Light Environment Research Articles

Illumination Intelligent Adaptation and Analysis Framework: A comprehensive solution for enhancing nighttime driving fatigue monitoring.

Nighttime driving presents a critical challenge to road safety due to insufficient lighting and increased risk of driver fatigue. Existing methods for monitoring driver fatigue, mainly focusing on behavioral analysis and biometric monitoring, face significant challenges under low-light conditions. Their effectiveness, especially in dynamic lighting environments, is limited by their dependency on specific environmental conditions and active driver participation, leading to reduced accuracy and practicality in real-world scenarios. This study introduces a novel 'Illumination Intelligent Adaptation and Analysis Framework (IIAAF)', aimed at addressing these limitations and enhancing the accuracy and practicality of driver fatigue monitoring under nighttime low-light conditions. The IIAAF framework employs a multidimensional technology integration, including comprehensive body posture analysis and facial fatigue feature detection, per-pixel dynamic illumination adjustment technology, and a light variation feature learning system based on Convolutional Neural Networks (CNN) and time-series analysis. Through this integrated approach, the framework is capable of accurately capturing subtle fatigue signals in nighttime driving environments and adapting in real-time to rapid changes in lighting conditions. Experimental results on two independent datasets indicate that the IIAAF framework significantly improves the accuracy of fatigue detection under nighttime low-light conditions. This breakthrough not only enhances the effectiveness of driving assistance systems but also provides reliable scientific support for reducing the risk of accidents caused by fatigued driving. These research findings have significant theoretical and practical implications for advancing intelligent driving assistance technology and improving nighttime road safety.

Performance Characterization of an Illumination-Based Low-Cost Multispectral Camera.

Spectral imaging has many applications, from methane detection using satellites to disease detection on crops. However, spectral cameras remain a costly solution ranging from 10 thousand to 100 thousand euros for the hardware alone. Here, we present a low-cost multispectral camera (LC-MSC) with 64 LEDs in eight different colors and a monochrome camera with a hardware cost of 340 euros. Our prototype reproduces spectra accurately when compared to a reference spectrometer to within the spectral width of the LEDs used and the ±1σ variation over the surface of ceramic reference tiles. The mean absolute difference in reflectance is an overestimate of 0.03 for the LC-MSC as compared to a spectrometer, due to the spectral shape of the tiles. In environmental light levels of 0.5 W m-2 (bright artificial indoor lighting) our approach shows an increase in noise, but still faithfully reproduces discrete reflectance spectra over 400 nm-1000 nm. Our approach is limited in its application by LED bandwidth and availability of specific LED wavelengths. However, unlike with conventional spectral cameras, the pixel pitch of the camera itself is not limited, providing higher image resolution than typical high-end multi- and hyperspectral cameras. For sample conditions where LED illumination bands provide suitable spectral information, our LC-MSC is an interesting low-cost alternative approach to spectral imaging.

The Nurse-Implemented Chronotherapeutic Bundle in Critically Ill Children, RESTORE Resilience (R 2 ): Pilot Testing in a Two-Phase Cohort Study, 2017-2021.

Pilot test the nurse-led chronotherapeutic bundle in critically ill children, RESTORE Resilience (R 2 ). A two-phase cohort study was carried out from 2017 to 2021. Two similarly sized and organized PICUs in the United States. Children 6 months to 17 years old who were mechanically ventilated for acute respiratory failure. R 2 seven-item chronotherapeutic bundle, including: 1) replication of child's pre-hospital daily routine (i.e., sleep/wake, feeding, activity patterns); 2) cycled day-night light/sound modulation; 3) minimal effective sedation; 4) night fasting with bolus enteral daytime feedings; 5) early progressive mobility; 6) nursing care continuity; and 7) parent diaries. Children underwent environmental (light, sound) and patient (actigraphy, activity log, salivary melatonin, electroencephalogram) monitoring. Parents completed the Child's Daily Routine and Sleep Survey (CDRSS) and Family-Centered Care Scale. The primary outcome was post-extubation daytime activity consolidation (Daytime Activity Ratio Estimate [DARE]). Twenty baseline-phase (2017-2019) and 36 intervention-phase (2019-2021) participants were enrolled. During the intervention phase, nurses used the CDRSS to construct children's PICU schedules. Overall compliance with nurse-implemented R 2 elements 1-5 increased from 18% (interquartile range, 13-30%) at baseline to 63% (53-68%) during the intervention phase ( p < 0.001). Intervention participants were exposed to their pre-hospitalization daily routine ( p = 0.002), cycled day-night light/sound modulation ( p < 0.001), and early progressive mobility on more PICU days ( p = 0.02). Sedation target identification, enteral feeding schedules, and nursing care continuity did not differ between phases. Parent diaries were seldom used. DARE improved during the intervention phase and was higher pre-extubation (median 62% vs. 53%; p = 0.04) but not post-extubation (62% vs. 57%; p = 0.56). In the PICU, implementation of an individualized nurse-implemented chronotherapeutic bundle is feasible. Children who received the R 2 bundle had increased pre-extubation daytime activity consolidation compared to children receiving usual care. Given variation in protocol adherence, further R 2 testing should include interprofessional collaboration, pragmatic trial design, and implementation science strategies.

