scholarly journals Revealing Hidden Features in Multilayered Artworks by Means of an Epi-Illumination Photoacoustic Imaging System

2021 ◽  
Vol 7 (9) ◽  
pp. 183
Author(s):  
George J. Tserevelakis ◽  
Antonina Chaban ◽  
Evgenia Klironomou ◽  
Kristalia Melessanaki ◽  
Jana Striova ◽  
...  
Keyword(s):  
Near Infrared ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Structural Features ◽  
Thickness Measurement ◽  
Imaging Method ◽  
Nir Imaging ◽  
Wide Range ◽  
Detection Of Signals ◽  
Cultural Heritage Objects

Photoacoustic imaging is a novel, rapidly expanding technique, which has recently found several applications in artwork diagnostics, including the uncovering of hidden layers in paintings and multilayered documents, as well as the thickness measurement of optically turbid paint layers with high accuracy. However, thus far, all the presented photoacoustic-based imaging technologies dedicated to such measurements have been strictly limited to thin objects due to the detection of signals in transmission geometry. Unavoidably, this issue restricts seriously the applicability of the imaging method, hindering investigations over a wide range of cultural heritage objects with diverse geometrical and structural features. Here, we present an epi-illumination photoacoustic apparatus for diagnosis in heritage science, which integrates laser excitation and respective signal detection on one side, aiming to provide universal information in objects of arbitrary thickness and shape. To evaluate the capabilities of the developed system, we imaged thickly painted mock-ups, in an attempt to reveal hidden graphite layers covered by various optically turbid paints, and compared the measurements with standard near-infrared (NIR) imaging. The obtained results prove that photoacoustic signals reveal underlying sketches with up to 8 times improved contrast, thus paving the way for more relevant applications in the field.

scholarly journals Performance Evaluation of Dorsal Vein Network of Hand Imaging Using Relative Total Variation-Based Regularization for Smoothing Technique in a Miniaturized Vein Imaging System: A Pilot Study

2021 ◽  
Vol 18 (4) ◽  
pp. 1548 ◽  
Author(s):  
Kyuseok Kim ◽  
Hyun-Woo Jeong ◽  
Youngjin Lee
Keyword(s):  
Image Quality ◽  
Total Variation ◽  
Near Infrared ◽  
Imaging System ◽  
Histogram Equalization ◽  
Evaluation Performance ◽  
Visual Evaluation ◽  
Évaluation Performance ◽  
Nir Imaging ◽  
Relative Total Variation

Vein puncture is commonly used for blood sampling, and accurately locating the blood vessel is an important challenge in the field of diagnostic tests. Imaging systems based on near-infrared (NIR) light are widely used for accurate human vein puncture. In particular, segmentation of a region of interest using the obtained NIR image is an important field, and research for improving the image quality by removing noise and enhancing the image contrast is being widely conducted. In this paper, we propose an effective model in which the relative total variation (RTV) regularization algorithm and contrast-limited adaptive histogram equalization (CLAHE) are combined, whereby some major edge information can be better preserved. In our previous study, we developed a miniaturized NIR imaging system using light with a wavelength of 720–1100 nm. We evaluated the usefulness of the proposed algorithm by applying it to images acquired by the developed NIR imaging system. Compared with the conventional algorithm, when the proposed method was applied to the NIR image, the visual evaluation performance and quantitative evaluation performance were enhanced. In particular, when the proposed algorithm was applied, the coefficient of variation was improved by a factor of 15.77 compared with the basic image. The main advantages of our algorithm are the high noise reduction efficiency, which is beneficial for reducing the amount of undesirable information, and better contrast. In conclusion, the applicability and usefulness of the algorithm combining the RTV approach and CLAHE for NIR images were demonstrated, and the proposed model can achieve a high image quality.

