1. Articles from Zhifang Li

    1-18 of 18
    1. Depth-independent internal fingerprint based on optical coherence tomography

      Depth-independent internal fingerprint based on optical coherence tomography

      Optical coherence tomography (OCT) was used for imaging three-dimensional fingerprint to overcome the effects of different skin states and fake fingerprint. However, the OCT-based fingerprint features depend on the depth of fingertip skin which is still challenging for biometric recognition and encryption. In this work, we presented a new approach of maximum intensity projection (MIP) image of the epidermal-dermal junction (DEJ) to extract the internal fingerprint that is independent of the depth of fingertip skin. To begin with, the surface and DEJ were segmented based on the deep learning algorithm. Then the internal fingerprint was extracted by the MIP image ...

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    2. Orthogonal‐polarization‐gating optical coherence tomography for human sweat ducts in vivo

      Orthogonal‐polarization‐gating optical coherence tomography for human sweat ducts in vivo

      We propose an orthogonal‐polarization‐gating optical coherence tomography (OPGOCT) for human sweat ducts in vivo . OPG‐OCT is composed of the orthogonal linearly polarized light of a sample arm individually interfering with orthogonal linearly polarized lights of the reference arms, where OPG‐OCT induces two images, one reflecting the projection intensity and the other the horizontal linear diattenuation (HLD). The results demonstrate that OPG‐OCT projection intensity could improve the image quality of sweat ducts. HLD also clearly illustrates the spiral shape of the sweat ducts. Finally, sweat ducts in intensity image are segmented by employing convolutional neural networks ...

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    3. Orthogonal-polarization-gating optical coherence tomography for human sweat ducts in vivo

      Orthogonal-polarization-gating optical coherence tomography for human sweat ducts in vivo

      We propose an orthogonal-polarization-gating optical coherence tomography (OPGOCT) for human sweat ducts in vivo. OPG-OCT is composed of the orthogonal linearly polarized light of a sample arm individually interfering with orthogonal linearly polarized lights of the reference arms, where OPG-OCT induces two images, one reflecting the projection intensity and the other the horizontal linear diattenuation (HLD). The results demonstrate that OPG-OCT projection intensity could improve the image quality of sweat ducts. HLD also clearly illustrates the spiral shape of the sweat ducts. Finally, sweat ducts in intensity image are segmented by employing convolutional neural networks (CNN). The proportions of left-handed ...

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    4. Depth-resolved mapping of muscular bundles in myocardium pulmonary junction using optical coherence tomography

      Depth-resolved mapping of muscular bundles in myocardium pulmonary junction using optical coherence tomography

      Atrial fibrillation (AF) is the most common cardiac arrhythmia and has high patient morbidity. One of the root causes of AF is initiating triggers from atrial myocardium extending into the pulmonary veins. Visualizing the muscular bundles of myocardial extension is essential to guide the catheter radio-frequency ablation and confirm the curative tissue necrosis thereafter. We applied optical coherence tomography (OCT) for direct visualization of cardial muscle extension in myocardium pulmonary junction. Two perspectives (cross-sectional and en face images) are presented for imaging myocardial extensions. The results demonstrated that cross-sectional images can quickly locate the myocardium pulmonary junction. And en face ...

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    5. Monitoring Kidney Microanatomy Changes During Ischemia-Reperfusion Process Using Texture Analysis of OCT Images

      Monitoring Kidney Microanatomy Changes During Ischemia-Reperfusion Process Using Texture Analysis of OCT Images

      Impact Statement: Tubular diameter has been developed previously as a potential biomarker for the transplant kidney. However, the tubular lumens were segmented out based on an empirically-determined threshold. In our study, a fully automatic texture analysis algorithm has been developed for OCT image analysis of kidney microanatomy during ischemia-reperfusion process. Our method can potentially be applicable in evaluating the status of donor kidneys prior to and after their transplantation. Abstract: Kidney ischemia-reperfusion (I/R) accounts for the majority of acute kidney injury cases, whose consequences are commonly encountered after kidney transplantation. Optical coherence tomography (OCT) has been applied to image ...

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    6. Reform and practice of optical coherence tomography (OCT) system-driven teaching for optoelectronic instrument principle and design

      Reform and practice of optical coherence tomography (OCT) system-driven teaching for optoelectronic instrument principle and design

      Optoelectronic instrument principle and design includes the optical, mechanical, electrical and count modules for one system. We change traditional mode of customary specialty course design for only taking the cell design ability into account. Optical coherence tomography (OCT) can provide high-resolution 3D imaging system and wide application for tissue in vivo. In this work, we carry out OCT system– driven teaching into execution in the course design teaching, and decompose OCT system into four modules for teaching progress. The reform is not only cultivating student design ability based on OCT system exploitation, improving the engineering ability, but also help scientific ...

