• Journal of Chest Surgery
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• v.41 no.5
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• pp.659-662
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• 2008

Video-assisted pulmonary lobectomy was introduced in the early 1990's by several authors, and the frequency of video-assisted thoracic surgery (VATS) lobectomy for lung cancer has been slowly increasing because of its safety and oncologic acceptability in patients with early stage lung cancer However, VATS is limited by 2D imaging, an unsteady camera platform, and limited maneuverability of its instruments. The da Vinci Surgical System was recently introduced to overcome these limitations. It has a 3D endoscopic system with high resolution and magnified binocular views and EndoWrist instruments. We report three cases of da Vinci robot system-assisted pulmonary lobectomy in patients with early stage lung cancer.

• Journal of Korea Multimedia Society
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• v.18 no.6
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• pp.701-709
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• 2015

Image stitching method is a technique for obtaining an high-resolution image by combining two or more images. In X-ray image for clinical diagnosis, the size of the imaging region taken by one shot is limited due to the field-of-view of the equipment. Therefore, in order to obtain a high-resolution image including large regions such as a whole body, the synthesis of multiple X-ray images is required. In this paper, we propose a rapid stitching method of digital X-ray images using template-based registration. The proposed algorithm use principal component analysis(PCA) and k-nearest neighborhood(k-NN) to determine the location of input images before performing a template-based matching. After detecting the overlapping position using template-based matching, we synthesize input images by alpha blending. To improve the computational efficiency, reduced images are used for PCA and k-NN analysis. Experimental results showed that our method was more accurate comparing with the previous method with the improvement of the registration speed. Our stitching method could be usefully applied into the stitching of 2D or 3D multiple images.

• Journal of the Korean Society of Radiology
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• v.2 no.1
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• pp.17-21
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• 2008

Because of the reason that the meningioma is enhanced lately, we started the study to maximally enhance the meningioma. we were to know the relation between meningioma and vessels in the skull and compared 3D CT angiography with the conventional angiography. we got the data from 6 patients performed by both 3D CT angiography and there were 5 cases in sphenoidal ridge and 1 case parasagittal sinus. Injecting the contrast media at 3 ml/sec, 120 ml and then the CT number reached 100, we started the study using the medical system Program(smart prep). The scan parameters were HS-Mode(1.25 mm / 7.5 mm) right after being injected all and reconstructed with 0.5 mm interval. We compared the study with the conventional angiography after reconstructing the images required by using 3D-Med software Program(Rapidia). Seeing the consequences, the maximum enhancing time in the menigioma is about 120~180 seconds after injecting the contrast media and we distinguished the relation between vessels and tumors at the time and 1 case showed us the aneurysm with a tumor clearly at the time too. It was very helpful to the operation that the 3D images required by injecting the contrast media to the patients with meningioma distingushed between tumors and vessels dimensionally.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.68.2-68.2
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• 2020

UVO-Multiband Polarizing Imager System (UVOMPIS) is an ultraviolet to visible light multi-wavelength polarization/imaging system for Compact Advanced Satellite. We developed Linear Astigmatism Free-Three Mirror System (LAF-TMS) D200F2 as an optical system of UVOMPIS which has an entrance pupil diameter of 200 mm, a focal ratio of 2, a field of view of 2° × 4°. LAF-TMS is a confocal off-axis reflecting telescope system that removes linear astigmatism, and its all mirrors (M1, M2, M3) are optimized with the freeform surface to reduce high-order aberrations. Through the sensitivity analysis and Monte-Carlo simulation as the tolerance analysis, we can confirm the feasibility of the system, relatively sensitive parameters (tilt, decenter, despace, surface RMS error), and considerations for optomechanical design. From the sensitivity analysis, we can discover the relatively sensitive optical alignment parameters to a single perturbation. Further more, in the monte-carlo simulation, we investigate the minimum tolerance budget satisfying the required optical performance and whether the tolerance range is satisfied within manufacturing error.

• Journal of Sensor Science and Technology
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• v.27 no.5
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• pp.317-327
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• 2018

Terahertz (THz) time-domain spectroscopy(TDS), imaging techniques, and related systems have become mature technologies, widely used in many universities and research laboratories. However, the development of creative technologies still requires improved THz application systems. A few key points are discussed, including the innovative advances of mode-locking energy-emitting semiconductor lasers and better photoconductive semiconductor quantum structures. To realize a compact, low cost, and high performance THz system, it is essential that THz spectroscopy and imaging technologies are better characterized by semiconductor and nano-devices, both static and time-resolved. We introduce the THz spectroscopy and imaging systems, the OSCAT(Optical Sampling by laser CAvity Tuning) system and the ASOPS(ASynchronous Optical Sampling) system, are constructed by our research team. We report on the THz images obtained from their use.