Nanostructured Nickel Oxide Films Prepared by Chemical Vapor Deposition and Their Electrochromic Properties

2008 ◽  
Vol 8 (5) ◽  
pp. 2703-2706 ◽  
Author(s):  
J. R. Vargas Garcia ◽  
E. M. Lazcano Ugalde ◽  
F. Hernandez Santiago ◽  
J. M. Hallen Lopez
Keyword(s):  
Chemical Vapor Deposition ◽  
Nickel Oxide ◽  
Vapor Deposition ◽  
Near Infrared ◽  
Chemical Vapor ◽  
Optical Transmittance ◽  
Structural Features ◽  
Electrochromic Properties ◽  
Wide Range ◽  
Nio Films

The influence of the deposition conditions on the structural features and electrochromic properties of nickel oxide (NiO) films prepared by chemical vapor deposition has been investigated. NiO films have been prepared on fluorine doped tin oxide (FTO) coated glass substrates from nickel-acetylacetonate precursor and their electrochromic properties have been studied by cyclic voltammetry in a 0.1 M KOH solution at room temperature. Films exhibiting only the NiO phase were obtained at deposition temperatures higher than 450 °C in a wide range of reactor pressures (0.13 to 66.6 kPa). Particularly, NiO films prepared at 500–550 °C from 0.13 to 53.3 kPa are transparent in nature and exhibit a crystallite size varying from 10 to 60 nm. An appreciable anodic electrochromic change from transparent to black coloured resulted from a very porous surface morphology and film thickness of about 3.5 μm. The electrochromic change was maintained over 3000 switching cycles. Nanostructured 3.5 μm-thick NiO films showed a maximum difference in optical transmittance of about 40% in the near-infrared region. These results make the nanostructured NiO films comparables with those prepared by other deposition techniques.

scholarly journals Light-Emitting Diode Based Photoacoustic Imaging System

2020 ◽  
Author(s):  
Ebrahim Najafzadeh ◽  
Parastoo Farnia ◽  
Alireza Ahmadian ◽  
Hossein Ghadiri
Keyword(s):  
Imaging System ◽  
Photoacoustic Imaging ◽  
Light Emitting Diode ◽  
Imaging Modality ◽  
Optical Excitation ◽  
Poly Vinyl Alcohol ◽  
Ultrasound Images ◽  
Light Emitting ◽  
Non Invasive ◽  
Wide Range

Purpose: A Photoacoustic Imaging (PAI) as a non-invasive hybrid imaging modality has the potential to be used in a wide range of pre-clinical and clinical applications. There are different optical excitation sources that affect the performance of PAI systems. Our goal is proving the capability of the Light-Emitting Diode (LED) based PAI system for imaging of objects in different depths. Materials and Methods: In this study the Full Width of Half Maximum (FWHM) and Contrast to Noise Ratio (CNR) of LED-based PAI system is evaluated using agar, and Poly-Vinyl Alcohol Cryogel (PVA-C) phantoms. Results: The results show that axial and lateral FWHM of the photoacoustic image in agar phantom 1%, are 0.59 and 1.16 mm, respectively. It is capable of distinguishing objects about 250 µm. Furthermore, one of the main improvements of photoacoustic images is achieved by proposed LED-based system that is a 26% higher CNR versus the ultrasound images. Conclusion: Therefore, the provided technical characteristics in this study have made designed LED-based PAI system as a suitable tool for preclinical and clinical imaging.

scholarly journals Near-infrared imaging of brain tumors using the Tumor Paint BLZ-100 to achieve near-complete resection of brain tumors

2014 ◽  
Vol 36 (2) ◽  
pp. E1 ◽  
Author(s):  
Pramod V. Butte ◽  
Adam Mamelak ◽  
Julia Parrish-Novak ◽  
Doniel Drazin ◽  
Faris Shweikeh ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Imaging System ◽  
Signal To Noise Ratio ◽  
Ccd Camera ◽  
Complete Resection ◽  
Human Glioma ◽  
Nir Imaging ◽  
The Brain

