The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform

Colin J. R. Sheppard - One of the best experts on this subject based on the ideXlab platform.

  • interpretation of the Optical Transfer Function significance for image scanning microscopy
    Optics Express, 2016
    Co-Authors: Colin J. R. Sheppard, Stephan Roth, Rainer Heintzmann, Marco Castello, Giuseppe Vicidomini, Rui Chen, Xudong Chen, Alberto Diaspro
    Abstract:

    The Optical Transfer Function (OTF) is widely used to compare the performance of different Optical systems. Conventionally, the OTF is normalized to unity for zero spatial frequency, but in some cases it is better to consider the unnormalized OTF, which gives the absolute value of the image signal. Examples are in confocal microscopy and image scanning microscopy, where the signal level increases with pinhole or array size. Comparison of the respective unnormalized OTFs gives useful insight into their relative performance. The significance of other properties of the general OTF is discussed.

  • Joint Distribution Functions and the Generalized Optical Transfer Function
    AIP Conference Proceedings, 2006
    Co-Authors: Colin J. R. Sheppard, Kieran G. Larkin
    Abstract:

    The ambiguity Function and the Wigner distribution Function have both been applied in the Optical area for many years. Later, the fractional Fourier transform has also been used. The connection between the ambiguity Function and the defocused Optical Transfer Function has also been described. Here we consider the connections with the generalized Optical Transfer Function, first proposed in 1965, which is a two (three) dimensional Optical Transfer Function for the two (three) dimensional case. The two dimensional form can be used as the basis for phase retrieval algorithms, but is also valid in the non‐paraxial domain.

  • a 3d vectorial Optical Transfer Function suitable for arbitrary pupil Functions
    Optics Communications, 2002
    Co-Authors: Matthew R Arnison, Colin J. R. Sheppard
    Abstract:

    We calculate the 3D vectorial Optical Transfer Function directly from the vectorial pupil Function, without making the paraxial assumption nor assuming radially symmetric pupils. Our model uses a single autocorrelation integral with Cartesian pupil co-ordinates to calculate the Transfer Function. Results for Herschel and aplanatic systems are presented. We discuss the meaning and application of a vectorial Transfer Function as a tool for analysing high aperture incoherent microscopy modes including fluorescence and transmission.

  • focal shift Optical Transfer Function and phase space representations
    Journal of The Optical Society of America A-optics Image Science and Vision, 2000
    Co-Authors: Colin J. R. Sheppard, Kieran G. Larkin
    Abstract:

    The focal shift for a lens of finite value of Fresnel number can be defined in terms of the second moment of the intensity distribution in transverse planes. The connection with the Optical Transfer Function is described. The specification of the focused amplitude in terms of the fractional Fourier transform is discussed, and the connections among the fractional Fourier transform, the Wigner distribution, and the ambiguity Function are described, leading to a model for effects of Fresnel number in terms of a rotation in phase space. The uncertainty principle is discussed, including the significance of the beam propagation factor M 2 and the width of Optical fiber beam modes. Calculation of the moments in terms of the modulus and the phase of the illuminating wave is presented, and the use of the Kaiser‐Teager energy operator is also described. © 2000 Optical Society of America [S0740-3232(00)00404-X] OCIS codes: 060.2270, 070.2580, 070.2590, 140.3300, 260.1960.

  • Optical Transfer Function analysis for two-photon 4Pi confocal fluorescence microscopy
    Optics Communications, 1995
    Co-Authors: Min Gu, Colin J. R. Sheppard
    Abstract:

    The imaging behaviour in a two-photon 4Pi confocal fluorescence microscope is analysed in terms of the Optical Transfer Function. For comparison, the Optical Transfer Function for two-photon non-4Pi confocal fluorescence imaging is also given. It is shown that the Optical Transfer Function for two-photon 4Pi confocal fluorescence imaging is significantly enhanced at high axial spatial frequencies, thus providing a physical explanation of axial super-resolution obtained in this system. © 1995.

Andrew R Harvey - One of the best experts on this subject based on the ideXlab platform.

  • decomposition of the Optical Transfer Function wavefront coding imaging systems
    Optics Letters, 2005
    Co-Authors: Gonzalo Muyo, Andrew R Harvey
    Abstract:

    We describe the mapping of the Optical Transfer Function (OTF) of an incoherent imaging system into a geometrical representation. We show that for defocused traditional and wavefront-coded systems the OTF can be represented as a generalized Cornu spiral. This representation provides a physical insight into the way in which wavefront coding can increase the depth of field of an imaging system and permits analytical quantification of salient OTF parameters, such as the depth of focus, the location of nulls, and amplitude and phase modulation of the wavefront-coding OTF.

Jim Schwiegerling - One of the best experts on this subject based on the ideXlab platform.

