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1.
PLoS One ; 15(7): e0236835, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730365

RESUMO

We propose a new optical method based on comparative holographic projection for visual comparison between two abnormal follow-up magnetic resonance (MR) exams of glioblastoma patients to effectively visualize and assess tumor progression. First, the brain tissue and tumor areas are segmented from the MR exams using the fast marching method (FMM). The FMM approach is implemented on a computed pixel weight matrix based on an automated selection of a set of initialized target points. Thereafter, the associated phase holograms are calculated for the segmented structures based on an adaptive iterative Fourier transform algorithm (AIFTA). Within this approach, a spatial multiplexing is applied to reduce the speckle noise. Furthermore, hologram modulation is performed to represent two different reconstruction schemes. In both schemes, all calculated holograms are superimposed into a single two-dimensional (2D) hologram which is then displayed on a reflective phase-only spatial light modulator (SLM) for optical reconstruction. The optical reconstruction of the first scheme displays a 3D map of the tumor allowing to visualize the volume of the tumor after treatment and at the progression. Whereas, the second scheme displays the follow-up exams in a side-by-side mode highlighting tumor areas, so the assessment of each case can be fast achieved. The proposed system can be used as a valuable tool for interpretation and assessment of the tumor progression with respect to the treatment method providing an improvement in diagnosis and treatment planning.


Assuntos
Algoritmos , Neoplasias Encefálicas/patologia , Encéfalo/anatomia & histologia , Holografia/métodos , Imageamento Tridimensional/métodos , Imagem por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico por imagem , Progressão da Doença , Humanos , Processamento de Sinais Assistido por Computador
2.
Proc Natl Acad Sci U S A ; 117(17): 9223-9231, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32284403

RESUMO

Many medical and biological protocols for analyzing individual biological cells involve morphological evaluation based on cell staining, designed to enhance imaging contrast and enable clinicians and biologists to differentiate between various cell organelles. However, cell staining is not always allowed in certain medical procedures. In other cases, staining may be time-consuming or expensive to implement. Staining protocols may be operator-sensitive, and hence may lead to varying analytical results, as well as cause artificial imaging artifacts or false heterogeneity. We present a deep-learning approach, called HoloStain, which converts images of isolated biological cells acquired without staining by holographic microscopy to their virtually stained images. We demonstrate this approach for human sperm cells, as there is a well-established protocol and global standardization for characterizing the morphology of stained human sperm cells for fertility evaluation, but, on the other hand, staining might be cytotoxic and thus is not allowed during human in vitro fertilization (IVF). After a training process, the deep neural network can take images of unseen sperm cells retrieved from holograms acquired without staining and convert them to their stainlike images. We obtained a fivefold recall improvement in the analysis results, demonstrating the advantage of using virtual staining for sperm cell analysis. With the introduction of simple holographic imaging methods in clinical settings, the proposed method has a great potential to become a common practice in human IVF procedures, as well as to significantly simplify and radically change other cell analyses and techniques such as imaging flow cytometry.


Assuntos
Holografia/métodos , Microscopia/métodos , Coloração e Rotulagem/métodos , Algoritmos , Aprendizado Profundo , Citometria de Fluxo , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Redes Neurais de Computação , Espermatozoides/metabolismo
3.
J Vis Exp ; (155)2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-32009642

RESUMO

This paper demonstrates a method to record a set of twelve ultra-realistic full-color analog holograms presenting the same brightness, transparency and homogeneous colors for the fabrication of a Fantatrope, a dynamic holographic 3D display, without the need for special viewing aids. The method involves the use of 3D printer technology, a single-beam full-color Denisyuk optical setup with three low-power lasers (red, green, and blue) and an iso-panchromatic high-sensitive silver-halide holographic emulsion specially designed for recording analog holograms without any diffusion. A cyclic animation is created with a 3D computer graphics program and different elements are 3D printed to form models for the holograms. Holograms are recorded with a full-color holographic setup and developed using two simple chemical baths. To prevent any emulsion thickness variations, the holograms are sealed with optical glue. Results confirm that all holograms recorded with this protocol present the same characteristics, which allow them to be used in the Fantatrope.


