A method to improve the visibility of ghost images obtained by thermal light

A method, which is based on the correlation measurement of intensity fluctuations in time-space-average domain, is invented to improve the visibility of ghost images obtained by thermal light. We demonstrate that the visibility of ghost images can be significantly enhanced using this method. A corresponding evaluation standard of the visibility of images and effects influencing the visibility of ghost images, such as the weight factor γ and speckle frame numbers, are also discussed.     

Face and eyes localization algorithm in thermal images for temperature measurement of the inner canthus of the eyes

In this paper, a novel algorithm for the detection and localization of the face and eyes in thermal images is presented, particularly the temperature measurement of the human body by measuring the eye corner (inner canthus) temperature. The algorithm uses a combination of the template-matching, knowledge-based and morphological methods, particularly the modified Randomized Hough Transform (RHT) in the localization process, also growing segmentation to increase accuracy of the localization algorithm. In many solutions, the localization of the face and/or eyes is made by manual selection of the regions of the face and eyes and then the average temperature in the region is measured. The paper also discusses experimental studies and the results, which allowed the evaluation of the effectiveness of the developed algorithm. The standardization of measurement, necessary for proper temperature measurement with the use of infrared thermal imaging, are also presented.     

红外热成像法研究电路板热分布特性

介绍了一种红外热成像处理技术,以及利用这种红外热成像处理系统研究通电电路板的热平衡分布特性。     

Skin temperature evaluation by infrared thermography: Comparison of image analysis methods

Body temperature in medicine is a parameter indicating abnormal activity of human tissues; it is used to diagnose specific pathologies or as an indicator of the muscle activity during physical exercise.Temperature measurements through infrared thermography have the advantages to be non-invasive and to record temperature data simultaneously from different points on a wide area of the body.The difference between the values of temperature traditionally measured with contact probes or standard technique and the ones measured by thermal imaging lies in the fact that the first produces a scalar value, while the second gives a distribution over a surface. The analysis of thermographic images, with the goal of obtaining a temperature value representative of a specific area, is usually performed by different methods of averaging temperature values inside a selected Region of Interest (Troi and Tot). In this paper the authors present a critical comparison between the methods mainly used in literature in the specific case of a muscular group of calves on a population of 33 healthy subjects. Here, the authors describe an alternative method (Tmax) to obtain a temperature value of a specific area based on maximal temperature detection instead of considering the average temperature on the selected area. No meaningful difference in mean temperature between Troi and Ttot was found (p = 0.9), while temperature values calculated using Tmax were higher than the above methods (p < 0.001). The high correlation among the compared methods prove that they can equally represent temperature trends in cutaneous thermographic analyses.     

Abdominal apparent diffusion coefficient measurements: effect of diffusion-weighted image quality and usefulness of anisotropic images

This study aimed to assess the effect of diffusion-weighted image (DWI) quality on abdominal apparent diffusion coefficient (ADC) measurements and the usefulness of anisotropic images. Twenty-six patients (10 men and 16 women; mean, 58.1 years) who underwent DW imaging and were diagnosed not to have any abdominal diseases were analyzed. Single-shot spin-echo echo-planar DW imaging was performed, and one isotropic and three orthogonal anisotropic images were created. ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail) and renal parenchyma. Image quality for each organ part was scored visually. We estimated the correlation between ADC and image quality and evaluated the feasibility of using anisotropic images. ADCs and image quality were affected by motion probing gradient directions in the liver and pancreas. A significant inverse correlation was found between ADC and image quality. The r values for isotropic images were −.46, −.48, −.70 and −.28 for the liver, spleen, pancreas and renal parenchyma, respectively. Anisotropic images had the best quality and lowest ADC in at least one organ part in 17 patients. DWIs with the best quality among isotropic and anisotropic images should be used in the liver and pancreas.     

The use of thermal imaging to monitoring skin temperature during cryotherapy: A systematic review

Cryotherapy has been applied on clinical injuries and as a method for exercise recovery. It is aimed to reduce edema, nervous conduction velocity, and tissue metabolism, as well as to accelerate the recovery process of the muscle injury induced by exercise. Objective: This review aim to investigate the applicability of thermal imaging as a method for monitoring skin temperature during cryotherapy. Method: Search the Web of Science database using the terms “Cryotherapy”, “Thermography”, “Thermal Image” and “Cooling”. Results: Nineteen studies met the inclusion criteria and pass the PEDro scale quality evaluation. Evidence support the use of thermal imaging as a method for monitoring the skin temperature during cryotherapy, and it is superior to other contact methods and subjective methods of assessing skin temperature. Conclusion: Thermography seems to be an efficient, trustworthy and secure method in order to monitoring skin temperature during cryotherapy application. Evidence supports the use of thermography in detriment of contact methods as well as other subjective ones.     

