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This PDF file contains the front matter associated with SPIE Proceedings Volume 11502, including the Title Page, Copyright Information, and Table of Contents.
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Considering the disadvantages of low definition, low image contrast and brightness, inconspicuous details, which make image analysis more complicate, we developed quantum medical image processing system software. It includes quantum image enhancement module, quantum image denoising module and quantum image segmentation module, which respectively study the quantum enhancement algorithm, quantum denoising algorithm and quantum segmentation algorithm. Quantum denoising algorithm firstly add noise to the image and then carries out a logarithmic transformation and a double density dual-tree complex wavelet transform on the noise-added image, later a denoising of the wavelet coefficients based on Bayesian theory, and the Maxaposterior (MAP) is performed to estimate the variance of the double-tree complex wavelet. Finally the denoised image is obtained from the inverse transform of the dual-tree complex wavelet. Quantum enhancement algorithm improves image quality through quantum inspired and unsharp masking. First, a quantum enhancement operator based on quantum superposition state theory was constructed to enhance image contrast ratio, then the processed image quality was improved by unsharp masking. Quantum segmentation algorithm searches automatically the optimal threshold through improved quantum genetic algorithm, which reduces the complexity of program and improves the information entropy compared with traditional methods. More image information can be retained and more ideal segmentation effect is realized through the algorithm. Experiment show that the peak signal-to-noise ratio (PSNR) for the quantum algorithm is improved by over 2dB and the edge retention index (EPI) is 0.1 higher than that for common methods, image information entropy and clarity index are significantly improved.
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As a combination of laser technology and modern photoelectric detection technology, lidar (laser radar) has notable advantages compared with traditional radar such as high resolution, strong anti-interference ability, and good low-altitude detection performance. However, with continuous application in aerospace, military, artificial intelligence and other fields, lidar has reached the limits of classical physics and can’t meet the requirements in detection, measurement and imaging. In order to break the bottleneck, worldwide researchers have developed a new type of radar-quantum lidar, which is based on the combination of traditional radar technology and quantum information technology. Its main principle is to get imaging through squeezed light that is below the noise limit of classical physics and then manipulated by the quantum state to achieve imaging with higher quality. Quantum lidar in the paper injects quantum squeezed light to receiver end and uses quantum phase-sensitive amplifier technology to compensate the photon loss that caused by insufficient quantum power to further improve resolution. In the squeezed light, the generation of quantum squeezed light and detection theory are studied, the resonant cavity locking principle and balanced homodyne detection principle are analyzed, and a mode cleaner with narrow line width is designed to improve beam transverse mode quality of laser and filter high frequency noise. In order to reduce quantum noise and improve resolution, quantum lidar imaging system is developed and the theoretically derivation and numerical simulation results show that the resolution of quantum lidar imaging is 1.71 times higher than that of lidar imaging.
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Taeangun is a small peninsular district located on the west coast of the main Korean peninsula. To the west, it faces with the yellow sea while its east side is bordered with the main land Korea. This area is well known to have 1) busy mid and high altitude air traffic routes between Korea and neighboring countries and 2) complex and rapid changes in its atmospheric characteristics that tends to reduce the performances of mid infrared (IR) surveillance equipment looking at the aerial targets. In this conference, we report a progress of our study on atmospheric radiative transfer characterization of a coastal interface area, as a precursor to the main study for Taeangun, by using a black body and a mid IR camera. Mid-wave IR camera used are the model X8500 and SC7600 with a lens assembly of 200mm focal length from FLIR® Systems. A blackbody of 7 inch in aperture with the uniformity of ±0.010 and emissivity ℃ of 0.97±0.02.is used as the target to be measured. The camera and the target blackbody are stationed at the distance of 0.73km to each other. The target was observed across the mid IR wavelength range. In this report, we summarize the current progress of the simulation of atmospheric transmission characterization and of the analysis result of experiment data.
