지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
논문 기본 정보
- 자료유형
- 학위논문
- 저자정보
- 지도교수
- 천권수
- 발행연도
- 2014
- 저작권
- 대구가톨릭대학교 논문은 저작권에 의해 보호받습니다.
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Assessment methods of medical image were also improved in digital imaging systems had been developed. One of them is edge method to determine MTF(Modulation Transfer Function) based on Fujita(1992). Fujita is use slightly angulated slit to pixel array for compositing finely sampled LSF(Line Spread Function) to determine presampling MTF. In this study, we investigated the effect of sampling interval on the deviation of MTF by using wire method which was equivalent to slit method except signal appearance. We used a mammography system manufactured by Siemens which is a-Se digital detector consist of 0.085 mm × 0.085 mm size of pixels. FID(Focus to Image-receptor Distance) in the system is 650mm, and tungsten wire with 0.05mm in diameter was used to get the LSF for determining the presampling MTF.
Consequently, we acquired accuracy of 98% on 10% and 50% of MTF in twice sampling interval compared with that of Fujita. However, when the sampling interval is larger than three times, accuracy of MTF is reduce to 95% at 50% of MTF and 91% at 10% of MTF. Therefore, When determining the presampling MTF to assessment of image quality or image acquisition systems, the sampling interval should be maintained less than two times compared with Fujita theory.
Consequently, we acquired accuracy of 98% on 10% and 50% of MTF in twice sampling interval compared with that of Fujita. However, when the sampling interval is larger than three times, accuracy of MTF is reduce to 95% at 50% of MTF and 91% at 10% of MTF. Therefore, When determining the presampling MTF to assessment of image quality or image acquisition systems, the sampling interval should be maintained less than two times compared with Fujita theory.
목차
Ⅰ. 서론 11. 연구배경 12. 연구목적 2Ⅱ. 이론적 배경 31. Digital Image Detector 31.1 Computed Radiography : CR 31.2 Digital Radiography : DR 41) Direct Digital Radiography : DDR 42) Indirect Digital Radiography : IDR 52. Fourier Transformation 62.1 Fourier Series 72.2 Fourier Transformation 82.3 Discrete Fourier Transformation : DFT 93. Presampling MTF(Presampling Modulation Transfer Function) 103.1 변조전달함수(Modulation Transfer Function, MTF) 103.2 Presampling method 12Ⅲ. 실험방법 161. 실험재료 161.1 영상획득 장치 161.2 Tungsten wire 182. 영상의 획득 193. Presampling MTF 산출 213.1 N값 확인 213.2 Line Spread Function 정규화 223.3 노이즈 제거 233.4 Presampling MTF 계산 25Ⅳ. 결과 281. 평가방법 292. MTF 곡선의 변화 312.1 Sampling interval 2배 증가 312.2 Sampling interval 3.5배 증가 322.3 Sampling interval 5.5배 증가 333. Sampling interval에 따른 선예도 평가 지수 변화 344. Sampling interval에 따른 해상도 평가 지수 변화 355. Sampling interval에 따른 pixel resolution에서의 MTF 변화 36Ⅴ. 결론 및 고찰 38참고문헌 40
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