Assuntos
Holografia/métodos , Cor
4.
Nat Commun ; 11(1): 171, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949134

RESUMO

The optical detection of nanoparticles, including viruses and bacteria, underpins many of the biological, physical and engineering sciences. However, due to their low inherent scattering, detection of these particles remains challenging, requiring complex instrumentation involving extensive sample preparation methods, especially when sensing is performed in liquid media. Here we present an easy-to-use, high-throughput, label-free and cost-effective method for detecting nanoparticles in low volumes of liquids (25 nL) on a disposable chip, using an acoustically actuated lens-free holographic system. By creating an ultrasonic standing wave in the liquid sample, placed on a low-cost glass chip, we cause deformations in a thin liquid layer (850 nm) containing the target nanoparticles (≥140 nm), resulting in the creation of localized lens-like liquid menisci. We also show that the same acoustic waves, used to create the nanolenses, can mitigate against non-specific, adventitious nanoparticle binding, without the need for complex surface chemistries acting as blocking agents.


Assuntos
Holografia/métodos , Nanopartículas/química , Acústica , Holografia/instrumentação , Lentes
5.
Ann Surg ; 271(1): e4-e7, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31425293

RESUMO

OBJECTIVE: The aim of this study was to investigate the potential of an intraoperative 3D hologram, which was a computer graphics model liver, with mixed reality techniques in liver surgery. SUMMARY BACKGROUND DATA: The merits for the application of a hologram for surgical support are: 1) no sterilized display monitor; 2) better spatial awareness; and 3) 3D images shared by all the surgeons. METHODS: 3D polygon data using preoperative computed tomography data was installed into head mount displays, HoloLens (Microsoft Corporation, Redmond, WA). RESULTS: In a Wi-Fi-enabled operative room, several surgeons wearing HoloLens succeeded in sharing the same hologram and moving that hologram from respective operators' angles by means of easy gesture-handling without any monitors. The intraoperative hologram contributed to better imagination of tumor locations, and for determining the parenchymal dissection line in the hepatectomy for the patients with more than 20 multiple colo-rectal liver metastases. In another case, the hologram enabled a safe Gliisonean pedicle approach for hepato-cellular carcinoma with a hilar anatomical anomaly. Surgeons could easily compare the real patient's anatomy and that of the hologram just before the hepatic hilar procedure. CONCLUSIONS: This initial experience suggested that an intraoperative hologram with mixed reality techniques contributed to "last-minute simulation," not for "navigation." The intraoperative hologram might be a new next-generation operation-supportive tool in terms of spatial awareness, sharing, and simplicity.


Assuntos
Hepatectomia/métodos , Holografia/métodos , Imageamento Tridimensional/métodos , Neoplasias Hepáticas/cirurgia , Fígado/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Cirurgia Assistida por Computador/métodos , Humanos , Fígado/cirurgia , Neoplasias Hepáticas/diagnóstico , Reprodutibilidade dos Testes
6.
J Synchrotron Radiat ; 27(Pt 1): 185-198, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31868751

RESUMO

Friedreich's ataxia (FRDA) is a neurodegenerative disease characterized by an increase in intracytoplasmic iron concentration. Here the nanoscale iron distribution within single fibroblasts from FRDA patients was investigated using synchrotron-radiation-based nanoscopic X-ray fluorescence and X-ray in-line holography at the ID16A nano-imaging beamline of the ESRF. This unique probe was deployed to uncover the iron cellular two-dimensional architecture of freeze-dried FRDA fibroblasts. An unsurpassed absolute detection capability of 180 iron atoms within a 30 nm × 50 nm nanoscopic X-ray beam footprint was obtained using state-of-the-art X-ray focusing optics and a large-solid-angle detection system. Various micrometre-sized iron-rich organelles could be revealed for the first time, tentatively identified as endoplasmic reticulum, mitochondria and lysosomes. Also a multitude of nanoscopic iron hot-spots were observed in the cytosol, interpreted as chaperoned iron within the fibroblast's labile iron pool. These observations enable new hypotheses on the storage and trafficking of iron in the cell and ultimately to a better understanding of iron-storage diseases such as Friedreich's ataxia.


