Infrared Video Camera Research Articles

The effect of non-uniform skelp temperature on X70 steel coil cooling

This study explored the effect of varying steel skelp temperature (500 °C–600 °C) on the subsequent temperature-time ( T- t) profile during and after coiling of low C (0.05 wt. %) X70 microalloyed steels. Three industrially produced steel coils with similar rough rolling temperatures (∼1050 °C) and finish rolling temperatures (∼850 °C) but different coiling temperatures (500 °C–600 °C) and different skelp thicknesses (19 mm and 25 mm) were studied. The surface temperature of each coil was measured using an infrared video camera. A three-dimensional heat transfer model was developed to predict the T- t profiles. A lower (∼60 °C) initial skelp temperature near the head and tail of the skelp led to a reduced coil temperature. A higher (∼50 °C) temperature near the head and tail region of the skelp resulted in a more uniform coil temperature (a difference of ∼10 °C instead of ∼50 °C).

In the arm-in-cage test, topical repellents activate mosquitoes to disengage upon contact instead of repelling them at distance

Topical repellents provide protection against mosquito bites and their efficacy is often assessed using the arm-in-cage test. The arm-in-cage test estimates the repellent’s protection time by exposing a repellent-treated forearm to host-seeking mosquitoes inside a cage at regular intervals until the first confirmed mosquito bite. However, the test does not reveal the repellents’ behavioural mode of action. To understand how mosquitoes interact with topical repellents in the arm-in-cage test, we used a 3D infrared video camera system to track individual Aedes aegypti and Anopheles stephensi females during exposure to either a repellent-treated or an untreated forearm. The repellents tested were 20% (m/m) ethanolic solutions of N, N-diethyl-meta-toluamide, p-menthane-3,8-diol, icaridin and ethyl butylacetylaminopropionate. All four repellents substantially reduced the number of bites compared to an untreated forearm, while the flight trajectories indicate that the repellents do not prevent skin contact as the mosquitoes made multiple brief contacts with the treated forearm. We conclude that, in the context of the arm-in-cage test, topical repellents activate mosquitoes to disengage from the forearm with undirected displacements upon contact rather than being repelled at distance by volatile odorants.

Experimental investigation of electrically enhanced boiling of FC 72 using high-resolution phase-detection diagnostics

This work features the boiling of FC72 on a transparent sapphire substrate. Tests are performed using a thin ITO film (indium tin oxide) coated on the sapphire substrate as the heat source, a fast speed video camera to capture the boiling process using a technique to track the phase (liquid or vapor) in contact with the heating surface, an InfraRed video camera to capture the average temperature on the surface, and a metallic grid to impose an electric field perpendicular to the boiling surface. The maximum average electric field tested in this work is 3.3kV/mm, which led to a 18% increase of the critical heat flux. This study analyses in detail the phase distribution data showing that (1) there is no evidence of microlayer formation, and suggesting that (2) the triple contact line evaporation accounts for approximately 20% of the total heat flux, while (3) the quenching stage accounts for approximately 80%. Finally, phase distribution images are processed to characterize the size of vapor patches, showing that a boiling crisis occurs when the distribution of the vapor patches becomes scale-free, and corroborating the hypothesis that the boiling crisis can be modelled as a bubble interaction instability using a percolation model.

Measuring the thermal diffusivity and conductivity of thermal insulators using laser-spot step-heating thermography

In laser-spot step-heating thermography the sample surface is illuminated by a focused laser beam while the surface temperature rise is monitored by an infrared video camera. By analysing the temperature profile at several instants after the laser beam is switched on, the in-plane thermal diffusivity can be obtained. In this work, we show that in thermal insulators heat conduction to the surrounding gas, which is typically neglected in this kind of experiments, plays a significant role and allows determining both thermal diffusivity and conductivity simultaneously.