Untangling light in noisy luminous environments

Electric light sources, including displays and luminaires, often exhibit rapid light fluctuations called temporal light modulation (TLM). TLM can be seen as their electrical footprint. This work demonstrates that TLM can be remotely detected and used to perform in situ photometric and spectroradiometric measurements of very low light levels superimposed to intense backgrounds. Illuminance levels about 500 000 times smaller than the background were reliably measured by lock-in detection, allowing photometric measurements to be performed during daytime, even with sunny conditions. Using a new type of optical lock-in spectrometer, it becomes possible to retrieve spectral quantities through the TLM of the light source. The spectral distribution of an LED lamp was measured against a daylit background more than 1500 times brighter. Lock-in detection is an excellent technique to perform in situ measurements of electric light, even at very low level, in the presence of daylight and other background lights, opening interesting opportunities to characterize anthropogenic light pollution.

Effect of Experimental Parameters on the Electrochemical Current during Scanning Electrochemical Microscopy of Living Cells

Scanning Electrochemical Microscopy (SECM) is gaining popularity for its application to live cell imaging to monitor electrochemical processes occurring at the interface of living cells and electrodes. [1] Although many studies have been reported varying the instrumental parameters and using various probe designs, [2] the influence of experimental parameters on the electrochemical current must not be neglected, in order to generate reliable results. Our work explores parameters, such as temperature, light exposure and cell media during the SECM analysis of Adenocarcinoma Cervical cancer (HeLa) cells. The experimental and numerical studies with temperature variation revealed that temperature changes of 2ᵒC influence the reaction kinetics of single living cells. [3] Further, it was observed during light exposure that the electrochemical current becomes stabilized after 20 minutes of constant light environment compared to dark, where the standard deviation of the electrochemical current showed an increase in trend overtime. Furthermore, electrochemical current responses of HeLa cells in Phosphate Buffered Solution (PBS), Dubelcco’s Modified Eagle Medium (DMEM) and DMEM with 10% Fetal Bovine Serum (FBS) is being explored. These results will help to understand the origin of potential electrochemical current changes and the ideal experimental conditions to perform SECM measurements with living cells.[1] I. Beaulieu, S. Kuss, J. Mauzeroll, M. Geissler, Biological scanning electrochemical microscopy and its application to live cell studies, Anal. Chem. 83 (2011) 1485–1492. https://doi.org/10.1021/ac101906a.[2] D. Polcari, P. Dauphin-Ducharme, J. Mauzeroll, Scanning Electrochemical Microscopy: A Comprehensive Review of Experimental Parameters from 1989 to 2015, Chem. Rev. 116 (2016) 13234–13278. https://doi.org/10.1021/acs.chemrev.6b00067.[3] N. Thomas, D. Lima, D. Trinh, S. Kuss, Temperature Effect on the Electrochemical Current Response during Scanning Electrochemical Microscopy of Living Cells, Anal Chem. 95 (2023) 17962-17967. https://doi.org/10.1021/acs.analchem.3c03716

Interference of skeleton photoperiod in circadian clock and photosynthetic efficiency of tea plant: in-depth analysis of mathematical model.