Assuntos
Fibroblastos/química , Ataxia de Friedreich/patologia , Holografia/métodos , Ferro/análise , Análise de Célula Única/métodos , Espectrometria por Raios X/métodos , Carbono , Citoplasma/química , Fibroblastos/ultraestrutura , Liofilização , Humanos , Nanoestruturas , Organelas/química , Organelas/ultraestrutura , Análise de Célula Única/instrumentação , Síncrotrons , Fixação de Tecidos/métodos
7.
Neuron ; 104(6): 1056-1064.e3, 2019 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-31708306

RESUMO

Three-dimensional documentation of the axonal pathways connecting gray matter components of the human brain has wide-ranging scientific and clinical applications. Recent attempts to map human structural connectomes have concentrated on using tractography results derived from diffusion-weighted imaging data, but tractography is an indirect method with numerous limitations. Advances in holographic visualization platforms provide a new medium to integrate anatomical data, as well as a novel working environment for collaborative interaction between neuroanatomists and brain-imaging scientists. Therefore, we developed the first holographic interface for building axonal pathways, populated it with human histological and structural MRI data, and assembled world expert neuroanatomists to interactively define axonal trajectories of the cortical, basal ganglia, and cerebellar systems. This blending of advanced visualization hardware, software development, and neuroanatomy data enabled the translation of decades of amassed knowledge into a human axonal pathway atlas that can be applied to educational, scientific, or clinical investigations.


Assuntos
Atlas como Assunto , Encéfalo/anatomia & histologia , Holografia/métodos , Vias Neurais/anatomia & histologia , Humanos , Neuroimagem/métodos
8.
Opt Express ; 27(22): 32228-32234, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31684439

RESUMO

For better understanding of brain functions, optogenetic neural modulation has been widely employed in neural science research. For deep tissue in vivo applications, large-scale two-photon based near simultaneous 3D laser excitation is needed. Although 3D holographic laser excitation is nowadays common practice, the inherent short coherence length of the commonly used femtosecond pulses fundamentally restricts the achievable field-of-view. Here we report a technique for near simultaneous large-scale femtosecond holographic 3D excitation. Specifically, we achieved two-photon excitation over 1.3 mm field-of-view within 1.3 milliseconds, which is sufficiently fast even for spike timing recording. The method is scalable and compatible with the commonly used two-photon sources and imaging systems in neuroscience research.


Assuntos
Encéfalo/fisiologia , Holografia/métodos , Optogenética/métodos , Algoritmos , Fluorescência , Fótons , Fatores de Tempo
9.
Appl Opt ; 58(27): 7416-7423, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31674390

RESUMO

The intracellular dynamics of onion epidermal cells during the dehydration process is observed by holographic microscopy. Both the nucleus and cytoplasm are accurately revealed by quantitative phase imaging while dehydration takes place. Indeed, we notice that the contrast of phase images increases with the decrease in cellular water content. We foresee that such a dehydrating process can be effective for improving phase contrast, thus permitting better imaging of plant cells with the scope of learning more about cellular dynamics and related phenomena. Exploiting this concept, we observe intracellular cytoplasmic circulation and transport of biological material.


Assuntos
Citoplasma/fisiologia , Holografia/métodos , Microscopia de Contraste de Fase/métodos , Cebolas/citologia , Células Vegetais/fisiologia , Água/fisiologia , Transporte Biológico/fisiologia , Desidratação , Epiderme Vegetal/fisiologia
10.
Science ; 365(6453)2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31320556

RESUMO

Perceptual experiences may arise from neuronal activity patterns in mammalian neocortex. We probed mouse neocortex during visual discrimination using a red-shifted channelrhodopsin (ChRmine, discovered through structure-guided genome mining) alongside multiplexed multiphoton-holography (MultiSLM), achieving control of individually specified neurons spanning large cortical volumes with millisecond precision. Stimulating a critical number of stimulus-orientation-selective neurons drove widespread recruitment of functionally related neurons, a process enhanced by (but not requiring) orientation-discrimination task learning. Optogenetic targeting of orientation-selective ensembles elicited correct behavioral discrimination. Cortical layer-specific dynamics were apparent, as emergent neuronal activity asymmetrically propagated from layer 2/3 to layer 5, and smaller layer 5 ensembles were as effective as larger layer 2/3 ensembles in eliciting orientation discrimination behavior. Population dynamics emerging after optogenetic stimulation both correctly predicted behavior and resembled natural internal representations of visual stimuli at cellular resolution over volumes of cortex.