  • Optical Transfer Function expansion of quadratic pupils
    International Optical Design Conference 2017, 2017
    Co-Authors: Jim Schwiegerling
    Abstract:

    Quadratic pupils representing Gaussian apodization and defocus are expanded into Zernike polynomials. Combinations of the pupil expansion coefficients are used, in turn to expand the Optical Transfer Function into a novel set of basis Functions.

  • linear decomposition of the Optical Transfer Function for annular pupils
    Current Developments in Lens Design and Optical Engineering XVIII 2017, 2017
    Co-Authors: Jim Schwiegerling
    Abstract:

    A technique for decomposing the Optical Transfer Function (OTF) into a novel set of basis Functions has been developed. The decomposition provides insight into the performance of Optical systems containing both wavefront error and apodization, as well as the interactions between the various components of the pupil Function. Previously, this technique has been applied to systems with circular pupils with both uniform illumination and Gaussian apodization. Here, systems with annular pupils are explored. In cases of annular pupil with simple defocus, analytic expressions for the OTF decomposition coefficients can be calculated. The annular case is not only applicable to Optical systems with central obscurations, but the technique can be extended to systems with multiple ring structures. The ring structures can have constant area as is often found in zone plates and diffractive lenses or the rings can have arbitrary areas. Analytic expressions for the OTF decomposition coefficients again can be determined for ring structures with constant and quadratic phase variations. The OTF decomposition provides a general tool to analyze and compare a diverse set of Optical systems.

  • relating wavefront error apodization and the Optical Transfer Function on axis case
    Journal of The Optical Society of America A-optics Image Science and Vision, 2016
    Co-Authors: Jim Schwiegerling
    Abstract:

    The incoherent Optical Transfer Function (OTF) describes contrast degradation and phase shifts of sinusoidal objects of all spatial frequencies and orientations. The OTF is calculated as either an autocorrelation of the pupil Function or the Fourier transform of the point spread Function. Even with fast algorithms, these calculations can be slow for a densely sampled pupil. Here, a linear expansion of the OTF is developed in which the expansion coefficients are related to the wavefront error and apodization coefficients. The advantage of such a representation is that the OTF can be quickly generated from parameters of the Optical system.

  • Relating wavefront error, apodization, and the Optical Transfer Function: on-axis case: reply.
    Journal of the Optical Society of America. A Optics image science and vision, 2016
    Co-Authors: Jim Schwiegerling
    Abstract:

    Efficient coding enables rapid calculation of basis Functions for a linear expansion of the Optical Transfer Function.

  • Optical Transfer Function optimization based on linear expansions
    Proceedings of SPIE, 2015
    Co-Authors: Jim Schwiegerling
    Abstract:

    The Optical Transfer Function (OTF) and its modulus the Modulation Transfer Function (MTF) are metrics of Optical system performance. However in system optimization, calculation times for the OTF are often substantially longer than more traditional optimization targets such as wavefront error or transverse ray error. The OTF is typically calculated as either the autocorrelation of the complex pupil Function or as the Fourier transform of the Point Spread Function. We recently demonstrated that the on-axis OTF can be represented as a linear combination of analytical Functions where the weighting terms are directly related to the wavefront error coefficients and apodization of the complex pupil Function. Here, we extend this technique to the off-axis case. The expansion technique offers a potential for accelerating OTF optimization in lens design, as well as insight into the interaction of aberrations with components of the OTF.

Gonzalo Muyo - One of the best experts on this subject based on the ideXlab platform.

  • decomposition of the Optical Transfer Function wavefront coding imaging systems
    Optics Letters, 2005
    Co-Authors: Gonzalo Muyo, Andrew R Harvey
    Abstract:

    We describe the mapping of the Optical Transfer Function (OTF) of an incoherent imaging system into a geometrical representation. We show that for defocused traditional and wavefront-coded systems the OTF can be represented as a generalized Cornu spiral. This representation provides a physical insight into the way in which wavefront coding can increase the depth of field of an imaging system and permits analytical quantification of salient OTF parameters, such as the depth of focus, the location of nulls, and amplitude and phase modulation of the wavefront-coding OTF.

Alberto Diaspro - One of the best experts on this subject based on the ideXlab platform.

  • interpretation of the Optical Transfer Function significance for image scanning microscopy
    Optics Express, 2016
    Co-Authors: Colin J. R. Sheppard, Stephan Roth, Rainer Heintzmann, Marco Castello, Giuseppe Vicidomini, Rui Chen, Xudong Chen, Alberto Diaspro
    Abstract:

    The Optical Transfer Function (OTF) is widely used to compare the performance of different Optical systems. Conventionally, the OTF is normalized to unity for zero spatial frequency, but in some cases it is better to consider the unnormalized OTF, which gives the absolute value of the image signal. Examples are in confocal microscopy and image scanning microscopy, where the signal level increases with pinhole or array size. Comparison of the respective unnormalized OTFs gives useful insight into their relative performance. The significance of other properties of the general OTF is discussed.