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- 2019
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- infrared image
- target detection
- lucas–kanade method (LK)
- local contrast method (LCM)
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- target detection
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- Image processing
- Infrared camera
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- Optoelectronic Information Science and Engineering
- Chinese Academy of Sciences
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- Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Science
- University of Science and Technology of China
- Space Star Technology Co. LTD
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[IEEE 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - Bento Gon?alves, Brazil (2018.8.27-2018.8.31)] 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - Non uniformity correction in a Long Wave Infrared Focal Plane Array as a function of the higher calibration temperature
摘要： It is well known that every detector in a Focal Plane Array (FPA) has a different responsivity and offset. These variations result in a specific kind of noise, the Fixed Pattern Noise (FPN) or spatial noise. During the image processing, those pixels who has a large deviation in responsivity are considered a bad pixel, and has its value removed of FPA. Knowing the answer of in a FPA all those pixels are the first test procedure characterization. However, during the bad pixels analysis it is necessary to choose two reference temperatures, calibration points, and those temperature affects important parameters such as Uniformity, Noise Equivalent Temperature Difference (NETD) and Signal Transfer Function (SiTF). This work will study the influence of higher calibration temperature on the Non-Uniformity Correction (NUC) quality.
关键词： Focal Plane Array,Uniformity,Signal Transfer Function,Noise Equivalent Temperature Difference,Long Wave Infrared
更新于2025-09-04 15:30:14
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Role of Multiphoton Ionization in the Short-Wavelength Broadening of the Spectrum of a Light Bullet in the Middle Infrared Range
摘要： The short-wavelength cutoff of the anti-Stokes wing of the supercontinuum in the spectrum of a light bullet at filamentation of femtosecond radiation at a wavelength tunable in a wide range of the middle infrared range in fused silica and fluorides has been studied for the first time. A physical model for the formation of the spectrum of the light bullet has been proposed on the basis of the spectral broadening caused by the phase self-modulation of the light field on the trailing edge of the light bullet at the generation of a plasma in the process of multiphoton ionization. Within this model, a function has been obtained to determine the wavelength shift of the short-wavelength cutoff as a function of the multiphoton order. This function is in agreement with experimental results.
关键词： supercontinuum,light bullet,spectral broadening,multiphoton ionization,middle infrared range
更新于2025-09-04 15:30:14
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A Novel Edge-Map Creation Approach for Highly Accurate Pupil Localization in Unconstrained Infrared Iris Images
摘要： Iris segmentation in the iris recognition systems is a challenging task under noncooperative environments. The iris segmentation is a process of detecting the pupil, iris’s outer boundary, and eyelids in the iris image. In this paper, we propose a pupil localization method for locating the pupils in the non-close-up and frontal-view iris images that are captured under near-infrared (NIR) illuminations and contain the noise, such as specular and lighting reflection spots, eyeglasses, nonuniform illumination, low contrast, and occlusions by the eyelids, eyelashes, and eyebrow hair. In the proposed method, first, a novel edge-map is created from the iris image, which is based on combining the conventional thresholding and edge detection based segmentation techniques, and then, the general circular Hough transform (CHT) is used to find the pupil circle parameters in the edge-map. Our main contribution in this research is a novel edge-map creation technique, which reduces the false edges drastically in the edge-map of the iris image and makes the pupil localization in the noisy NIR images more accurate, fast, robust, and simple. The proposed method was tested with three iris databases: CASIA-Iris-Thousand (version 4.0), CASIA-Iris-Lamp (version 3.0), and MMU (version 2.0). The average accuracy of the proposed method is 99.72% and average time cost per image is 0.727 sec.
关键词： pupil localization,iris segmentation,edge-map creation,non-close-up iris images,circular Hough transform,near-infrared illuminations
更新于2025-09-04 15:30:14
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Rapid determination of phytosterols by NIRS and chemometric methods
摘要： Phytosterols have been extensively studied because it plays essential roles in the physiology of plants and can be used as nutritional supplement to promote human health. We use a rapid method by coupling near-infrared spectroscopy (NIRS) and chemometric techniques to quickly and efficiently determine three essential phytosterols (β-sitosterol, campesterol and stigmasterol) in vegetable oils. Continuous wavelet transform (CWT) method was adopted to remove the baseline shift in the spectra. The quantitative analysis models were constructed by partial least squares (PLS) regression and randomization test (RT) method was used to further improve the models. The optimized models were used to calculate the phytosterol contents in prediction set in order to evaluate their predictability. We have found that the phytosterol contents by the optimized models and Gas Chromatography/Mass Spectrometry (GC/MS) analysis are almost consistent. The root mean square error of prediction (RMSEP) and ratio of prediction to deviation (RPD) for the three phytosterols are 525.7590, 212.2245, 65.1611 and 4.0060, 4.7195 and 3.5441, respectively. The results have proved the feasibility of the proposed method for rapid and non-destructive analysis of phytosterols in edible oils.