Assuntos
Neocórtex/fisiologia , Neocórtex/ultraestrutura , Neurônios/fisiologia , Percepção Visual/fisiologia , Animais , Organismos Aquáticos/genética , Células Cultivadas , Channelrhodopsins/genética , Holografia/métodos , Camundongos , Imagem Molecular , Opsinas/genética , Optogenética , Orientação/fisiologia , Estimulação Luminosa , Percepção Visual/genética
11.
Biochemistry (Mosc) ; 84(Suppl 1): S124-S143, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31213199

RESUMO

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia accompanied by the disruption of carbohydrate, lipid, and proteins metabolism and development of long-term microvascular, macrovascular, and neuropathic changes. This review presents the results of spectroscopic studies on the glycation of tissues and cell proteins in organisms with naturally developing and model diabetes and in vitro glycated samples in a wide range of electromagnetic waves, from visible light to terahertz radiation. Experiments on the refractometric measurements of glycated and oxygenated hemoglobin in broad wavelength and temperature ranges using digital holographic microscopy and diffraction tomography are discussed, as well as possible application of these methods in the diabetes diagnostics. It is shown that the development and implementation of multimodal approaches based on a combination of phase diagnostics with other methods is another promising direction in the diabetes diagnostics. The possibilities of using optical clearing agents for monitoring the diffusion of substances in the glycated tissues and blood flow dynamics in the pancreas of animals with induced diabetes have also been analyzed.


Assuntos
Diabetes Mellitus/diagnóstico por imagem , Hemoglobina A Glicada/ultraestrutura , Animais , Velocidade do Fluxo Sanguíneo , Glicosilação , Holografia/métodos , Humanos , Microscopia/métodos , Espectrofotometria Infravermelho/métodos , Espectroscopia Terahertz/métodos , Tomografia/métodos
12.
J Clin Neurosci ; 67: 234-238, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221576

RESUMO

During neurological surgery, neurosurgeons have to transform the two-dimensional (2D) sectional images into three-dimensional (3D) structures at the cognitive level. The complexity of the intracranial structures increases the difficulty and risk of neurosurgery. Mixed reality (MR) applications reduce the obstacles in the transformation from 2D images to 3D visualization of anatomical structures of central nervous system. In this study, the holographic image was established by MR using computed tomography (CT), computed tomography angiography (CTA) and magnetic resonance imaging (MRI) data of patients. The surgeon's field of vision was superimposed with the 3D model of the patient's intracranial structure displayed on the mixed reality head-mounted display (MR-HMD). The neurosurgeons practiced and evaluated the feasibility of this technique in neurosurgical cases. We developed the segmentation image masks and texture mapping including brain tissue, intracranial vessels, nerves, tumors, and their relative positions by MR technologies. The results showed that the three-dimensional imaging is in a stable state in the operating room with no significant flutter and blur. And the neurosurgeon's feedback on the comfort of the equipment and the practicality of the technology was satisfactory. In conclusion, MR technology can holographically construct a 3D digital model of patient's lesions and improve the anatomical perception of neurosurgeons during craniotomy. The feasibility of the MR-HMD application in neurosurgery is confirmed.


Assuntos
Craniotomia/métodos , Holografia/métodos , Cirurgia Assistida por Computador/métodos , Idoso , Neoplasias Encefálicas/cirurgia , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X/métodos
13.
Appl Opt ; 58(15): 4042-4046, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31158157

RESUMO

This paper utilized digital holographic microscopy and optical tweezers to study microdeformation of red blood cells (RBCs) dynamically under oxidative stress. RBCs attached with microbeads were stretched by dual optical tweezers to generate microdeformation. Morphology of RBCs under manipulation were recorded dynamically and recovered by off-axis digital holographic microscopy method. RBCs treated with H2O2 at different concentrations were measured to investigate the mechanical properties under oxidative stress. Use of optical tweezers and off-axis digital holographic microscopy enhanced measuring accuracy compared with the traditional method. Microdeformation of RBCs is also more consistent with the physiological situation. This proposal is meaningful for clinical applications and basic analysis of Parkinson's disease research.


Assuntos
Deformação Eritrocítica/fisiologia , Eritrócitos/citologia , Holografia/métodos , Pinças Ópticas , Estresse Oxidativo , Forma Celular/fisiologia , Elasticidade/fisiologia , Humanos , Microscopia/métodos
14.
Opt Express ; 27(10): 13581-13595, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31163820

