Infrared Thermography Technology Research Articles

Evaluation of infrared technology to detect category I and suspected deep tissue injury in hospitalised patients.

To evaluate the use of an infrared thermography device in assessing skin temperature among category I pressure ulcer (PU) and/or suspected deep tissue injuries (SDTI) with intact skin. An observational cross-sectional study design was used. Adult inpatients (cases) who had a category I PU or suspected deep tissue injury (skin intact) on the sacral or heel during the study period (March to April 2018) were recruited. Patients without a PU were also recruited to act as control. Thermal images of the patient's PU site and non-PU site were taken within 24 hours of PU occurrence. Thermal images of the control patients (no PU) were also taken. Each PU case was matched to three control patients in terms of age, gender, race and anatomical sites. All thermal images were taken using a portable CAT S60 Thermal Imaging Rugged Smartphone (Caterpillar Inc., US) that provided readings of the skin temperature in degrees Celsius. A total of 17 cases and 51 controls were recruited. Among the cases, the mean difference in skin temperature between the PU site (mean: 31.14°C; standard deviation [SD]: 1.54) and control site within the cases (mean: 28.93°C; SD: 3.47) was significant (difference: 2.21±3.66°C; p=0·024). When comparing between all cases and controls, the mean temperature difference was non-significant. When comparing between the category I PU and suspected deep pressure injury cases, the mean difference was also non-significant. Using infrared thermography technology at the bedside to measure skin temperature will support the clinical diagnosis of patients with skin types I to III. However, there is a need for a more accurate and objective measurement to identify and diagnose early category I PU or suspected deep tissue injury in adult patients with darker skin types 4 and above, enabling early initiation of preventive measures in the hospital acute care setting.

An experimental study of the effects of climate conditions on thermography and pavement assessment

ABSTRACT This paper presents a testing set-up that helps to observe and quantify the effects of different weather conditions on the thermal profiles related to the surface crack on concrete infrastructures. The temperature data for this research are generated using infrared thermography (IRT). IRT is prominently used to monitor surface and close-to-surface defects on pavements. However, the method is more prone to adverse effects of weather conditions compared to other types of nondestructive tests. This is because IRT relies on the temperature profile of the surface of the target. In this research, a full laboratory study is conducted to experimentally quantify the effects of weather conditions and surface coating on the ability of IRT to assess surface cracks on concrete pavements. The goal is to determine the significance of these effects on IRT under each weather condition. IRT technology can be affected by critical environmental conditions, such as sunlight, ambient temperature variation, wind speed and humidity. Many research studies have mentioned the importance of the effect of weather conditions, but no research is dedicated to experimentally quantifying the effect. Around 90 different tests have been conducted from which 1050 unique data points have been extracted. Eventually, around 1,260,000 temperature data have been gathered which gives a huge dataset will give us the opportunity to do several statistical analyses. It is found that wind has a higher effect on the temperature of the crack on concrete pavements compared to humidity in the air. Even though both wind and humidity can affect the temperature of the crack, the different wind speeds and humidity levels have roughly the same amount of effect on the temperature.

IR Thermography from UAVs to Monitor Thermal Anomalies in the Envelopes of Traditional Wine Cellars: Field Test

Infrared thermography (IRT) techniques for building inspection are currently becoming increasingly popular as non-destructive methods that provide valuable information about surface temperature (ST) and ST contrast (delta-T). With the advent of unmanned aerial vehicle (UAV)-mounted thermal cameras, IRT technology is now endowed with improved flexibility from an aerial perspective for the study of building envelopes. A case study cellar in Northwest (NW) Spain is used to assess the capability and reliability of low-altitude passive IRT in evaluating a typical semi-buried building. The study comparatively assesses the use of a pole-mounted FLIR B335 camera and a drone-mounted FLIR Vue Pro R camera for this purpose. Both tested IRT systems demonstrate good effectiveness in detecting thermal anomalies (e.g., thermal bridges, air leakages, constructive singularities, and moisture in the walls of the cellar) but pose some difficulties in performing accurate ST measurements under real operating conditions. Working with UAVs gives great flexibility for the inspection, but the angle of view strongly influences the radiometric data captured and must be taken into account to avoid disturbances due to specular reflections.

