Wiener 필터를 이용한 물체표면 음향영상의 품질향상

문건 濟州大學校 産業技術硏究所 1996 산업기술연구소논문집 Vol.7 No.1

Althogh acoustic image is an effective and powerful method for image of materials. the technique is limitted b\. the blurring and distortion introduced by limits of the image system. Therefore, some method of image-signal processing is essential to improve and restore the acquired images and to provide a qualitative improvement of the image evaluation process. The Wiener filtering method is one such proven method of image-signal restoration. This paper discusses the implementation of a Wiener filter in two dimensional apllication for image processing. Theoretical aspects of Wiener filter are briefly discussed. Results of processing acoustic signal and images acquired from coin samples are provided, also compared the methods and results betaeen non-using Wiener filter and using Wiener filter.

음향현미경의 V(z)곡선을 이용한 재료의 특성에 관한 연구

문건,고대식,전계석,Moon, G.,Ko, D.S.,Jun, K.S. 한국음향학회 1988 韓國音響學會誌 Vol.7 No.2

본 논문에서는 음향현미경의 V(z)곡선을 해석하고 실험결과와 비교 고찰하였으며 V(z)곡선과 재료의 탄성 특성사이의 관계를 연구분석하였다. V(z)곡선의 이론적인 해석은 angular spectrum과 ray optics 이론을 사용하였고 실험은 동작주파수가 3MHz인 음향현미경을 구성하여 행하였다. 실험결과 V(z)곡선은 재료마다 고유의 형태를 나타내며 V(z) 곡선에서 극대치 사이의 간격은 재료에서 Rayleigh 파의 음향속도를 산출하는 데 이용될 수 있음을 보였다. In this paper, V(z) curve has been analyzed theoretically and compared with the experimental result, and the relation between the V(z) curve and the material characteristic has been studied. Angular spectrum and ray optics theory have been used for theoretical analysis and the acoustic microscope operating at a center frequency of 3 MHz has been used for experiment. In experiment, it has been shown that each material has a V(z) curve of a unique form and the interval of dips appearing in the V(z) curves have been used to determine the Rayleigh wave velocity.

음향횡파를 이용한 고체내부의 영상검출 개선에 관한 연구

문건,Moon, Gun 한국통신학회 1991 韓國通信學會論文誌 Vol.16 No.12

본 연구에서는 음향파의 입사각을 횡파임계각도 이상으로 하여 횡파를 발생시키고 이를 이용하여 종래방식보다 고체 내부에 존재하는 미소결함의 검출한계를 개선시키는 방법을 연구분석하였다. 실험을 위하여 중심주파수3MHz인 반사형 음향현미경 시스템을 구성하였고 서로 다른 깊이에 임의의 결함을 갖는 시료를 제작하였으며 defocus 깊이를 변화시키면서 실험하였다. 실험결과 고체내부 Rayleigh파장의 3배정도 깊이에 존재하는 1mm 크기의 결함을 검출할 수 있었다.

집속음향파를 이용한 고체특성 판별에 관한 연구

문건,Moon, Gun 한국통신학회 1993 韓國通信學會論文誌 Vol.18 No.1

본 연구에서는 3MHZ의 접속 음향변환자를 사용하여서 고체 샘플에서 반사되어 오는 음향파를 검출하는 시스템을 구성하였고, 이를 이용하여 음향 변환자의 촛점위치와 고체표면과의 거리(Z)에 따른 음향 반사신호의 특성곡선 V(Z)을 검출하였다. 여러가지 고체재료의 V(Z) 특성곡선을 실험에의해 검출한 결과 고체에따라 그들 고유의 V(Z)특성곡선 모양을 나타내고 있음을 보여 주었다. 본 연구에서는 V(Z)곡선을 분석하면 고체특성을 판별할 수 있음을 제시하였다. On this study. Constructed the system detecting the reflective acoustic waves from the solid-samples using the 3MHZ focused-acoustic transducer and detected the V(Z) charateristics curves varied by the distance between the focusing position and the solid surface. The results of the experimental detection to various solid materials showed that the materials have their own unique shape of V(Z) curves. This paper suggested the possibility distinguishing the solid characteristics by analysing the V (Z) curves.