RESUMO

Lens-free holographic microscopy (LFHM) provides a cost-effective tool for large field-of-view imaging in various biomedical applications. However, due to the unit optical magnification, its spatial resolution is limited by the pixel size of the imager. Pixel super-resolution (PSR) technique tackles this problem by using a series of sub-pixel shifted low-resolution (LR) lens-free holograms to form the high-resolution (HR) hologram. Conventional iterative PSR methods require a large number of measurements and a time-consuming reconstruction process, limiting the throughput of LFHM in practice. Here we report a deep learning-based PSR approach to enhance the resolution of LFHM. Compared with the existing PSR methods, our neural network-based approach outputs the HR hologram in an end-to-end fashion and maintains consistency in resolution improvement with a reduced number of LR holograms. Moreover, by exploiting the resolution degradation model in the imaging process, the network can be trained with a data set synthesized from the LR hologram itself without resorting to the HR ground truth. We validated the effectiveness and the robustness of our method by imaging various types of samples using a single network trained on an entirely different data set. This deep learning-based PSR approach can significantly accelerate both the data acquisition and the HR hologram reconstruction processes, therefore providing a practical solution to fast, lens-free, super-resolution imaging.


Assuntos
Holografia/métodos , Aumento da Imagem/métodos , Microscopia/métodos , Redes Neurais de Computação , Algoritmos , Aprendizado de Máquina
15.
Opt Express ; 27(10): 13706-13720, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31163830

RESUMO

An outstanding challenge for immunology is the classification of immune cells in a label-free fashion with high speed. For this purpose, optical techniques such as Raman spectroscopy or digital holographic microscopy have been used successfully to identify immune cell subsets. To achieve high accuracy, these techniques require a post-processing step using linear methods of multivariate processing, such as principal component analysis. Here we demonstrate for the first time a comparison between artificial neural networks and principal component analysis (PCA) to classify the key granulocyte cell lineages of neutrophils and eosinophils using both digital holographic microscopy and Raman spectroscopy. Artificial neural networks can offer advantages in terms of classification accuracy and speed over a PCA approach. We conclude that digital holographic microscopy with convolutional neural networks based analysis provides a route to a robust, stand-alone and high-throughput hemogram with a classification accuracy of 91.3 % at a throughput rate of greater than 100 cells per second.


Assuntos
Eosinófilos/citologia , Holografia/métodos , Redes Neurais de Computação , Neutrófilos/citologia , Análise Espectral Raman/métodos , Linhagem da Célula , Separação Celular/métodos , Citometria de Fluxo , Humanos , Análise de Componente Principal
16.
Appl Opt ; 58(12): 3104-3114, 2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31044784

RESUMO

Modern microscopes are designed with functionalities that are tailored to enhance image contrast. Dark-field imaging, phase contrast, differential interference contrast, and other optical techniques enable biological cells and other phase-only objects to be visualized. Quantitative phase imaging refers to an emerging set of techniques that allow for the complex transmission function of the sample to be measured. With this quantitative phase image available, any optical technique can then be simulated; it is trivial to generate a phase contrast image or a differential interference contrast image. Rheinberg illumination, proposed almost a century ago, is an optical technique that applies color contrast to images of phase-only objects by introducing a type of optical staining via an amplitude filter placed in the illumination path that consists of two or more colors. In this paper, the complete theory of Rheinberg illumination is derived, from which an algorithm is proposed that can digitally simulate the technique. Results are shown for a number of quantitative phase images of diatom cells obtained via digital holographic microscopy. The results clearly demonstrate the potential of the technique for label-free color staining of subcellular features.


Assuntos
Diatomáceas/citologia , Holografia/métodos , Iluminação , Microscopia de Contraste de Fase/métodos , Coloração e Rotulagem/métodos , Algoritmos
17.
JAMA Netw Open ; 2(4): e192633, 2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-31002326

