Passive IR Research Articles

The thermal infrared optical depth of mineral dust retrieved from integrated CALIOP and IIR observations

Recent studies have suggested that global climate models tend to underestimate dust particle size in particular, the very coarse mode, leading to an underestimated direct radiative effect (DRE) of dust in the longwave (LW) thermal infrared (TIR) region. However, the magnitude of LW DRE remains highly uncertain, because of limited observations of dust optical depth at the TIR (DAODTIR). This study presents a simple approach to retrieve the DAODTIR over the oceans during nighttime through synergistic use of observations from the Infrared Imaging Radiometer (IIR) and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), both onboard of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission. For each cloud-free dust-laden profile identified by the IIR-CALIOP observation, a Lookup-Table (LUT) of the 10.6 μm IIR band brightness temperatures (BT) difference (dBT) under different DAODTIR with respect to their dust-free BTs is constructed based on the CALIOP retrieved dust vertical profile and a priori dust scattering properties using a fast radiative transfer model. Then the DAODTIR is retrieved by projecting the IIR-observed dBT on the LUT. Sensitivity studies show that the DAODTIR retrieval at 10.6 μm is more susceptible to the dust particle size distribution (PSD) assumption than dust refractive indices. To estimate the uncertainty caused by PSD assumption, two DAODTIR retrieval products, one based on the dust PSD from the AERONET at Cape Verde and the other on an in situ measured PSD from the recent Fennec campaign, are provided. The retrieval uncertainty is mainly contributed by the BT difference between the observation and simulation using auxiliary atmospheric data. The climatology of the retrieval from 2013 to 2019 shows reasonable spatiotemporal variations of DAODTIR with the global-averaged value of 0.008 and 0.013 based on different pre-assumed dust PSDs. Climatological results agree reasonably well with two independent DAODTIR retrieval products based on the Infrared Atmospheric Sounding Interferometer (IASI) over the active dust transport regions, such as North and Tropical Atlantic (r = 0.9 and r = 0.8) and Indian Ocean (r = 0.8). The seasonal and interannual variation is also well-compared (r = 0.76) with AERONET coarse-mode AOD at 97 selected sites. The synergic CALIOP observation allows the retrieved DAODTIR to directly compare with the extrapolated DAODTIR from DAOD in the visible (i.e., 532 nm), which helps evaluate the observational constraints on DAODTIR. Our study clearly reveals that the retrieved DAODTIR from IIR is much less susceptible to various uncertainties than converted results from CALIOP. It also offers a unique prospect of collocated active lidar and passive IR observations for retrieving dust DAODTIR.

Qualitative timber structure assessment with passive IR thermography. Case study of sources of common errors

The use of infrared thermography, a non-destructive technique for detecting structural failures or hidden defects, has become ever more common in the last 10 years. The combination of its growing popularity, the relatively small price tag on low-resolution devices and the lack of operator experience has fostered significant errors in the interpretation of the resulting images. This paper describes the use of infrared thermography and imaging to assess the condition of a historic timber-roofed building in Madrid, Spain. It aimed primarily to determine the utility of thermographic techniques in the detection of flaws such as cracks, moisture content and detachment. On the other hand, the limitations of IR techniques and the errors most commonly committed in interpreting the results must be identified to determine how to avoid misleading interpretations. The survey methodology deployed here followed a procedure established for earlier studies of historic buildings in which preliminary fact sheets were drawn up to determine the areas of the building’s structural members most in need of assessment. Changes in timber properties and weather-mediated moisture content were identified on the grounds of material emissivity using passive thermography. Active thermography is recommended to detect internal flaws.

Potential for dietary competition between the threatened black-flanked rock-wallaby and sympatric western grey kangaroo

An overabundance of western grey kangaroo (Macropus fuliginosus) can detrimentally impact agriculture and compete with threatened fauna for food resources. In Paruna Wildlife Sanctuary, south-western Western Australia, kangaroos are common and widespread. By contrast, the endangered black-flanked rock-wallaby (Petrogale lateralis lateralis) are spatially constrained to rock refuges. We investigated the potential for dietary competition between these two species by measuring the overlap in their diets, spatial overlap in their foraging patches, and comparing their diets with food resource availability. A combination of scat analysis, passive IR camera trapping and vegetation surveys were employed around rock outcrops used by rock-wallabies within the sanctuary. Rock-wallaby diets were dominated by forbs, overlapping 56% with kangaroo diet, which included mostly browse and forbs. Some of their shared preferred food resources were spatially and/or temporally limited, suggesting potential competition for these food plants. There was also a 33% spatial overlap of foraging patches between the two species. The dietary and spatial overlap detected between rock-wallabies and kangaroos suggest there is potential for resource competition, which may be exacerbated if kangaroo numbers increase. Future conservation actions include monitoring western grey kangaroo densities and food plant availability. Population control for kangaroos may be required, particularly for increasingly hot and dry years, as predicted under climate change.