Developing a Hidden Markov model for occupancy prediction in high-density higher education buildings

The number of occupants in a building as well as the occupancy patterns and profiles have a significant impact on the building energy consumption associated with heating, cooling, ventilation, and lighting systems. A range of approaches has been used in previous studies for building occupancy prediction. However, there were limitations associated with the methods used for data collection. For instance, the prediction of occupancy based on the concentration of CO2 level adds an additional level of uncertainty into the estimation of the building occupancy level. To avoid such uncertainties, high-resolution passive infrared video camera sensors were used to capture occupancy data for an extended period of one year. The collected occupancy data have then been used to develop a Hidden Markov Model (HMM), to predict the occupancy levels in a high-density higher education case study building. The model is trained under different scenarios to find the most appropriate set of attributes associated with occupancy data that can be used to develop the data driven HMM. The occupancy attributes considered include day, week, month, and term. Moreover, the collected dataset was optimally split into 70% for training and 30% for validation using cross-validation, which yields high prediction accuracy. The results of the prediction model under different scenarios were evaluated using root mean square error and Kullback Leibler (KL) divergence.

A Comparison of Inertial Measurement Units and Overnight Videography to Assess Sleep Biomechanics.

The assessment of sleep biomechanics (comprising movement and position during sleep) is of interest in a wide variety of clinical and research settings. However, there is no standard method by which sleep biomechanics are measured. This study aimed to (1) compare the intra- and inter-rater reliability of the current clinical standard, manually coded overnight videography, and (2) compare sleep position recorded using overnight videography to sleep position recorded using the XSENS DOT wearable sensor platform. Ten healthy adult volunteers slept for one night with XSENS DOT units in situ (on their chest, pelvis, and left and right thighs), with three infrared video cameras recording concurrently. Ten clips per participant were edited from the video. Sleeping position in each clip was coded by six experienced allied health professionals using the novel Body Orientation During Sleep (BODS) Framework, comprising 12 sections in a 360-degree circle. Intra-rater reliability was assessed by calculating the differences between the BODS ratings from repeated clips and the percentage who were rated with a maximum of one section of the XSENS DOT value; the same methodology was used to establish the level of agreement between the XSENS DOT and allied health professional ratings of overnight videography. Bennett's S-Score was used to assess inter-rater reliability. High intra-rater reliability (90% of ratings with maximum difference of one section) and moderate inter-rater reliability (Bennett's S-Score 0.466 to 0.632) were demonstrated in the BODS ratings. The raters demonstrated high levels of agreement overall with the XSENS DOT platform, with 90% of ratings from allied health raters being within the range of at least 1 section of the BODS (as compared to the corresponding XSENS DOT produced rating). The current clinical standard for assessing sleep biomechanics, manually rated overnight videography (as rated using the BODS Framework) demonstrated acceptable intra- and inter-rater reliability. Further, the XSENS DOT platform demonstrated satisfactory levels of agreement as compared to the current clinical standard, providing confidence for its use in future studies of sleep biomechanics.

Nest predators of Chinese Grouse (Tetrastes sewerzowi) at Lianhuashan, Gansu, China

Predation is the most important cause of nest failure in the Chinese Grouse (Tetrastes sewerzowi). However, no studies have been conducted to document the nest predators responsible for nest predation events. During 2012–2016, we monitored 17 nests using infrared video cameras to identify nest predators of Chinese Grouse. Six nests were preyed upon during the incubation period. We successfully identified the predators responsible for 5 depredated nests: Asian badger (Meles leucurus), hog badger (Arctonyx collaris), and Blue Eared Pheasant (Crossoptilon auritum). The Asian badger was responsible for 3 of these nest predation events. We recorded Siberian chipmunk (Tamias sibiricus) and an unidentified rodent species attempting to prey upon grouse eggs, but none of them were successful.

Water temperature and precipitation stimulate small-sized Japanese eels to climb a low-height vertical weir.