Object The intraoperative clear delineation between brain tumor and normal tissue in real time is required to ensure near-complete resection without damaging the nearby eloquent brain. Tumor Paint BLZ-100, a tumor ligand chlorotoxin (CTX) conjugated to indocyanine green (ICG), has shown potential to be a targeted contrast agent. There are many infrared imaging systems in use, but they are not optimized to the low concentration and amount of ICG. The authors present a novel proof-of-concept near-infrared (NIR) imaging system using a standard charge-coupled device (CCD) camera for visualizing low levels of ICG attached to the tumors. This system is small, inexpensive, and sensitive. The imaging system uses a narrow-band laser at 785 nm and a notch filter in front of the sensor at the band. The camera is a 2-CCD camera, which uses identical CCDs for both visible and NIR light. Methods The NIR system is tested with serial dilution of BLZ-100 from 1 μM to 50 pM in 5% Intralipid solution while the excitation energy is varied from 5 to 40 mW/cm2. The analog gain of the CCD was changed from 0, 6, and 12 dB to determine the signal-to-noise ratio. In addition to the Intralipid solution, BLZ-100 was injected 48 hours before euthanizing the mice that were implanted with the human glioma cell line. The brain was removed and imaged using the NIR imaging system. Results The authors' results show that the NIR imaging system using a standard CCD is able to visualize the ICG down to 50 nM of concentration with a high signal-to-noise ratio. The preliminary experiment on human glioma implanted in mouse brains demonstrated that BLZ-100 has a high affinity for glioma compared with normal brain tissue. Additionally, the results show that NIR excitation is able to penetrate deeply and has a potential to visualize metastatic lesions that are separate from the main tumor. Conclusions The authors have seen that BLZ-100 has a very high affinity toward human gliomas. They also describe a small, cost-effective, and sensitive NIR system for visualizing brain tumors tagged using BLZ-100. The authors hope that the use of BLZ-100 along with NIR imaging will be useful to delineate the brain tumors in real time and assist surgeons in near-complete tumor removal to increase survival and reduce neurological deficits.

scholarly journals Recent advances in melanin-like nanomaterials in biomedical applications: a mini review

2019 ◽  
Vol 23 (1) ◽  
Author(s):  
Jihyo Park ◽  
Haeram Moon ◽  
Seonki Hong
Keyword(s):  
Biomedical Applications ◽  
Near Infrared ◽  
Inflammatory Diseases ◽  
Photoacoustic Imaging ◽  
Radical Scavenging ◽  
Main Body ◽  
Photothermal Conversion ◽  
Chemical Structures ◽  
Wide Range ◽  
Analytical Tools

Abstract Background Melanins are a group of biopigments in microorganisms that generate a wide range of colorants. Due to their multifunctionality, including ultraviolet protection, radical scavenging, and photothermal conversion, in addition to their intrinsic biocompatibility, natural melanins and synthetic melanin-like nanomaterials have been suggested as novel nano-bio platforms in biomedical applications. Main body Recent approaches in the synthesis of melanin-like nanomaterials and their biomedical applications have briefly been reviewed. Melanin-like nanomaterials have been suggested as endogenous chromophores for photoacoustic imaging and radical scavengers for the treatment of inflammatory diseases. The photothermal conversion ability of these materials under near-infrared irradiation allows hyperthermia-mediated cancer treatments, and their intrinsic fluorescence can be an indicator in biosensing applications. Furthermore, catechol-rich melanin and melanin-like nanomaterials possess a versatile affinity for various functional organic and inorganic additives, allowing the design of multifunctional hybrid nanomaterials that expand their range of applications in bioimaging, therapy, theranostics, and biosensing. Conclusion Melanin-like natural and synthetic nanomaterials have emerged; however, the under-elucidated chemical structures of these materials are still a major obstacle to the construction of novel nanomaterials through bottom-up approaches and tuning the material properties at the molecular level. Further advancements in melanin-based medical applications can be achieved with the incorporation of next-generation chemical and molecular analytical tools.

scholarly journals High-Resolution Thermal Imaging and Analysis of TIG Weld Pool Phase Transitions

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6952
Author(s):  
Nicholas Boone ◽  
Matthew Davies ◽  
Jon Raffe Willmott ◽  
Hector Marin-Reyes ◽  
Richard French
Keyword(s):  
Phase Transitions ◽  
High Resolution ◽  
Weld Pool ◽  
Thermal Imaging ◽  
Near Infrared ◽  
Imaging System ◽  
Travel Speed ◽  
Tig Welding ◽  
Infrared Radiance ◽  
Wide Range