Studies of a Lacustrine‐Volcanic Mars Analog Field Site With Mars‐2020‐Like Instruments

AbstractOn the upcoming Mars‐2020 rover two remote sensing instruments, Mastcam‐Z and SuperCam, and two microscopic proximity science instruments, Scanning for Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) and Planetary Instrument for X‐ray Lithochemistry (PIXL), will collect compositional (mineralogy, chemistry, and organics) data essential for paleoenvironmental reconstruction. The synergies between and limitations of these instruments were evaluated via study of a Mars analog field site in the Mojave desert, using instruments approximating the data that will be returned by Mars‐2020. A ground truth data set was generated for comparison to validate the results. The site consists of a succession of clay‐rich mudstones of lacustrine origin, interbedded tuffs, a carbonate‐silica travertine deposit, and gypsiferous mudstone strata. The major geological units were mapped successfully using simulated Mars‐2020 data. Simulated Mastcam‐Z data identified unit boundaries and Fe‐bearing weathering products. Simulated SuperCam passive shortwave infrared and green Raman data were essential in identifying major mineralogical composition and changes in lacustrine facies at distance; this was possible even with spectrally downsampled passive IR data. Laser‐induced breakdown spectroscopy and simulated PIXL data discriminated and mapped major element chemistry. Simulated PIXL revealed millimeter‐scale zones enriched in zirconium, of interest for age dating. Scanning for SHERLOC‐like data mapped sulfate and carbonate at submillimeter scale; silicates were identified with increased laser pulses/spot or by averaging of hundreds of spectra. Fluorescence scans detected and mapped varied classes of organics in all samples, characterized further with follow‐on spatially targeted deep‐UV Raman spectra. Development of dedicated organics spectral libraries is needed to aid interpretation. Given these observations, the important units in the outcrop would be sampled and cached for sample return.

Inline quantification and localization of transverse matrix cracking in cross-ply CFRP during quasi-static tensile testing by a joint event-based evaluation of acoustic emission and passive IR thermography

Understanding the complex damage characteristics of fiber reinforced plastics under mechanical loading is essential for lightweight design. In this study, acoustic emission (AE)1 analysis and passive IR thermography (pIRT) are coherently combined for the quantitative characterization and localization of damage progression in cross-ply carbon fiber reinforced plastics under quasi-static tensile loading. A new evaluation methodology is presented that utilizes acoustic events as trigger for pIRT analysis. Rigourosly transferring the event-based evaluation scheme from AE to pIRT analysis allowed for the first time to extract and compare characteristic features from both: thermal and corresponding acoustic events and to correlate them to the underlying damaging event. This way, the thermal and acoustic footprint of transverse matrix cracking (TMC) in the outer 90° layers was successfully identified and used for the determination of TMC onset and density throughout the test. This highlights the potential for the inline characterization of damage progression with this new approach.

Determination of the Technical Condition of Industrial Chimneys by the Passive IR Thermography Method

Determination of the Technical Condition of Industrial Chimneys by the Passive IR Thermography Method

Visualization of Hydrogen Flame by Passive UV and IR Remote Sensing

Visualization of Hydrogen Flame by Passive UV and IR Remote Sensing

基于集成学习的红外双波段被动测距模型

基于集成学习的红外双波段被动测距模型

Modeling the Performance of Mosaic Uncooled Passive IR Sensors in CMOS–SOI Technology

This paper analyzes the performance of mosaic nonimaging passive infrared (PIR) sensors fabricated by the CMOS–SOI–MEMS technology. The elementary sensor, forming a subpixel, is a thermally isolated nanomachined CMOS transistor, dubbed TMOS, operating at subthreshold. The mosaic uncooled PIR sensors are composed of several TMOS subpixels, which are electrically connected, either in parallel or in series as well as a combination of both options. These mosaic sensors, which are manufactured by nanofabrication methods, exhibit enhanced performance and robust manufacturing on wafer level. The overall figures of merit of these sensors, which are modeled in this paper, indicate why they are most suitable for consumer electronics, including smart homes, wearables, Internet of Things as well as mobile applications.