The circadian system of plants is a complex physiological mechanism, a biological process in which plants can adjust themselves according to the day and night cycle. To understand the effects of different photoperiods on the biological clock of tea plants, we analyzed the expression levels of core clock genes (CCA1, PRR9, TOC1, ELF4) and photosynthesis-related genes (Lhcb, RbcS, atpA) under normal light (light/dark = 12h/12h, 12L12D) and took the cost function defined by cycle and phase errors as the basic model parameter. In the continuous light environment (24h light, 24L), the peak activity and cycle of key genes that control the biological clock and photosynthesis were delayed by 1-2h. Under a skeleton photoperiod (6L6D, 3L3D), the expression profiles of clock genes and photosynthesis-related genes in tea plants were changed and stomatal opening showed a circadian rhythm. These observations suggest that a skeleton photoperiod may have an effect on the circadian rhythm, photosynthetic efficiency and stomatal regulation of tea plants. Our study and model analyzed the components of circadian rhythms under different photoperiodic pathways, and also revealed the underlying mechanisms of circadian regulation of photosynthesis in tea plants.

Making the most of canopy light: Shade avoidance under a fluctuating spectrum and irradiance.

In the field, plants face constantly changing light conditions caused by both atmospheric effects and neighbouring vegetation. This interplay creates a complex, fluctuating light environment within plant canopies. Shade-intolerant species rely on light cues from competitors to trigger shade avoidance responses, ensuring access to light for photosynthesis. While research often uses controlled growth chambers with steady light to study shade avoidance responses, the influence of light fluctuations in real-world settings remains unclear. This review examines the dynamic light environments found in woodlands, grasslands, and crops. We explore how plants respond to some fluctuations but not others, analyse the potential reasons for these differences, and discuss the possible molecular mechanisms regulating this sensitivity. We propose that studying shade avoidance responses under fluctuating light conditions offers a valuable tool to explore the intricate regulatory network behind them.

Interfacial engineering of Pickering emulsions stabilized by pea protein-alginate microgels for encapsulation of hydrophobic bioactives

This study aims to investigate the effects of interfacial layer composition and structure on the formation, physicochemical properties and stability of Pickering emulsions. Interfacial layers were formed using pea protein isolate (PPI), PPI microgel particles (PPIMP), a mixture of PPIMP and sodium alginate (PPIMP-SA), or PPIMP-SA conjugate. The encapsulation and protective effects on different hydrophobic bioactives were then evaluated within these Pickering emulsions. The results demonstrated that the PPIMP-SA conjugate formed thick and robust interfacial layers around the oil droplet surfaces, which increased the resistance of the emulsion to coalescence, creaming, and environmental stresses, including heating, light exposure, and freezing-thawing cycle. Additionally, the emulsion stabilized by the PPIMP-SA conjugate significantly improved the photothermal stability of hydrophobic bioactives, retaining a higher percentage of their original content compared to those in non-encapsulated forms. Overall, the novel protein microgels and the conjugate developed in this study have great potential for improving the physicochemical stability of emulsified foods.

Media Network and Citizen Journalism: The Transition from Agenda Setting to Agenda Loop

ABSTRACT This study examines agenda-setting and citizen journalism networks between Baidupedia, the Chinese version of Wikipedia, and various media channels, demonstrating the influence of effective agenda-setting on individuals’ engagement in citizen journalism behavior. Using social network analysis and Granger causality tests, we found that Baidupedia is part of the agenda network of mainstream media, portal websites, and other media outlets. Our research also highlights the “agenda loop” phenomenon, where outcomes from individuals’ news production shape the agendas of other media channels, expanding our understanding of agenda-setting on an individual’s level. Cultural influences and regulations as well as the political system also significantly contribute to the intermedia agenda-setting effect. These findings contribute to our understanding of agenda-setting in the present media environment and shed light on the correlation between effective agenda-setting and people’s participation in citizen journalism production.

Enhancing the phytoremediation efficiency of Bacopa monnieri (L.) Wettst. using LED lights: a sustainable approach for heavy metal pollution control.

