Plant water stress can be remotely monitored by means of thermography due to its increasing effect on plant temperature. For a more accurate estimation of plant water status, its temperature should be normalised against environmental conditions. In this paper, the aim was to investigate a recently proposed method of normalisation using artificial reference surfaces, different measurement times in a

The aim of the research presented in this work was to verify the occurrence of the thermoelastic effect in compacted steel wire ropes for future research applications and TSA methods. It was examined using a Testo 890 thermal camera during tests consisting of 10 cycles of loading of rope samples to levels under the yield stress, performed on a tensile strength machine. Average measured changes of temperature

The article presents the theoretical basics and definitions of radiant heat transfer with practical examples of calculation for the infrared (IR) used in infrared thermography measurements. In order to illustrate the practical possibilities of using the theoretical basics described for radiant heat transfer, the article presents some original, useful and practical examples including author’s methods

Unidirectional freeze casting for polymers and ceramics has been performed extensively; however, the mechanisms involved in unidirectional freezing are not thoroughly understood and therefore, in this study, polyvinyl (alcohol) hydrogels were freeze-thawed by unidirectional freezing and the resultant freezing profile was investigated using thermal imagery to comprehend the physical mechanism involved

At the Physikalisch-Technische Bundesanstalt, the National Metrology Institute of the Federal Republic of Germany, the traceability of non-contact temperature measurement to the International Temperature Scale (ITS-90) is realised without gaps over a temperature range from −170°C to 3000°C. In this paper the main calibration facilities for the calibration of radiation thermometers at temperatures above

This paper presents a novel approach for sinusitis detection by means of thermography. So far, the role of passive static thermography (PST) for diagnosing the sinusitis has been remarked by many studies. But, it has not been proved as an effective approach for sinusitis detection. With this aim, the automatic and active dynamic thermography (ADT) based approach has been proposed. The study has four

Automated systems for behaviour classification of laboratory animals are an attractive alternative to manual scoring. However, the proper animals separation and tracking, especially when they are in close contact, is the bottleneck of the behaviour analysis systems. In this paper, we propose a method for the segmentation of thermal images of laboratory rats that are in close contact during social behaviour

In this paper, an environmental barrier coating (EBC), which has undergone thermal cycling under spatiotemporal gradients, is inspected using active thermography. The technique considered herein is known as laser spot thermography. This study deals with the detection of a very thin crack network of unknown orientation. A numerical analysis is presented to investigate the sensitivity of experimental

Thermography is an imaging technique that records the infrared radiation of the skin with a potential to detect asymmetries in body temperature and relating them to pathologies or risk of injury. However, the location of landmarks and region of interest (ROI) can influence the recording process. In this study we describe the reliability of a method to select the ROI without modifying the original thermogram

Displaced enhancement devices are inserts positioned inside pipes that increase the heat transfer rate. This study presents an original application of an inverse analysis technique to experimental infrared temperature data to estimate the local convective heat flux for forced convection flow in a pipe in which this kind of device is present. Butterfly-shaped inserts have been investigated to determine

Here we propose a protocol to (i) generate skin temperature (SkT) oscillations on glabrous tissues (plantar foot) in healthy subjects under controlled clinical environment conditions; (ii) measure quantitative temperature fields with an inexpensive microbolometer (MB) infrared camera in a clinical environment; and (iii) quantify the characteristics of skin temperature (SkT) oscillations through spectral

The increasing use of honeycomb structures in the aircraft industry has demonstrated the need for the development of more effective evaluation methodologies. In recent years, thermography has received vast and growing attention as a reliable technique for non-destructive testing and evaluation of composite materials due to its remarkable advantages of non-contact, full area coverage, high speed, safe

Additively manufactured test specimens made of polyamide 12 (PA 12) by Laser Sintering as well as of acrylonitrile butadiene styrene (ABS) by Fused Layer Modelling, were characterised with active thermography directly after manufacturing and after artificial weathering. For this, two different excitation methods (flash and pulse heating) were used and compared, regarding their suitability for the detection

An infrared (IR) thermal camera may provide a tool for real-time temperature monitoring for precise disease treatment using heat generated by light-induced photosensitisers, i.e. photothermal/ablation therapies. In this work, we quantitatively demonstrated that the spatial resolution of a low-cost low-resolution IR camera could be improved via two deconvolution methods. The camera point spread function

Continuous infrared imaging revealed transient changes in forearm temperature during arterial occlusion, reperfusion, and recovery in a healthy subject group. Processing the imaging data with the k-means algorithm further revealed reactive vascular sites in the skin with rapid or delayed temperature amplification. The observed temporal and spatial diversity of blood-flow-derived forearm temperature

Thermal representations on the surface of a human forearm of underlying perforator vessels have previously been mapped via recovery-enhanced infrared imaging, which is performed as skin blood flow recovers to baseline levels following cooling of the forearm. We noted that the same vessels could also be observed during reactive hyperaemia tests after complete 5-min occlusion of the forearm by an inflatable

In this work we demonstrate that functional infrared imaging is capable of detecting low frequency temperature fluctuations in intact human skin and revealing spatial, temporal, spectral, and time-frequency based differences among three tissue classes: microvasculature, large sub-cutaneous veins, and the remaining surrounding tissue of the forearm. We found that large veins have stronger contractility

In the field of thermography, the main problem in measuring true temperature lies in determining the emissivity. Thermoreflectometry overcomes this problem by an in-situ emissivity determination method based on bidirectional reflectivity measurement. This method introduces a diffusion function model which links the bidirectional reflectivity measured to the emissivity. The true temperature and the

Welding processes are influenced by many parameters. By merging data to multimodal information from multichannel images and signals of various welding parameters, the correlation of these and their influence on weld seam imperfections are investigated. The application of a multispectral area camera array enables a new approach on non-destructive testing particularly supported by the passive thermography

ABSTRACT The purpose of this work is to evaluate the suitability of lock-in infrared thermography for luminescent glass development. Lithium borate glass of different composition is fabricated and studied to detect changes in the thermal diffusivity as the composition changes and property modifiers are introduced. In addition, the effect of terbium doping on the thermal diffusivity of the glass is

This paper analyzes the application of an innovative method for thermographic NDT data processing to inspections on real aeronautical components. The results provided by this method are related to thermal diffusivity values obtained by projecting the characteristics of a 3D thermal diffusion model onto one of the coordinate planes. In previous studies, laboratory experiments demonstrated that this

We have obtained an analytical expression for the surface temperature of a sample that is moving at constant velocity when it is illuminated by a modulated and focused laser beam, which remains at rest. From this expression it is found that while the temperature amplitude thermogram shows the expected elongated shape in the direction of the sample movement, the phase thermogram surprisingly shows a

Photothermal radiometry with an infrared camera allows the contactless temperature measurement of multiple surface pixels simultaneously. A short light pulse heats the sample. The heat propagates through the sample by diffusion and the corresponding temperature evolution is measured at the surface of the sample by an infrared camera. The main drawback in radiometric imaging is the loss of the spatial

(2019). Correction. Quantitative InfraRed Thermography Journal. Ahead of Print.

Results of a novel method of testing natural, tanned hides, in particular full grains, for both internal and external structural defects are presented. Such defects may occur while the animal is still alive or during the hide tanning and finishing processes. The method, still under development, uses a specially designed lamp to produce a thermal excitation impulse and an infrared camera to measure

We present a new imaging approach to determine porosity in carbon fibre-reinforced polymers by active thermography in the reflection mode. The infrared radiation is excited with help of a semiconductor laser. We use rectangular pulses for the excitation light – either single pulses or a sequence of a couple of pulses – and measure the succeeding temperature transients. These signals are transferred

The purpose of this study has been to develop a multivariate model for predicting body fat mass in women by using the technique of infrared (IR) thermography. Sixty-nine healthy women, aged from 16 to 29, were investigated by using a body composition analyser and IR thermographic temperature measurement. The correlation analysis was performed to reveal the problem of multicollinearity. The technique

Three nondestructive testing techniques, namely, optically- and ultrasonically stimulated infrared thermography, ultrasonic laser vibrometry and laser ultrasonics, have been comparatively investigated in the inspection of a graphite-epoxy sample characterized by a complicated geometry to demonstrate advantages and drawbacks of each technique in the detection of different types of defects.

