1. Articles from Tiancheng Huo

    1-16 of 16
    1. Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography

      Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography

      Multiple scattering in biomedical tissue limits the imaging depth within a range of 1–2 mm for conventional optical imaging techniques. To extend the imaging depth into the scattering medium, a computational method based on the reflection matrix measurement has been developed to retrieve the singly back-scattered signal light from the dominant detrimental multiple-scattered background. After applying singular value decomposition on the measured matrix in the post-process, the target image underneath the turbid media is clearly recovered. To increase the depth of focus of the incident light by elongating the focal spot along the optical axis, a digital grating pattern ...

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    2. Multimodality endoscopic optical coherence tomography and fluorescence imaging technology for visualization of layered architecture and subsurface microvasculature

      Multimodality endoscopic optical coherence tomography and fluorescence imaging technology for visualization of layered architecture and subsurface microvasculature

      Endoscopic imaging technologies, such as endoscopic optical coherence tomography (OCT) and near-infrared fluorescence, have been used to investigate vascular and morphological changes as hallmarks of early cancer in the gastrointestinal tract. Here we developed a high-speed multimodality endoscopic OCT and fluorescence imaging system. Using this system, the architectural morphology and vasculature of the rectum wall were obtained simultaneously from a Sprague Dawley rat in vivo . This multimodality imaging strategy in a single imaging system permits the use of a single imaging probe, thereby improving prognosis by early detection and reducing costs.

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    3. Quantitative angle-insensitive flow measurement using relative standard deviation OCT

      Quantitative angle-insensitive flow measurement using relative standard deviation OCT

      Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear ...

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    4. Feature Of The Week 11/26/2016: Tsinghua University Demonstrates Optical Computing Technique and Achieves High Speed OCT of 10 Mega-A-Scans/Second.

      Feature Of The Week 11/26/2016: Tsinghua University Demonstrates Optical Computing Technique and Achieves High Speed OCT of 10 Mega-A-Scans/Second.

      In the past few decades, OCT has been applied in a wide range of applications including clinical and material research areas. For some biomedical applications such as surgical guidance, real-time volumetric OCT (4D-OCT) imaging is in high demand. However, for high definition volumetric imaging in real time, i.e., 1000 pixels along 3 spatial dimensions and 30 volumetric imaging per second, the data flow will be 1000×1000×1000×30=30GVoxel/s. To process these massive data is a big challenge to the performance of current GPUs and CPUs. Professor Ping Xue, Postdoc Xiao Zhang and their colleagues from Tsinghua ...

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    5. Optical computing for optical coherence tomography

      Optical computing for optical coherence tomography

      We propose an all-optical Fourier transformation system for real-time massive data processing in high speed optical coherence tomography (OCT). In the so-called optical computing OCT, fast Fourier transformation (FFT) of A-scan signal is optically processed in real time before being detected by photoelectric detector. Therefore, the processing time for interpolation and FFT in traditional Fourier domain OCT can be dramatically eliminated. A processing rate of 10 mega-A-scans/second was experimentally achieved, which is, to our knowledge, the highest speed for OCT imaging. Due to its fiber based all-optical configuration, this optical computing OCT system is ideal for ultrahigh speed volumetric ...

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    6. Ultrahigh-speed optical coherence tomography utilizing all-optical 40 MHz swept-source

      Ultrahigh-speed optical coherence tomography utilizing all-optical 40 MHz swept-source

      We present an ultrahigh-speed optical coherence tomography (OCT) based on an all-optical swept-source with an A-scan rate of 40 MHz. The inertia-free swept-source, which has its output power of 41.2 mW and tuning range of 40 nm and high scan linearity in wavenumber with Pearson’s correlation coefficients r of 0.9996, consists of a supercontinuum laser, an optical band-pass filter, a linearly chirped fiber Bragg grating, an erbium-doped fiber amplifier, and two buffer stages. With sensitivity of 87 dB, high-speed OCT imaging of biological tissue in vivo is also demonstrated.

