Conventional full-view imaging systems, which often need complicated image processing algorithms to reconstruct full-view images captured by motional/multiple cameras from different views, cannot have good real-time i...
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Conventional full-view imaging systems, which often need complicated image processing algorithms to reconstruct full-view images captured by motional/multiple cameras from different views, cannot have good real-time imaging capability. We design curved-to-flat conversion lens (CFCL) based on optic-null medium, which can directly project/image optical patterns from closed object surface onto image plane (e.g., the focal plane of microscopy), and shows good real-time full-view imaging performance. To realize the CFCL, the reduced opticnull medium is designed by subwavelength metal channels filled with homogeneous isotropic dielectrics. Numerical simulation results verify the function of the designed CFCL, which can image various dynamic optical patterns from the closed object surface to the finite-view image plane. The designed CFCL may have many applications in real-timely observing dynamic closed surfaces in full view, e.g., living tissue/cell and soft material's surface. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
A method is proposed for evaluating the quality of higher-order Bessel light beams (BLBn, order n > 0) by analyzing digital computer images of two-dimensional transverse intensity distributions. One image is suffic...
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A method is proposed for evaluating the quality of higher-order Bessel light beams (BLBn, order n > 0) by analyzing digital computer images of two-dimensional transverse intensity distributions. One image is sufficient to assess the quality in a specific transverse cross section of a BLBn. algorithms are described which ensure correct implementation of this method: an algorithm for evaluating the position of the axis of an annular beam based on cluster analysis, an algorithm for estimating an initial approximation of the conicity parameter when approximating experimental diametral intensity distributions by the square of a Bessel function based on analyzing the spectral power density of the diametral distribution. The proposed method and algorithms are implemented in the form of an extension of a software package for analyzing the quality of Bessel light beams. The software package is used to test the method experimentally to analyze a BLB1 produced with the aid of KTP (KTiOPO4) and KGW (KGd(WO4)(2)) crystals from a study of a semiconductor laser module (SCLM) and a helium-neon laser (HNL). It is shown that the beam formed by the HNL retains a constant radius along different azimuthal directions while the conformity to the shape of an ideal BLB1 is lost over a larger distance from the axicon than the SCLM, but also loses its constant intensity more rapidly along different azimuthal directions in the first annulus.
Measurements of angular vibration of aerial cameras in a variety of operating conditions are critical to analyze the performance of the vibration isolation system. Instead of using an additional optical system to meas...
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Measurements of angular vibration of aerial cameras in a variety of operating conditions are critical to analyze the performance of the vibration isolation system. Instead of using an additional optical system to measure the angular motion of the camera, an image-based and easy-to-implement method is proposed for the linear array camera to measure the image motions captured by the camera directly. The natural frequencies of the vibration isolation were also measured by laboratory vibration test. For image vibration measuring, the angular vibration is represented in image motion by the relationship between the image motion and angular motion of the camera. Based on the push-broom imaging principle, the image motion at the edge of the foreground image of the linear object is extracted using imageprocessing technology including image segment and edge detection methods. Then the image motion is analyzed in the time and frequency domains. The proposed method has been successfully demonstrated for the angular vibration measurement by a flight test. The results of the vibration sensors and the position and orientation system of the flight tests are also given to validate the effectiveness and accuracy of the proposed approach. (C) 2021 Optical Society of America
We describe an end-to-end image systems simulation that models a device capable of measuring fluorescence in the oral cavity. Our software includes a 3D model of the oral cavity and excitation-emission matrices of end...
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We describe an end-to-end image systems simulation that models a device capable of measuring fluorescence in the oral cavity. Our software includes a 3D model of the oral cavity and excitation-emission matrices of endogenous fluorophores that predict the spectral radiance of oral mucosal tissue. The predicted radiance is transformed by a model of the optics and image sensor to generate expected sensor image values. We compare simulated and real camera data from tongues in healthy individuals and show that the camera sensor chromaticity values can be used to quantify the fluorescence from porphyrins relative to the bulk fluorescence from multiple fluorophores (elastin, NADH, FAD, and collagen). Validation of the simulations supports the use of soft-prototyping in guiding system design for fluorescence imaging. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
This feature issue of Biomedical Optics Express covered all aspects of translational photoacoustic research. Application areas include screening and diagnosis of diseases, imaging of disease progression and therapeuti...
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This feature issue of Biomedical Optics Express covered all aspects of translational photoacoustic research. Application areas include screening and diagnosis of diseases, imaging of disease progression and therapeutic response, and image-guided treatment, such as surgery, drug delivery, and photothermal/photodynamic therapy. The feature issue also covers relevant developments in photoacoustic instrumentation, contrast agents, imageprocessing and reconstruction algorithms. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
The depth-of-field of imaging systems can be enhanced by placing a phase mask in their aperture stop and deconvolving the image. In general, the mask is optimized using a closed-form image quality criterion assuming d...
