- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- 2018
- infrared image
- target detection
- lucas–kanade method (LK)
- local contrast method (LCM)
- facet model
- target detection
- zero-crossing point
- Image processing
- Infrared camera
- Eye movement
- Optoelectronic Information Science and Engineering
- Chinese Academy of Sciences
- Gunma University
- University of Chinese Academy of Science
- Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Science
- University of Science and Technology of China
- Space Star Technology Co. LTD
-
Long Wavelength Infrared Quantum Cascade Detector
摘要： The effect of the barrier width in the photovoltaic-type quantum cascade detector structure on the responsivity and the zero-bias resistance of the device are opposite. A wide barrier can increase the zero-bias resistance but hinder the transport of photo-generated carriers and decrease the responsivity. The design of a long wave infrared cascade detector usually focuses on increasing the zero bias resistance by using wide barriers to lower the thermal noise, but the photocurrent might be low in this case. Even though the thermal noise that dominates the noise performance of a photovoltaic quantum cascade detector is very low, it is possible that effective photoresponse signals cannot be obtained when the photocurrent is as low as the noise current of measurement circuits, which might be higher than the thermal noise of the detector itself. In this work, we modified the structure of our previous long wavelength infrared quantum cascade detector by increasing the number of cascaded stages, while reducing the barrier thickness to improve the responsivity of the device. Although the device’s zero bias resistance decreases due to thinning of the barrier, the detectivity is almost unaffected due to the significant increase in response. More importantly, the operating temperature of the device is increased. Therefore, optimization of long wave infrared QCDs should consider both the resistance and the photocurrent flow.
关键词： Quantum Cascade Photodetector,Long Wavelength Infrared
更新于2025-09-04 15:30:14
-
Anomalous carrier transport model for broadband infrared absorption in metals
摘要： We derive a model for accurately reproducing the broadband infrared optical response of common engineering metals. Here we use “broadband infrared” to refer to wavelengths beginning at 1 μm and extending to approximately 100 μm or more. The model generalizes the Drude theory to account for sources of anomalous intraband absorption. This is accomplished by modeling these sources as elements of disorder that introduce diffusive perturbations into the local ?eld. In the stationary setting, the memory kernel description of the ?eld relaxation leads to a fractional derivative with an order that corresponds to the memory decay strength. We demonstrate that this model is fully consistent with the Drude theory and that the semiclassical theory is recovered under requisite assumptions on the ?eld relaxation or radiative wavelength. The anomalous model component is shown to reproduce empirically observed anomalous absorption that has been traditionally corrected by models possessing empirical components that have not been formally derived. Results are presented for several common metals for which the proposed model accurately reproduces the data over the entire modeled bandwidth. A comparative analysis con?rms that the proposed model represents a robust, high ?delity alternative to previously proposed models that do not capture the observed physical response over the extended infrared range.
关键词： broadband infrared,anomalous intraband absorption,fractional derivative,Drude theory,memory kernel
更新于2025-09-04 15:30:14
-
[IEEE 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Chongqing (2018.6.27-2018.6.29)] 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Infrared Object Recognition Based on Monogenic Features and Multiple Kernel Learning
摘要： Infrared object recognition is an important branch in the field of image processing and computer vision. This paper proposes a novel infrared object recognition method based on monogenic features and multiple kernel learning. Specifically, the proposed features are mainly derived from the ideas of the monogenic signal. The applicability of the monogenic signal within the field of infrared object recognition is demonstrated by its capability of capturing both the spectral information and spatial localization with compact support. Second, to reduce the dimensionalities of the monogenic features, the principal component analysis is applied. Third, the reduced monogenic features are adaptively fused in the multiple kernel learning framework. At last, a multiple kernel learning support vector machine classifier is designed for recognizing the infrared objects. The experimental results show that the proposed method leads to good infrared object recognition performance.
关键词： object recognition,monogenic feature,infrared,multiple kernel learning
更新于2025-09-04 15:30:14
-
IR and XAFS studies of photoluminescent Ag-type zeolite-A
摘要： We examined the relation between the zeolite framework, Ag clusters, and properties of photoluminescence (PL) using in-situ infrared spectroscopy (IR) and X-ray absorption fine structure (XAFS). The Ag clusters are generated in the cavity of Ag-type zeolite-A that is cooled to room temperature after heating at 500°C for 24 hour under vacuum or in atmosphere. The Ag clusters in the zeolite cavity break down when air is introduced. According to the formation and breakdown of the Ag cluster, the infrared spectrum of the zeolite framework changed slightly. Then, this change was compensated by irradiation of the excitation light. Results suggest that the structural change in the zeolite induced by the formation and breakdown of the Ag clusters is a key point of the PL mechanism.