The last decade of bioacoustics at the Office of Naval Research

The goal of the ONR Marine Mammals and Biology (MMB) program is to enable Navy to and meet operational training and testing objectives in an environmentally responsible and legal manner. The ONR Marine Mammals and Biology program invests in Monitoring and Detection topic with the goal is to improve marine mammal monitoring capabilities over current methods. Develop new and existing technology such as passive acoustics, IR, and others. Recent research efforts on passive acoustics include the development and testing of new autonomous hardware platforms and signal processing algorithms for detection, classification, and localization of marine mammals. Ultimately, the ONR goal is to adapt those algorithms for use on a variety of fixed, towed, floating, and profiling platforms. For example, over the last several years ONR has adapted the use of autonomous ocean gliders for marine mammal monitoring to create the desired capability of persistent, autonomous, passive acoustic monitoring of an area for marine mamm...

Application of Satellite- and NWP-Derived Wind Profiles to Military Airdrop Operations

AbstractThe Joint Precision Airdrop System (JPADS) has revolutionized military high-altitude airdrop capability, allowing delivery of equipment and supplies to smaller drop zones from higher altitudes than was previously possible. This capability relies on accurate wind data, currently provided by GPS dropsondes released in the vicinity of the drop zone shortly before the airdrop. This research investigates the potential for a wind-profiling algorithm to generate the required wind data from passive IR and microwave satellite soundings, eliminating the requirement for a hazardous dropsonde pass near the drop zone. The Atmospheric Infrared Sounder (AIRS) provides a 3D temperature field and determines the heights of 100 standard levels. From these data, the slopes of the isobaric pressure surfaces and temperature gradients are used to calculate wind speed and direction using the thermal wind relationship. The accuracy of these satellite-derived wind profiles is evaluated through comparison with rawinsonde measurements near the coordinates and time of the AIRS sounding. Further investigation of the wind profile accuracy is made by a comparison with numerical weather prediction (NWP) data worldwide, and the effect of cloud cover in the vicinity of the target coordinates is analyzed. The AIRS-derived winds are found to be less accurate than short-term NWP winds for the JPADS application, but the technique developed may be applied to alternate applications, such as use in the stratosphere, where NWP winds are not widely available. The agreement between satellite-retrieved temperatures and measurements at altitudes above 30 km indicates the AIRS data could be used to create accurate, 3D fields of optical turbulence strengths for directed-energy applications.

Initializing HYSPLIT with satellite observations of volcanic ash: A case study of the 2008 Kasatochi eruption

AbstractThe current work focuses on improving volcanic ash forecasts by integrating satellite observations of ash into the Lagrangian transport and dispersion model, HYSPLIT. The accuracy of HYSPLIT output is dependent on the accuracy of the initialization: the initial position, size distribution, and amount of ash as a function of time. Satellite observations from passive infrared, IR, sensors are used both to construct the initialization term and for verification. Space‐based lidar observations are used for further verification. We compare model output produced using different initializations for the 2008 eruption of Kasatochi in the Aleutian Islands. Simple source terms, such as a uniform vertical line or cylindrical source above the vent, are compared to initializations derived from satellite measurements of position, mass loading, effective radius, and height of the downwind ash cloud. Using satellite measurements of column mass loading of ash to constrain the source term produces better long‐term predictions than using an empirical equation relating mass eruption rate and plume height above the vent. Even though some quantities, such as the cloud thickness, must be estimated, initializations which release particles at the position of the observed ash cloud produce model output which is comparable to or better than the model output produced with source terms located above and around the vent. Space‐based lidar data, passive IR retrievals of ash cloud top height, and model output agree well with each other, and all suggest that the Kasatochi ash cloud evolved into a complex three‐dimensional structure.

Animal Classification System Based on Image Processing & Support Vector Machine

This project is mainly focused to develop system for animal researchers & wild life photographers to overcome so many challenges in their day life today. When they engage in such situation, they need to be patiently waiting for long hours, maybe several days in whatever location and under severe weather conditions until capturing what they are interested in. Also there is a big demand for rare wild life photo graphs. The proposed method makes the task automatically use microcontroller controlled camera, image processing and machine learning techniques. First with the aid of microcontroller and four passive IR sensors system will automatically detect the presence of animal and rotate the camera toward that direction. Then the motion detection algorithm will get the animal into middle of the frame and capture by high end auto focus web cam. Then the captured images send to the PC and are compared with photograph database to check whether the animal is exactly the same as the photographer choice. If that captured animal is the exactly one who need to capture then it will automatically capture more. Though there are several technologies available none of these are capable of recognizing what it captures. There is no detection of animal presence in different angles. Most of available equipment uses a set of PIR sensors and whatever it disturbs the IR field will automatically be captured and stored. Night time images are black and white and have less details and clarity due to infrared flash quality. If the infrared flash is designed for best image quality, range will be sacrificed. The photographer might be interested in a specific animal but there is no facility to recognize automatically whether captured animal is the photographer’s choice or not.