Although river-crossing structures can have a detrimental effect on the movement and distribution of anguillid eels (genus Anguilla), they have inhabited locations upstream of river-crossing structures in many rivers. However, the growth stage in which the eels start to climb river-crossing structures remains unclear. In this study, we directly observed, using infrared video camera systems, that the Japanese eel (Anguilla japonica) climbs a low-height vertical weir as a migratory barrier, confirming the ability of eels to climb over a low-height weir within a river. All eels climbed the weir at night, between sunset and sunrise. We observed that the total length of Japanese eels that climbed the weir ranged from 60 to 140 mm, suggesting that eels inhabiting the upstream area of a weir climbed it when they were small and then lived and grew upstream. Moreover, the general additive model showed considerable effects of water temperature and precipitation on eel climbing, suggesting that water temperature and precipitation are important for its activation. The results of this study also show the effectiveness of infrared video cameras in monitoring eel climbing, which could be applied to monitor fish migratory behavior through fish passages. The findings of this study are useful for the comprehensive management and conservation of wild eel stocks.

Dabbling Duck Eggs Hatch after Nest Abandonment in the Wild

In most birds, parental incubation of eggs is necessary for embryo development and survival. Using a combination of weekly nest visits, temperature dataloggers, infrared video cameras, and GPS tracking of hens, we documented several instances of duck eggs hatching after being abandoned by the incubating female. Of 2826 Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) nests monitored 2015–2019 in Suisun Marsh, California, 48 (1.7%) were abandoned during late incubation (≥ 20 days). Of these, we identified six (12.5%) where at least one egg hatched 2–9 days after abandonment. In all six cases, eggshell membranes were found in the nest (indicating hatch), and ducklings were observed at three nests. Abandoned nests were unattended for an average of 5.9 days before eggs hatched; during this time, mean nest temperatures (23.6°C–29.0°C) were substantially lower than before nest abandonment (31.7°C–36.4°C). We estimated that abandonment resulted in a 9% longer time period between clutch completion and hatch (0–4 days longer) and a lower rate of egg hatching success (36%). Our results provide evidence that some older embryos (≥ 20 days) in mild climates can survive without parental incubation for several days and continue to develop (at a reduced rate) to the point of successfully hatching.

Spontaneous nocturnal erections and masturbation in captive male chimpanzees (Pan troglodytes)

Abstract Nocturnal penile tumescence (NPT) has been reported for males of only a few mammalian species, including humans, albeit this scarcity might be an artefact of the difficulty of documenting it. We investigated NPT in 12 adult male chimpanzees living in an all-male group at Kumamoto Sanctuary, Japan. Recorded non-invasively with infrared video cameras across 72 nights (6 per individual), we observed NPT in two thirds of the individuals (8/12), with events in total. More than three quarters occurred during a transition from sleep to wakefulness, suggesting NPT may be associated with rapid eye movement sleep, similar to humans. Masturbation occurred in conjunction with NPT, including the likely consumption of ejaculate, in 4–6 individuals. While detailing nocturnal erections in chimpanzees may help us to better understand this robust physiological phenomenon in humans, further comparative research is necessary to reconstruct its phylogenetic history. At present, our findings support hypothetical functional explanations such as the facilitation of nocturnal emissions in order to increase ejaculate quality or an increase in tissue oxygenation to prevent erectile dysfunction.

An assessment of the spontaneous locomotor activity of BALB/c mice

The surrounding environment affects the behavior of an animal. Therefore, long-term observation of an animal's behavior in its natural breeding environment is an effective approach to predict and understand animal behavior in greater detail. Spontaneous locomotor activity (SLA), the movement of animals in their breeding environment, is one of the most important behavioral indices for experimental animals. We here established an SLA measurement system using image analyses to obtain basic data from BALB/c mice. To record the movement of the mice, we used an infrared video camera. SLA of mice were calculated by detecting their geometric center in each frame. This system could detect the mouse correctly more than 99.999% in all frames. Further, we investigated the effects of habituation, age, and sex on the SLA of BALB/c mice. Three days of habituation were required to decrease the SLA of mice placed in novel cages. The 16- and 32-week-old mice were less active than 4-week-old mice. No significant differences were detected between males and females. We also found that BALB/c and C57BL/6 mice differed in their active and resting rhythms. In conclusion, we developed an SLA measurement system and obtained basic SLA data from BALB/c mice.