• Journal of the Optical Society of Korea
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• v.8 no.3
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• pp.132-136
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• 2004

Delayed luminescence of plant leaves was imaged by a 2-D cooled charge-coupled device. We report the delayed luminescence imaging of normal/injured leaves picked ami the leaves intact. The luminescent intensity was lower in leaf veins, scars and edge cut. The intensity of delayed luminescence from intact leaves was higher than that of picked leaves. These results indirectly support the argument that the delayed luminescence of a photosynthetic system is closely related to the electron transfer process of PSII in the thylakoid membrane.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3178-3180
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• 1999

초음파 진단기의 신호처리에 필요한 8-b 해상도와 40MS/s 이상의 변환속도를 갖는 ADC를 Folding and Interpolating 형태로 설계했다. 전력소모와 입력단의 오프셋에 의한 영향을 줄이기 위해 프리엠프의 출력을 Interpolation하여 그 개수를 절반으로 줄임으로써 전력소모를 줄였고, 기존의 전압모드 Interpolation 회로에서의 단순한 source follower를 정궤환을 이용한 버퍼의 형태로 바꾸어 이득을 개선시킴으로써 전압의 이용율을 높일 수 있었다. ADC에서 가장 중요한 비교기를 설계함에 있어서는 다이나믹 전력 소모만 있는 구조에 킥-백 노이즈를 줄이기 위한 설계를 했다 $0.6{\mu}m$ CMOS 공정을 이용해 설계되었고, Layout 결과 칩의 면적은 $1.3mm{\times}1.3mm$. 모의 실험결과 40MS/s에서 70mw의 전력을 소모하였다.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.300-305
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• 2007

In this study, we have studied the fabrication and the performance evaluation of digital radiation detector of the based on selenium (a-Se) prototype which is widely researched about recently. The detector was fabricated using amorphous selenium in the specification of active area size $7{\times}8.5"$, pixel pitch $139{\mu}m$, and 12 bit ADC. In order for the performance evaluation of the fabricated detector, we used radiation quality RQA 5 that is suggested by the International Electrotechnical Commission (IEC), and evaluated modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Concerning MTF measurement, we used slit camera (Nuclear Associates, Model : 07-624-2222), and evaluated in the slit method. Also so as to compare the performance evaluation on the detector fabricated in this study, we used Hologic Direct-Ray (DR-1000) and GE Revolution XQ/I system, and evaluated and compared in the same method MTF, NPS, and DQE which are image quality factors. And as a result, the MTF of each detector In Nyquist frequency were evaluated to be 58% (at 3.5 lp/mm) in the case of DR-1000 and 65% (at 2.5 lp/mm) in the case of XQ/I, and that for the detector fabricated in this study was evaluated to be 36% (at 3.51 lp/mm). Also in the case of DQE(0), the detector fabricated in this study, DR-1000 of Hologic company, and XQ/I system of GE company respectively were evaluated as 36%, 32%, and 50%.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.224-232
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• 2016

The methodology to visualize the shape of blood vessel and its blood flow have been attracting as a very interesting problem to forecast and examinate a disease in thrombus precursor protein. May previous visualization researches have been appeared for designing the blood vessel and also modeling the blood flow using a doppler imaging technique which is one of nondestructive testing techniques. General visualization methods are to depict the blood flow obtained from doppler effects with fragmentary stream lines and also visualize the blood flow model using volume rendering. However, these visualizeation techniques have the disadvantage which a set of small line segments does not give the overall observation of blood flows. Therefore, we propose a visualization system which reconstruct the continuity of the blood flow obtained from doppler effects and also visualize the blood flow with the vector field of blood particles. This system will use doppler phase difference from medical equipments such as OCT with low penetration and reconstruct the blood flow by the curvature estimation from vector field of each blood particle.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2679-2691
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• 2012

In this paper, a high accuracy stereo reconstruction method for surgery instruments positioning is proposed. Usually, the problem of surgical instruments reconstruction is considered as a basic task in computer vision to estimate the 3-D position of each marker on a surgery instrument from three pairs of image points. However, the existing methods considered the 3-D reconstruction of the points separately thus ignore the structure information. Meanwhile, the errors from light variation, imaging noise and quantization still affect the reconstruction accuracy. This paper proposes a method which takes the structure information of surgical instruments as constraints, and reconstructs the whole markers on one surgical instrument together. Firstly, we calibrate the instruments before navigation to get the structure parameters. The structure parameters consist of markers' number, distances between each markers and a linearity sign of each instrument. Then, the structure constraints are added to stereo reconstruction. Finally, weighted filter is used to reduce the jitter. Experiments conducted on surgery navigation system showed that our method not only improve accuracy effectively but also reduce the jitter of surgical instrument greatly.