Microclimatic performance of a free-air warming and CO2 enrichment experiment in windy Wyoming, USA.

In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO2 enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms-1 average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO2 had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO2. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the time.

Activity monitoring for multi-inhabitant smart homes

Activity recognition and monitoring play important roles in smart home systems, which rely on perceiving and understanding inhabitants’ behavior to generate a response. Applications that require such pattern recognition include alarms to detect anomalies and personalized home automation systems (where automatic lighting, heating, or security are tailored to the habits of the inhabitants). To observe activity in an environment by the least intrusive means, we considered the use of ambient sensors, rather than cameras or wearables. Most existing work in this area focuses on environments with single inhabitants,1 or on laboratories or temporarily occupied spaces,2 and is conducted using high-density motion sensors.3 We aim to provide a solution that includes tools for tracking, recognizing, and monitoring the day-to-day activities of inhabitant(s), but which is also suitable for real-life settings, under a strict policy that we discuss and agree with the inhabitants. Our testbed was a 260m2 home in Carinthia, Austria, based on a framework similar to that of the Casa Vecchia project.4 A family of four inhabited the house: parents, aged 46 and 45, and two children, aged 10 and 13, and there were also regular visitors. Around the house we installed passive IR motion sensors, magnetic contacts for doors and cupboards, in-between switches, and window blind actuators (see Figure 1). All the devices (except the blind actuators) generated binary values (on/off, open/closed) when triggered by their interactions with the inhabitants. For privacy reasons, we were unable to use video cameras for observation, and for comfort and practicality we selected not to use identification devices (radio-frequency identification bracelets, for example). Therefore, to recognize and track movement by each person as they move around the space, we Figure 1. Left: Floor plan of the testbed house and sensor placements for the ambient sensor network. Right: Examples of the sensors: a motion sensor on the wall (top), a magnetic contact on a shower door (center), and an in-between switch for the TV (bottom).

Biomechanical Analysis of Squat Jump and Countermovement Jump From Varying Starting Positions

The purpose of this study was to investigate the effect of 2 strategies, defined by foot placement during the initiation of the take-off on performance in vertical jumps. The additional area of interest in this experiment was whether technique of the take-off phase might be an exploratory factor that has different electromyogram (EMG) muscle activity during squat jump (SJ) and countermovement jump (CMJ) performed starting from the standard position, with parallel foot placement, and from the experimental one, with straddle foot placement. Six well-experienced male 100-400 m sprinters, who were members of the Polish youth and senior national team (mean values: age 21.6 years, best performance: 100 m in 10.54 seconds and 400 m in 45.54 seconds), performed vertical SJ and vertical CMJ from 2 initial positions with different foot placement. To collect all selected kinematic and kinetic data, the video recording system BTS Vixta was used in conjunction with force platforms (Kistler model 9286B). The latest system for 3D motion analysis, BTS SMART, based on the passive IR reflective markers was also applied. Electromyograms of 6 lower limb muscles were collected using a Noraxon EMG device. The CMJ was on average 7 cm higher than the SJ (CMJ, 85 cm and SJ, 78 cm), which amounts to 8.97%. This was not because of the increase of center of gravity (COG) velocity at take-off because velocities of center of gravity (COG) projection were almost equal (SJ, 2.93 m·scompared with CMJ, 2.99 m·s). No significant differences of both magnitude and rate of development of the muscle torques and powers between jumps were found, but when we analyzed the problem with division into single legs (right and left) and with division into different jumps (SJ and CMJ), the differences were evident. The profiles of EMG activity of selected muscles showed some differences between SJ and CMJ. The vertical SJ and CMJ performance measurement may be of value to coaches and conditioning specialists who wish to develop or assess the power ability of lower extremities either unilaterally (single leg) or bilaterally (sum of both legs).