Simultaneous determination of gas leakage location and leakage rate based on local temperature gradient

In this study, a quantitative non-contact detection method for gas leakage problem based on infrared thermography technology is developed. First, the relationship between the gas leakage rate and the temperature gradient at the edge of the leaking hole is established based on thermodynamics, dimensional analysis and numerical methods. Second, the temperature fields surrounding the gas leakage location are extracted using an infrared thermal imager. Both the gas leakage location and leakage rate are obtained for the damaged rubber seals. Finally, the detections of gas leakage location with arbitrary shape and no obvious temperature difference are discussed and generalized. These results will play an important role in detecting the leakage rate for the damaged seal structures or containers.

RPCA Based Temperature Digit Extraction for Electrical Equipment Infrared Images

Infrared thermography technology is one of the most important ways to diagnosis the status of electrical equipment. The data we get is thousands of infrared images. In order to meet the demands of massive electrical equipment infrared images automatic diagnosis and provide reliable analysis basis, in this paper, a temperature digit extraction method based on RPCA is proposed. The assumption of this paper is that the infrared images have lost their temperature information during data circulating. In this case, to analyze the infrared images quantitatively, the most important thing is to recover the temperature matrix by digit recognition. The first step is to get the temperature region and then separate each single digit area. In order to achieve this goal, we first take advantage of RPCA to get the temperature area and then use histogram statistics to get a single number or symbol area. We take 6000 sample images including transmission and transformation equipment to evaluate the performance of the temperature region extraction method. The experimental results show that the algorithm can extract the digits with high accuracy which could provide data foundation for quantitative infrared image fault analysis. Furthermore, we will aim at finding a more flexible algorithm to get the digit rapidly and reliably.

Mottling score and skin temperature in septic shock: Relation and impact on prognosis in ICU.

IntroductionMottling score, defined by 5 areas over the knee is developed to evaluate tissue perfusion at bedside. Because of the subjective aspect of the score, we aimed to compare mottling score and skin temperature in septic shock with infrared thermography in ICU and the correlation to survival.MethodsWe conducted a prospective and observational study in a teaching hospital in France during 8 months in ICU. All patients with sepsis requiring vasoactive drugs were included. We recorded epidemiologic data, hemodynamic parameters, mottling score and skin temperature with a thermic camera of the 5 mottling areas around the knee (temperatures recorded with FLIR™ software) at bedside. Measures were performed at ICU admission (H0) and six hours after initial resuscitation (H6).Results46 patients were included. Median age was 69 (60–78), SOFA score 11 (8–12) mean SAPS II was 57±20 and 28-day mortality rate was 30%. Patients with mottling (score≥1), had a skin temperature of the knee significantly lower (30.7 vs 33,2°C p = 0.01 at H6) than patients without mottling (score = 0). Skin temperatures of the knee in mottling groups 1 to 5 were similar at H0 and H6. Neither mottling score nor skin temperature of the knee were associated with prognostic regarding day-28 mortality.ConclusionsSkin temperature measured with infrared thermography technology around the knee is lower when mottling sign is present and sign microcirculation alterations. This method, compared to standard mottling score is objective and allows data collections. However, this method failed to predict mortality in ICU patients.

Distribution law of temperature changes during methane adsorption and desorption in coal using infrared thermography technology

Gas adsorption and desorption is a thermodynamic process that takes place within coal as temperature changes and that is related to methane (CH4) storage. As infrared thermographic technology has been applied in this context to measure surface temperature changes, the aim of this research was to further elucidate the distribution law underlying this process as well as the thermal effects induced by heat adsorption and desorption in coal. Specimens of two different coal ranks were used in this study, and the surface temperature changes seen in the latter were detected. A contour line map was then drawn on the basis of initial results enabling a distribution law of temperature changes for samples. The results show that different regions of coal sample surfaces exhibit different heating rates during the adsorption process, but they all depends on gas storage capacity to a certain extent. It proposes a correlation coefficient that expresses the relationship between temperature change and gas adsorption capacity that could also be used to evaluate the feasibility of coalbed CH4 extraction in the field. And finally, this study is deduced a method to reveal the actual adsorption capacity of coal or CH4 reservoirs in in situ coal seams.

The Application Status of Infrared Thermal Imaging Non-destructive Testing

The infrared thermal imaging nondestructive testing is to get the temperature distribution of the component by extrinsic stimulation，there are a lot of advantages when compared with other methods, and the application prospect is widespread. This paper shows three types of infrared thermal imaging nondestructive testing technology, the research status at home and abroad, and the application of it. We think the infrared thermography technology is fast, real-time detection and no contact. it is going to be a very effective detection method.

