Method for the measurement of the modulation transfer function of sampled imaging systems from bar-target patterns

Sitter, David N.; Goddard, Jim; Ferrell, Regina

doi:10.1364/ao.34.000746

Cited by 79 publications

(29 citation statements)

References 2 publications

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“…24 Second, a simple DOF measurement was used and we did not test whether applying the new contrast calculation methods proposed recently could achieve more accurate results. [25][26][27][28][29] Third, although the DOF of the human eye is also an important factor affecting subjective evaluation of the cytogenetic image qualities, 30,31 it was not tested or discussed. Hence, a more comprehensive investigation is underway from which we hope to acquire better knowledge about the designing trade-off parameters to optimize the automated digital microscopic image scanning systems for cytogenetic image diagnosis and other digital pathology applications in the future.…”

Section: Discussionmentioning

confidence: 99%

Impact of the optical depth of field on cytogenetic image quality

Qiu

Chen

et al. 2012

J. Biomed. Opt

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Abstract. In digital pathology, clinical specimen slides are converted into digital images by microscopic image scanners. Since random vibration and mechanical drifting are unavoidable on even high-precision moving stages, the optical depth of field (DOF) of microscopic systems may affect image quality, in particular when using an objective lens with high magnification power. The DOF of a microscopic system was theoretically analyzed and experimentally validated using standard resolution targets under 60× dry and 100× oil objective lenses, respectively. Then cytogenetic samples were imaged at in-focused and off-focused states to analyze the impact of DOF on the acquired image qualities. For the investigated system equipped with the 60× dry and 100× oil objective lenses, the theoretical estimation of the DOF are 0.855 μm and 0.703 μm, and the measured DOF are 3.0 μm and 1.8 μm, respectively. The observation reveals that the chromosomal bands of metaphase cells are distinguishable when images are acquired up to approximately 1.5 μm or 1 μm out of focus using the 60× dry and 100× oil objective lenses, respectively. The results of this investigation provide important designing trade-off parameters to optimize the digital microscopic image scanning systems in the future.

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Section: Discussionmentioning

confidence: 99%

Impact of the optical depth of field on cytogenetic image quality

Qiu

Chen

et al. 2012

J. Biomed. Opt

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“…MTF는 다양한 방법으로 측정되며, 가장 일반적으로 쓰이 는 방식은 크게 핀홀/슬릿 측정법 [16] , 가장자리 측정법 [17] 및 사각 물체 측정법 [18] 이 있다. 사각 물체를 이용한 측정법은 그 림 4와 같은 사각 패턴의 콘트라스트 변화 즉, 콘트라스트 전달 함수(CTF, Contrast transfer function)를 측정한다.…”

Section: Mtf 측정법unclassified

“…사각 물체를 이용한 측정법은 그 림 4와 같은 사각 패턴의 콘트라스트 변화 즉, 콘트라스트 전달 함수(CTF, Contrast transfer function)를 측정한다. 단일 주파수를 갖는 사인(sin) 형태의 연속 밝기 변화 물체 콘트라스 트 전달 함수인 MTF와 달리, CTF는 사각 형태에서 발생하는 고주파 항의 효과를 포함하고 있으나, 많은 경우 그 차이가 적어 CTF가 MTF를 대체하여 사용된다 [18] . 본 실험에서는 사각 물체를 이용하여 광학계의 CTF를 측정하였고, 이와는 별도로 사각 패턴의 가장자리 프로파일의 미분 및 프리에 변 환을 이용하여 MTF를 측정하였다.…”

Section: Mtf 측정법unclassified

Environmental Test Results of a Flight Model of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Lee

Kim²,

Lee³

et al. 2011

Korean Journal of Optics and Photonics

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Environmental Test Results of a Flight Model of a Compact Imaging Spectrometer for a Microsatellite STSAT-3A compact imaging spectrometer (COMIS) was developed for a microsatellite STSAT-3. The satellite is now rescheduled to be launched into a low sun-synchronous Earth orbit (~700 km) by the end of 2012. Its main operational goal is the imaging of the Earth's surface and atmosphere with ground sampling distance of 27 m and 2 -15 nm spectral resolution over visible and near infrared spectrum (0.4 -1.05 μm). A flight model of COMIS was developed following an engineering model that had successfully demonstrated hyperspectral imaging capability and structural rigidity. In this paper we report the environmental test results of the flight model. The mechanical stiffness of the model was confirmed by a small shift of the natural frequency i.e., < 1% over 10 gRMS random vibration test. Electrical functions of the model were also tested without showing any anomalies during and after vacuum thermal cycling test with < 10 -5 torr and-30℃ -35℃. The imaging capability of the model, represented by a modulation transfer function (MTF) value at the Nyquist frequency, was also kept unvaried after all those environmental tests.

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“…3,4 For measuring the MTF of solid-state cameras, the literature cites different methods that differ essentially in the type of target or pattern used as the object. Thus, for example, methods use bar targets, 5 random targets, 6,7 canted self-imaging targets, 8 and interferometric fringes. 9,10 One of the methods to measure the MTF, established in our laboratory, is based on using a laser-speckle pattern as the object.…”

Section: Introductionmentioning

confidence: 99%

Measuring the image quality of digital-camera sensors by a ping-pong ball

et al. 2014

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In this work, we present a low-cost experimental setup to evaluate the image quality of digital-camera sensors, which can be implemented in undergraduate and postgraduate teaching. The method consists of evaluating the modulation transfer function (MTF) of digital-camera sensors by speckle patterns using a ping-pong ball as a diffuser, with two handmade circular apertures acting as input and output ports, respectively. To specify the spatial-frequency content of the speckle pattern, it is necessary to use an aperture; for this, we made a slit in a piece of black cardboard. First, the MTF of a digital-camera sensor was calculated using the ping-pong ball and the handmade slit, and then the MTF was calculated using an integrating sphere and a high-quality steel slit. Finally, the results achieved with both experimental setups were compared, showing a similar MTF in both cases.

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Method for the measurement of the modulation transfer function of sampled imaging systems from bar-target patterns

Cited by 79 publications

References 2 publications

Impact of the optical depth of field on cytogenetic image quality

Impact of the optical depth of field on cytogenetic image quality

Environmental Test Results of a Flight Model of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Measuring the image quality of digital-camera sensors by a ping-pong ball

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