• Title/Summary/Keyword: imaging physics

검색결과 634건 처리시간 0.029초

Optimized Working Distance of a Micro-optic OCT Imaging Probe

  • Kim, Da-Seul;Moon, Sucbei
    • Current Optics and Photonics
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    • 제4권4호
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    • pp.330-335
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    • 2020
  • We have investigated optimization of the working distance (WD) for a highly miniaturized imaging probe for endoscopic optical coherence tomography (OCT). The WD is the axial distance from the distal end of the imaging probe to its beam focus, which is demanded for dimensional margins of protective structures, operational safety, or full utilization of the axial imaging range of OCT. With an objective lens smaller than a few hundred micrometers in diameter, a micro-optic imaging probe naturally exhibits a very short WD due to the down-scaled optical structure. For a maximized WD careful design is required with the optical aperture of the objective lens optimally filled by the incident beam. The diffraction-involved effect was taken into account in our analysis of the apertured beam. In this study, we developed a simple design formula on the maximum achievable WD based on our diffraction simulation. It was found that the maximum WD is proportional to the aperture size squared. In experiment, we designed and fabricated very compact OCT probes with long WDs. Our 165-㎛-thick fiber-optic probes provided WDs of 3 mm or longer w ith reasonable OCT imaging performance.

집적영상에서 기본영상 재배열시 수렴광축을 이용한 불연속성 개선 (Reduction of Discontinuity by Using Converging Pick-Up in Remapped Three-Dimensional Integral Imaging)

  • 유현우;서광범;이호철;차성도;신승호
    • 한국광학회지
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    • 제30권3호
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    • pp.106-113
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    • 2019
  • 집적영상에서 깊이역전 문제를 해결하기 위해 기본영상 재배열이 제안되었지만 시점영상이 연속적으로 재생되지 못하는 불연속성 문제를 포함하고 있다. 본 논문에서는 불연속성 요인을 분석하였다. 수렴광축으로 기본영상을 획득하고, 재배열한 후 실상 및 허상모드를 동시에 재생하는 불연속성 개선 방법을 제안하고, 평행광축을 이용하여 획득하고 실상모드로 재생하는 일반적인 방법과 비교하여 유효성을 정량적으로 검증하였다.

영상진단용 초음파 트랜스듀서를 위한 멀티레벨 음향 프레넬 렌즈의 제작 및 특성 (Fabrication and characteristics of multilevel acoustic Fresnel lens for ultrasonic transducer for diagnostic imaging)

  • 김동현;하강렬;김무준;김정순
    • 센서학회지
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    • 제18권1호
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    • pp.33-41
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    • 2009
  • A multilevel acoustic Fresnel lens (MAFL) for the ultrasonic imaging transducer of which center frequency is approximately 5.MHz was newly designed and fabricated. The phase level of the lens was 64, and the focal length and the aperture width were 30.mm and 11.mm, respectively. The characteristics of impulse response, acoustic field and imaging performance of the transducer attached the lens were compared with the transducer attached a conventional refraction type acoustic lens (RAL). The results show that the center frequency, the loop sensitivity, and the focal depth of the MAFL transducer were higher or larger than those of the RAL transducer by approximately 0.2.MHz, 1.4.dB, and 2.mm, respectively. Consequently, it was shown that the brighter acoustic images with higher lateral resolution and the increased imaging performance for deep targets can be obtained by using the MAFL transducer.