Crack Detection in Frozen Soils Using Infrared Thermographic Camera.

Frozen soils are encountered on construction sites in the polar regions or regions where artificial frozen ground (AFG) methods are used. Thus, efficient ways to monitor the behavior and potential failure of frozen soils are currently in demand. The advancement of thermographic technology presents an alternative solution as deformation occurring in frozen soils generate heat via inter-particle friction, and thus a subsequent increase in temperature. In this research, uniaxial compression tests were conducted on cylindrical frozen soil specimens of three types, namely clay, sand, and gravel. During the tests, surface temperature profiles of the specimens were recorded through an infrared video camera. The thermographic videos were analyzed, and subsequent results showed that temperature increases caused by frictional heat could be observed in all three frozen soil specimens. Therefore, increases in temperature can be deemed as an indicator for the potential failure of frozen soils and this method is applicable for monitoring purposes.

A novel method to individually track spawning females in aquaculture tanks using the European sea bass (Dicentrarchus labrax) as a model

Mass reproduction is widely used in fish farms because it is relatively easy and inexpensive. It also enables the development of mass selection programmes that provide gains for traits with high heritability. The main weakness of this approach is that it is currently impossible to know which females participated in reproductive events, unless by conducting expensive genomic experiments. We tested oviduct-inserted floating passive integrated transponder tags as a new method to detect (i) the identity of spawners and (ii) the timing of spawning. We first conducted a preliminary experiment using four small tanks (1.5 m3) each containing one male and one female tracked by infrared video cameras to test the experimental device. We then tested it in “real” aquaculture conditions, using a bigger tank (10 m3) containing 89 adult fish. Results showed that this tracking system accurately identified the timing of spawning of individual fish. We confirm that European sea bass preferentially spawn at sunrise or sunset. This proof-of-concept developed for one commercially important fish species could also be used for novel species of interest for aquaculture, for example, to determine the exact timing of spawning after hormonal treatment of novel species.

Designing an Efficient Emergency Response Airborne Mapping System with Multiple Sensors

Multisource remote sensing data have been extensively used in disaster and emergency response management. Different types of visual and measured data, such as high-resolution orthoimages, real-time videos, accurate digital elevation models, and three-dimensional landscape maps, can enable producing effective rescue plans and aid the efficient dispatching of rescuers after disasters. Generally, such data are acquired using unmanned aerial vehicles equipped with multiple sensors. For typical application scenarios, efficient and real-time access to data is more important in emergency response cases than in traditional application scenarios. In this study, an efficient emergency response airborne mapping system equipped with multiple sensors was designed. The system comprises groups of wide-angle cameras, a high-definition video camera, an infrared video camera, a LiDAR system, and a global navigation satellite system/inertial measurement unit. The wide-angle cameras had a visual field of 85° × 105°, facilitating the efficient operation of the mapping system. Numerous calibrations were performed on the constructed mapping system. In particular, initial calibration and self-calibration were performed to determine the relative pose between different wide-angle cameras to fuse all the acquired images. The mapping system was then tested in an area with altitudes of 1000 m–1250 m. The biases of the wide-angle cameras were small bias values (0.090 m, −0.018 m, and −0.046 m in the x-, y-, and z-axes, respectively). Moreover, the root-mean-square error (RMSE) along the planer direction was smaller than that along the vertical direction (0.202 and 0.294 m, respectively). The LiDAR system achieved smaller biases (0.117, −0.020, and −0.039 m in the x-, y-, and z-axes, respectively) and a smaller RMSE in the vertical direction (0.192 m) than the wide-angle cameras; however, RMSE of the LiDAR system along the planar direction (0.276 m) was slightly larger. The proposed system shows potential for use in emergency response systems for efficiently acquiring data such as images and point clouds.

