This PDF file contains the front matter associated with SPIE Proceedings Volume 10816, including the Title Page, Copyright information, Table of Contents, Introduction, Author and Conference Committee lists

Fluorescence imaging is widely employed in biological discovery due to its excellent molecular sensitivity and contrast. However, due to light scattering wide-field fluorescence images are blurred resulting in very low spatial resolution and low image contrast. The existing scanning optical microscopy techniques are commonly restricted to sub-millimeter field-of-view or otherwise slow imaging speeds, limiting their applicability for imaging of fast biological dynamics occurring on larger spatial scales. Herein, we developed a rapid scanning wide-field multifocal structured illumination microscopy method based on a beam-splitting grating and an acousto-optic deflector synchronized with a high speed camera. The multi-beam pattern is focused by a condensing lens and a macroscopic objective to generate multifocal structured illumination profile on the imaged sample that is rapidly scanned at kHz rates. Experimental results show that the proposed method can achieve real-time fluorescence microscopy over a centimeter-scale field of view. Owing to the low numerical aperture of the diffracted beams, the illumination has a large depth of focus and hence is generally not affected by the sample’s curvature, which allowed here imaging of perfusion in the entire mouse cerebral cortex noninvasively. The new approach can be readily incorporated into traditional wide-field microscopes to attain optimal tradeoff between spatial resolution and field of view. It further establishes a bridge between conventional wide-field macroscopy and laser scanning confocal microscopy, thus anticipated to find broad applicability in a variety of applications looking at large-scale fluorescent-based biodynamics.

Three dimensional (3D) fluorescence microscopy has proven essential in biological studies. It allows interrogation of structure and function at spatial scales spanning the macromolecular, cellular, and tissue levels. Two-photon excitation fluorescence microscopy (TPM) is especially well suited to 3D imaging in samples tens to hundreds of microns in thickness, enabling better background rejection than alternatives due to the long wavelength, nonlinear excitation of fluorescence. However, the spatial resolution of conventional TPM is limited by diffraction to ~0.3 um laterally and ~0.8 um axially. In this report, we will introduce our new developed two-photon excitation structured illumination microscopy which combines the two-photon microscopy capability and the super-resolution microscopy capability in the same system. In addition, optical aberrations caused by optical system and biological samples are determined using direct wavefront sensing with a nonlinear guide star (two-photon-excited fluorescence emitted either from the labeled sample or an exogenous marker) and subsequently corrected using a deformable mirror, restoring super-resolution information that is otherwise lost. We demonstrate that both resolution and fluorescence intensity of our super-resolution microscope is improved on a variety of samples, including bead phantoms, cultured cells in collagen gels, and Drosophila brain tissue slides.

We have been developing a large-field and high-resolution micro-CT system that is highly specialized for visualization of the entire secondary pulmonary lobule in a large human lung specimen using a consumer-grade 36M-pixel single lens reflex camera. The secondary pulmonary lobule, a fundamental unit of lung structure, reproduces the lung in miniature. The lung specimen was set in an acrylic cylindrical case with 36 mm diameter and 40 mm height. A field of view of the micro-CT is 40.6 mm wide × 15.1 mm high with pixel size of 3.07 μm using offset CT scanning for enlargement of the field of view. In all, 7200 projections were acquired over an angular range of 360 deg with an angular step of 0.05 deg. Then, we constructed a 13,220 × 13,220 × 4912 voxel image with an isotropic voxel size of 3.07μm for threedimensional visualization of the entire secondary lobule. The whole specimen is depicted in the image using large field of view imaging and micro-architectures of alveolar shapes visualized in the identical image.