Tungsten inert gas (TIG) welding is a well-established joining process and offers the user flexibility to weld a large range of materials. Ultra-thin turbine tipping is an important application for TIG welding that is exceptionally challenging due to the wide range of variables needed to accurately control the process: slope times, arc control, travel speed, etc. We offer new insight into weld pool characteristics, utilizing both on- and off-line measurements of weld tracks. High-resolution thermal imaging yields spatially and temporally resolved weld pool phase transitions coupled with post-weld photographs, which gives a novel perspective into the thermal history of a weld. Our imaging system is filtered to measure a 10 nm window at 950 nm and comprises a commercial Sigma lens to produce a near-infrared (NIR) camera. The measured near-infrared radiance is calibrated for temperature over the range of from 800 to 1350 °C.

scholarly journals Low-cost photoacoustic imaging systems based on laser diode and light-emitting diode excitation

2017 ◽  
Vol 10 (04) ◽  
pp. 1730003 ◽  
Author(s):  
Qingkai Yao ◽  
Yu Ding ◽  
Guodong Liu ◽  
Lvming Zeng
Keyword(s):  
Laser Diode ◽  
Near Infrared ◽  
Photoacoustic Imaging ◽  
Light Emitting Diode ◽  
Imaging Modality ◽  
Low Cost ◽  
Laser System ◽  
Great Promise ◽  
Light Emitting ◽  
Wide Range

Photoacoustic imaging, an emerging biomedical imaging modality, holds great promise for preclinical and clinical researches. It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission. In order to generate photoacoustic signal efficiently, bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization. As an alternative, the miniaturized semiconductor laser system has the advantages of being inexpensive, compact, and robust, which makes a significant effect on production-forming design. It is also desirable to obtain a wavelength in a wide range from visible to near-infrared spectrum for multispectral applications. Focussing on practical aspect, this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.

scholarly journals Spectroscopic photoacoustic imaging of cervical tissue composition in excised human samples

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247385
Author(s):  
Yan Yan ◽  
Maryam Basij ◽  
Alpana Garg ◽  
Aneesha Varrey ◽  
Ali Alhousseini ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Histological Analysis ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Collagen Content ◽  
P Value ◽  
Imaging Method ◽  
Tissue Composition ◽  
Cervical Tissue ◽  
Cross Sectional

Objective Cervical remodeling is an important component in determining the pathway of parturition; therefore, assessing changes in cervical tissue composition may provide information about the cervix’s status beyond the measurement of cervical length. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by tissue components in response to laser pulses. This optical information allows for the determination of the collagen-to-water ratio (CWR). The purpose of this study was to compare the CWR evaluated by using spectroscopic photoacoustic (sPA) imaging in cervical samples obtained from pregnant and non-pregnant women. Methods This cross-sectional study comprised cervical biopsies obtained at the time of hysterectomy (n = 8) and at the scheduled cesarean delivery in pregnant women at term who were not in labor (n = 8). The cervical CWR was analyzed using a fiber-optic light-delivery system integrated to an ultrasound probe. The photoacoustic signals were acquired within the range of wavelengths that cover the peak absorption of collagen and water. Differences in the CWR between cervical samples from pregnant and non-pregnant women were analyzed. Hematoxylin and eosin and Sirius Red stains were used to compare the collagen content of cervical samples in these two groups. Results Eight cervix samples were obtained after hysterectomy, four from women ≤41 years of age and four from women ≥43 years of age; all cervical samples (n = 8) from pregnant women were obtained after 37 weeks of gestation at the time of cesarean section. The average CWR in cervical tissue samples from pregnant women was 18.7% (SD 7.5%), while in samples from non-pregnant women, it was 55.0% (SD 20.3%). There was a significantly higher CWR in the non-pregnant group compared to the pregnant group with a p-value <0.001. A subgroup analysis that compared the CWR in cervical samples from pregnant women and non-pregnant women ≤41 years of age (mean 46.3%, SD 23.1%) also showed a significantly higher CWR (p <0.01). Lower collagen content in the pregnancy group was confirmed by histological analysis, which revealed the loss of tissue composition, increased water content, and collagen degradation. Conclusion The proposed bimodal ultrasound and sPA imaging system can provide information on the biochemical composition of cervical tissue in pregnant and non-pregnant women. Photoacoustic imaging showed a higher collagen content in cervical samples from non-pregnant women as compared to those from pregnant women, which matched with the histological analysis. This novel imaging method envisions a new potential for a sensitive diagnostic tool in the evaluation of cervical tissue composition.