In this study, the impacts of LEDs on the phytoremediation of arsenic (As) and mercury (Hg) by Bacopa monnieri (L.) Wettst. were investigated, along with the examination of the biochemical characteristics of plants exposed to metal-induced toxicity. In vitro multiple and rapid plant propagations were successfully achieved by adding 1.0mg/L 6-Benzyl amino purine (BAP) to the Murashige and Skoog (MS) basal salt and vitamin culture medium. For plant-based remediation experiments, different concentrations of As (0-1.0mg/L) and Hg (0-0.2mg/L) were added to the water environment, and trials were conducted for four different application periods (1-21days). White, red, and blue LEDs, as well as white fluorescent light, were preferred as the light environment. The results revealed that LED lights were more effective for heavy metal accumulation, with red LED light significantly enhancing the plant's phytoremediation capacity compared to other LED applications. Moreover, when examining biochemical stress parameters such as levels of photosynthetic pigments, protein concentrations, and lipid peroxidation, plants under red LED light showed better results. Generally, the lowest results were obtained under white fluorescent light. These findings contribute to phytoremediation studies by highlighting the integration of LED lights, thereby enabling the development of a more effective, cost-efficient, and environmentally sustainable remediation system compared to other treatment methods.

Effect of ultraviolet on the environmental adaptability of Megalurothrips usitatus (Thysanoptera: Thripidae).

Megalurothrips usitatus Bagnall, an important pest of bean plants, is primarily managed with synthetic insecticides. M. usitatus has developed considerable resistance to various insecticides in multiple cowpea-growing areas in Hainan Province, China, posing challenges to its control in the field. Light control technology is a potentially effective physical control method for M. usitatus. The vision of thrips is highly sensitive to UV light, whereas other biological characteristics remain unknown. Therefore, this study evaluated the effects of ultraviolet light on the biological characteristics of M. usitatus. Results showed that the egg, larval, and pupal stages of M. usitatus were significantly shortened, and the emergence rate (79.59%) and adult survival rate (77.95%) were reduced under a devoid of UV light environment (UV-), compared with the full-spectrum light (control treatment group, CK) (p < 0.05). However, the single spawning quantity and total amount of spawning were significantly higher, and the sex ratio (57%) was the highest under UV- (p < 0.05). Single UV light (UV+) only affected the pupation rate. Also, the antioxidant enzymes, polyphenol oxidase, superoxide dismutase (SOD), and peroxidase activities were significantly and negatively correlated with the progression of generations under UV-, whereas catalase and SOD activities were significantly and positively correlated with the progression of generations under UV+. The UV- light conditions significantly interfered with the behavior selection of M. usitatus. The results of this study showed that the adaptability of M. usitatus populations would be greatly reduced in the absence of ultraviolet light, providing a theoretical basis for the control of M. usitatus populations.

Developmental control of rod number via a light-dependent retrograde pathway from intrinsically photosensitive retinal ganglion cells.

Photoreception is essential for the development of the visual system, shaping vision's first synapse to cortical development. Here, we find that the lighting environment controls developmental rod apoptosis via Opn4-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). Using genetics, sensory environment manipulations, and computational approaches, we establish a pathway where light-dependent glutamate released from ipRGCs is detected via a transiently expressed glutamate receptor (Grik3) on rod precursors within the inner retina. Communication between these cells is mediated by hybrid neurites on ipRGCs that sense light before eye opening. These structures span the ipRGC-rod precursor distance over development and contain the machinery for photoreception (Opn4) and neurotransmitter release (Vglut2& Syp). Assessment of the human gestational retina identifies conserved hallmarks of an ipRGC-to-rod axis, including displaced rod precursors, transient GRIK3 expression, and ipRGCs with deep-projecting neurites. This analysis defines an adaptive retrograde pathway linking the sensory environment to rod precursors via ipRGCs prior to eye opening.

Design of Mask Detection Application Using Tensorflow Lite based on Android Mobile

A mask is a type of personal protective equipment (PPE) that is essential for protecting the nose and mouth from contamination by droplets or airborne particles. The use of masks became highly popular during the Covid-19 pandemic, which began in December 2019 in China and peaked in Indonesia in 2020. Despite the pandemic subsiding and vaccinations increasing immunity, some companies still require masks to prevent the spread of illnesses such as colds and flu, especially in work processes that produce smoke, such as soldering and welding. To ensure employees comply with mask usage, effective supervision is necessary. Manual supervision is less efficient, thus a digital detection method is needed. This study developed a mask detection application using deep learning algorithms and the TensorFlow Lite framework on an Android platform. The application can detect mask usage with 100% accuracy at a distance of 1 to 5 meters. The system was tested under various lighting conditions and environments to ensure reliability. Additionally, the implementation of this technology can be extended to other public areas to ensure compliance with health protocols. This tool helps companies easily monitor and enforce mask-wearing discipline among employees, thereby enhancing workplace safety and health. Future work could explore the integration of this system with other health monitoring tools to create a comprehensive safety solution.

