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Image Quality for Scanning and Digital Imaging Systems
Published in Gerald F. Marshall, Glenn E. Stutz, Handbook of Optical and Laser Scanning, 2018
Donald R. Lehmbeck, John C. Urbach
For engineering analysis, use of convolutions and measurements of spread functions are often found to be difficult and cumbersome. The use of an optical transfer function (OTF) is considered to have many practical advantages from both the testing and theoretical points of view. The OTF is the Fourier transform of the line spread function. This function consists of a modulus to describe normalized signal contrast attenuation (or amplification), and a phase to describe shift effects in location, both given as a function of spatial frequency. The signal is characterized as the modulation of the sinusoidal component at the indicated frequency. Therefore the contrast altering function is described as a modulation transfer function (MTF). The value of OTF analysis is that all of the components in a linear system can be described by their OTFs, and these are multiplied together to obtain the overall system response. The method and theory of this type of analysis has been covered in many journal articles and reference books.13,47,78,102
Telescopes
Published in Daniel Malacara-Hernández, Brian J. Thompson, Fundamentals and Basic Optical Instruments, 2017
Marija Strojnik, Maureen S. Kirk
The modern ray trace programs tend to summarize the performance of an optical system in terms of its capacity to image the individual spatial frequency components of the object faithfully. This presentation of results assumes that the object emittance (see the radiometry chapter elsewhere in this volume) is decomposed into its Fourier components. Then, the optical system may be considered as a black box that progressively decreases the modulation of the increasingly higher spatial frequencies. Furthermore, it usually modifies their phases as well. Imaging analysis theory then says that Fourier frequencies of the object multiplied by the optical transfer function, interpreted as a black box, provide Fourier frequencies of the image. The magnitude of an optical transfer function (OTF) is a modulation transfer function (MTF), often the quantity of the primary concern when the phase is not of interest. The significance of the modulation transfer function to modify the amplitudes of the spatial frequency components is illustrated in Figure 11.9.
Super-resolution Optical Microscopy with Structured Illumination
Published in Guy Cox, Fundamentals of Fluorescence Imaging, 2019
Liisa M. Hirvonen, Trevor A. Smith
The resolution of a microscope is often defined as the full width at half maximum of the point-spread function (PSF). Its Fourier transform, the optical Transfer function (OTF), defines the maximum transferable frequency, kcut. In Fourier space it defines a circular region in the kxky plane with radius kcut (Fig. 15.2a,b). In the axial direction the OTF is doughnut-shaped with a “missing cone” around the axis, resulting in poor optical sectioning (Fig. 15.2c). Any details about the object outside the support of the OTF are normally lost.
Determination of Doping Concentration of ICF Shells by an Improved Equivalent Absorption Method Based on Real-Time X-Ray Imaging
Published in Fusion Science and Technology, 2019
Zongwei Wang, Qi Wang, Xuesen Zhao, Yong Hu, Dangzhong Gao, Jie Meng, Xing Tang, Xiaojun Ma
where optical transfer function OTFG.U. for an extended source can be expressed as =by Wigner distribution,7,8 is the Bessel function of the first order in the first type, is spatial frequency, , cis the diameter of the X-ray focus; optical transfer function OTFdet for detector resolution is given as =, and are pixel sizes in the directions of and , respectively.
Visible imaging characteristics of space targets oriented to on-orbit observation
Published in Journal of Modern Optics, 2018
Qing-yu Hou, Yi-hui Wang, Fan-jiao Tan, Yu-jia Huo, Peng Wu, Zhi-peng Wang
The optical transfer function characterizes the transmission of spatial frequency components. The calculation formula for the optic system is (17) where is the spectrum frequency, , is the imaging wavelength of the system, f is the focal length of the optical system, D is the exit pupil diameter and is the F number of the system. is the cutoff frequency of the optical system.
Blind structured illumination as excitation for super-resolution photothermal radiometry
Published in Quantitative InfraRed Thermography Journal, 2020
Peter Burgholzer, Thomas Berer, Mathias Ziegler, Erik Thiel, Samim Ahmadi, Jürgen Gruber, Günther Mayr, Günther Hendorfer
In optical microscopy, Gustafson achieved super-resolution by using spatially structured illumination in a wide-field fluorescence microscope. The sample was illuminated by a series of excitation light patterns, which caused high-resolution information to be encoded into the observed image. The recorded images were linearly processed to extract the new information and produced a reconstruction with up to twice the normal resolution. Even if the structured illumination pattern is known, the resolution enhancement in structured illumination microscopy is limited to about a factor of two because the maximum spatial frequency of the illumination pattern is constrained by the optical transfer function of the microscope [7].