Challenges to Global Implementation of Infrared Thermography Technology: Current Perspective.

Medical infrared thermography (IT) produces an image of the infrared waves emitted by the human body as part of the thermoregulation process that can vary in intensity based on the health of the person. This review analyzes recent developments in the use of infrared thermography as a screening and diagnostic tool in clinical and nonclinical settings, and identifies possible future routes for improvement of the method. Currently, infrared thermography is not considered to be a fully reliable diagnostic method. If standard infrared protocol is established and a normative database is available, infrared thermography may become a reliable method for detecting inflammatory processes.

Infrared thermography as a complementary tool for the evaluation of heat transfer in the freezing of fruit juice model solutions

The heat transfer process during the freezing of 600 kg of fruit juice model solutions in common containers (boxes, buckets and metallic drums), and different settings in a freezing tunnel, was studied. The air velocity was measured at several points in the entire tunnel. Thermocouples were installed to monitor the temperature profiles within the solution, at the packaging surface and cooling air. To measure the experimental effective heat transfer coefficients conventional temperature measurements with thermocouples and infrared thermography technology were used to map the distribution of the coefficients throughout the surface. Energy consumption involved in each configuration was evaluated. The higher velocities occurred at greater height (above the stacking and drums), being possible to verify the existence of preferential airflow pathways near the door and at the tunnel bottom. The highest air velocities observed were 2.85 m s−1; 2.72 m s−1, and 2.62 m s−1 for drums, boxes and buckets, respectively. The movement of the freezing front has begun from the outermost containers toward those located in the center of the stacks and the average freezing time was 51 h (plastic boxes), 55 h (plastic buckets) and 102 h for metal drums. The energy consumption for drums has been almost the double when comparing with buckets and boxes. The distribution of the local convective heat coefficients throughout the freezing process was not constant. Variations and different intensities of scatter were observed for the different packaging configurations and for the different periods during the freezing process (precooling, phase change and tempering). Thermal imaging technology proved useful in the study of heat transfer coefficients, allowing their complete mapping on the surface of the packaging, without the necessity of direct contact with the product.

Hot chicks, cold feet

Infrared thermography (IRT) is increasingly applied as a noninvasive technique for measuring surface body temperature alterations related to e.g. stress, emotions and leg pathologies in avian species. As a basis for the validation of IRT as a future tool for veterinary diagnostics such as detection and/or prediction of subclinical footpad pathologies in broiler chickens, this study explored effects of manual restraint at two different ages on footpad temperatures. Head region temperatures were applied as additional measures of emotional arousal and stress. The study demonstrated that footpad temperatures dropped during 10min of restraint (p<0.001, −0.45°C 95% CI (−0.49, −0.41) per min), whilst head region temperatures (e.g. nostril, wattle, eye, and average head temperature) rose (p=0.004, 0.76°C 95% CI (0.39, 1.15) per 10min), which is consistent with body temperature alterations during emotional arousal and stress, termed stress-induces hyperthermia. Temperature differed between 30 and 36 d (p<0.001, 1.71°C 95% CI (1.04, 2.38) per week), but it is impossible to draw conclusions whether this effect was caused by age or by conditioning. Furthermore, sequential sampling order affected temperature (p=0.04, 0.13°C 95% CI (0.01, 0.25)). In conclusion, one needs to take into account the duration of handling and restraint during the assessment of footpad temperatures, as well as the chickens age, previous experience and sequential sampling order, when using IRT technology as a future noninvasive tool to study temperature alterations associated with subclinical footpad pathologies in broiler chickens.

A pilot study of online non-invasive measuring technology based on video magnification to determine skin temperature

Much attention was paid on human centered design strategies for environmental control systems of indoor built environments. The goal is to achieve thermally comfortable, healthy and safe working or living environments in energy efficient manners. Normally building Heating, Ventilation and Air Conditioning (HVAC) systems have fixed operating settings, which can't satisfy human thermal comfort requirements under transient and non-uniform indoor thermal environments. Therefore, human thermal physiology signal such as skin temperature, which can reflect human body thermal sensation, has to be measured over time. Several trials have been performed by minimizing measuring sensors such as i-Button and mounting measuring sensors into wearable devices such as glasses. Infrared thermography technology has also been tried to achieve non-invasive measurements. However, it would be much more convenient and feasible if normal computer camera could record images, which could be used to obtain human thermal physiology signals. In this study, skin temperature of hand back, which has a high density of blood vessels and is normally not covered by clothing, was measured by i-button sensors. Images recorded by normal camera were amplified to analyzing skin temperature variation, which are impossible to see with naked eyes. The agreement between i-button sensor measuring results and image magnification results demonstrated the possibility of non-invasive measuring technology by image magnification. Partly personalized saturation-temperature model (T = 96.5 × S + bi) can be used to predict skin temperatures for young East Asia females.

Detecting the Honeycomb Sandwich Composite Material's Moisture Impregnating Defects by Using Infrared Thermography Technique

Many composite materials are used in the aerospace industry because of their excellent mechanical properties. However, the nature of aviation exposes these materials to high temperature and high moisture conditions depending on climate, location, and altitude. Therefore, the molecular arrangement chemical properties, and mechanical properties of composite materials can be changed under these conditions. As a result, surface disruptions and cracks can be created. Consequently, moisture-impregnating defects can be induced due to the crack and delamination of composite materials as they are repeatedly exposed to moisture absorption moisture release, fatigue environment, temperature changes, and fluid pressure changes. This study evaluates the possibility of detecting the moisture-impregnating defects of CFRP and GFRP honeycomb structure sandwich composite materials, which are the composite materials in the aircraft structure, by using an active infrared thermography technology among non-destructive testing methods. In all experiments, it was possible to distinguish the area and a number of CFRP composite materials more clearly than those of GFRP composite material. The highest detection rate was observed in the heating duration of 50 mHz and the low detection rate was at the heating duration of over 500 mHz. The reflection method showed a higher detection rate than the transmission method.

Eye and Ear Temperature Using Infrared Thermography Are Related to Rectal Temperature in Dogs at Rest or With Exercise.

Rectal body temperature (BT) has been documented in exercising dogs to monitor thermoregulation, heat stress risk, and performance during physical activity. Eye (BTeye) and ear (BTear) temperature measured with infrared thermography (IRT) were compared to rectal (BTrec) temperature as the reference method and assess alternative sites to track hyperthermia, possibly to establish BTeye IRT as a passive and non-contact method. BT measures were recorded at 09:00, 11:30, 12:30, and 02:30 from Labrador Retrievers (N = 16) and Beagles (N = 16) while sedentary and with 30-min play-exercise (pre- and 0, 15, 30-min post-exercise). Total exercise locomotor activity counts were recorded to compare relative intensity of play-exercise between breeds. BTrec, BTeye, and BTear were measured within 5 min of the target time. Each BT method was analyzed by analysis of variance for main effects of breed and time. Method differences were compared using Bland–Altman plots and linear regression. Sedentary BT differed by breed for BTrec (p < 0.0001), BTear (p < 0.0001), and BTeye (p = 0.06) with Labs having on average 0.3–0.8°C higher BT compared to Beagles. Readings also declined over time for BTeye (p < 0.0001) and BTear (p < 0.0001), but not for BTrec (p = 0.63) for both breeds. Total exercise (30-min) activity counts did not differ (p = 0.53) between breeds. Time and breed interaction was significant in response to exercise for both BTrec and BTear (p = 0.035 and p = 0.005, respectively), with a marginal interaction (p = 0.09) for BTeye. All the three methods detected hyperthermia with Labs having a higher increase compared to Beagles. Both BTear and BTeye were significantly (p < 0.0001) related to BTrec in all dogs with sedentary or exercise activity. The relationship between BTeye and BTrec improved when monitoring exercise hyperthermia (r = 0.674) versus measures at rest (r = 0.381), whereas BTear was significantly related to BTrec regardless of activity (r = 0.615–0.735). Although BT readings were significantly related, method bias (p < 0.02) was observed for BTeye to slightly underestimate BTrec, whereas no bias was observed between BTear and BTrec. This study demonstrates that IRT technology effectively measures both ear and eye temperature and enables effective monitoring of BT changes at rest, with exercise, and between breeds. However, ear, and not eye, temperature is a better reflection of rectal temperature.