Optimisation of light environment in architectural space based on multi strategy collaboration – A case study of a manual drawing classroom

From the perspective of dynamic lighting throughout the year, reflector and louvre are proposed to add to the south-facing window. The optimal parameter is 2.0 m height and 1.0 m width reflector and a louvre angle of 75°. However, when further analysing the indoor illumination and uniformity, the classroom still had high or low illumination during certain periods solely relying on natural lighting, indicating that a single strategy alone cannot meet the overall lighting environment comfort needs of the space. The study suggests that different lighting environments should be used in different seasons, periods and areas of the classroom. The proportion of natural light, combined light and artificial light environments should be 30%, 45% and 25%, respectively. At the same time, considering the transformation and optimisation of the lamps, the improvement measures for windows facing other directions in the classroom is recommended, the lamps be symmetrically distributed in the horizontal direction, with a hanging height of 1.9 m in the vertical direction, which is 0.4 m higher than the original. The lighting power is 34 W and 26 W, and corresponding optimisation strategies for the intelligent control system are proposed.

Influence of an adjacent tunnel connecting zone shading shed on drivers’ eye movement characteristics

A tunnel shading shed is crucial in improving driving safety as a type of traffic facility to ease the transition of light environments. To study the effect of installation of a shading shed on the visual characteristics of drivers in the connecting zone of the adjacent tunnels, a total of 32 drivers were gathered to perform a real vehicle experiment. The study zone of the adjacent tunnels was divided into three sections: upstream tunnel exit; connecting zone; and downstream tunnel threshold zone. Fixation duration, saccade duration and saccade frequency were selected as research indexes. The results suggest that installation of a shading shed in the connecting zone significantly reduced the fixation (saccade) duration in the upstream tunnel exit and downstream tunnel threshold zones, with a significantly higher saccade frequency. In addition, fixation is better improved at the downstream tunnel entrance, and saccade is better enhanced at the upstream tunnel exit.

Enhanced photocatalytic degradation of polylactide (PLA) through TiO2-based up-conversion nanoparticles

As a degradable polymer material, the regulation of the degradation rate of polylactide (PLA) under an actual light exposure environment is of significant importance for realizing its multifaceted applications. This study aims to enhance the photodegradation of PLA under irradiation with lower-energy wavelengths by using TiO2-based up-conversion nanoparticles (UCNPs). Two modification methods were employed: doping TiO2 with Yb3+/Er3+/Tm3+ ions integrated within the TiO2 lattice, and creating a composite photocatalyst by adhering Y2O3: Yb3+/Er3+/Tm3+ to the exterior of TiO2 grains. The study investigated the impact of these two different TiO2-based UCNPs on the photocatalytic degradation rate and mechanism of PLA under simulated sunlight irradiation. Research has found that the doped TiO2, due to its narrower bandgap and higher photon utilization efficiency during the up-conversion process, exhibited superior catalytic efficiency in catalyzing the photodegradation reactions of PLA compared to unmodified TiO2 and composite TiO2. This work proposes a novel strategy for preparing PLA composites with enhanced photodegradation speed provided by modified TiO2, efficient light energy utilization offered by the up-conversion process, and potential applications in more advanced packaging and agricultural fields.

Optical scattering measurement of highly reflective coatings with the cavity ring-down technique.

Cavity ringdown (CRD) is employed for the first time, to the best of our knowledge, to precisely measure the optical scattering of highly reflective (HR) optics with measurement sensitivity greatly enhanced via power trapping inside the ringdown cavity. The scattering measurement accuracy is significantly improved by calibrating the photo-detector for the scattering measurement with the low transmittance of the cavity mirror or test HR mirror, which is also accurately measured by CRD. The influence of environmental stray light (such as the probe light scattered by optics and mechanical parts outside the ringdown cavity) and other background noises on the scattering measurement is greatly eliminated by the temporal behavior of the scattering CRD signal. A scattering measurement sensitivity of 4.0 × 10-13 is experimentally achieved with a laser with output power of 12 mW.