RESUMO

Importance: Nephron-sparing surgery can be considered in well-defined cases of unilateral and bilateral Wilms tumors, but the surgical procedure can be very challenging for the pediatric surgeon to perform. Objective: To assess the added value of personalized 3-dimensional (3-D) kidney models derived from conventional imaging data to enhance preoperative surgical planning. Design, Setting, and Participants: In a survey study, the conventional imaging data of 10 Dutch children with Wilms tumors were converted to 3-D prints and augmented reality (AR) holograms and a panel of pediatric oncology surgeons (n = 7) assessed the quality of the different imaging methods during preoperative evaluation. Kidney models were created with 3-D printing and AR using a mixed reality headset for visualization. Main Outcomes and Measures: Differences in the assessment of 4 anatomical structures (tumor, arteries, veins, and urinary collecting structures) using questionnaires. A Likert scale measured differences between the imaging methods, with scores ranging from 1 (completely disagree) to 5 (completely agree). Results: Of the 10 patients, 7 were girls, and the mean (SD) age was 3.7 (1.7) years. Compared with conventional imaging, the 3-D print and the AR hologram models were evaluated by the surgeons to be superior for all anatomical structures: tumor (median scores for conventional imaging, 4.07; interquartile range [IQR], 3.62-4.15 vs 3-D print, 4.67; IQR, 4.14-4.71; P = .008 and AR hologram, 4.71; IQR, 4.26-4.75; P = .002); arteries (conventional imaging, 3.62; IQR, 3.43-3.93 vs 3-D print, 4.54; IQR, 4.32-4.71; P = .002 and AR hologram, 4.83; IQR, 4.64-4.86; P < .001), veins (conventional imaging, 3.46; IQR 3.39-3.62 vs 3-D print, 4.50; IQR, 4.39-4.68; P < .001 and AR hologram, 4.83; IQR, 4.71-4.86; P < .001), and urinary collecting structures (conventional imaging, 2.76; IQR, 2.42-3.00 vs 3-D print, 3.86; IQR, 3.64-4.39; P < .001 and AR hologram, 4.00; IQR, 3.93-4.58; P < .001). There were no differences in anatomical assessment between the two 3-D techniques (the 3-D print and AR hologram). Conclusions and Relevance: In this study, the 3-D kidney models were associated with improved anatomical understanding among the surgeons and can be helpful in future preoperative planning of nephron-sparing surgery for Wilms tumors. These models may be considered as a supplementary visualization in clinical care.


Assuntos
Realidade Aumentada , Holografia/métodos , Neoplasias Renais/diagnóstico por imagem , Modelos Anatômicos , Impressão Tridimensional , Tumor de Wilms/diagnóstico por imagem , Pré-Escolar , Feminino , Humanos , Masculino , Período Pré-Operatório
18.
Appl Opt ; 58(5): A258-A266, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30873999

RESUMO

The computer-generated hologram (CGH) technique is a technique that simulates the recording of holography. Although the CGH technique has a lot of advantages, it also has some disadvantages; one of them is the long calculation time. Much research on the human eye has established that humans see 135° vertically and 160° horizontally, but can see fine detail within an only 5° central circle. Foveated rendering uses this characteristic of the human eye to reduce image resolution in the peripheral area and achieve a high calculation speed. In this paper, a new method for CGH fast calculation with foveated rendering using an angle-changeable ray-tracing method is introduced. The experiments demonstrate the effectiveness and high-speed calculation of this method.


Assuntos
Holografia/métodos , Aumento da Imagem/métodos , Algoritmos , Desenho de Equipamento , Humanos , Imageamento Tridimensional/métodos , Processamento de Sinais Assistido por Computador , Acuidade Visual/fisiologia
19.
Sensors (Basel) ; 19(5)2019 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-30862101

RESUMO

Continuous cell culture monitoring as a way of investigating growth, proliferation, and kinetics of biological experiments is in high demand. However, commercially available solutions are typically expensive and large in size. Digital inline-holographic microscopes (DIHM) can provide a cost-effective alternative to conventional microscopes, bridging the gap towards live-cell culture imaging. In this work, a DIHM is built from inexpensive components and applied to different cell cultures. The images are reconstructed by computational methods and the data are analyzed with particle detection and tracking methods. Counting of cells as well as movement tracking of living cells is demonstrated, showing the feasibility of using a field-portable DIHM for basic cell culture investigation and bringing about the potential to deeply understand cell motility.


Assuntos
Rastreamento de Células/métodos , Microscopia/métodos , Técnicas de Cultura de Células , Holografia/métodos , Humanos
20.
Molecules ; 24(6)2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30875723

RESUMO

Holographic volume phase gratings are recorded in an epoxy-based, free-surface, volume holographic recording material. Light-induced gratings are formed by photo-triggered mass migration caused by component diffusion. The material resolution enables a wide range of pattern spacings, to record both transmission and reflection holograms with many different spatial frequencies. An optimum spatial frequency response is found between the low spatial frequency roll-off and the high spatial frequency cut-off. The influence of the energy density of exposure on the spatial frequency response is investigated. Secondary volume holographic gratings (parasitic gratings) are observed in the high frequency range. The possibility of distinguishing the regular grating from the secondary grating is discussed in the form of probe wavelength detuning.


Assuntos
Holografia/métodos , Fármacos Fotossensibilizantes/química , Polímeros/química , Luz , Refratometria , Propriedades de Superfície
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