Double-ring perfect vortex beams (DR-PVBs), characterized by their unique doublering radii that are independent of topological charges, have significant potential for applications in optical manipulation and communica...
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Double-ring perfect vortex beams (DR-PVBs), characterized by their unique doublering radii that are independent of topological charges, have significant potential for applications in optical manipulation and communication. However, their wavefronts experience significant distortion when transmitted through strongly scattering media (SSM). In this study, we propose a method to reconstruct DR-PVBs through SSM using full vector transmission matrix-based vector point spread function (VTM-VPSF) engineering. Our approach involves computing a VTM-based operator by performing spatial filtering on each component of the full VTM using a carefully designed vector filtering mask in the Fourier domain. Next, two orthogonal input wavefronts are generated using digital optical phase conjugation (DOPC) on the VTM-based operator. The DR-PVBs with independently controllable topological charge, radius, amplitude, and polarization states for each ring are then reconstructed through the SSM. Additionally, petal-like intensity patterns can be formed when the inner and outer rings with different topological charges are adjusted to the same size. This work provides a promising approach for enhancing optical manipulation and communication of DR-PVBs in scattering environments.
Due to the complexity of acoustic wave propagation in multi-layered objects, their ultrasonic testing is associated with challenges. This paper considers the method of calculating the point spread function (PSF) in th...
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Due to the complexity of acoustic wave propagation in multi-layered objects, their ultrasonic testing is associated with challenges. This paper considers the method of calculating the point spread function (PSF) in the ultrasonic testing of multi-layered materials. This method covers ultrasonic testing using the Total Focusing Method (TFM), which is considered as a benchmark in the field of ultrasonic imaging in NDT. An experimental verification demonstrates the efficiency of the proposed method to solve applied problems in the field of TFM imaging of multi-layered objects.
We propose a model for imaging point objects through a dielectric interface or stratified media. The model is applicable to conventional and confocal fluorescence microscopy, with single- or multi-photon excitation. A...
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We propose a model for imaging point objects through a dielectric interface or stratified media. The model is applicable to conventional and confocal fluorescence microscopy, with single- or multi-photon excitation. An analytical solution is obtained in the form of readily computable functions. When large mismatches occur in the refractive indices of the media of the objective lens and specimen the illumination and detection point spread functions differ significantly, showing that currently used imaging models may fail to correctly predict imaging properties of optical microscopes. (C) 2003 Optical Society of America.
We perform a rigorous, diffraction-based two-dimensional analysis to develop an analytical expression for the point spread function (PSF) of the multiple Bracewell interferometric (in-line, even-numbered multi-apertur...
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We perform a rigorous, diffraction-based two-dimensional analysis to develop an analytical expression for the point spread function (PSF) of the multiple Bracewell interferometric (in-line, even-numbered multi-aperture) configurations proposed for extrasolar planet detection. The number of apertures, total length of interferometer array, and the diameter and shape of individual apertures control the PSF. We show that there are theoretically just a few points where the PSF is zero for monochromatic radiation. These zero-irradiance points disappear due to the spectral width of the source spectrum. When including, also, the finite spatial extend of the source, it is impossible to detect an image of a planet with just a two-aperture interferometer. This analysis further demonstrates that the so-called nulling interferometric techniques decrease the amount of detected radiation originating at the bright star by the same factor as that emitted by the planet. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
X-ray cone-beam computed tomography （CT） has such notable features as high efficiency and precision, and is widely used in the fields of medical imaging and industrial non-destructive testing, but the inherent imagi...
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X-ray cone-beam computed tomography （CT） has such notable features as high efficiency and precision, and is widely used in the fields of medical imaging and industrial non-destructive testing, but the inherent imaging degradation reduces the quality of CT images. Aimed at the problems of projection image degradation and restoration in cone-beam CT, a point spread function （PSF） modeling method is proposed first. The general PSF model of cone- beam CT is established, and based on it, the PSF under arbitrary scanning conditions can be calculated directly for projection image restoration without the additional measurement, which greatly improved the application convenience of cone-beam CT. Secondly, a projection image restoration algorithm based on pre-filtering and pre-segmentation is proposed, which can make the edge contours in projection images and slice images clearer after restoration, and control the noise in the equivalent level to the original images. Finally, the experiments verified the feasibility and effectiveness of the proposed methods.