Study of the negative thermal expansion of cuprite-type structures by means of temperature-dependent pair distribution function analysis: Preliminary results

Copper (I) and silver (I) oxides crystallize with the same structure, and both show a wide range of negative thermal expansion (NTE): Cu₂O contracts with temperature up to about 200 K and then expands, while Ag₂O has a NTE up to its decomposition temperature at about 450 K. Here we report a careful temperature-dependent pair distribution function (PDF) analysis that showed that copper oxide, at about 200 K, exhibits geometric distortions of the tetrahedral units, probably related to a change in the solid angle of the polyhedra. Silver oxide, on the other hand, showed the same distortions even at the lowest temperature measured (10 K): structural refinements of the PDF confirmed the presence of local distortions (below 10 Å) at all temperatures.     

基于GIS的高密度城市声景质量及其影响因素研究——以广州天河区为例

高密度城市空间背景下,声景质量对居民生活品质及身心健康具有显著影响.已有声景研究针对街区尺度的声景质量及其形成机制的探讨仍较为不足,尚未能为高质量宜居城市空间建设提供循证基础.该文基于地理学视角,通过声景漫步与问卷调查对广州市天河区南部声源类型、声环境特征、心理声学感知进行调查研究,旨在阐述城市街区尺度声景质量的空间特...     

Study of cerebrovascular reserve capacity by magnetic resonance perfusion weighted imaging and photoacoustic imaging

The aim of this work was to assess the feasibility of photoacoustic imaging (PAI) and MR imaging for evaluating the cerebrovascular reserve capacity (CVRC) in animal models. Wistar-Kyoto (WKY) rats and spontaneous hypertensive rats (SHR) were used for MRI. BALB/c mice were used for PAI. MR perfusion weighted imaging (PWI) was performed on a 1.5-T whole-body MR system before and after oral administration of acetazolamide (ACZ). The region of interest (ROI) was chosen in the bilateral frontal lobe for measuring regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time (MTT). The vessel diameters of the superficial layer of the cortex were measured by PAI in the resting and ACZ-activated mice. The results showed that there was a statistical difference between the resting and ACZ-activated animals in vessel diameter, rCBV and rCBF values. The increments in rCBV and rCBF of WKY rats between resting and ACZ test states were significantly higher than that of SHR. The pathological findings of small arterial walls and lumen of the brain were also different between WKY and SHR rats. The diameters of blood vessels in the superficial layer of the brain measured by PAI were enlarged after the ACZ tolerance test. This result was also observed in the MRI CBV map, where the signal of the vessel in the superficial layer of the cortex became redder after the ACZ stimulation, suggesting the increase of blood flow. It can be concluded that MR PWI and PAI combined with the ACZ test might be useful in evaluating the CVRC and revealing the pathologic changes in cerebral vessels.     

Quantitative assessment of iron deposition in the midbrain using 3D-enhanced T2 star weighted angiography (ESWAN): A preliminary cross-sectional study of 20 Parkinson’s disease patients

Conventional magnetic resonance imaging (MRI) assesses neurodegenerative structural changes in the cerebral anatomy of Parkinson's disease (PD) patients but cannot detect non-structural abnormalities; however, enhanced T2 star weighted angiography (ESWAN) can precisely indicate PD-related substantia nigra (SN) iron deposition. The differences in ESWAN-based parameters between different PD stages were assessed using midbrain iron deposits of 20 PD patients aged 64.3 ± 12.7 (41–85) years grouped by Hoehn and Yahr staging into minimal (stages ≤ 2.5) or moderate to severe (stages ≥ 3.0) motor impairment groups and 14 healthy control subjects. Conventional MRI and ESWAN measurements of mean phase value (MPV) and midbrain dimensions (width and diameter) revealed similar anatomical characteristics; however, ESWAN revealed the presence of smaller MPVs and SN pars compacta (SNc) (P < 0.01) and a negative correlation between reduction extent and motor impairment (P < 0.01). SNc width to midbrain diameter was reduced in moderate to severe impairment patients versus control and minimal impairment patients (both P < 0.01). A positive correlation was found between MPV and width or SNc width to midbrain diameter ratio (P < 0.01 and P < 0.05, respectively). Minimal impairment group mean MPV and substantia nigra pars reticulata (SNr) width evidenced no significant reduction, unlike significant reductions in the moderate to severe impairment group (P < 0.01). No significant changes were observed in MPV or width in the RN region (P > 0.05). ESWAN allows for early and accurate iron deposition determination in PD patients, particularly useful as a supplement to conventional MRI in early-stage PD patients.