Computational ghost imaging (CGI) is expected to be applied to noninvasive biomedical imaging because of its characteristic which allows us to obtain the object's image under a low signal to noise ratio (SNR) condition. However only an amplitude distribution can be obtained by the CGI. Therefore the imaging of the pure phase objects is difficult. Although the phase shifting digital holography has been used for reconstruction of the complex amplitude in the CGI, its experimental setup is cumbersome and sensitive to vibrations. Furthermore four holograms are required for the reconstruction of the complex amplitude because of the phase shifting algorithm, rendering the acquisition time of the phase image slow. Therefore the method is difficult to be applied to the biomedical imaging. An alternative non-interferometric method is proposed in this study. The proposed method uses the transport of intensity equation for the phase retrieval of the pure phase objects, termed transport-of-intensity CGI (TI-CGI). In the TI-CGI, the phase distribution is retrieved from a single defocused image obtained by a modulated optical setup of the CGI, achieving the fast and robust imaging compared with the conventional phase shifting method. Therefore the TI-CGI may be more suitable for the biomedical imaging than the phase shifting method. The TI-CGI is demonstrated by an optical experiment under the low SNR condition generated by the neutral density filters with 1% and 0.1% transmittance. The experimental results conform the effectiveness of the TI-CGI.

In the field of imaging through a single multimode fiber (MMF), various methods have been explored to reconstruct the object. In all these methods, deep learning is more robust and the imaging system is less complex. In this paper, we verified the reconstruction of images from a few-mode fiber with deep learning methods based on the intensity of the light filed with simulation and experiments. Compared with another broadly used method that depends on the measurement of optical fiber transmission matrix, the reconstructed images with deep learning method are not affected by the circular field of view of the fiber aperture.

Optical coherence tomography (OCT) is an imaging technology which can be used to obtain the high resolution cross sectional image of living biological tissues. It has been used to evaluate the structure and function of animal and human kidneys. Preliminary animal and human data suggest that OCT imaging might be a useful non-invasive tool for characterizing renal tubular lumens, such as the opening status of tubular lumens. In this pilot study, living animal kidneys (dog, rat and mouse) were imaged using a swept source OCT (SS OCT) or spectral domain OCT(SD OCT). In vivo imaging scans were carried out using an OCT microscope setup (5×) and by placing the imaging probe above the surface of the living kidney. Semi-quantitative analysis of the OCT images was performed to evaluate the density of the kidney tubules on the surface layer of the cortex. In addition, histological images of the kidneys were restructured to form nephron three-dimensional structure for comparison with the 3D OCT imaging. This study suggests that quantitative OCT imaging might be useful for visualizing the fine structure of the living kidney and determining the density of renal tubules.

Ship target detection is increasingly important to the current war today. Space-based Detection is an important way for getting the remote-sensing image included the ship target. Ship target characteristics analysis is the key of infrared image reorganization. It includes the thermal radiation of the target and background, Atmospheric transmission characteristics, imaging characteristics of detector and target characteristics. In order to get the simulation image in the infrared long-waveband, it analyses the characteristics of the infrared ship target and background. The target characteristics are known clearly, it could make the extraction process of target more effective and accurate. The target characteristics analysis is more conducive to the detection and recognition of the target.

Recently, experiments of X-ray free electron lasers (XFEL) single-particle coherent diffraction imaging (CDI) have demonstrated the potential to reconstruct the three-dimensional (3D) structure of non-crystalline biological samples with high spatial resolution. For successful reconstructions, a complete 3D Fourier transform of the particle is to be assembled by a lot of diffraction patterns from identical particles. In practice, this is difficult because the orientations of the injected particles are random. Incomplete 3D Fourier transform composed of limited projection orientations may cause lower resolution of 3D reconstruction. To get superior 3D reconstructions, equally sloped tomography (EST) may be applied to the incomplete 3D Fourier transform data set of single-particle CDI. In this paper, some challenges and corresponding approaches to CDI are briefly discussed. In principle, CDI can yield wavelength-limited resolution without any of the limitations of physical lenses. At present, CDI is deceptively simple to implement. Successful application of CDI to experimental data, however, is not universal and requires considerable mathematical physics skills and interdisciplinary experiences. Whether or not lensless microscopy can outweigh the lens-based one will depend on the competition between the computational power and the precise manufacturing technique of lens in the future, especially in the field of real time imaging. As a type of quickly developing algorithmic microscopy, researchers still should improve the precision, robustness and convergence speed of CDI reconstruction algorithms.

In the traditional fluorescence detection, samples are tested in the solvent, and the mutual effect of solvent, micro impurity and sample affects the fluorescence characteristics. Meanwhile, such effect includes vibrational relaxation, electron rearrangement of solvent molecule, special role of the sample with the solvent molecules and so on. The experiment of fluorescence quantum efficiency at atmosphere reduces the interference, because the distance between molecules is much larger in gas phase. In addition, the research of quantum efficiency can also promote the understanding of LIF and expand the range.