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Taean is a small peninsular along the west coast of the mainland of Korean peninsula. It faces with the yellow sea to the west, while it is bordered with the mainland Korea to the east. The area is well known to have 1) heavy mid and high altitude air traffic, 2) busy traffic routes of ocean liners between Korea and neighboring countries and 3) complex and rapid changes in its atmospheric characteristics that tends to reduce the accuracy of regional weather forecast and therefore influencing the local industry including ocean liners. In this conference, we report a progress on customization of atmospheric transmission model suitable for direct solar irradiance measurement in the region. A large volume of direct solar irradiance and atmospheric variable data were collected over the period of 12 months in 2018. The data were obtained not only from the ground stations for low altitude, but also from the radiosonde measurement for high altitude. Initial analysis using MODTRAN showed some portions of the direct solar irradiance data that disagree with the predictions from the MODTRAN standard atmospheric models. Further in-depth study including sensitivity analysis were carried out and resulted in construction of a customized MODTRAN atmospheric model offering more accurate prediction to the measured direct solar irradiance data of the local area.
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ESA’s ExoMars program comprises two missions including the Trace Gas Orbiter (TGO), launched in 2016, and a rover and surface platform, to be launched in 2022. The main scientific objectives of the program are to investigate the Martian environment and climate and search for past or present signs of life. For this purpose, a suite of three infrared spectrometers for remote sensing (Atmospheric Chemistry Suite, ACS) is in use on TGO. One of these instruments is a Fourier transform spectrometer, TIRVIM (Thermal IR V-shape Interferometer Mounting in honor of Vassili Ivanovich Moroz), operating in nadir, limb or solar occultation mode between 1.7 and 17 μm. On ExoMars22’s surface platform the spectrometer FAST (Fourier for Atmospheric Species and Temperature) will study the atmosphere and surface at the landing site in the same wavelength range as TIRVIM on TGO. This paper presents the objectives of TIRVIM and FAST. It summarizes selected results of the determination of temperature profiles and dust content in the lower atmosphere of Mars based on radiative transfer modeling of TIRVIM data. Synergetic analyses of TIRVIM spectra and InSight (NASA) in situ measurements of temperature and pressure at InSight’s landing site in Elysium Planitia enable improvements of procedures to retrieve parameters from TIRVIM observations. First results on surface temperature obtained from these different data sets together with the measurements to be expected in the future from FAST offer a unique opportunity to compare in situ and IR remote sensing measurements.
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The Venus Emissivity Mapper (VEM) has a mature design with an existing laboratory prototype verifying an achievable instrument SNR of well above 1000 as well as a predicted error in the retrieval of relative emissivity of better than 1%. VEM will provide a global map of surface composition as well as redox state of the surface by observing the surface with six narrow band filters, ranging from 0.86 to 1.18 μm. Continuous observation of Venus’ thermal emission will place tight constraints on current day volcanic activity. Eight additional channels provide measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamics and permit accurate correction of atmospheric interference on the surface data. A mission combining VEM with a high-resolution radar mapper such as the ESA EnVision or NASA VERITAS mission proposals will provide key insights in the divergent evolution of Venus. Here we discuss the approach and results of the evaluation of the VEM sensor’s radiometric performance by an analysis of the corresponding signal processing chain. The passage of a simulated radiometric scene signal of the planet Venus through the VEM optics, detector, analog and digital electronics has been evaluated based on a theoretical model of the system. The goal was to verify the overall system performance with respect to the scientific requirements. This is building on our preliminary evaluation of the VEM laboratory prototype and confirms that the VEM design has significant performance margins.
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Remote spectroscopic observations of the lunar surface is now complemented by in situ reflectance spectra obtained by the Chang’E 3 and Chang’E 4 missions. The material at landing site includes also a fragment of rock with a small- to medium grained plutonic texture. Current spectral databases primarily contain spectra measured on powder samples, while spectra of coarse-grained rock samples are rare. Rock samples returned from the Apollo missions indicate that lunar anorthosites are typically coarse grained and reach grain sizes larger than 1 cm. We present the extension of the current spectral databases by new spectral data of whole rock samples, crucial for the interpretation of current in situ/remote analyses for lunar and other planetary missions, as Hayabusa2 and OSIRIS-REx. Spectral data is recorded at the Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin. The suite of samples selected for this work includes: - slabs and stone chunks of plagioclases such as anorthosite, diorite, monzodiorite, gabbro and diabas; - salts such as hexahydride; - iron meteorite samples, among them ataxites and octahedrites. Emissivity is measured in vacuum at 100° C, 200° C, 300° C and 400° C in the MIR and FIR spectral ranges. Thermally processed samples are measured in hemispherical and bi-directional reflectance in the full spectral range from UV to FIR. A sample of graphite (measured in emissivity under the same configuration and procedure as for the samples) is used to calibrate the sample emissivity.