scholarly journals Design and enhance the vein recognition using near infrared light and projector

2017 ◽  
Vol 20 (K2) ◽  
pp. 91-95
Author(s):  
Tien Van Tran ◽  
Hieu Sy Dau ◽  
Dan Tri Nguyen ◽  
Sang Quoc Huynh ◽  
Linh Quang Huynh
Keyword(s):  
Near Infrared ◽  
New Technologies ◽  
Infrared Imaging ◽  
Infrared Light ◽  
Imaging Method ◽  
Clinical Issue ◽  
Intravenous Access ◽  
Nir Imaging ◽  
Vein Recognition ◽  
Important Clinical Issue

The difficulty of intravenous access in patients is an important clinical issue. Recently, many studies and several devices have been developed to assist physicians, nurses and surgeons in finding veins. Amongst them, near infrared imaging technology is one of the new technologies being widely used in the biomedical. NIR imaging allows visualizing veins underneath the skin of those having non-visibility of veins problem, mapping the normal and abnormal veins in treating disorders, or diagnosing related diseases. In this paper, we will introduce a portable device which can help doctors and nurses visualize blood vessel maps of their patients. On basic of combining a vein infrared imaging method and a projector system, this vein instrument can be optimally designed for viewing veins in the monitor or displaying vessel maps of patients directly on their skin.

An Application for the Quantitative Analysis of Pharmaceutical Tablets Using a Rapid Switching System Between a Near-Infrared Spectrometer and a Portable Near-Infrared Imaging System Equipped with Fiber Optics

2018 ◽  
Vol 72 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Kodai Murayama ◽  
Daitaro Ishikawa ◽  
Takuma Genkawa ◽  
Yukihiro Ozaki
Keyword(s):  
Ascorbic Acid ◽  
Near Infrared ◽  
Imaging System ◽  
Spot Size ◽  
Switching System ◽  
Pharmaceutical Tablets ◽  
Nir Imaging ◽  
Imaging Results ◽  
Rapid Switching ◽  
Mean Square Errors

We present a rapid switching system between a newly developed near-infrared (NIR) spectrometer and its imaging system to select the spot size of a diffuse reflectance (DR) probe. In a previous study, we developed a portable NIR imaging system, known as D-NIRs, which has significant advantages over other systems. Its high speed, high spectral resolution, and portability are particularly useful in the process of monitoring pharmaceutical tablets. However, the spectral accuracies relating to the changes in the formulation of the pharmaceutical tablets have not been fully discussed. Therefore, we improved the rapid optical switching system and present a new model of D-NIRs (ND-NIRs) here. This system can automatically switch the optical paths of the DR and NIR imaging probes, greatly contributing to the simultaneous measurement of both the imaging and spot. The NIR spectra of the model tablets, including 0–10% ascorbic acid, were measured and simultaneous NIR images of the tablets were obtained. The predicted results using spot sizes for the DR probe of 1 and 5 mm diameter, resulted in concentrations of R2 = 0.79 and 0.94, with root mean square errors (RMSE) of 1.78 and 0.89, respectively. For tablets with a high concentration of ascorbic acid, the NIR imaging results showed inhomogeneity in concentration. However, the predicted values for the low concentration samples appeared higher than the known concentration of the tablets, although the homogeneity of the concentration was confirmed. In addition, the optimal spot size using NIR imaging data was estimated to be 5–7 mm. The results obtained in this study show that the spot size of the fiber probe, attached to a spectrometer, is important in developing a highly reliable model to determine the component concentration of a tablet.

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