关键词： phytosterol,vegetable oil,near-infrared spectroscopy,partial least squares,wavelength selection
更新于2025-09-04 15:30:14
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EXPRESS: Application of Different Fourier Transform Infrared (FT-IR) Methods in the Characterization of Lime-Based Mortars with Oxblood
摘要： Organic compounds have frequently been added into lime mortars for property modifications, in order to satisfy various functional needs in building techniques. This study applies Fourier transform infrared (FT-IR) spectroscopy in transmission, reflection, and attenuated total reflection (ATR) modes to characterize lime-based mortar specimens containing oxblood, which has been used as additive as a common practice of long history in many parts of the world. The specimens were prepared basing upon a 19th-century Italian historic recipe, with the intention to have a better understanding on the possible characteristics of such mortars. Thermal analysis, color measurement and static contact angle test were also used. After curing, the specimens show a distinctive dark-red color on the top surface, which is different from the bulk. Color measurements on the surface suggest that this color was formed at an early stage and was able to maintain stable for a relatively long period of time. Both transmission and reflection FT-IR confirm the preferential accumulation of proteins on the top surface, which should have induced their water repellency according to the static contact angle test. In addition, specimens show weaker calcite bands in FT-IR transmission, reflection, as well as ATR spectra; the pattern of ATR spectra after the thermal analysis to 500 °C suggests the formation of amorphous calcium carbonate, which is related to the presence of oxblood.
关键词： Mortar,oxblood,attenuated total reflection,ATR,reflection Fourier transform infrared,FT-IR,building techniques,organic additives
更新于2025-09-04 15:30:14
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Compositional correlation and polymorphism in BaF2-PrF3 thin films deposited using electron-beam evaporation
摘要： Infrared low-index evaporation materials are essential in the broadband antire?ection coatings to reduce Fresnel re?ections on the surfaces of infrared optical components. Although the layers of praseodymium ?uoride (PrF3) show an excellent transparency and the lower refractive index n and extinction coe?cient k in the spectral range of thermal infrared, the tensile stress presented in the layers prohibits PrF3 from being used as infrared low-index coating materials. A practical solution to reduce stress is to directly evaporate the admixture of PrF3 with alkaline ?uorides, such as barium ?uoride (BaF2). However, due to the signi?cant di?erence of vapor pressures between PrF3 and BaF2, it is commonly di?cult to congruently deposit PrF3-BaF2 thin ?lms utilizing evaporating directly from a single source. Moreover, more details are unknown about the phase compositions of PrF3-BaF2 thin ?lms. In our investigation, BaF2-PrF3 thin ?lms were deposited using electron beam evaporation from the sintered ingots of PrF3 admixed with BaF2. The compositions of thin ?lms were characterized using energy dispersive X-ray spectroscopy (EDX), the crystallographic structures were explored by X-ray-di?raction (XRD). It was revealed that the concentration of BaF2 in thin ?lms can be correlated to that in the admixtures. Moreover, in addition to PrF3 and BaF2, the phase compositions in thin ?lms include also secondary phases, such as PrOF, PrF4, Pr2F2, BaPrF6, and that of elemental Ba.
关键词： Infrared low-index evaporation materials,BaF2-PrF3,Compositional correlation,Polymorphism,Electron beam evaporation
更新于2025-09-04 15:30:14
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Category identification of textile fibers based on near-infrared spectroscopy combined with data description algorithms
摘要： Cashmere is a kind of luxury ?ber produced by goats and has high economic value. The temptation of huge pro?ts makes it a common phenomenon to fake cashmere with cheap materials. There is increasing demand to develop simple methods for distinguishing cashmere with other animal ?bers. The feasibility of combining near-infrared (NIR) spectroscopy and three kind of data descriptions, i.e., support vector data description(SVDD), k-nearest neighbor data description (KNNDD) and GAUSS methods, for this goal is explored. The Relie? algorithm is used for variable selection and principal component analysis (PCA) is used as an exploratory tool and feature extraction. A total of 395 samples belonging to four categories were collected for the experiment. The number of samples used for model construction are 69, 71, 61 and 50 for A, B, C and D as the target class, respectively. Based on the selected 67 variables and only two principal components (PCs), three types of data descriptions are obtained. The SVDD model exhibits the most ?exible and tightest boundary and also achieves 100% sensitivity on the independent test set. It indicates that NIR combined with SVDD and Relie? is feasible for category identi?cation of di?erent animal ?bers.