Camera traps with white flash are a minimally invasive method for long‐term bat monitoring

AbstractCamera traps are an increasingly popular survey tool for ecological research and biodiversity conservation, but studies investigating their impact on focal individuals have been limited to only a few mammal species. In this context, echolocating bats are particularly interesting as they rely less on vision for navigation, yet show a strong negative reaction to constant illumination. At hibernacula, camera traps with white flash could offer an efficient alternative method for monitoring threatened bat species, but the potential negative impact of white flash on bat behavior is unknown. Here, we investigate the effect of camera traps emitting white flash at four hibernation sites fitted with infrared light barriers, infrared video cameras, and acoustic recorders over 16 weeks. At each site, the flash was turned off every second week. We quantified whether flash affected (1) nightly bat passes using generalized linear mixed models, (2) flight direction of entering bats using permutational multivariate analyses, and (3) latency of the first echolocation call after the camera trap trigger using randomization tests. Additionally, we quantified and corrected for the potential impact of confounding factors, such as weather and social interactions. Overall, white flash did not influence short‐ or long‐term bat activity, flight direction or echolocation behavior. A decrease in nightly bat activity was observed with an increasing proportion of hours with rain. Moreover, flight direction was affected by the presence of other bats, likely due to chasing and avoidance behavior. Our findings highlight the potential of camera traps with white flash triggered by infrared light barriers as a minimally invasive method for long‐term bat population monitoring and observation of species‐specific phenology. Such automated monitoring technologies can improve our understanding of long‐term population dynamics across a wide range of spatial‐temporal scales and taxa and consequently, contribute to data‐driven wildlife conservation and management.

Effect of Facial Parameters on the Incidence of Rejection and Artifacts on the Video Head Impulse Test

Background and Objectives: The video head impulse test (vHIT) is a useful tool that uses a high-speed infrared video camera and an inertial accelerometer to quantify the vestibulo-ocular reflex. Despite advancements in recording technology, physicians should be aware of measurement artifacts induced by examiners. However, little is known about the impact of facial anatomy on artifacts. Therefore, we investigated how variance in facial anatomy affects measurement artifacts. Materials and Methods: This study enrolled nine subjects from November 2018 through November 2019. A digital camera was used to measure facial parameters, including head ratio, binocular spacing, nasofrontal angle, depth of nasion, and pupil ratio. Two examiners performed vHITs with ICS Impulse System (GN Otometrics). All impulses were assessed for artifacts, including rejection, notch during head impulse (notchduring), notch after head impulse (notchafter), and rebound. Results: The rejection rate was significantly correlated with depth of nasion, as measured by the experienced examiner, and with pupil ratio, as measured by the inexperienced examiner. notchduring rate was significantly correlated with nasofrontal angle, as measured by the inexperienced examiner. Rebound rate was significantly correlated with head ratio, as measured by both examiners. Conclusions: Measurement artifacts were significantly correlated with head ratio, depth of nasion, nasofrontal angle, and pupil ratio. (J Clinical Otolaryngol 2021;32:101-110)

Qualitative and quantitative analyses of polysomnographic measurements in foals

Veterinary and human medicine are still seeking a conclusive explanation of the function of sleep, including the change in sleep behaviour over the course of an individual’s lifetime. In human medicine, sleep disorders and abnormalities in the electroencephalogram are used for prognostic statements, therapeutic means and diagnoses. To facilitate such use in foal medicine, we monitored 10 foals polysomnographically for 48 h. Via 10 attached cup electrodes, brain waves were recorded by electroencephalography, eye movements by electrooculography and muscle activity by electromyography. Wireless polysomnographs allowed us to measure the foals in their home stables. In addition, each foal was simultaneously monitored with infrared video cameras. By combining the recorded data, we determined the time budgeting of the foals over 48 h, whereby the states of vigilance were divided into wakefulness, light sleep, slow-wave sleep and rapid-eye-movement sleep, and the body positions into standing, suckling, sternal recumbency and lateral recumbency. The results of the qualitative analyses showed that the brain waves of the foals differ in their morphology from those previously reported for adult horses. The quantitative data analyses revealed that foals suckle throughout all periods of the day, including night-time. The results of our combined measurements allow optimizing the daily schedule of the foals according to their sleep and activity times. We recommend that stall rest should begin no later than 9.00 p.m. and daily stable work should be done in the late afternoon.