한계레벨 가변방식에 의한 음향영상 분리검출

문건 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.1

On this study. constructed the reflective acoustic C-scanning system using 15MHz transducer. The image-detection in solid-interior in case images are existed on same perpendicular axis have been known as very difficult. This study showed the methode detecting separately the acoustic images existed very closely on the same axis by using the variation methode of threshold levels which are acquired from the time gated pulse signal. The integrated circuit(IC) is used as the experimental sample and I detected the subsurface images by using the proposed methode rejecting the strong surface image among the acoustic signals returned from the sample IC. The experimental results confirmed the possibility for the separating and detecting satisfactorily the acoustic images existed on the multiple layers and I convinced this technique to be very useful one in separating multiple layers images in none destructive testing.

디포커스를 이용한 고체내부 음향영상의 해상도 개선에 관한 연구

문건 濟州大學校工科大學産業技術硏究所 1999 尖端技術硏究所論文集 Vol.10 No.1

The most difficult problem has to be solved in acoustic image detection existing in solid-interior is to reduce the strong surface signals. In order to solve this problem, this paper proposed the new technique enhancing the resolution of acoustic images by applying the defocus method which can reduce the reflected surface signals efficiently. The key point of this technique is to find the optimum defocus distance between acoustic transducer and sample object. Using the packaged LSI as the experimental sample, I detected the subsurface IC images applying the proposed defocus technique. The experimental results showed the better resolution and confirmed this technique can by used usefully in acoustic none destructive test.

디포커스를 이용한 고체내부 음향영상의 해상도 개선에 관한 연구

문건 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.1

The most difficult problem has to be solved in acoustic image detection existing in solid-interior is to reduce the strong surface signals. In order to solve this problem, this paper proposed the new technique enhancing the resolution of acoustic images by applying the defocus method which can reduce the reflected surface signals efficiently. The key point of this technique is to find the optimum defocus distance between acoustic transducer and sample object. Using the packaged LSI as the experimental sample, I detected the subsurface IC images applying the proposed defocus technique. The experimental results showed the better resolution and confirmed this technique can be used usefully in acoustic none destructive test.

음향파를 이용한 금속 부식상태 판별에 관한 연구

문건 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.2

On this study, constructed the reflective acoustic detecting system using 15MHz acoustic transducer. The most difficult problem in metal substance is to discriminate the corrosion state using none destructive method. As the test samples. the six 100 won coins which are issued on the different years are used. The experimental results showed the distinct difference among the acoustic signals accorded to its issued years. I catched the common regulation in acquisited acoustic signals and convinced this technique to be very useful in corrosion discrimination of the metal substances on none destructive testing.

Trigger Pulser 를 부가한 안정 SAW Pulse 발생기 설계

문건 군산대학교 1984 群山水産專門大學 硏究報告 Vol.18 No.3

The utilization of SAW delay lines-device for stabilizing the frequencies of pulse generators is described in this paper. As electronics circuit, the trigger pulser is utilized. Experimental SAW-stabilized pulse generator (SSPG) was designed, and its short-termstability computed by design-values reached to be about 10-5. The using of ST-cut quartz as delay lines is believed to be possible with excellent thermal stability. Furthermore, SSPG is expected to be useful for data and digital communication especially required very stable and high frequencies. The most useful advantage of SSPG is that power consumption is very small.

증식당뇨망막병증 환자에서 발생한 친수성 아크릴 인공수정체 혼탁 1예

문건,김광수,김유철,Kun Moon,Kwang Soo Kim,Yu Cheol Kim 대한안과학회 2012 대한안과학회지 Vol.53 No.8

Purpose: To report a case of hydrophilic acrylic intraocular lens (IOL) opacification in a patient who underwent vitrectomy and cataract surgery for the treatment of diabetic retinopathy. Case summary: A 54-year-old female complained of blurred vision for 15 months after having combined vitrectomy and phacoemulsification with IOL (Rayner? Superflex? 620H) implantation for the treatment of high-risk proliferative diabetic retinopathy. On slit-lamp examination, IOL opacification was evident. IOL exchange was performed and the explanted IOL analyzed. Scanning electron microscopy (SEM) revealed the presence of translucent granular deposits on the anterior subsurface of the IOL. Energy dispersive X-ray spectroscopy (EDS) demonstrated calcium and phosphate deposition within the IOL optic. J Korean Ophthalmol Soc 2012;53(8):1172-1176