关键词： infrared spectroscopy,XAFS,Ag clusters,photoluminescence,Ag-type zeolite-A
更新于2025-09-04 15:30:14
-
Recent Advances and Applications of Near Infrared Spectroscopy for Honey Quality Assessment
摘要： Currently, most of the technologies used to identify honey quality are inefficient and costly. There is a necessity to develop a more effective one for honey quality assessment. Near Infrared Spectroscopy (NIRS) has the potential to be such a technique for its unique characteristics. This study reviews recent advances and applications of NIR spectroscopy in honey authentication domain including constituents, adulteration, brand, botanical origin and geographical origin. It presents a comprehensive using of this technology, with advantages and limitations, in honey quality detection, which offers insights on selecting the most appropriate NIR spectroscopic method for samples presentation, spectral acquisition, spectral pretreatment and modeling. Future research is to be focused on increasing model robustness, developing overall NIR spectroscopic database and a NIR-based integrated technology system on honey quality assessment.
关键词： honey,near infrared spectroscopy,Advances,detection,applications
更新于2025-09-04 15:30:14
-
Quantification of Total Phenolic and Carotenoid Content in Blackberries (Rubus Fructicosus L.) Using Near Infrared Spectroscopy (NIRS) and Multivariate Analysis
摘要： A rapid method to quantify the total phenolic content (TPC) and total carotenoid content (TCC) in blackberries using near infrared spectroscopy (NIRS) was carried out aiming to provide reductions in analysis time and cost for the food industry. A total of 106 samples were analysed using the Folin-Ciocalteu method for TPC and a method based on Ultraviolet-Visible Spectrometer for TCC. The average contents found for TPC and TCC were 24.27 mg·g?1 dw and 8.30 μg·g?1 dw, respectively. Modified partial least squares (MPLS) regression was used for obtaining the calibration models of these compounds. The RPD (ratio of the standard deviation of the reference data to the standard error of prediction (SEP)) values from external validation for both TPC and TCC were between 1.5 < RPDp < 2.5 and RER values (ratio of the range in the reference data to SEP) were 5.92 for TPC and 8.63 for TCC. These values showed that both equations were suitable for screening purposes. MPLS loading plots showed a high contribution of sugars, chlorophyll, lipids and cellulose in the modelling of prediction equations.
关键词： bioanalytical applications,chemometrics,blackberries,near infrared,phenolics,carotenoids,Rubus fructicosus
更新于2025-09-04 15:30:14
-
Robust fusion algorithm based on RBF neural network with TS fuzzy model and its application to infrared flame detection problem
摘要： A robust fusion algorithm based on Radial Basis Function (RBF) neural network with Takagi-Sugeno (TS) fuzzy model is proposed in view of the data loss, data distortion or signal saturation which is usually occurred in the process of infrared flame detecting with multiple sensors. To initialize the model, the traditional K-means clustering algorithm is used to obtain the number of the fuzzy rules and the center of the membership function. Compared with the traditional RBF neural network with TS fuzzy model, the output of the node in the proposed model is constructed taking into account the membership degree of the feature components in each item of the output polynomial of the hidden layer nodes in consequent fuzzy network. A new weighted activation degree (WAD) is defined to calculate the firing strength (i.e., fuzzy rule applicability) of the fuzzy node instead of the commonly used Mahalanobis distance. The feature representation coefficients used in the above WAD fully consider the variant representation degree of different features in different fuzzy clusters, thus the developed method can deal with the abnormal outputs of the fuzzy rules caused by the variation of the feature components of the raw data obtained from the complex industrial environments. The robustness of the proposed approach is validated with experimental data obtained from a developed triple-channel infrared flame detector and the experiment results show that the convergence rate, accuracy and generalization ability of the proposed method are improved compared with the traditional RBF neural network with TS fuzzy model in [1] and the GA-BP (Genetic Algorithm-Back Propagation) model in [2]. In particular, the required number of the hidden layer nodes in the proposed approach is the least among the aforementioned methods.