Intraocular Scattering, Blinking Rate, and Tear Film Osmolarity After Exposure to Environmental Stress

PurposeDry environments, such as those in offices or aircraft cabins, can potentially generate ocular discomfort and alter the tear film. We compare light scatter, blinking rate, and tear osmolarity in young and older subjects after exposure to low humidity using a controlled environmental chamber.MethodsTwo groups of healthy subjects were recruited; younger (N = 13, 27 ± 6 years) and older (N = 23, 71 ± 7 years). Measurements were carried out before and after 90-minute exposure to low relative humidity (5%) and constant temperature (23 degrees). Ocular light scatter was measured using a double-pass instrument (OQAS, Visiometrics, Spain). Blinking rate was monitored using an infrared video camera. Tear osmolarity was measured using the TearLab system (Escondido, CA, USA).ResultsOcular light scatter increased by a factor of 10% after exposure to low humidity in the older group (P = 0.03) but did not change significantly in the younger group. Blinking rate increased significantly (40% more blinks) in both groups but there was no difference between the groups. No significant differences in osmolarity were shown between two age groups or as result of environmental stress.ConclusionsExposure to dry environment increased light scatter in older subjects. Although more blinks were triggered in both younger and older groups to prevent corneal dehydration, there was no difference between the groups. Blink rate and osmolarity are not associated with the difference in light scatter.Translational RelevanceOur work approaches a clinical care problem using basic research methods (measuring ocular scatter and blink ratio).

Thermographic imaging of mouse across circadian time reveals body surface temperature elevation associated with non-locomotor body movements.

Circadian clocks orchestrate multiple different physiological rhythms in a well-synchronized manner. However, how these separate rhythms are interconnected is not exactly understood. Here, we developed a method that allows for the real-time simultaneous measurement of locomotor activity and body temperature of mice using infrared video camera imaging. As expected from the literature, temporal profiles of body temperature and locomotor activity were positively correlated with each other. Basically, body temperatures were high when animals were in locomotion. However, interestingly, increases in body temperature were not always associated with the appearance of locomotor activity. Video imaging revealed that mice exhibit non-locomotor activities such as grooming and postural adjustments, which alone induce considerable elevation of body temperature. Noticeably, non-locomotor movements always preceded the initiation of locomotor activity. Nevertheless, non-locomotor movements were not always accompanied by locomotor movements, suggesting that non-locomotor movements provide a mechanism of thermoregulation independent of locomotor activity. In addition, in the current study, we also report the development of a machine learning-based recording method for the detection of circadian feeding and drinking behaviors of mice. Our data illustrate the potential utility of thermal video imaging in the investigation of different physiological rhythms.

Sleep Patterns of Aging Chimpanzees (Pan troglodytes)

Diurnal primates spend around half of their lifetime sleeping or inactive. These nocturnal behaviors are considerably understudied compared to daytime activities. While it is well established that sleep quality diminishes with age in humans, little is known about the effects of advanced age on sleep in our closest primate relatives. We aimed to describe captive chimpanzee (Pan troglodytes) sleep patterns and examine whether individual sleep quality changed over an 11-yr period. We recorded the individual night rooms of 12 chimpanzees for six nights using infrared video cameras and analyzed 72 nights (936 h) of video. To evaluate long-term changes, we compared our data from 2018–2019 with previously published data from 2007–2008 on the same individuals living under the same conditions. We used complete inactivity and a head-down, lying posture as a proxy measurement for sleep. Each night individuals slept a mean of 10.5 (± SD 1.8) h and woke up 15.1 (± 3.6) times. The mean duration of sleep bouts was 45.4 (± 16.8) and the mean duration of awake bouts was 10.2 (± 8.2) min. We found that as chimpanzees aged they experienced significantly more frequent awakenings and shorter sleep bouts (i.e., more fragmented sleep), but nightly sleep duration and the length of awake bouts did not differ significantly between the two study periods. Our results suggest that chimpanzees experience some changes in sleep with age similar to those in humans and other animals.