In this paper, the fluorescence quantum efficiency of 3 different samples at atmosphere was compared, and the electrospray ionization source was selected for its soft ionization characteristics. The ionization method did not spoil the fluorophore of the sample, and the drift tube of ion mobility spectrometry (IMS) was used for ions transport and desolvation. The ionization source was on the one side of the drift tube and the test point was on the other side. The paths of excited laser and emission light were orthogonal at the test point. Meanwhile, stable ions flowed through the drift tube. The emission light was captured by the camera, which was coupled with a long-wave pass filter. The test samples were Rhodamine 6G，Rhodamine B and amino copper indium sulfide quantum dots of the same mass fraction. The energy of excited laser was between 30 mW and 150 mW. Then the results showed that the emission intensity was proportional to the laser power in gas phase, and the sort of the fluorescence quantum efficiency was the quantum dots>Rhodamine 6G>Rhodamine B.

As the development of the polychrome printing technology, more and more pigments are available on printing and packaging industry, which has brought new requirements to the on-line color defect detection for printed matter. There are always difficulties for traditional detecting approaches with commercial RGB cameras to provide competent color resolution due to the color gamut limitation. In this communication, we proposed a snapshot multispectral imaging method using a novel spectral filter array (SFA), which has eight spectral channels and one panchromatic channel. Spectral reconstruction and color reproduction was carried out by using BP network with the training on Munsell colors and typical printed samples. We defined the empirical threshold values for color defect detection in the spectral vector space, and demonstrated the validity of this method with practical printed matter experiments.

Synthetic aperture particle image velocimetry (SAPIV) is a flow field diagnostic technique that provides instantaneous velocimetry information non-intrusively. In SAPIV, particle scattering images are captured from different cameras with camera array configuration. To acquire refocusing images, images are remapped and accumulated in pre-designed remapping planes. During the refocused images, particles that lie in the remapped plane are aligned and appear sharp, whereas particles off this surface are blurred due to parallax between the cameras. During the remapping process, captured images are back-projected to different remapped planes of different depth z within the volume. The projected images from different cameras, which are called remapped images, are merged to generate refocused images at different depth z. We developed a remap method based on the weight coefficient to improve the quality of the reconstructed velocity field. The images captured from the cameras are remapped into different remapped planes by use of homography matrix. The corresponding pixels of the remapped images in the same remapped plane are first added and averaged. The corresponding pixels of the remapped images in the same remapped plane are multiplied and the obtained intensity values act as the weight coefficients of the intensity in the added refocused image stacks. The unfocused speckles can be restrained to a great degree, and the focused particles are retained in the added refocused image stacks. A 16-camera array and a vortex ring field at two adjacent frames are simulated to evaluate the performance of our proposed method. In the simulation, a vortex ring can be clearly seen. An experimental system consisting of 16 cameras was also used to show the capability of our improved remap method. The results show that the proposed method can effectively restrain the unfocused speckles and reconstruct the velocity field in the flow field.

Polarization-resolved stimulated Raman scattering spectroscopies and microscopies have been utilized to investigate the symmetry and orientation of molecular vibrational modes and to provide extra spectral signatures, while the polarization modulation introduced additional complexity and the successive measurement on different polarization states limits the imaging speed. Here we demonstrate dual-polarization hyperspectral stimulated Raman scattering microscopy which enables detailed imaging measurement in two orthogonal polarization states simultaneously at video-rate speed. Two polarized Raman images can be obtained within ~0.03s, while the Raman shift is scanned in the CH stretching region in 3 s by virtue of rapid wavelength tunability of laser pulses. We observed different kinds of polymer beads and liquid, the results of which prove the ability to measure the symmetry of vibrational modes and to distinguish the overlapped peaks. Moreover, HeLa cells were imaged to prove the applicability to biological samples and show additional spectral signatures in perpendicular spectra. This novel method endows fast yet detailed imaging analysis of biomolecules in live specimens to research on drug delivery, electric stimulation, metabolic engineering etc.

