1. Tianjin University

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    1. Mentioned In 33 Articles

    2. Defocus and contrast agent absorption compensation method in intravascular optical coherence tomography imaging

      Defocus and contrast agent absorption compensation method in intravascular optical coherence tomography imaging
      Intravascular optical coherence tomography (IVOCT) has been widely used in clinical coronary artery intervention field. Owing to defocus and contrast agent absorption effects, the intensity fluctuation caused by imaging catheter locating at an eccentric position significantly influence the quality of IVOCT imaging and even plaque type identification. In this paper, we present a novel method to compensate intensity fluctuation caused by defocus and contrast agent absorption in IVOCT imaging. We ...
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    3. Texture preservation and speckle reduction in poor optical coherence tomography using the convolutional neural network

      Texture preservation and speckle reduction in poor optical coherence tomography using the convolutional neural network
      For a poor quality optical coherence tomography (OCT) image, quality enhancement is limited to speckle residue and edge blur as well as texture loss, especially at the background region near edges. To solve this problem, in this paper we propose a de-speckling method based on the convolutional neural network (CNN). In the proposed method, we use a deep nonlinear CNN mapping model in the serial architecture, here named as OCTNet ...
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    4. Fast Retinal Segmentation Based on the Wave Algorithm

      Fast Retinal Segmentation Based on the Wave Algorithm
      The retinal layer segmentation technique of optical coherence tomography (OCT) data is essential for the diagnosis of ophthalmic and systemic diseases. To achieve fast and accurate retinal layer segmentation, a new medical image segmentation method (wave algorithm) is proposed based on the mathematical model of the fluid potential energy equation in fluid mechanics. A change in the gray value in the image is converted into a change in the potential ...
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    5. Identification of atherosclerotic plaques in intravascular optical coherence tomography images based on textures and artificial neural network

      Identification of atherosclerotic plaques in intravascular optical coherence tomography images based on textures and artificial neural network
      Intravascular optical coherence tomography (IVOCT) is becoming an important choice for in vivo diagnosis of coronary artery diseases. The atherosclerotic disease can be detected from IVOCT images, but the segmentation of IVOCT images and identification of plaques are mainly performed manually. This process is laborious and time consuming and its accuracy relies on the expertise of the observer. To address these limitations, a semi-automated identification algorithm based on texture features ...
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    6. Selective retinex enhancement based on the clustering algorithm and block-matching 3D for optical coherence tomography images

      Selective retinex enhancement based on the clustering algorithm and block-matching 3D for optical coherence tomography images
      It is important to enhance the contrast and remove the speckle noise for optical coherence tomography (OCT) images. In this paper, we propose a selective retinex enhancement method based on the fuzzy c-means (FCM) clustering algorithm to enhance only the structure part in OCT images and combines with the block-matching 3D (BM3D) algorithm for filtering. In the proposed selective retinex enhancement method, we first calculate the feature image of the ...
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    7. Automatic Lumen Segmentation in Intravascular Optical Coherence Tomography Using Morphological Features

      Automatic Lumen Segmentation in Intravascular Optical Coherence Tomography Using Morphological Features
      Lumen segmentation in intravascular optical coherence tomography (IVOCT) images is a fundamental work for more advanced plaque analysis, stent recognition, fractional flow reserve (FFR) assessment, and so on. However, the catheter, guide-wire, inadequate blood clearance, and other factors will impact on the accuracy of lumen segmentation. We present a simple and effective method for automatic lumen segmentation method in IVOCT based on morphological features. We use image enhancement, median filtering ...
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    8. Texture preservation and speckle reduction in optical coherence tomography using the shearlet-based total variation algorithm

      Texture preservation and speckle reduction in optical coherence tomography using the shearlet-based total variation algorithm
      In optical coherence tomography (OCT), speckle residue, texture loss, and edge blur are the main factors that limit the image quality improvement during speckle reduction, especially for human retinal OCT images. This paper proposes a shearlet-based total variation de-speckling framework (STV method) to address this problem. This method includes a de-speckling regularisation term, an edge-preserving regularisation term, and a fidelity term. By assigning a suitable weight to each term, speckle ...
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    9. 3D Strain and Elasticity Measurement of Layered Biomaterials by Optical Coherence Elastography based on Digital Volume Correlation and Virtual Fields Method