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    7. Single camera spectral domain polarization-sensitive optical coherence tomography based on orthogonal channels by time divided detection

      Single camera spectral domain polarization-sensitive optical coherence tomography based on orthogonal channels by time divided detection

      We demonstrate a simple polarization-sensitive spectral-domain optical coherence tomography implement by using a single line-scan camera based on time divided detection. Two light shutters were placed on the dual assembly reference arm that provides a divided detection between the orthogonal vertical and horizontal polarized lights. The relative reflectivity and the retardance information were available by recombining the two orthogonal polarization images. This system can be employed to implement high speed polarization-sensitive OCT images.

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    8. Depth-resolved imaging of colon tumor using optical coherence tomography and fluorescence laminar optical tomography

      Depth-resolved imaging of colon tumor using optical coherence tomography and fluorescence laminar optical tomography

      Early detection of neoplastic changes remains a critical challenge in clinical cancer diagnosis and treatment. Many cancers arise from epithelial layers such as those of the gastrointestinal (GI) tract. Current standard endoscopic technology is difficult to detect the subsurface lesions. In this research, we investigated the feasibility of a novel multi-modal optical imaging approach including high-resolution optical coherence tomography (OCT) and high-sensitivity fluorescence laminar optical tomography (FLOT) for structural and molecular imaging. The C57BL/6J-Apc Min /J mice were imaged using OCT and FLOT, and the correlated histopathological diagnosis was obtained. Quantitative structural (scattering coefficient) and molecular (relative enzyme activity ...

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    9. A method to improve the measurement stability of scattering coefficients in lip with optical coherence tomography

      A method to improve the measurement stability of scattering coefficients in lip with optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive imaging technique that provides real-time two- and three-dimensional images of scattering tissues with micrometer resolution. Scattering coefficient is estimated based on the slope of OCT dependent of depth. However, stability of the OCT signal slope is dependent on tissue heterogeneity. Our work is to provide a method of combining post-processing Fourier filtration with automatic identification of fitting range to reduce the effect of tissue heterogeneity on scattering coefficient, and used for noninvasive monitoring of glucose concentration in lip. Axial and lateral resolutions of OCT are 20 μm and 15 μm respectively. OCT images ...

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    10. In vivo noninvasive measurement of preprandial and postprandial blood glucose using optical coherence tomography

      In vivo noninvasive measurement of preprandial and postprandial blood glucose using optical coherence tomography

      Blood glucose concentration measurement is essential for the diagnosis and treatment of diabetes. However, conventional glucose measurement methods are invasive and not suitable for real-time monitoring. This study demonstrated a noninvasive blood glucose measurement method using optical coherence tomography to image human lip in vivo. Optical coherence tomography (OCT) is a noninvasive and depth-resolved technique capable of acquiring tissue structure images in real time. Human lip has very thin skin and is full of blood vessels, which is appropriate for noninvasive glucose measurement. To verify the feasibility of OCT for glucose concentration monitoring, two groups of OCT imaging data were ...

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    11. OCT imaging of myocardium extending to pulmonary vein

      OCT imaging of myocardium extending to pulmonary vein

      In this study, we propose to use optical coherence tomography to enable a direct visualization of myocardium extending into the pulmonary vein (PV). The results showed that there are obvious differences in the morphology of myocardium and fibrous tissue in the transition region of myocardial sleeve, which is in agreement with the histological analysis. In addition, the myocardial area in transition point has three layers in the depth of 1 mm, and the depth-resolved myocardial fiber show different orientation in the different layers. This characteristic was applied for segmentation of the structures of myocardium extending into PV.

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    12. Detection and analysis of multi-dimensional pulse wave based on optical coherence tomography

      Detection and analysis of multi-dimensional pulse wave based on optical coherence tomography

      Pulse diagnosis is an important method of traditional Chinese medicine(TCM). Doctors diagnose the patients’ physiological and pathological statuses through the palpation of radial artery for radial artery pulse information. Optical coherence tomography (OCT) is an useful tool for medical optical research. Current conventional diagnostic devices only function as a pressure sensor to detect the pulse wave,which can just partially reflect the doctors feelings and lost large amounts of useful information. In this paper, the microscopic changes of the surface skin above radial artery had been studied in the form of images based on OCT. The deformation of surface ...

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    13. Experimental research and observation of the skin response of mice with a second-degree scald duringirradiation by a CO 2 laser

      Experimental research and observation of the skin response of mice with a second-degree scald duringirradiation by a CO 2 laser

      Second-degree scalding is a common dermatological injury. Inappropriate treatment methods in clinical practice always produce scarring, and can lead to skin cancer and other complications in the longer term. In this study optical coherence tomography (OCT) combined with a skin detector was used to monitor the response of second-degree scalded skin tissue irradiated by a CO2 laser. The process of treatment of second-degree scalding was systematically studied from the perspective of tissue optics. The OCT signal intensity was stronger within the whole recovery period in the experimental group undergoing CO2 laser treatment, and the attenuation coefficient (μt) returned ...