Theoretical and experimental study on thermal barrier coating (TBC) uneven thickness detection using pulsed infrared thermography technology

TBC uneven thickness detection has been carried out using pulsed infrared thermography technology. A three-dimensional heat conduction model of pulsed heat in the coating structure was built, based on which FEM simulation was done, and the influence of coating thickness, sampling frequency and sampling time was analyzed. Pulsed infrared thermography experiments were carried out to SiC coated superalloy specimens with uneven coating thickness prepared by plasma spraying method, and the relationship between parameters including impulse energy, sampling frequency, sampling time and the characterization parameter contrast ratio was analyzed.

Three-point-bending fatigue behavior of AZ31B magnesium alloy based on infrared thermography technology

The fatigue behavior of the AZ31B magnesium alloy subjected to three-point-bending tests was studied. Real-time recording of the surface-temperature-evolution data of specimens was obtained using the infrared thermography technology during fatigue. The characteristics of heat production and transfer were described, and the correlation between temperature and stress distribution was analyzed. The surface temperature of specimens undergoes four stages: (I) Initial rapid increase stage, (II) Decrease stage, (III) Steady-state stage, and (IV) Abrupt fracture stage during the course of the experiment. The fracture surface of specimens was observed by Scanning Electron Microscope (SEM). The result demonstrates that the AZ31B alloy possess by the quasi-cleavage fracture. The development of twins was analyzed to confirm the reason for temperature changing. An energy model based on the fatigue-damage-accumulation theory was established to predict the fatigue prediction of AZ31B-magnesium-alloy specimens. The fatigue strength of the AZ31B magnesium alloy using the Luong’s method is 128.97MPa, is close to the experimental result of 133.87MPa, the fatigue strength of the prediction model gives 137.33MPa, which is comparable to the experimental results.

Quantitative detection of defects based on Markov–PCA–BP algorithm using pulsed infrared thermography technology

Quantitative detection of debonding defects’ diameter and depth in TBCs has been carried out using pulsed infrared thermography technology. By combining principal component analysis with neural network theory, the Markov–PCA–BP algorithm was proposed. The principle and realization process of the proposed algorithm was described. In the prediction model, the principal components which can reflect most characteristics of the thermal wave signal were set as the input, and the defect depth and diameter was set as the output. The experimental data from pulsed infrared thermography tests of TBCs with flat bottom hole defects was selected as the training and testing sample. Markov–PCA–BP predictive system was arrived, based on which both the defect depth and diameter were identified accurately, which proved the effectiveness of the proposed method for quantitative detection of debonding defects in TBCs.

Quantitative detection of thermal barrier coating thickness based on simulated annealing algorithm using pulsed infrared thermography technology

Quantitative detection of thermal barrier coating thickness based on simulated annealing (SA) algorithm has been carried out using pulsed infrared thermography technology. The principle of quantitative detection of thermal barrier coating thickness was given, and the model of inverse heat conduction problem was built. The basic principle and implementation process of SA algorithm was described. The specimen with uneven coating thickness was detected using pulsed infrared thermography system, and the coating thickness was calculated using SA algorithm. Results show that when the coating thickness is 45~130 µm, compared with eddy current testing results, the relative error is less than 10%, which proves the effectiveness of the coating thickness detection method proposed in this paper.

Research on Defects Inspection of Solder Bumps Using Active Infrared Thermography Technology

Research on Defects Inspection of Solder Bumps Using Active Infrared Thermography Technology

Skin temperature reveals the intensity of acute stress

Acute stress triggers peripheral vasoconstriction, causing a rapid, short-term drop in skin temperature in homeotherms. We tested, for the first time, whether this response has the potential to quantify stress, by exhibiting proportionality with stressor intensity. We used established behavioural and hormonal markers: activity level and corticosterone level, to validate a mild and more severe form of an acute restraint stressor in hens (Gallus gallus domesticus). We then used infrared thermography (IRT) to non-invasively collect continuous temperature measurements following exposure to these two intensities of acute handling stress. In the comb and wattle, two skin regions with a known thermoregulatory role, stressor intensity predicted the extent of initial skin cooling, and also the occurrence of a more delayed skin warming, providing two opportunities to quantify stress. With the present, cost-effective availability of IRT technology, this non-invasive and continuous method of stress assessment in unrestrained animals has the potential to become common practice in pure and applied research.