Performance evaluation of SILAR deposited Rb-Doped ZnO thin films for photodetector applications

ZnO-based photodetectors (PDs) compose a remarkable optoelectronic device field due to their high optical transmittance, electrical conductivity, wide band gap, and high binding energy. This study examined the visible light photodetector performance of the pristine and Rubidium (Rb)-doped ZnO thin films. The influence of Rb doping amount (2, 4, and 6 wt% in solution) on the electrical, optical, and structural properties of the ZnO-based thin films produced by the Successive Ion Layer Adsorption and Reaction (SILAR) technique was analyzed. Structural analyses showed that all peaks correspond to hexagonal wurtzite structure with no other peak from Rb-based phases, suggesting the high quality of the crystalline pristine and Rb-doped ZnO thin films. The morphology of the thin films shows homogenous layers formed of nanoparticles where particle size was first decreased and then increased with the increasing Rb doping according to Scanning Electron Microscope (SEM) morphology analysis. Besides that, Raman spectroscopy analyses indicate that the phonon lifetimes of the ZnO-based thin films slightly increased due to the improvement of the crystal quality with the increasing amount of Rb in the SILAR solution. Photosensor measurements of the nanostructured pristine and Rb-doped ZnO thin films were measured at different light power intensities under the visible light environment. Photosensor properties were examined depending on the doping amount and light power density. In light of the literature review, our study is the first to produce Rb-doped ZnO thin films via the SILAR method, which has a promising potential for photosensor applications.Graphical

Establishment and Solution of a Finite Element Gas Exchange Model in Greenhouse-Grown Tomatoes for Two-Dimensional Porous Media with Light Quantity and Light Direction

An accurate gas utilization model is essential for precisely detecting plant photosynthetic capacity. Existing equipment for measuring the plant photosynthetic rate typically considers the key parameters of mesophyll cell conductance and a photosynthetic model based on the carbon reaction process under direct light conditions. However, the light environment signals received by the plant canopy not only vary significantly in incidence angles, but the effective light intensity also differs greatly from the measured values under vertical incidence conditions. To reduce the deviation between existing photosynthetic models and the actual photosynthetic efficiency of leaves, this study employs the gas diffusion method from engineering, using the finite element approach. Based on elastic mechanics and seepage mechanics, the internal stress field control equation of tomato leaves and the two-phase flow equation under a CO2 porous medium were derived. A mathematical model of porous gas–liquid two-phase fluid-solid coupling was established, solved, and analyzed. Preliminary verification was conducted through tests. The results show that in the initial stage of CO2 entering the leaf, the gas flow velocity is higher because of the larger pressure gradient between the pore and the leaf. In this stage, the gas diffusion rate is higher. As the intake time increases, the pressure gradient gradually decreases, and the inlet velocity slows down. Consequently, the diffusion rate gradually reduces. Because of the coupling of light quantity and light direction, the gas diffusion rate significantly increases compared with the uncoupled model. Additionally, a diffusion model that does not consider fluid–solid coupling will overestimate the gas flow rate as the depth of gas entry increases. Therefore, the internal gas diffusion model must account for the effect of coupling on the diffusion rate.

Experimental Study on Heat Transfer Characteristics of Hollowing Defect Areas on Building Facade

Infrared detection is more and more widely used in the field of non-destructive testing of buildings to detect whether there is a defect on the surface of the building facade. In many cases, it is necessary to obtain more information about the defect, such as the depth of the defect, so as to evaluate the severity of the defect and repair. The theoretical formula of hollowing defect depths was derived in this paper based on the heat transfer characteristics of the intact and defective areas on the building facade, and the influence of defects with different shapes, sizes and cavity thicknesses on the temperature distribution of the building facade was summarized quantitatively. Firstly, the theoretical formula of the hollowing defect depth and the factors affecting the distribution of the temperature gradient on the building facade excited by external thermal source was derived and restricted by the boundary condition. Secondly, three sets of physical building facade models that contained hollowing defects with different shapes, sizes and cavity thicknesses were fabricated and designed, and the experimental platform was built. The infrared thermograms and the temperature characteristic curves of the hollowing defect in a natural light environment were obtained and fitted according to the temperature differences of the defective area, while analyzing the influence of the size, shape and cavity thicknesses on surface temperature distribution. Finally, the theoretical formula of the defect depth that is applicable to the building façade was validated through the experimental simulation of 14 forms of hollowing. The experimental results demonstrated that the revised formula of defect depth is consistent with the actual defect depth, and the three-dimensional positioning of the hollow drum defect of the building facade can be effectively carried out and combined with the defect size taken from the obtained infrared thermal image.