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    14. Simultaneous determination of the tissue light scattering coefficient and Brownian diffusion coefficient using optical coherence tomography

      Simultaneous determination of the tissue light scattering coefficient and Brownian diffusion coefficient using optical coherence tomography

      Diseased tissue has different optical properties and dynamic behaviors from normal tissue, and this can be exploited for diagnostics and therapeutics. We present a model for simultaneously estimating the optical scattering coefficient and Brownian diffusion coefficient of superficial biological tissue. This theoretical model predicts that the U-quadratic distribution approximates the Lorentzian power spectrum due to the Brownian motion, when the frequency width of integration is much less than the power spectrum linewidth. Furthermore, it shows that the logarithmic intensity of all calculated wavelet frequencies is linearly dependent on the scattering coefficient and the standard deviation of the Doppler frequency shift ...

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    15. Optical features for chronological aging and photoaging skin by optical coherence tomography

      Optical features for chronological aging and photoaging skin by optical coherence tomography

      Abstract  The characteristics of skins in different aging processes were obtained by optical coherence tomography (OCT) single scattering model, and their optical parameters were analyzed quantitatively. Significant differences were found in epidermis thickness and attenuation coefficients in chronological aging skins and photonaging skins. These parameters can be served as indicators of skin type as well as the progress of aging. These results are valuable to the study of aging skin, and they could further help to understand the mechanism of aging.

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    16. Monitoring the process of tissue healing of rat skin in vivo after laser irradiation based on optical coherence tomography

      Monitoring the process of tissue healing of rat skin in vivo after laser irradiation based on optical coherence tomography
      It is imperative to evaluate the tissue wound healing response after laser irradiation so as to develop effective devices for this clinical indication, and evaluate the thermal damage degree to take appropriate treatment. In our research, we prepare 6 white rat (approximately 2 months old, weight :28±2g). Each rat was injected intraperitoneally a single dose of 2% pentobarbital sodium. After the rat was anesthetized, the two side of the rats' back were denuded and antisepsised a standardized. An Er:YAG laser (2940nm, 2.5J/cm2, single spot, 4 times) was irradiated on rat skin in vivo, and the skin ...
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    17. Combined optical coherence tomography based on the extended Huygens-Fresnel principle and histology of mouse skin

      Combined optical coherence tomography based on the extended Huygens-Fresnel principle and histology of mouse skin

      Noninvasive measurement technique to obtain tissue optical properties such as the scattering coefficient µs and the anisotropy factor g using optical coherence tomography (OCT) scattering model which based on the Extended Huygens-Fresnel principle is developed in our paper. Older and younger mouse-skin are as animal model to compare its scattering coefficient µs and the anisotropy factor g, the outcome shows that scattering coefficient µs is increased with the age of mouse-skin. Furthermore, we have made age's mouse-skin into H.E stain slices; the result of its morphology is consistent with the OCT imaging and OCT-EHF principle. All of that ...

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    18. Speckle imaging by combination of mathematical morphology and contrast ratio

      Speckle imaging by combination of mathematical morphology and contrast ratio

      This paper reports a combined speckle and polarization-difference approach for imaging absorbing inhomogeneities embedded in optical scattering medium. Mathematical morphological operation has been used to suppress the speckle coarse grains and reconstruct the position of the absorbing inhomogeneities embedded in turbid medium. Moreover, we quantify the scattering coefficient of the background medium using the average granulometric size. Then the local speckle contrast ratio is applied to enhance the edges of absorbing objects.

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    1-18 of 18
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    1. (11 articles) Fujian Normal University
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    Speckle imaging by combination of mathematical morphology and contrast ratio Combined optical coherence tomography based on the extended Huygens-Fresnel principle and histology of mouse skin Monitoring the process of tissue healing of rat skin in vivo after laser irradiation based on optical coherence tomography Optical features for chronological aging and photoaging skin by optical coherence tomography Simultaneous determination of the tissue light scattering coefficient and Brownian diffusion coefficient using optical coherence tomography Experimental research and observation of the skin response of mice with a second-degree scald duringirradiation by a CO 2 laser Detection and analysis of multi-dimensional pulse wave based on optical coherence tomography OCT imaging of myocardium extending to pulmonary vein Depth-resolved imaging of colon tumor using optical coherence tomography and fluorescence laminar optical tomography Monitoring Kidney Microanatomy Changes During Ischemia-Reperfusion Process Using Texture Analysis of OCT Images Quantification of biomechanical properties of human corneal scar using acoustic radiation force optical coherence elastography Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb