Hai Zhang

Harbin Institute of Technology | HIT · School of Astronautics

Place recognition is a fundamental task for robotic application, allowing robots to perform loop closure detection within simultaneous localization and mapping (SLAM), and achieve relocalization on prior maps. Current range image-based networks use single-column convolution to maintain feature invariance to shifts in image columns caused by LiDAR v...

This study investigates the effect of electrospun nylon nanofibres modification on the low-velocity impact resistance of carbon fibre reinforced polymer (CFRP) laminates. Integration of multiple excitation infrared thermography using advanced image processing techniques is used to characterize the damage as a function of impact energy. The results...

The line optical tweezers (LOT) has been proven to be an alternative technique to manipulating the biological cells because of the bigger potential compared with traditional optical tweezers with a highly focused spot. We deduce the 4 × 4 optical matrix of the astigmatic LOT to investigate the optical characteristics related to the systematic param...

The optimization and control of traffic signals is very important for logistics transportation. It not only improves the operational efficiency and safety of road traffic, but also conforms to the direction of the intelligent, green, and sustainable development of modern cities. In order to improve the optimization effect of traffic signal control,...

Non-Destructive Testing and Evaluation (NDT&E) plays an increasing role in the modern era. Infrared thermography and calorimetry (e.g., DSC) are increasingly being used for material defect detection and performance evaluation thanks to their physical and intuitive advantages. Recently, they were also applied in a synergistic sense showing promise f...

This work utilizes infrared and terahertz non-invasive imaging techniques to conduct a multispectral inspection of two marqueteries. Specifically, a flat sample with artificial defects and a curved sample without flaws are used. To cross-reference with the experimental results, a finite element simulation was carried out. Finally, two different exp...

In recent years, the conservation and protection of ancient cultural heritage have received increasing attention, and non-destructive testing (NDT), which can minimize the damage done to the test subject, plays an integral role therein. For instance, NDT through active infrared thermal imaging can be applied to ancient polyptychs, which can realize...

Impact damage constitutes a major threat to the performance and safety of fiber-reinforced composites. In this regard, transmission air-coupled ultrasound inspection technology has been identified as an ideal method for detection of common structural defects in modern multilayer composites. However, traditional machine learning algorithms and ultra...

Early defects in artworks, which are unnoticeable by the naked eye, can evolve in severity if left unattended; therefore, their timely and accurate detection is of vital importance. Infrared-based non-destructive testing (NDT) methods are widely seen as an effective means to detect defects in artworks. However, most existing methods still rely on t...

In nighttime driving scenes, due to insufficient and uneven lighting, and the scarcity of high-quality datasets, the miss rate of nighttime pedestrian detection (PD) is much higher than that of daytime. Vision-based distance detection (DD) has the advantages of low cost and good interpretability, but the existing methods have low precision, poor ro...

This work is based on a comparative study of three Non-destructive Testing NDT techniques for the inspection of an old book that was bound in the XIXth century. Infrared thermography (IRT), terahertz time-domain spectroscopy (THz-TDS) and air-coupled ultrasonic C-scan (ACU) were used to retrieve both damages and defects in the book cover. Then, the...

Photovoltaic (PV) cells are a major part of solar power stations, and the inevitable faults of a cell affect its work efficiency and the safety of the power station. During manufacturing and service, it is necessary to carry out fault detection and classification. A convolutional-neural-network (CNN)-architecture-based PV cell fault classification...

With increasing attention paid to the protection of cultural relics, non-destructive testing (NDT) technologies are thought to be profoundly rewarding, resulting in a widespread uptake of feature-extraction algorithms and defect-detection techniques. Among various alternatives, infrared thermography (IRT) and Terahertz time-domain spectroscopy (THz...

Composite materials are one of the primary structural components in most current transportation applications, such as the aerospace industry. Composite material diagnostics is a promising area in the fight against structural damage in aircraft and spaceships. Detection and diagnostic technologies often provide analysts with a valuable and rapid mec...

The investigation of cultural heritage objects is commonly carried out by using non-destructive inspection techniques. In fact, due to the artistic peculiarities of cultural heritage objects, conventional contact-type inspection techniques such as ultrasonic scan cannot always be applied. The objective of this study is to develop a new autonomous d...

Detection of subsurface defects has hitherto been regarded as an important element in the course of preserving cultural heritage. To do so, non-invasive imaging approaches for viewing and determining the location of splitting inside the sample under test are required, which constitute the subject of the present study. Both active thermography and t...

The reinforcement of polymer composites using plant fibres has received vast and growing attention for investigation owing to their capability to serve as semi-structural materials, especially as a substitute for fiberglass. However, in this type of research, the structural complexity, due to geometrical mismatches and inherent variability to the p...

The non-uniformity of non-planar object inspection data makes their analysis challenging. This paper reports a study of the use of recurrent neural network and artificial feed-forward neural network in pulsed thermography during the automated inspection of non-planar carbon fiber reinforced plastic samples. The time series, including the raw temper...

In this work, infrared thermography is used to detect defects on a 3D hybrid aluminium-CFRP composite structure. First, radiometric calibration and geometric distortion correction are performed for 3D inspection. Second, we propose a new unsupervised probabilistic low-rank component factorization thermographic de-noising model to improve image perf...

Perovskite solar cells (PSCs) are attracting much attention and are on the way to commercialization. However, some modules are subject to reverse bias in actual fields, so it is meaningful to investigate the reverse-bias behavior of PSCs. Herein, an in-situ temperature and current measurement technique was developed. Intriguingly, some hot spots we...

This work presents a comparative study for the inspection of an old book, which was bound in the XIXth century. Infrared thermography (IRT), terahertz time-domain spectroscopy (THz-TDS) and air-coupled ultrasonic C-scan (ACU) were used to retrieve the damages and defects in the book cover. Image processing techniques including Fast Fourier Transfor...

Defects inside cultural heritage objects and composite structures have the potential to cause extensive damage. There is a need to develop 3D non-destructive imaging techniques to determine and visualize the positions of defects. The aim of this research is to develop a new non-destructive imaging technique using infrared-terahertz fusion approach....

The imaging of structures with a complex material composition and geometry is still a challenge in the field of non-destructive testing (NDT). In this study, a non-invasive imaging technique is proposed for the non-destructive inspection of both cultural heritage and natural fiber composites. The proposed technique combines the surface information...

Fibre metal laminates are widely implemented in the aerospace industry owing to the merits of fatigue resistance and plastic properties. An effective defect assessment technique needs to be investigated for this type of composite materials. In order to achieve accurate impact-induced damage evaluation, a multi-excitation infrared fusion method is i...

Advanced materials such as composite materials are extensively used in military and civil aeronautical industries due to their excellent specific mechanical properties. Techniques and protocols to ensure the quality of parts, components, and structures made with such class of advanced materials, both in the manufacturing stage and throughout its li...

Nowadays, infrared thermography, as a widely used non-destructive testing method, is increasingly studied for impact evaluation of composite structures. Sparse pattern extraction is attracting increasing attention as an advanced post-processing method. In this paper, an enhanced sparse pattern extraction framework is presented for thermographic seq...

This work aims to address the effectiveness and challenges of non-destructive testing (NDT) by active infrared thermography (IRT) for the inspection of aerospace-grade composite samples and seeks to compare uncooled and cooled thermal cameras using the signal-to-noise ratio (SNR) as a performance parameter. It focuses on locating impact damages and...

The present study discusses the experimental physicochemical results obtained from the historical vaulted ceilings of an ancient church located in central Italy. Infrared thermography (IRT) in the active configuration was used to map subsurface defects caused by a seismic event and to discover buried structures, while the visible and near-infrared...

The conservation of artworks is playing an increasingly important role in society today. Non-destructive investigation can provide the potential to identify deterioration as early as possible. In this research, transmission mid-wave infrared (MWIR) vision and air-coupled ultrasound (ACU) were used to investigate two paintings on canvas made from di...

In addition to being a serious threat to aircraft safety, kiss-bonding is also difficult to detect using conventional non-destructive testing techniques. It is the objective of this study to develop an autonomous high resolution technique to detect kiss-bonds and disbonds between carbon nanotube (CNT) skins and the host substrate of large-scale nan...

This work presents a non-destructive analysis based on infrared thermography (IRT) and speckle inspection methods performed on a helicopter blade. In both cases, thermal stresses are needed in order to provoke the visualization of defects. The sample possess fabricated defects, and three techniques were selected, namely, long-pulse thermography, fl...

This work is focused on the use of line-scan thermography (LST) method for the inspection of an ancient book cover. Three widely used image post-processing techniques (i.e., pulsed phase thermography, partial least square thermography and principal component thermography) were applied to the acquired thermal sequences. Flash thermography (FT) antic...

InfraRed Thermography, IRT, is one of the most recent techniques to monitor heritage elements, finding existing pathologies in order to implement the required maintenance tasks. However, most IRT results on cultural heritage are interpreted subjectively. Then, this work presents a methodology for the automatic detection and delimitation of moisture...

This work presents a robotized line-scan thermography (LST) modality for the inspection of two paintings on canvas, which are the mock-ups of a famous oil painting, titled Portrait of the Painter’s Mother. Two widely used image post-processing methods were applied on the acquired LST thermal sequences. X-ray radiography was used to anticipate the t...

Ceramic-coated materials used in different engineering sectors are the focus of world-wide interest and have generated a need for inspection techniques that detect very small structural anomalies. Non-destructive testing is increasingly being used to evaluate coating thickness and to test for coating flaws. The main pros of non-destructive testing...

This paper reports on the use of a neural network in infrared thermography to classify defects, such as air, oil, and water, which can degrade material performance. A finite element method and experiment were adopted to simulate air, water, and oil ingress. Raw data, and thermographic signal reconstruction coefficients were used to train, and test...

This work aims to address the challenge of NDT automated inspection and improve the defects’ detection by suggesting an autonomous thermographic imaging approach using a UAV (Unmanned Aerial Vehicle) active thermographic system. The concept of active thermography is discussed and presented in the inspection of aircraft CFRP panels along with the mi...

In order to study the stress detection method on long-distance oil and gas pipeline, the distribution characteristics of the surface remanence signals in the stress concentration regions must be known. They were studied by using the magnetic domain model in the non magnetic saturation state. The finite element method was used herein with the aim to...

Recently, various thermographic data analysis methods have been utilized in the field of non-destructive evaluation (NDE) to process thermal images and enhance the visibility of defects. However, most of them extract only linear features, leading to cumbersome results. In this work, manifold learning is introduced into the thermographic data analys...

This study is devoted to the analysis of impact damage in composite samples by applying techniques of IR and Terahertz imaging. The samples made of high-density homogeneous particleboards of sugarcane bagasse and castor oil polyurethane resin were subjected to impacts with the energy from 5 to 30 J. The impact damage defects were evaluated by apply...

This work aims to address the effectiveness and challenges of Non-Destructive Testing (NDT) inspection and improve the detection of defects without causing damage to the material or operator. It focuses on two types of NDT methods; pulsed thermography and vibrothermography. The paper also explores the possibility of performing automated aerial insp...

Early cancer non-invasive diagnosis is a leading medical topic worldwide due to the threat to human life and the high death rate of this disease. Light-absorption-based thermophotonic diagnostic imaging is well positioned for this challenge thanks to its speed, safety, and high molecular contrast advantages. In this Letter, an enhanced truncated-co...

A thermographic non-destructive inspection conducted during the winter season on precious walls confined to an indoor environment (Baiocco room, L’Aquila, Italy) is illustrated herein. The use of a heat conveyor ad hoc selected has produced a particular benefit in terms of defect detection after the application of advanced algorithms because the th...

Composite materials are being successfully used in aeronautics for more than two decades. This great success is mainly because this kind of materials is typically lighter when compared to metals and more resistant to corrosion. Resistance and stiffness of composite materials are usually related to their fiber orientation. The development of non-des...

Weak magnetic stress detection is an important issue in oil–gas pipeline internal detection area. In order to verify the characteristics of weak magnetic stress internal detection signals, we built herein a magneto-mechanics equivalent model having a balanced magnetic field. First, we calculated the relationship between the stress and the weak magn...

Recently, basalt-carbon hybrid composite structures have attracted increasing attention due to their better damage tolerance, if compared with carbon fiber-reinforced polymer composites (CFRP). Low-velocity is considered as one of the most severe threats to composite materials as it is usually invisible and it occurs frequently in service. With thi...

The interest toward lightweight composites in the aeronautical industry grows year by year. The challenge is the identification and characterization of defects by using an integration of different techniques. The use of the infrared thermography (IRT) method for the inspection of lightweight composites is poorly documented in the open literature, d...

Aircraft manufacturers are constantly improving their aircraft ensuring they are more cost-efficient to do this the weight of the aircraft needs to be reduced, which results in less fuel required to power the aircraft. This has led to an increased use of composite materials within an aircraft. Carbon fibre reinforced polymer (CFRP) composite is use...

As an emerging non-destructive diagnostic and monitoring technique, terahertz time-domain spectroscopy (THz-TDS) imagery is attracting more attention. In this regard, new THz image processing algorithms based on infrared thermography (IRT) concepts are greatly needed, since most IRT imagery modalities are fast for in-line industrial inspection. How...

In order to study the effects of magnetic memory signals affected by the external magnetic field, the magnetic domain model is used herein to quantify the distribution characteristics of the surface of the magnetic signals linked to the stress concentration areas. By using the method of finite element (FE) analysis, the magneto-mechanical model of...

The metal magnetic memory (MMM) detection technology has great application potential in the field of stress internal detection of long distance oil and gas pipeline due to the non-contact online detection to stress damage; however, the scientific significance of the pipeline stress internal detection results is questioned because the detection sign...

https://www.journals.elsevier.com/infrared-physics-and-technology/call-for-papers/call-for-papers-2

In this paper, both infrared thermography (IRT) and terahertz time-domain imaging (THz-TDI) were used to evaluate impacted homogeneous particleboards of sugarcane bagasse (SCB), which have the thickness of 2 cm. In this study, the THz data were processed by applying the well-known image processing algorithms used in IRT. The comparative results sho...

In this paper, terahertz time-domain spectroscopy (THz-TDS) is used for the first time to detect fabricated defects in a glass fiber-skinned lightweight honeycomb composite panel. A novel amplitude polynomial regression (APR) algorithm is proposed as a pre-processing method. This method segments the amplitude-frequency curves to simulate the heatin...

In this paper, eddy current pulsed thermography was used to evaluate ballistic impact damages in basalt-carbon hybrid fiber-reinforced polymer composite laminates for the first time, to our knowledge. In particular, different hybrid structures including intercalated stacking and sandwich-like sequences were used. Pulsed phase thermography, wavelet...

Infrared moving target tracking plays a fundamental role in many burgeoning research areas of Smart City. Challenges in developing a suitable tracker for infrared images are particularly caused by pose variation, occlusion, and noise. In order to overcome these adverse interferences, a total variation regularization term-based low-rank and sparse m...

Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were analyzed in terms of...

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber compo...

Carbon fibres have become the natural choice as reinforcements for polymer composite materials (PMCs). The non-destructive inspection of dry carbon fibre preforms has the potential to increase the reproducibility and reduce the cost of PMC manufacturing, by identifying defects in dry multilayer preforms prior to resin injection. However, use of opt...

With a view to gaining an in-depth assessment of the response of particleboards (PBs) to different in-service loading conditions, samples of high-density homogeneous PBs of sugarcane bagasse and castor oil polyurethane resin were manufactured and subjected to low velocity impacts using an instrumented drop weight impact tower and four different ene...

In this paper, shortwave infrared (SWIR), mid-wave infrared (MWIR) thermography, air-coupled ultrasound (ACU), and X-ray radiography results were combined to retrieve the differences between a painting on the canvas sample constructed following the art master rules and an imitation far from it. Advanced image processing techniques including pulsed...

In this paper, an infrared pre-processing modality is presented. Different from a signal smoothing modality which only uses a polynomial fitting as the pre-processing method, the presented modality instead takes into account the low-order derivatives to pre-process the raw thermal data prior to applying the advanced post-processing techniques such...

In this work, the potentialities of the infrared vision to explore sub-superficial defects in polychromatic statues were investigated. In particular, it was possible to understand how the reflector effect of the exterior golden layers could be minimized, applying advanced statistical algorithms to thermal images. Since this noble metal is present a...

The detection of delaminations in composite laminates using automated thermographic scanning is a quite challenging task. The set-up parameters are not only dependent on the equipment, but on the inspected component as well. In this work, a methodology is discussed to use Finite Element (FE) model updating to automatically establish the most suitab...

In this paper, eddy current pulsed thermography (ECPT) was used to detect the damages caused by ballistic impacts in basalt-carbon hybrid fiber-reinforced polymer laminates. In particular, different hybrid structures including intercalated stacking and sandwich-like structures were used. Numerical simulations were performed to predict the damages d...

In this paper, short-wave infrared (SWIR), mid-wave infrared (MWIR) thermography, air- coupled ultrasonic C-scan (ACU) and X-ray radiography results were combined to retrieve differences between a painting on canvas constructed following the art master rules and an imitation. Advanced image processing techniques including pulsed phase thermography...

In this paper, optical and mechanical excitation thermography were used to investigate basalt fiber reinforced polymer (BFRP), carbon fiber reinforced polymer (CFRP) and basalt-carbon fiber hybrid specimens subjected to impact loading. Interestingly, two different hybrid structures including sandwich-like and intercalated stacking sequence were use...

Stitching can reinforce T-joint structure. However, T-joint and stitching might cause new types of internal flaws due to the characteristic of the structure. The corresponding study was poorly documented, especially using NDT. The purpose of this paper is to indicate internal flaws caused by T-joint and stitching in stitched 3D T-joint carbon fiber...

In the aeronautical industry, there is an increasing need for lightweight composites above all for the internal design. In this regard, the final products should not contain any inclusion of foreign material in order to not compromise both the aesthetical beauty and the mechanical properties subjected to vibrational loads. In this work, the infrare...

Long Wavelength Infrared (LWIR) cameras can provide a representation of a part of the light spectrum that is sensitive to temperature. These cameras also named Thermal Infrared (TIR) cameras are powerful tools to detect features that cannot be seen by other imaging technologies. For instance they enable defect detection in material, fever and anxie...

In this paper, thermographic inspections, ultrasonic C-scan and terahertz imaging were used to detect damages caused by impacts in natural, non-natural and hybrid composites. In particular, different hybrid structures were used. In some samples, numerical simulations were performed to predict the damage. A comparison of the results based on experim...

Nondestructive inspection of mosaic structures is not a novelty in the thermographic scene. Interesting works can be retrieved from scientific literature, some of them dedicated to the use of static active configurations and/or the passive approach for the inspection of plastered mosaics or the assessment of mosaic floors. In the present study, a m...