The principal component analysis method (PCA) and the kernel entropy component analysis method (KECA) are used to construct the spectral reflectance, and study the color reproduction. . This study compares reconstruction precision through the spectral reflectance reconstruction methods based on principal component analysis (PCA), kernel principal component analysis (KPCA), and kernel entropy component analysis (KECA). Experimental results show that spectral reconstruction algorithm based on KECA is superior than PCA and KPCA in chromaticity precision and spectral precision. It has certain application value for the true color reproduction of the object surface.

We set up the terahertz continuous reflectometry imaging system and the spatial resolution of our system was roughly 0.6×0.6mm at 2.52 THz. We also demonstrated that the paraffin embedded traumatic brain injury (TBI) in rat model sample can be differentiated clearly. The results show that the THz reflection intensity of the TBI area was lower than that of normal area. These promising results suggest that THz reflection imaging has great potential as an alternative method for the fast diagnosis of TBI.

The loop-closure detection module in visual SLAM eliminates cumulative error from the front-end by detecting the fact that the camera passes through the same place as it passed before, providing the back-end optimization with constraints among longer intervals apart from neighboring frames, resulting in globally consistent trajectories and maps. In order to solve the problem of time-consuming and poor robustness existed in feature point matching based loop-closure detection algorithm, the article uses the Bag-of-words model based on ORB features to find loop-closure and performs spatial consistency verification on results. Firstly, the ORB feature points of image data sets are clustered to construct a dictionary. In order to complete query operations within logarithmic time, the data structure of k-ary tree is adopted. K-means++ clustering is implemented layer by layer to ensure uniform clustering. Afterwards with words bag, an image is expressed by a vector. The article uses Term Frequency-Inverse Document Frequency to assess the importance of each word so as to obtain an more effective description. Finally, the article select key frames to implement the detection. In this way repetitive detection of similar loops can be avoided and coverage of the entire environment can be guaranteed .The L1 norm is used to calculate the similarity scores between key frames. The scores are normalized using a priori similarity thus avoiding the introduction of absolute similarity thresholds, which makes the algorithm more adaptable. To remove wrong loop-closure, the spatial consistency test based on Pose Graph optimization is performed on detection results. Experiments show that the loop-closure detection algorithm used in the article has a good recall rate when the accuracy rate is high.

Ghost imaging is an imaging mechanism that can non-locally obtain an unknown object’s information with a single-pixel detector by the correlation of intensity fluctuations. To overcome the drawback of polarization compressive ghost imaging (PCGI), here we develop a novel adaptive polarization compressive ghost imaging (APCGI) method. By performing principal component analysis of the polarization statistics, we can compute the optimum unequal weighting coefficients forming as linear combinations of the light into bucket detectors. The specific steps of APCGI include calculating complete polarization parameters on the background, performing principal components analysis for optimal parameters, obtaining the information on the target-with-background scene. Experimental results demonstrate that adaptive polarization compressive ghost imaging performs better in restraining the background and pop out the details of targets as well as obtains better image quality.

Space target detection technology based on visible light image sequence is of great significance to improve the defense capability of space debris. The path of an empty debris target is usually a straight line on the image. Firstly, this paper established the motion model of the space target according to its motion characteristics, and proposed a target initial screening method based on image sequence projection frame. In the initial screening target, a directed graph is established according to the constraints of motion, and the trajectory parameters are obtained simultaneously. Then calculating the similarity between the trajectory parameters, from which the track correlation matrix could be obtained. According to the result of correlation, the initial target is reduced to form a directed graph, and the selected node is the target point. Extensive experimental results show that the proposed method can effectively detect space moving objects, and the performance of the proposed algorithm is better than other algorithms.

The traditional imaging method can only obtain the two-dimensional information of the object space in lateral resolution through a single exposure, but cannot obtain the longitudinal depth information. The depth information of the object space will be lost because the object cannot be reconstructed in three dimensions. The light field imaging technology enables reconstruction of three-dimensional objects by means of adding microlens arrays into a conventional camera system. The technology has a wide range of applications in medical, military, and entertainment. In this paper, a light field acquisition technology using microlens based on 3ds Max is proposed. A 3D object model was established using 3ds Max. By establishing a virtual microlens array, the crosstalk-free, high resolution and fast acquisition of the light field image by the microlens can be realized. Simulation study of the light field imaging technology can provide a highefficiency computational study. The acquired images are processed to reconstruct images from different perspectives. Finally, the light field imaging experiments based on microlens arrays is carried out to realize the image reconstruction in different perspective images. Reliability of the algorithm is verified.