      3D Strain and Elasticity Measurement of Layered Biomaterials by Optical Coherence Elastography based on Digital Volume Correlation and Virtual Fields Method
      The three-dimensional (3D) mechanical property characterization of biological tissues is essential for physiological and pathological studies. A digital volume correlation (DVC) and virtual fields method (VFM) based 3D optical coherence elastography (OCE) method is developed to quantitatively measure the 3D full-field displacements, strains and elastic parameters of layered biomaterials assuming the isotropy and homogeneity of each layer. The integrated noise-insensitive DVC method can obtain the 3D strain tensor with an ...
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    10. Vascular Stress Analysis During in vivo Intravascular Optical Coherence Tomography Imaging

      Vascular Stress Analysis During in vivo Intravascular Optical Coherence Tomography Imaging
      Intravascular optical coherence tomography (IVOCT) has been employed to clinical coronary imaging for several years. But the influence of flushing and OCT catheter to the blood vessel biomechanical properties have not been studied. In this paper, IVOCT imaging is integrated with the fluid-structure interaction (FSI) simulation to study the blood flow velocity and the stress distribution of a porcine carotid artery during IVOCT imaging. 3D geometric model is built based ...
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    11. Vascular Deformation Analysis Based On in vivo Intravascular Optical Coherence Tomography Imaging

      Vascular Deformation Analysis Based On in vivo Intravascular Optical Coherence Tomography Imaging
      Intravascular optical coherence tomography (OCT) has the characteristics of high resolution and fast imaging speed. Continuous images of the same section of the same vessel can reflect the deformation characteristics of the vessel wall under different blood pressure. Digital image processing may be used to segment various structures on the vascular wall and extract the deformation incorporating with biomechanical analysis. Image filtering plays a very important role in image processing ...
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    12. Ultrafast Wavenumber Linear-step-swept source Based on Synchronous Lightwave Synthesized Frequency Sweeper

      Ultrafast Wavenumber Linear-step-swept source Based on Synchronous Lightwave Synthesized Frequency Sweeper
      An ultrafast wavenumber linear-step-swept source based on a synchronous lightwave synthesized frequency sweeper (SLSFS) is demonstrated. A multi-wavelength source is used as a seed source. In SLSFS, the swept range of different wavelength components is precisely controlled by a stable programmable radio frequency (RF) signal applied on a dual-parallel Mach-Zehnder modulator (DP-MZM) instead of a conventional wavelength filter. The identical frequency shifting step of all the wavelength components promises high ...
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    13. Application of Spectral Domain Optical Coherence Tomography to Objectively Evaluate Posterior Capsular Opacity In Vivo

      Application of Spectral Domain Optical Coherence Tomography to Objectively Evaluate Posterior Capsular Opacity In Vivo
      Objectives . To objectively evaluate posterior capsular opacification (PCO) with RTVue-100 spectral domain-OCT and assess the agreement with the Pentacam system. Methods . Sixty-seven eyes diagnosed with PCO were included. RTVue-100 SD-OCT was used to scan the IOL outline and PCO at horizontal and vertical meridians. PCO was also imaged with a Pentacam and slit-lamp photography system. With RTVue-100 SD-OCT, the PCO area, thickness, density, and objective scores were recorded and used ...
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    14. A linearly frequency-swept high-speed-rate multi-wavelength laser for optical coherence tomography

      A linearly frequency-swept high-speed-rate multi-wavelength laser for optical coherence tomography
      We proposed and demonstrated a linearly frequency-swept multi-wavelength laser source for optical coherence tomography (OCT) eliminating the need of wavenumber space resampling in the postprocessing progress. The source consists of a multi-wavelength fiber laser source (MFS) and an optical sweeping loop. In this novel laser source, an equally spaced multi-wavelength laser is swept simultaneously by a certain step each time in the frequency domain in the optical sweeping loop. The ...
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    15. Optical coherence tomography with pre-calculated reference spectra

      Optical coherence tomography with pre-calculated reference spectra
      The resample of spectra which is essential for high-precision spectral-domain OCT data processing is sophisticated, and its precision is dependent on the method and equipment. In this paper, we proposed an OCT without inverse FFT. A series of reference spectra corresponding to different optical path length difference was used to convolve with spectra gotten by OCT to acquire time-domain tomography instead of inverse FFT, thus eliminating the resample of spectra ...
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    16. Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography
      Impact Statement: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura, and spinal cord in a piglet model. The PS-OCT can provide enhanced contrast characteristic structures compared to the intensity OCT; therefore it has the potential for guidance in spine interventional procedures. Abstract: We investigate polarization-sensitive ...
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    17. 1-15 of 33 1 2 3 »
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  2. About Tianjin University

    Tianjin University

    Tianjin University  is a national university under the direct administration of the Ministry of Education of China. It is the first university in modern Chinese education history.