matching clinical improvement. One continuous obstructive waveform led to minor amputation. Twelve underwent both PCR and MRA. Among 6 normal PCR, 5 showed normal and one stenosis in MRA. All 5 stenosis and one obstruction showed the same findings in MRA. It was a good tool to evaluate vascular compromise. They were treated with rapid rewarming (11.6%, 22.0%), hydrotherapy (16.3%, 29.3%), respectively. Six (14.6%) underwent STSG, 2 (4.9%) had digital amputation in DF. Berasil, Ibuprofen, Trental were commonly administered. PGE1 was administered selectively for 6.8, 10.8 days, respectively. Raynaud's syndrome (16.3%), CRPS (4.7%), LOM (14.6%) and toe deformity (4.9%) were specific sequelae. Conclusion: We should recommend intensive foot care education, early rewarming and evacuation to specialized units. The bone scanning and PCR should allow for a more aggressive and active approach to the management of tissue viability.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.8C
• /
• pp.712-719
• /
• 2007

In this paper, we propose a new, effective, fast motion estimation algorithms using $4{\times}4$ pixels Hadamard transform. The Hadamard transform has the advantage of simplicity because it uses only addition and subtraction. Motion estimation is composed of three stages. First, it should be decided whether to terminate the search early and use a previous motion vector with DC(Direct Current) coefficients. Then the adaptive matching scan order for motion estimation should be determined according to the image complexity using AC(Alternating Current) coefficients. Experimentally, we adapted this algorithms to MVFAST and PMVFAST algorithms, and the proposed algorithms turn out to be very efficient in terms of computational speed while remaining almost the same in terms of PSNR(Peak Signal-to-Noise Ratio) compared to MVFAST and PMVFAST algorithms.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.5
• /
• pp.87-92
• /
• 2022

In this paper, a study was conducted on the design of an array element that can be applied to the AESA radar for seeker. An antenna for application to AESA radar should choose an optimal radiation element to be applied to an array antenna in order to secure electronical beam steering characteristics, and consider beam steering characteristics when designing. In particular, in order to satisfy the wide-angle beam steering characteristics, the wide-angle impedance matching technique should be used to minimize the scan blindness region that may occur during wide-angle steering. As such, securing the stability of system operation is becoming an important design consideration for AESA radar. In this paper, WAIM is applied to the end of the radiation element to improve the characteristics of the radiation element applied to the AESA radar antenna device, and the change in the performance of the active reflection coefficient, which is a stable operation index of the system, is reviewed. The final performance result verified the validity of the proposed method by mathematically synthesizing the simulation data.