Gold nanorods (GNRs) are promising nanomaterials for applications in biomedicine because of their special optical properties, and tremendous works have reported their potential in imaging, diagnosis and treatment of cancer. Unfortunately, study on gold nanorods and cell interactions is still incomplete, and the interplay between gold nanorods and different subtype of breast cancer cells is rarely reported. In the study, two different type of gold nanorods (GNRs and GNRs@SiO₂) was synthesized. And we investigated the interactions of gold nanorods (GNRs and GNRs@SiO₂) with ER+ (MCF-7)/ER-(MDA-MB-231) breast cancer cells, including cytotoxicity, cellular uptake. Our results showed that GNRs are more cytotoxic to MCF-7 and MDA-MB-231 cells than GNRs@SiO₂. And MCF-7 and MDA-MB-231 cells internalize GNRs in a time dependence, and MCF-7 is far more effective in taking up GNRs. The result suggests different subtype of tumor cells should be considered to fully understand the interactions of gold nanorods and cells.

Fourier ptychographic microscopy (FPM) is a newly developed imaging approach for achieving wide field and high resolution. However, image quality will degraded by the pupil aberration because of the limitation of geometrical optics. In this paper, two correction algorithms of pupil aberration combining original FPM algorithm with ptychographical iterative engine (PIE) are presented and justified. And the standard coefficients of Zernike polynomial are applied for constructing the pupil aberration in the simulation. Compared to original FPM algorithm, these algorithms add constraints to the sample and the pupil during each iteration, so that the image can be reconstructed and the pupil function can be recovered simultaneously. Furthermore, we illustrate that these algorithms can not only improve robustness, but also have faster convergence under different aberrations.

A method for measuring the channel size of microfluidic chip by using optical coherence tomography (OCT) is investigated. Based on spectral-domain OCT imaging and image processing, an OCT system for measurement of the microfluidic channel size is developed, which is suitable for planar two-dimensional measurement. The cross-sectional images of the micro-channel of a microfluidic chip are obtained by using OCT continuous B-scan technology. With image processing for the acquired image in noise elimination and dispersion compensation, the size of the micro-channels in depth is achieved. Comparing with the single-scan OCT imaging mode, back-passing multiple-scans mode has the capability of high image quality to achieve high measurement precision of micro-channel size.

Ovarian cancer has become one of the most common malignant tumors threatening female genital health. Recently, biomechanical properties of single cell have been reported as a potential index for early cancer detection. In this study, the viscoelastic properties of ovarian cancer cells were determined using stress-relaxation approach by atomic force microscopy (AFM). Individual force-time curves were recorded at maximum loads of 0.5, 1 and 2 nN, and the stressrelaxation time was 2 s for all the stress-relaxation measurements. A theoretical method of stress relaxation was proposed and the viscoelasticity of the cells was obtained according to a linear solid model. The results showed that the values of average viscosity of ovarian cancer cells were respectively 54.0±6.5 Pa-s, 100.5±13.2 Pa-s and 113.6±13.2 Pa-s using the three different loading forces from 0.5 nN to 2 nN. Furthermore, the values of average elasticity modulus were respectively 657.0±69.9 Pa, 730.9±67.0 Pa, 895.0±71.3 Pa. In conclusion, the viscoelasticity properties of the cells increased as the loading force increased from 0.5 nN to 2 nN. Our study indicates that the viscoelasticity of the ovarian cancer cells can be acquired by stress-relaxation approach and the loading force is an important factor that can affect the cellular viscoelasticity. It will shed new light on cancer early detection based on cellular viscoelasticity index at single cell level.