Two original methods using lock-in thermography with a laser excitation are proposed for the estimation without contact of open crack depths in metal. The first uses a modulated punctual thermal source and is well suited for the study of complicated structures. In the second, a continuous moving thermal source allows to scan homogeneous structures. Each method relies on the heat diffusion modifications

Active thermography with electromagnetic excitation, is a reliable non-destructive evaluation method with a wide range of applications. It allows detecting inhomogeneities, like cracks, at or close to the surface of conductive components fast and reliable utilizing infrared imaging. Electric current can be used in two ways for thermography: In induction thermography a current is coupled to the component

Ladle breakout is a risky affair which is always present in steel making. The ladle breakout involves equipment damage and loss of production and sometimes loss of life. The present article describes the method of automatic detection of hotspot on the cold side of a ladle shell with the help of a group of infrared camera and subsequent processing of the infrared images in the LabVIEW platform. The

Infrared imaging has been used for detecting early-stage breast abnormalities. However, manual interpretation of these images is subjective and error prone. Automated analysis of thermal images using artificial intelligence increases the accuracy of detecting breast cancer and enables use in breast cancer screening programmes. A crucial step in automated analysis is tumour segmentation, which is the

Active infrared thermography is one of the methods of non-destructive testing widely used in modern industry. One of the basic advantages of this particular method is its versatility – it can be used for most of the materials regardless of their physical properties. Therefore, this technique is used for non-destructive testing of the composite structures, which lately became extremely important in

This work deals with the thermal characterisation of a low conductivity material of millimetre-sized used mainly in building insulation, the hemp shiv. Experimentally, the samples are positioned in a stainless steel chamber, in which it is possible to control the environment. They are heated during a few seconds on one side, and an infrared camera measures the temperature field of the sample surface

The rotary kiln is widely used for the thermal treatment of granular materials in various industries. A better understanding of the heat transfer phenomena, both inside and outside of the industrial rotary kiln, will lead to developing sustainable production techniques, such as materials recycling and heat waste recovery. The present paper summarises two complementary works based on infrared measurements

In Pulse-Compression Thermography, the impulse response of the Sample Under Test is retrieved pixelwise by applying a proper matched filter on the set of acquired thermal images obtained by stimulating the system with a heat source amplitude – modulated by a proper coded signal. Linear frequency-modulated chirp signals and binary codes are the most employed coded excitations, and to improve the detection

Investment casting is a leading technique to manufacture very reliable components. The design and the optimization of this process are usually performed by simulation software and/or by means of simplified models based on heat transfer coefficients obtained by solving the inverse heat conduction problem (IHCP). Both methods require experimental tests, that involve temperature measurements, aiming at

Additive manufacturing by laser cladding is a promising tool for rapid prototyping, construction of bionic structures and replacement part production. To ensure a constant quality of manufactured components and to shorten the development process between CAD model and suitable produced components quality management and process monitoring system is inevitable. Therefore, a system has been developed to

Face identification systems that operate on long wave infrared (LWIR) images are able to overcome some of the limitations of approaches based on visible images, such as dealing effectively with illumination variations. Nonetheless, distortions of perceptual image quality can impair the performance of thermal face recognition systems. Although the interaction between perceptual image quality and tasks

The paper examines the topic of identifying eggs freshness through an original approach based on pulsed thermography. The proposed method relies on a short thermal stimulation performed by means of a xenon flash, which rises up the temperature of the egg of less than 1°C. The entire process requires about 1 s, thus providing an effective quality control tool for assessing the freshness of eggs intended

ABSTRACT Inductive thermography is a non-destructive technique for detecting surface cracks in electrically conductive materials. The induced eddy currents and the heat diffusion are disturbed by surface cracks, which makes the defects visible in infrared images. In non-magnetic materials, with high electrical and thermal conductivity, a short heating pulse is necessary, otherwise the thermal signal

In-line inspection of advanced components, remains a challenging task in industry. A methodology is discussed which uses numerical simulations to automatically determine the best set of experimental parameters to inspect the structure on defects using active thermography. The inspection is performed using an industrial conveyor belt or a robotic arm optimized using a numerical model of the defected

In the present study, image reconstruction methods are applied in active dynamic thermography (ADT) to visualize the superficial blood vessel with high contrast. ADT is performed on the left forearm of a human subject by applying cooling based external thermal stimulation. Both non-parametrized, viz. sequence image, sequentially subtracted image, Discrete Fourier Transformation (phase and amplitude

ABSTRACT Lock-in thermography (LIT) is a dynamic variant of infrared thermography, where local heat sources are periodically pulsed and amplitude and phase images of the surface temperature modulation are obtained. If used in electronic device testing, this method enables the localization of very weak local heat sources below the surface. This contribution reviews the basics and application of LIT