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Radiometric Consideration in Remote Sensing Measurements
The output of a laser frequency comb is composed of 100,000+ perfectly spaced, discrete wavelength elements or comb teeth, that act as a massively parallel set of single frequency (CW) lasers with highly stable, well-known frequencies. In dual-comb spectroscopy, two such frequency combs are interfered on a single detector yielding absorption information for each individual comb tooth. This approach combines the strengths of both cw laser spectroscopy and broadband spectroscopy providing high spectral resolution and broad optical bandwidths, all with a single-mode, high-brightness laser beam and a simple, single photodetector, detection scheme. Here I will touch on the application of this system for open-path measurements of atmospheric trace gases (CH4, CO2, CO, NH3, water, ethane, and N2O) and volatile organic compounds (acetone, isopropanol, propane) with field applications targeting industrial oil and gas monitoring and agriculture.
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We present a multi-synchronous architecture for controlling multiple telescope or siderostat stations simultaneously from a central computer. This computer synchronously processes and distributes commands to six net- worked stations. The stations, comprised of a telescope or siderostat, a narrow angle tracker and a star-acquisition camera, are useful in the optical and infrared wavelengths. The central computer sends signed packets that include instructions for a particular station through the network at a rate of 600 Hz. A microcomputer at each station accepts its appropriate packets and parses the embedded data into control signals. These signals are then converted into appropriate outputs for motor controllers and piezoelectric actuators. The motors steer the siderostats while the piezoelectric actuators finely point the narrow angle tracker. A closed feedback loop couples the siderostat pointing with the narrow angle tracker to dynamically steer and maintain stable image positions of a stellar object. Two major components comprise this feedback loop: a wide-angle star acquisition camera inserted between a narrow angle tracker and siderostat, and a photon counter located near the end of the light path. The central computer utilizes positional error data from the camera to intricately align a siderostat. Simultaneously the computer processes pointing error derived from photon counts to finely correct a narrow angle tracker. This synchronized feedback and control system allows for precise, concurrent tracking over a wide range of stellar objects of interest. In this paper, we describe the parallelized software architecture, control hardware, experimental results, conclusions and recommendations.
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An all-reflective telescope based optical pyrometer has been designed and built to collect thermal radiation from a nanocrystalline diamond foil in harsh radiation environment at the Spallation Neutron Source accelerator. The primary use of this instrument is to monitor the foil temperature remotely while it is being bombarded by negative hydrogen ion beams with 1.4 MW power at 1.0 GeV energy. The pyrometer is composed of 4.0” Cassegrain reflector with f/10 configuration, two InGaAs PIN photodiodes, a dichroic mirror, two bandpass filters centered around 1000 nm and 1550 nm, a CMOS camera, and a pinhole mirror with 200 um diameter hole size. It is located 40 m from the foil in the accelerator. The measurement uncertainties demonstrated in this work was better than 2.5% for the temperature range of 1000 K to 2500 K. The design of the optical system, calibration with blackbody source and the temporally resolved measurements made with this pyrometer will be presented.
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Diffraction corrections are required in radiometric measurements in remote sensing. In this work, I will discuss the capabilities that we have developed to calculate them accurately and efficiently. Several aspects will be considered, namely, (1.) diffraction effects for a single aperture, for spectral power and total power in the case of radiation thermometry, including asymptotic behavior a small wavelengths and high temperatures; (2.) diffraction effects specific to multi-staged optics trains; (3.) applications in remote-sensing applications in test chambers use to simulate observation of remote objects in outer space; and (4.) solar radiometry.
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AIRS has provided highly stable and accurate radiances since 2002. Stability at the 2 mK/yr has been demonstrated relative to the sea surface temperature (SST) in the 8-12 micron window channels. However, there is evidence of a larger trend in the shortwave channels: 8mK/yr when viewing clear ocean at about 300K, about 200 mK/yr when viewing 220K DCC at night in the tropical oceans, but a trend of less than 20 mK/yr for Dome C at 220K. Under these conditions, the 8-12 micron window channels show trends of less than 20 mK/yr. This study proposes that the trends in the shortwave channels are the result of a wavelength dependent contamination of the scan mirror and the on-board calibration (OBC) blackbody. Scattered light from nearby scenes while viewing DCCs causes the large apparent radiometric trend in the shortwave channels and can be removed via spatial linear regression. An experiment that assumes the OBC blackbody emissivity has slightly decreased is tested to explain the smaller trends. The emissivity experiment results show similar stability drifts at 1231 cm-1 but not to other window channels. The emissivity decrease may explain some of the stability drift, but other unknown physical mechanisms are likely as well.