Fire has caused great losses to human beings. However, there are many problems in traditional fire detection methods.Considering the instability and high rate of erroneous recognition with these methods ,a flame recognition algorithm based on LVQ neural network is proposed in this paper. The basic characteristics and some information of the flame are analyzed.Moreover,the LVQ neural network technology is used to achieve fire detection.First, the suspicious targets of the image are extracted by flame color features.After the image morphological processing,the circular value is calculated and the interference regions with larger circular degree values is eliminated.Then,the dynamic features of the flame are extracted from the continuous frame. The area of fire will increase gradually and the image shows a continuous increase in high brightness area. The sharp corners of the flame are characterized by elongate and its number changes irregularly.Finally,the structure of the LVQ neural network, the designed of the input and output layers have been concluded. On this basis, a flame recognition algorithm based on LVQ neural network has been designed and a series of fire image experiments have been conducted.The experiment shows that the recognition accuracy of the algorithm reaches 96%.

A novel polymeric nanoparticle was developed between the negatively charged dendrimer phthalocyanine and positively triblock copolymer for the use as an effective photosensitizer in photodynamic therapy. The intracellular uptake of dendrimer phthalocyanines in HeLa cell was significantly enhanced by encapsulated into nanoparticles. The photocytotoxicity of dendrimer phthalocyanines incorporated into polymeric micelles was also increased. The presence of nanoparticles located induced efficient cell death.

Recently, nanostructures composed of tapered apertures have been researched for electromagnetic field enhancement. Tapered plasmonic aperture antenna can concentrate transverse electric dipoles and longitudinal magnetic dipoles in tiny volume of plasmonic waveguide or metasurface. It is an important element for efficient nonlinear optics, modification of spontaneous decay rates, and sensitive nanophotonic sensors to simultaneously intensify both of electric and magnetic fields. However, even though their advantages include apparent theory based on constructive interference of surface plasmons and relatively simple fabrication, the enhancement performances are not strong as much as those of conventional bridged bowtie aperture antenna. Here, we propose a novel design with reflection type metasurface patterned by a funnel-shaped waveguide cavity array. This supports longitudinal cavity mode along the direction of incident light in addition to perimeter cavity mode or transverse cavity mode of conventional tapered apertures. Longitudinal cavity mode contributes to electric and magnetic fields on transverse plane and transverse cavity mode with funnel shape induces strong circulating currents around tiny volume that generate magnetic dipoles on longitudinal plane. To demonstrate our proposed design, we carry out three-dimensional finite element method for numerical calculation. It shows resonant average (maximum) enhancements of electric and magnetic intensities reach about 177 (1484) and 91 (274), respectively, at the wavelength of 1120 nm. Furthermore, the enhancement of spontaneous decay rates and Purcell effect are verified numerically. Our design can offer a new approach of various nano-optical applications such as biochemical sensor, nonlinear optics, and photoluminescence application.

This paper deals with the problem of compressed-domain human fixations detection in the video sequences, and presents a fast and efficient algorithm based on Motion Vector Entropy (MVE) and Operational Block Description Length (OBDL). The two features are obtainable from the compressed video bitstream with partial decoding, and generate the feature maps. The two feature maps are processed, and generate MVE map and OBDL map respectively. Then the processed maps are fused. In order to further improve the global saliency detection, the fused map is worked by the Gaussian model whose center is determined by the feature values. The validation and comparison are made by several accuracy metrics on two ground truth datasets. Experimental results show that the proposed saliency detection model obtains superior performances over several state-of-the-art compressed-domain and pixel-domain algorithms on evaluation metrics. Computationally, our algorithm achieves the real-time requirements of the saliency detection.

Intraocular pressure (IOP) is the pressure exerted by the eye contents on the eyeball wall and is used to maintain the shape of the eyeball. It may cause glaucoma when the dynamic balance of the generation and excretion of aqueous humor in the eyeball is broken. The Goldmann applanation tonometer (GAT) based on the Imbert-Fick principle is considered to be the reference standard for glaucoma diagnosis in clinics. OCT is widely used for eye screening by imaging structural changes caused by various eye diseases. In this paper, we have developed an OCT-assisted transparent flexible force sensing system (O-FPSS) for IOP measurements. In general, the hybrid O-FPSS consists of a droplet-based flexible transparent force sensor placed over an optical coherence tomography imaging lens, in which the IOP measured once the apex of the cornea is flatted by the sensor. According to the Imbert-Fick law, when cornea is flattened, the pressure applied by the sensor equals to the IOP. Specially, the droplet-based capacitive flexible force sensor is consisted by two flexible conductive membranes, and an ionic is sandwiched in between, in which the force applied on the cornea can be monitored by the output. The sensing membrane deforms uniformly upon contacting the cornea, leading to the expansion of the droplet and an increase of the overall capacitance. On the other hand, to get the flatten area between the sensor and the cornea, a swept-source OCT (SS-OCT) is used to record the interfacial with a resolution of 5μm.