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The depth-of-field of imaging systems can be enhanced by placing a phase mask in their aperture stop and deconvolving the image. In general, the mask is optimized using a closed-form image quality criterion assuming deconvolution with a Wiener filter. However, nonlinear deconvolution algorithms may have better performance, and the question remains as to whether a better co-designed system could be obtained from optimization with a criterion based on such algorithms. To investigate this issue, we compare optimization of phase masks with criteria based on the Wiener filter and on a nonlinear algorithm regularized by total variation. We show that the obtained optimal masks are identical, and propose a conjecture to explain this fact. This result is important since it supports the frequent co-design practice consisting of optimizing a system with a closed-form criterion based on linear deconvolution and deconvolving with a nonlinear algorithm. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
We report experiments conducted in the field in the presence of fog, that were aimed at imaging under poor visibility. By means of intensity modulation at the source and two-dimensional quadrature lock-in detection by...
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We report experiments conducted in the field in the presence of fog, that were aimed at imaging under poor visibility. By means of intensity modulation at the source and two-dimensional quadrature lock-in detection by software at the receiver, a significant enhancement of the contrast-to-noise ratio was achieved in the imaging of beacons over hectometric distances. Further by illuminating the field of view with a modulated source, the technique helped reveal objects that were earlier obscured due to multiple scattering of light. This method, thus, holds promise of aiding in various forms of navigation under poor visibility due to fog. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
In this Letter, we present the modeling, design, and characterization of a light sheet-based structured light illumination (SLI) light field microscopy (LFM) system for fast 3D imaging, where a digital micromirror dev...
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In this Letter, we present the modeling, design, and characterization of a light sheet-based structured light illumination (SLI) light field microscopy (LFM) system for fast 3D imaging, where a digital micromirror device is employed to rapidly generate designed sinusoidal patterns in the imaging field. Specifically, we sequentially obtain uniformly illuminated and structured light field images, followed by post-processing with a new, to the best of our knowledge, algorithm that combines the deconvolution and HiLo algorithms. This enables fast volumetric imaging with improved optical cross-sectioning capability at a speed of 50 volumes per second over an imaging field of 250 x 250 x 80 mu m(3) in the x, y, and z axis, respectively. Mathematical models have been derived to explain the performance enhancement due to suppressed background noises. To verify the results, imaging experiments on fluorescence beads, fern spore, and Drosophila brain samples, have been performed. The results indicate that the light sheet-based SLI-LFM presents a fast 3D imaging solution with substantially improved optical cross-sectioning capability in comparison with a standard light sheet-based LFM. The new light field imaging method may find important applications in the field of biophotonics. (C) 2021 Optical Society of America.
Detail enhancement is the key to the display of infrared image. For the infrared image detail enhancement algorithms, it is very important to present a good visual effect for people effectively. A novel algorithm for ...
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Detail enhancement is the key to the display of infrared image. For the infrared image detail enhancement algorithms, it is very important to present a good visual effect for people effectively. A novel algorithm for detail enhancement of infrared images is proposed in this paper. The method is based on the relativity of Gaussian-adaptive bilateral Filter. The algorithm consists of three steps. The first step is to divide the input image into the base layer and the detail layer by the relativity of Gaussian-adaptive bilateral filter. In the second step, the detail layer is multiplied by the proposed weight coefficient, and the base layer is processed by histogram projection. The third step is to combine the detail layer and the base layer processed in the second step and output it to the 8-bit domain display. Compare with other methods, the new algorithm reduces the running time greatly. The experimental results showed that the proposed algorithm improves the contrast of infrared images effectively. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
The CMY colour camera is different from the RGB counterpart where the subtractive colours cyan, magenta and yellow are used. The CMY camera performs better than an RGB camera in low light conditions. However, conventi...
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The CMY colour camera is different from the RGB counterpart where the subtractive colours cyan, magenta and yellow are used. The CMY camera performs better than an RGB camera in low light conditions. However, conventional CMY colour filter technology made of pigments and dyes are limited in performance for next generation image sensors with submicron pixel sizes. This is because the conventional CMY filters cannot be fabricated in nanoscale as they use their absorption properties to subtract colours. This paper presents a CMOS compatible nanoscale thick CMY colour mosaic made of Al-TiO2-Al nanorods forming a total number of 0.82 million colour filter pixels with each filter pixel size of 4.4 mu m arranged in a CMYM pattern. The colour mosaic was then integrated on a MT9P031 image sensor to make a CMY camera and colour imaging is demonstrated using a 12 colour Macbeth chart. The developed technology will have applications in astronomy, low exposure time imaging in biology, and photography.
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