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Photosynthetically active radiation (PAR) is a vital parameter for various applications such as the study of plant physiology or greenhouse lighting. Since instruments for direct PAR measuring are very specific and have less accessibility compared to radiometric or photometric instruments, PAR is often estimated through empirical models that use meteorological parameters that describe the sky conditions as input data. Although it can be estimated through empirical models, these estimations are carried out only in a few areas of interest, for example, some areas of China and the Mediterranean basin, while in some agricultural areas of interest of North America the estimation of such radiation is scarce, being an example of this the Mexican Northern Plateau, which is a region with large agricultural production. In this work, the information obtained in different meteorological stations distributed within the Mexican Northern Plateau is used to assess several empirical models reported in the literature in order to know the behavior of PAR in this area. The performance validation of the models is done using statistical analysis of the Qp/Rsratios at noon and the monthly mean values of Qp obtained from each of the meteorological stations. The models used for its implementation were developed in various geographic areas along the planet, and based on the results obtained they are classified according to their performance to predict PAR within the study area.
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A laser shock wave (LSW) is a pressure wave in the range of gigapascals, duration in the order of nanoseconds, propagates at rates higher than Mach 1, and is induced by high power laser pulses. As an LSW propagates inside a solid, some physical material characteristics in the area of incidence are improved due to a residual compression stress field. However, since the LSW pressure reaches some tens of GPa, tensile stress damages the solid due to a spallation process if the material is fewer than 1 mm thick. A shock wave mitigation structure coupled to a solid reduces the LSW pressure due structure walls reflections, avoiding the spallation. In this work, a FEM simulation of LSW propagation in a 1 mm thick aluminum slab with a matrix of mitigating structures attached to the back is performed. The relationship among the induction area of the LSW, and the relative location of each mitigation structure in the matrix, has a direct influence on the pressure field distribution.
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We present recent progress on novel mid-infrared (MIR) light emitters and detectors. Optimized heterostructure and high-quality crystal growth allow for room temperature operation of interband cascade lasers (ICLs) with lasing wavelengths 𝜆 ≥ 6 μm. They employ asymmetric W-shaped optical quantum wells comprising highly strained layers of InAs/GaInSb/InAs with broken bandgap alignment. Furthermore, we discuss novel interband cascade detectors (ICDs) and resonant tunneling diode photodetectors (RTD-PDs) for MIR light detection. Different superlattice (SL) absorber design strategies for ICD cut-off wavelengths exceeding 𝜆 ≥ 7.0 μm are presented. SL absorbers ranging from standard InAs/GaSb SL to M-/W-shaped SL absorbers employing ternary barriers are compared.
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HAYABUSA2 asteroid probe has completed its mission successfully in the vicinity of asteroid Ryugu on November 13, 2019. It is on its way to the Earth now. Digital Electronics and Optical Navigation Camera (DE-ONC) was developed for scientific observation and real-time image recognition for optical navigation. The development process and its highspeed wire rate signal processing architecture of onboard electronics are explained in this lecture. Highly efficient lossless and lossy image compression algorithm were developed to send observed images through within the limited capacity of communication channels between the asteroid Ryugu and the Earth for scientific purposes. Onboard sensitivity and distortion correction functions for image sensors were also developed to improve compression ratio of images. High level synthesis technology was employed to implement the image recognition functions for optical navigation functions into limited numbers of space grade field programmable gate arrays (FPGAs) and to achieve wire rate signal processing speed. It must also satisfy high reliability and safety requirements of HAYABUSA2 missions. Functional distribution mode, standby redundancy mode and hot redundancy mode were realized with the same device configuration. Model based design was performed to satisfy these requirements. The onboard image processing unit of DE-ONC adopts a unified language processing system and a distributed memory model with reference to a parallel inference machine developed for the Fifth Generation Computer Systems aiming at artificial intelligence technology development. Its image processing module integrates a radiation hardened micro-controller unit (MCU) and FPGAs with the unified language processing system and the distributed object model.