Optical coherence tomography (OCT) is a useful optical biopsy tool. Its potential in the evaluation of living kidney has been demonstrated. One of such applications is to predict the acute tubular necrosis (ATN) associated with kidney transplantation. The light dense and lucent regions seen in 2D OCT scanning are considered as a useful marker of the renal tubules. In this study, the OCT examination of living human kidney was carried out using a swept source (SS) OCT (SS-OCT) system. The light lucent regions in the cortex obtained on the OCT scan were defined as low signal cavities. The structure features of characteristic cavities in 2D and simulated 3D OCT images were quantitatively analyzed using Amira and Matlab programs. Although the imaging acquisition and real-time analysis were feasible for the examination of donor kidney before and after the transplantation, as the imaging acquisition was obtained under the hand-hold fashion, OCT images might become blurred and the tubules became hardly distinguishable from cortex background, especially for 3D images. In order to optimize the scanning parameters of the OCT imaging process, the influence of the jittering of the living kidney on the quality of OCT imaging and the distortion of the renal tubule structure were studied.

Optical coherence tomography (OCT) is now a popular high resolution optical imaging technology capable of providing three-dimension images of internal microstructures within biological tissues. To date, the most successful application of OCT has been in ophthalmology, where the technology has become an indispensable diagnostic tool. It has proven able to image the structural changes due to various eye diseases. Besides, those structural changes may also be associated with certain physiological conditions, for instance, vessel density changes resulting from intraocular pressure change. Intraocular pressure (IOP) can also serve as an important physiological marker for the diagnosis of ophthalmic diseases. Therefore, in this study, we aim to develop ophthalmic OCT combined with a novel flexible pressure sensor for retina imaging and intraocular pressure measurement. A swept source OCT (SS-OCT) system is designed, and its axial resolution is about 5 μm. The OCT system is specially designed to allow for both anterior and posterior eye segment imaging. The anterior eye segment imaging is dedicated to measure the contact area between the pressure sensor and the cornea, which is needed by the pressure sensor to calculate the intraocular pressure. This system will be a versatile ophthalmic imaging platform: (1) conventional anterior and posterior eye imaging; (2) intraocular pressure measurement. Further, it will serve as a useful tool aiding in eye disease diagnostics in clinics.

Signal sampling is a bridge to analog source signal and digital signal. Over the years, the base theory of signal sampling is the famous Nyquist sampling theorem, but a large amount of data generated by the waste of storage space. Compressed Sensing proposes a new sampling theory that can sample signals well below the Nyquist sampling rate. Also, the varied reconstruction algorithms of CS can faithfully reconstruct the original signal back from fewer compressive measurements. Therefore, the theory of compressed sensing has been widely used in many fields such as analog-to-signal conversion, synthetic aperture radar imaging, and speech recognition. This paper first elaborates the basic theory model of compressed sensing and focuses on the latest developments in the three aspects of signal sparse transformation, observation matrix design, and reconstruction algorithms. Then this paper also reviews several open problems in CS theory and discusses the existing difficult problems. Secondly, the application and development of compressed sensing in the imaging field are described in detail, compressive imaging technology breaks through the traditional imaging system design concept and uses hardware to achieve non-adaptive linear projection of the target image, thereby achieving the purpose of acquiring a high-precision target image with a smaller number of detectors. And in-depth discussion and analysis of current common compressive imaging systems. Finally, this paper also highlights some of the challenges and research directions in this field.

The aspects of the use of dioptric optics for DUV microscopy are considered. The transition to the NUV and DUV range can significantly improve the resolving power of the microscope. Different kinds of crystals can be used as optical materials.