On ear-based human identification in the mid-wave infrared spectrum

In this paper the problem of human ear recognition in the Mid-wave infrared (MWIR) spectrum is studied in order to illustrate the advantages and limitations of the ear-based biometrics that can operate in day and night time environments. The main contributions of this work are two-fold: First, a dual-band database is assembled that consists of visible (baseline) and mid-wave IR left and right profile face images. Profile face images were collected using a high definition mid-wave IR camera that is capable of acquiring thermal imprints of human skin. Second, a fully automated, thermal imaging based, ear recognition system is proposed that is designed and developed to perform real-time human identification.The proposed system tests several feature extraction methods, namely: (i) intensity-based such as independent component analysis (ICA), principal component analysis (PCA), and linear discriminant analysis (LDA); (ii) shape-based such as scale invariant feature transform (SIFT); as well as (iii) texture-based such as local binary patterns (LBP), and local ternary patterns (LTP). Experimental results suggest that LTP (followed by LBP) yields the best performance (Rank1=80:68%) on manually segmented ears and (Rank1=68:18%) on ear images that are automatically detected and segmented. By fusing the matching scores obtained by LBP and LTP, the identification performance increases by about 5%. Although these results are promising, the outcomes of our study suggest that the design and development of automated ear-based recognition systems that can operate efficiently in the lower part of the passive IR spectrum are very challenging tasks.

Passive IR field gradient detection of thermal objects in active Fresnel zones

A dual element Passive-Infrared (PIR) sensor is used with a rotating slit aperture to map a narrow scanning beam on the sensing elements through each lens of a Fresnel lens array. The stimuli generated due to each thermal object fall in the active Fresnel zones in a certain direction based on their locations and temperature variations on the surfaces of the sources. These signals are used to analyze the signatures of stationary thermal objects, their slight movements and thermal field gradient changes of the source surfaces provided the object projected area is less than the area of the active zone. Pattern matching is performed using Dynamic-Time-Warping (DTW) algorithm on STFT reduced length time vectors. The object space is divided into m-active zones that correspond to the Fresnel zones in a Fresnel lens array. Within passive IR region from each of the active zones, the system identifies not only the heat intensity changes but also detects the slight movement of the thermal source. The efficiency of the system is dependent on the number of active Fresnel zones and the angular separation between them. This single node PIR sensor system is designed to cover an angular view of ∼10°×80° while horizontal Field of View (FOV) is divided into 4 active Fresnel zones. Generally costly Thermal-IR camera is used for thermal analysis. Our system is comparatively less costly and active coverage zones are easily configurable by increasing number of Fresnel lenses.

激光红外主被动复合导引系统

A compound guided system by combining the laser 3D active imaging and passive IR imaging was proposed to improve the operational effectiveness for air-ground missiles and the recognition ability for IR stealthy targets.The detail design program and reasonable guided strategy were also given.This system has the ability of IR wide field searching and laser 3D imaging in a narrow field and its abundant image information makes the operational object recognition more easy.The structure of the whole system is simple and easy to process.When the aperture of the compound guided system is limited at about 100 mm,the guided distance is longer than 4 km.This technology is important to develop compound guided systems and improve the missile operational ability in our country.

EVALUATION OF DUAL-SPECTRUM IR SPECTROGRAM SYSTEM ON INVASIVE DUCTAL CARCINOMA (IDC) BREAST CANCER

Invasive Ductal Carcinoma (IDC) is one of the most frequently diagnosed breast cancers. IDC accounts for about 8 out of 10 of all invasive breast cancers. While early detection of breast cancer is essential for the reduction of death rate, there may be already more than 107 cells in a breast cancer when it can be observed by X-ray mammogram. In contrast, the passive IR spectrogram proposed by Szu et al. was shown to be promising in detecting breast cancers several months ahead of mammogram. With energy readings from two IR cameras, middle wavelength IR (MIR, 3–5 μm) and long wavelength IR (LIR, 8–12 μm), dual-spectrum IR (DS-IR) spectrogram may be computed by using the deterministic neighborhood-based blind source separation algorithm developed by Szu et al..4–7 To evaluate the performance of the DS-IR spectrogram on detection of IDC, a DS-IR spectrogram hardware system is built and a sub-pixel super-resolution registration is developed to implement the deterministic neighborhood-based blind source separation algorithm. Clinical tests have been carried out with the approval of Institutional Review Board of National Taiwan University Hospital. From August 2007 to June 2008, 35 patients aged between 30–66 (average age 49) with IDC breast cancers were recruited in this project. The results demonstrate that 62.86% of success rate for IDC detection may be achieved with the cross-sectional data. Longitudinal study shows that breast cancers may be detected more accurately by cross-referencing s1 maps of multiple time-points.