关键词： robustness,feature representation coefficient,Infrared flame detector,TS fuzzy model,RBF neural network
更新于2025-09-04 15:30:14
-
Investigation of a Rapid Infrared Heating Assisted Mineralization of Soybean Matrices for Trace Element Analysis
摘要： A fast sample preparation procedure based on use of infrared (IR) assisted heating for mineralization of soybean derived samples has been developed for their subsequent multielement analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). A cold finger was examined for refluxing of acid vapors to determine its impact on efficiency and economy of digestion. The optimized procedure, based on 1 g subsamples, 8 ml of HNO3 (65% w/w) and exposure of the mixture to a 500 W IR source for 5 min without refluxing, permitted accurate determination of all analytes in NIST SRM 1568b (rice flour). Detection limits using ICP-OES were (μg/kg) 97, 1.0, 39, 185, 0.47 and 1200 for Ca, Cu, Fe, K, Mn and P, respectively, and 18 for Zn by FAAS. The IR-assisted digestion approach provided a low cost, easy to use system having great potential for implementation in routine analysis of trace elements in soybean and similar matrices.
关键词： ICP-OES,soybean,infrared radiation,sample preparation,trace element analysis
更新于2025-09-04 15:30:14
-
Methane on Mars: New insights into the sensitivity of CH4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration
摘要： The Nadir and Occultation for MArs Discovery instrument (NOMAD), onboard the ExoMars Trace Gas Orbiter (TGO) spacecraft was conceived to observe Mars in solar occultation, nadir, and limb geometries, and will be able to produce an outstanding amount of diverse data, mostly focused on properties of the atmosphere. The infrared channels of the instrument operate by combining an echelle grating spectrometer with an Acousto-Optical Tunable Filter (AOTF). Using in-flight data, we characterized the instrument performance and parameterized its calibration. In particular: an accurate frequency calibration was achieved, together with its variability due to thermal effects on the grating. The AOTF properties and transfer function were also quantified, and we developed and tested a realistic method to compute the spectral continuum transmitted through the coupled grating and AOTF system. The calibration results enabled unprecedented insights into the important problem of the sensitivity of NOMAD to methane abundances in the atmosphere. We also deeply characterized its performance under realistic conditions of varying aerosol abundances, diverse albedos and changing illumination conditions as foreseen over the nominal mission. The results show that, in low aerosol conditions, NOMAD single spectrum, 1σ sensitivity to CH4 is around 0.33 ppbv at 20 km of altitude when performing solar occultations, and better than 1 ppbv below 30 km. In dusty conditions, we show that the sensitivity drops to 0 below 10 km. In Nadir geometry, results demonstrate that NOMAD will be able to produce seasonal maps of CH4 with a sensitivity around 5 ppbv over most of planet's surface with spatial integration over 5 × 5° bins. Results show also that such numbers can be improved by a factor of ~10 to ~30 by data binning. Overall, our results quantify NOMAD's capability to address the variable aspects of Martian climate.
关键词： NOMAD,Instrumentation,Infrared spectroscopy,Mars atmosphere,Methane
更新于2025-09-04 15:30:14
-
Upconversion luminescence modification induced near infrared luminescence enhancement of Bi2Ti2O7:Yb3+, Er3+ inverse opals
摘要： To date, there are comprehensive researches on rare-earth doped photonic band gap (PBG) materials. The PBG materials can effectively modify the up-conversion luminescence (UCL) of rare earth ions. However, few people pay attention to the influence of modification of the UCL of rare earth ions on their near infrared (NIR) luminescence. In this article, the Bi2Ti2O7: Yb3+, Er3+ inverse opal PBG materials were prepared, and the influence of modification of the UCL of Er3+ on their NIR luminescence was investigated systematically by changing the PBG position. The green and red UCL were suppressed when the PBG was overlapped the UCL of Er3+. The UCL modification induced NIR luminescence enhancement was observed in the Bi2Ti2O7: Yb3+, Er3+ inverse opal, which was attributed to the energy redistribution caused by the PBG effect. The suppression of UCL results in that the electrons located at the UCL levels relax to the NIR luminescence level of 4I13/2, causing the NIR luminescence enhancement. Our research can provide a promising method for the enhancement of the NIR luminescence.
关键词： Enhancement,Inverse opal,up-conversion luminescence,Near infrared luminescence
更新于2025-09-04 15:30:14