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While uncooled microbolometer cameras have made infrared imaging accessible to a much wider range of applications than their cryo-cooled competitors, they are notorious for having poor noise performance and problems with calibration drift. The drift causes microbolometer cameras to lose radiometric accuracy over time, and this is a serious problem for radiometrically combining multiple detector arrays because the drift is not the same for each camera, and existing calibration methods cannot adequately compensate for it. We show methods to dynamically correct for calibration drift during measurements, so that multiple detector arrays can be kept in radiometric agreement with one another.
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The paper focuses on showing past, current and ready to start time and frequency (metrology) projects taking place in Europe aimed to long haul time and frequency transfers over optical fibers. It addresses both EURAMET and Horizon2020 projects’ scope. Focus will be given to Coordination and Support Action project CLOck NETwork Services (CLONETS) - Strategy and innovation for clock services over optical-fibre networks and proposed subsequent design study CLONETS-DS. Attention will be given also to effort of Research and Education Networks (NRENs) as pioneer network operators into this field.
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The optical profilometry techniques have become more and more used in dynamic 3-D shape measurement. In particular, there are two problems to overcome. One is to recover the phase from a single fringe. The second problem is the phase recovering from a pattern avoiding that the harmonics introduced by the projector. In this work, we analyzed two kinds of techniques: off-axis and slightly off-axis interferometry algorithms for phase retrieval. The Hilbert transform is implemented in both cases. Validation experiments are presented.
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In three-dimensional shape measurement by fringe projection, the calibration of the measurement system is an essential procedure to determine the relationship between the retrieval phase and the object height. In this work, we present an analysis of three calibration methods that had been proposed in the literature. These are based on three mathematical models: linear, quadratic and nonlinear. The linear and nonlinear mathematical models were deduced from the geometry of the measurement system, and parameters of the model were estimated by employing the ordinary least-squares method. The implementation of this calibration method was performed by translating a reference plane at different positions with known depths. The measurement accuracy for these three models was compared by numerical simulations, and the nonlinear model was employed to measure data.
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We propose to use the fast Fourier transformation (FFT) to analyze the spectral data of passively mode-locked fiber lasers, with the purpose of characterizing and classifying the different pulsed regimes arising in these lasers. The results show temporal information at the sub-ps scale. Specially, in the Fourier domain, the spectra of bound solitons depict several solitons with relative phases of π/2 and close to 0, distributed into a window that extends beyond the limited span of the autocorrelator. Besides, the FFT amplitude traces can help to classify the multi-pulse regimes generated by the laser; in particular, the exponential decay of intensity in such amplitude traces can be a fingerprint of noise-like pulses. Furthermore, the amplitude traces show some modulation that we attribute to Kelly’s sidebands. The proposed technique allows examining spectra from a mode-locked fiber laser independently of the active medium or laser cavity configuration without the need to use ultrafast photo- detectors.
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In this work, we proposed a procedure for the calibration of 3D surface shape measurement system, which is based on fringe projection and phase shifting algorithms. Our approach consists in the use of temporal phase unwrapping methods to determine the phase-to-height mapping relationship. In particular, we propose the use of the two-step temporal phase-unwrapping algorithm. For that, two sequences of fringe patterns (low and high sensitivity) are projected onto the reference plane, which is shifted perpendicularly to the camera-projector plane. Then, the phase maps at each shifting step are retrieved from acquired sequences of sinusoidal intensity patterns using the two-step temporal unwrapping formula. Finally, using the phase maps at well-known in a least-squares scheme, the system parameters, nonlinear model of calibration, are estimated, i.e. the phase-to-height mapping relationship. Validation experiments are presented.
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We present a calibration approach for rotating polarizer-analyzer polarimeter dedicated to retardance measurements. The rotating polarizer-analyzer polarimeter is based on retrieving a partial Mueller matrix measurement of a transparent sample to be later associated with its phase retardation properties. Through the Mueller matrix approach, we developed a calibration procedure considering the initial orientation of the two linear polarizers used, and we present experimental results showing the feasibility of our calibration approach.
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