Modern ground-based telescopes like the planned extremely large telescope (ELT) depend heavily on adaptive optics (AO) systems to correct for atmospheric turbulence. Even though AO correction is used, the quality of a...
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Modern ground-based telescopes like the planned extremely large telescope (ELT) depend heavily on adaptive optics (AO) systems to correct for atmospheric turbulence. Even though AO correction is used, the quality of astronomical images still is degraded due to the time delay stemming from the wavefront sensor integration time and temporal response of the deformable mirror(s) (DM). This results in a blur, which can be mathematically described by a convolution of the true image with the point spread function (PSF). We present an algorithm for single-conjugate adaptive optics PSF reconstruction adapted to the needs of ELTs in a storage efficient way. In particular, the classical PSF reconstruction algorithm is changed in several points to give a more accurate estimate for the post-AO PSF. Bilinear splines are used as basis functions to minimize the computational effort. Results obtained in an end-to-end simulation tool show qualitatively good reconstruction of the PSF compared with the PSF calculated directly from the simulated incoming wavefront. Furthermore, the used algorithm has a reasonable runtime and memory consumption. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)
We examined the point spread function of the polarized light field microscope and established a computational framework to solve the forward problem in polarized light field imaging, for the purpose of furthering its ...
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We examined the point spread function of the polarized light field microscope and established a computational framework to solve the forward problem in polarized light field imaging, for the purpose of furthering its use as a quantitative tool for measuring three-dimensional maps of the birefringence of transparent objects. We recorded experimental polarized light field images of small calcite crystals and of larger birefringent objects and compared our experimental results to numerical simulations based on polarized light ray tracing. We find good agreement between all our experiments and simulations, which leads us to propose polarized light ray tracing as one solution to the forward problem for the complex, nonlinear imaging mode of the polarized light field microscope. Solutions to the ill-posed inverse problem might be found in analytical methods and/or deep learning approaches that are based on training data generated by the forward solution presented here. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
A paraxial solution to the coaxial holographic storage algorithm is proposed based on the scalar diffraction theory and a VOHIL model (volume hologram being an integrator of the lights emitted from elementary light so...
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A paraxial solution to the coaxial holographic storage algorithm is proposed based on the scalar diffraction theory and a VOHIL model (volume hologram being an integrator of the lights emitted from elementary light sources), which can give insight into the optical characteristics of the collinear holographic storage system in an effective way, including the point spread function and shift selectivity. The paraxial solution shows that the reference pattern is the key issue in the point spread function. Thus, the bit error rate of the system can be improved by changing the reference pattern. The proposed solution will be useful in the design of a new reference pattern to perform a high-quality readout pattern in the coaxial holographic storage system. (c) 2007 Optical Society of America.
Most of the previous imaging characteristics analysis of the wavefront coding system has been carried out within the frequency domain. In this paper, the stationary phase method is employed to perform the analysis wit...
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Most of the previous imaging characteristics analysis of the wavefront coding system has been carried out within the frequency domain. In this paper, the stationary phase method is employed to perform the analysis within the spatial domain. The approximate expression of point spread function (PSF) in the presence of defocus aberration is derived for the system with a cubic phase mask, which shows a good agreement with the Fast Fourier Transform (FFT) approach. Based on this, the PSF characteristics are analyzed in terms of the boundaries, oscillations and sensitivities to defocus, astigmatism and coma. (c) 2007 Optical Society of America.
A major issue so far for digital holography is the low lateral resolution. In order to improve the resolution, we deduce the point spread function of the most common and practical digital holographic microscopy system...
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A major issue so far for digital holography is the low lateral resolution. In order to improve the resolution, we deduce the point spread function of the most common and practical digital holographic microscopy system. Based on the derived formulas, the determinant factor of lateral resolution of the system is analyzed. The results show that the optimal resolution of this system is limited by the numerical aperture of microscope objective, and the resolution can be further deteriorated by the recording media parameters and recording distance. By decreasing the recording distance the resolution can be improved dramatically. In addition, by choosing large photosensitive area and small pixel size camera the resolution of the holographic microscopy system can be improved a little. Moreover, the highest resolution and the best image quality can be achieved by image-plane digital holography. Experiment results demonstrate the correctness of the theoretical analysis. (C) 2014 Elsevier B.V. All rights reserved.
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