关键词： Textile,Fiber,Near-infrared,Data description
更新于2025-09-04 15:30:14
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Ba10Zn7M6Q26: Two New Mid-infrared Nonlinear Optical Crystals with T2 Supertetrahedron 3D Framework
摘要： Two new mid-infrared (MIR) nonlinear optical (NLO) chalcogenide crystals, Ba10Zn7In6S26, 1 and Ba10Zn7Ga6Se26, 2 are discovered by traditional solid state reactions. 1 and 2 are isostructural and they represent a novel three-dimensional (3D) framework made by apexe-sharing T2 supertetrahedron 2D layers that are stacked alternately by another kind of T2 supertetrahedra though sharing apexes along the c direction, with T1 tetrahedra inserting in the tunnels and Ba2+ cations locating both in the voids and tunnels. Among them, 1 shows attractive MIR NLO properties of a wide band gap of 3.0 eV, a strong second harmonic generation (SHG) signal about 4.1 times that of the commercial AgGaS2 at particle sizes of 30–46 μm under a 2.05 μm laser radiation, and a high LDT of 37.2 times that of benchmark AgGaS2 at particle sizes of 150–210 μm under a 1.064 μm laser radiation. This distinguishes 1 as a new promising MIR NLO material. In addition, the density functional theory (DFT) analyses suggest that the SHG response of 1 comes mainly from the electronic transitions from S 3p to Ba 5d, Zn 4s, Zn 3d, In 5s, In 5p states.
关键词： chalcogenide,mid-infrared,second harmonic generation,laser damage threshold,nonlinear optical,supertetrahedron
更新于2025-09-04 15:30:14
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<i>In Situ</i> IR Spectroscopy of Mesoporous Silica Films for Monitoring Adsorption Processes and Trace Analysis
摘要： Adsorption of molecules on high-surface-area materials is a fundamental process critical to many fields of basic and applied chemical research; for instance, it is among the simplest and most efficient principles for separating and remediating polluted water. However, established experimental approaches for investigating this fundamental process preclude in situ monitoring and thus obtaining real-time information about the ongoing processes. In this work, mid-infrared attenuated total reflection (ATR) spectroscopy is introduced as a powerful technique for quantitative in situ monitoring of adsorption processes and thus enrichment of traces of organic pollutants from aqueous solution in ordered mesoporous silica films. The synthesis, functionalization, and characterization of two silica films with 3D hexagonal and cubic pore structure on silicon ATR crystals are presented. Benzonitrile and valeronitrile as model compounds for aromatic and aliphatic water pollutants are enriched in hydrophobic films, while the matrix, water, is excluded from the volume probed by the evanescent field. Enrichment times of <5 s are observed during in situ measurements of benzonitrile adsorbing onto the film from aqueous solution. The sensing system is calibrated using the Freundlich adsorption equation as a calibration function. Enrichment factors of benzonitrile and valeronitrile within the film were determined to be >200 and >100, respectively, yielding detection limits in the low ppm range. Furthermore, fast and complete desorption of the analyte, ensuring reliable regeneration of the sensor, was verified. Lastly, we derive and experimentally validate equations for ATR spectroscopy with thin film adsorption layers to quantify the absolute mass of adsorbed pollutant in the film. The excellent agreement between recorded absorptions at target wavenumbers of the target analytes and corresponding simulations corroborates the validity of the chosen approach.
关键词： infrared spectroscopy,functional coatings,sensor,porous materials,thin film
更新于2025-09-04 15:30:14
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Transient effects in <i>Herschel</i> /PACS spectroscopy
摘要： Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident ?ux with a certain delay. This generates transient e?ects on the resulting signal which can be important and last for up to an hour. Aims. The paper presents a study of the e?ects of transients on the detected signal and proposes methods to mitigate them especially in the case of the unchopped mode. Methods. Since transients can arise from a variety of causes, we classi?ed them in three main categories: transients caused by sudden variations of the continuum due to the observational mode used; transients caused by cosmic ray impacts on the detectors; transients caused by a continuous smooth variation of the continuum during a wavelength scan. We propose a method to disentangle these e?ects and treat them separately. In particular, we show that a linear combination of three exponential functions is needed to ?t the response variation of the detectors during a transient. An algorithm to detect, ?t, and correct transient e?ects is presented. Results. The solution proposed to correct the signal for the e?ects of transients substantially improves the quality of the ?nal reduction with respect to the standard methods used for archival reduction in the cases where transient e?ects are most pronounced. Conclusions. The programs developed to implement the corrections are o?ered through two new interactive data reduction pipelines in the latest releases of the Herschel Interactive Processing Environment.
关键词： infrared: general,techniques: spectroscopic,methods: data analysis
更新于2025-09-04 15:30:14