Improvement of point spread function (PSF) using linear- quadratic aperture (original) (raw)
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A hyper-resolving polynomial aperture and its application in microscopy
Beni-Suef University Journal of Basic and Applied Sciences
Background A hyper-resolving aperture composed of a polynomial distribution is suggested. The point spread function (PSF) is computed and compared with that corresponding to linear, quadratic, and circular apertures. In addition, the influence of the number of zones on the PSF is discussed. An application on confocal scanning laser microscope using Siemen’s star pattern as an object considering the polynomial apertures is given. Results We have made polynomial apertures using MATLAB code, and we tested the resolution from the computation of the cut-off spatial frequency obtained from the computation of the point spread function. Conclusions We get compromised resolution and contrast for the polynomial apertures as compared with uniform circular apertures.
Pramana, 2006
In this paper, a novel aperture based on Tolardo concept composed of a central clear disc surrounded by a series of black and white (B/W) concentric annuli of equal transmittance is presented. Different apodized apertures of different number of B/W annuli are suggested in order to improve further the three-dimensional resolving power of confocal imaging systems. Both the axial and lateral point spread functions (PSF) and the corresponding irradiances are computed in both cases of conventional and confocal scanning microscopes for the above-mentioned amplitude filters. These results of axial and lateral irradiances are graphically represented by constructing a computer program using MATLAB. The obtained results are compared with that obtained in case of circular, annular, and Martinez-Corral apodized aperture.
Optimization of axial resolution in a confocal microscope with D-shaped apertures
Applied Optics, 2009
We show theoretically that the axial resolution is improved when two centrosymmetric D-shaped apertures are combined in a confocal microscope with a finite-sized pinhole. The optimum width of a divider that separates the D-shaped apertures to give the maximum axial resolution for a given pinhole size is investigated, and the magnitude of the signal level is explored.
A Study on Misaligned Modulated Apertures in Confocal Scanning Laser Microscope (CSLM)
2019
The famous work on the PSF is made by Sheppard et. al. [1-12] using annular and Gaussian apertures. Improvement of axial resolution in confocal microscopy using annular pupil is investigated in [9].Practical limits of resolution in confocal and nonlinear microscopy is presented in [11]. The effect of numerical aperture on interference fringe spacing is shown in [13]. Linear, quadratic, B/W concentric annuli, and graded index apertures is suggested by Hamed et. al. [14-20]. They computed the PSF considering the above modulated apertures giving lateral resolution improvement. Image analysis of modified Hamming aperture and an application on confocal microscopy and holography is given in [20]. Modulatedalignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues is presented in [21]. While an image scanning microscopy with a quadrant detector is recently investigated [22].
The Image of a Single Point in Microscopes of Large Numerical Aperture
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1982
The image of a single small hole in an opaque screen in a microscope of large numerical aperture is calculated. Both conventional microscopes and scanning optical microscopes are considered, the general trend being that the central peak is broadened, the outer rings strengthened and the minima made shallower as the numerical aperture is increased. In the conventional microscope the image is no longer independent of the illumination, as it is for paraxial theory.
Journal of Microscopy, 1991
We have measured the point-spread function (PSF) for an MRC-500 confocal scanning laser microscope using subresolution fluorescent beads. PSFs were measured for two lenses of high numerical aperture-the Zeiss plan-neofluar 63 x water immersion and Leitz plan-apo 63 x oil immersion-at three different sizes of the confocal detector aperture. The measured PSFs are fairly symmetrical, both radially
Imaging in a confocal microscope with one circular and one annular lens
Optics Communications, 1993
The imaging properties of a confocal reflection microscope with one narrow annular lens and one circular lens are investigated. By altering the radius of the circular lens between the inner and the outer radius of the annular lens, the difference in the coherent transfer functions results in different imaging properties. The results may explain the previously reported phenomenon of observation of spatial frequency harmonics in the imaging of a grating object. .
Optik, 1996
A simple technique for improving 3-D resolution in confocal scanning microscopy is presented. The technique is based on the equal contribution to the image of the illuminating and the collecting lenses. It is proposed, then, to apodize such lenses with complementary filters, the one designed for increasing the resolution in the image plane, and the other for achieving axial superresolution. Each pupil independently introduces zeros in the point spread function, the positions of which can be chosen to lie in the focal plane or along the optic axis. The combined action of both filters produces a narrowing of the point spread function of the system both in the image plane, and along the optical axis. A numerical example with two well-known pupil filters is carried out.