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    7. Feature Of The Week 2/2/14: Tsinghua University.Demonstrates Linear-in-Wavenumber Swept Laser with an Acousto-Optic Deflector for OCT

      Feature Of The Week 2/2/14: Tsinghua University.Demonstrates Linear-in-Wavenumber Swept Laser with an Acousto-Optic Deflector for OCT

      Compared to the conventional time domain OCT, the frequency domain (FD) detection techniques enable a dramatic increase in imaging speed. Spectrometer-based FD-OCT (SD-OCT) systems are already widely used, especially for ophthalmic application in the 800 nm wavelength range. Alternatively, the application of FD-OCT systems based on a rapidly swept, narrowband light source, i.e. swept source OCT (SS-OCT) offers the additional advantages of dual balance detection, potentially longer ranging depth and higher imaging speeds. However, a general disadvantage of most FD-OCT systems is the requirement to resample and recalibrate the detected OCT interference fringe prior to fast Fourier transformation, in ...

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    8. Linear-in-wavenumber swept laser with an acousto-optic deflector for optical coherence tomography

      Linear-in-wavenumber swept laser with an acousto-optic deflector for optical coherence tomography

      We report a novel linear-in-wavenumber ( k -linear) swept laser source based on an acousto-optic deflector (AOD). The AOD-based optical filter includes an acousto-optic deflector and a reflection grating. The laser may tune k linearly in wavenumber over time due to its appropriate configuration and is favorable for fast imaging because it avoids data resampling and recalibration, as are required in conventional swept source optical coherence tomography (SS-OCT). We achieved k -linearity with Pearson’s r correlation coefficients of 0.99995 without and 0.99997 with optimization. The laser has a tuning range of 50 nm, a 3 dB swept range ...

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    9. Feature Of The Week 10/13/13: Tsinghua University Demonstrates a Tiny OCT Endoscopic Probe Using a Hollow Ultrasonic Motor

      Feature Of The Week 10/13/13: Tsinghua University Demonstrates a Tiny OCT Endoscopic Probe Using a Hollow Ultrasonic Motor

      Optical coherence tomography (OCT) is an emerging modality for obtaining cross-sectional images. Due to limitation of the light penetration, small and high resolution probes for endoscopic OCT have been regarded as powerful tools in examining internal organs. Among them, circumferential probes are utilized extensively for imaging within hollow tissues, such as arteries, esophagus, and colon. In recent years, distal scanning is of high interest, as the whole fiber remains stationary in this case. The twisting and nonuniformity in the conventional proximal scanning are avoided. However, some problems emerge such as the wire-shadow effect and the relative large size of the ...

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    10. Tiny endoscopic optical coherence tomography probe driven by a miniaturized hollow ultrasonic motor

      Tiny endoscopic optical coherence tomography probe driven by a miniaturized hollow ultrasonic motor

      We present an endoscopic probe for optical coherence tomography (OCT) equipped with a miniaturized hollow ultrasonic motor that rotates the objective lens and provides an internal channel for the fiber to pass through, enabling 360 deg unobstructed circumferential scanning. This probe has an outer diameter of 1.5 mm, which is ultra-small for motorized probes with an unobstructed view in distal scanning endoscopic OCT. Instead of a mirror or prism, a customized aspheric right-angle lens is utilized, leading to an enlargement of the numerical aperture and thus high transverse resolution. Spectral-domain OCT imaging of bio-tissue and a phantom are demonstrated ...

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    11. Noninvasive three-dimensional live imaging methodology for the spindles at meiosis and mitosis

      Noninvasive three-dimensional live imaging methodology for the spindles at meiosis and mitosis

      The spindle plays a crucial role in normal chromosome alignment and segregation during meiosis and mitosis. Studying spindles in living cells noninvasively is of great value in assisted reproduction technology (ART). Here, we present a novel spindle imaging methodology, full-field optical coherence tomography (FF-OCT). Without any dye labeling and fixation, we demonstrate the first successful application of FF-OCT to noninvasive three-dimensional (3-D) live imaging of the meiotic spindles within the mouse living oocytes at metaphase II as well as the mitotic spindles in the living zygotes at metaphase and telophase. By post-processing of the 3-D dataset obtained with FF-OCT, the ...

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    12. Understanding three-dimensional spatial relationship between the mouse second polar body and first cleavage plane with full-field optical coherence tomography

      Understanding three-dimensional spatial relationship between the mouse second polar body and first cleavage plane with full-field optical coherence tomography

      he morphogenetic relationship between early patterning and polarity formation is of fundamental interest and remains a controversial issue in preimplantation embryonic development. We use a label-free three-dimensional (3-D) imaging technique of full-field optical coherence tomography (FF-OCT) successfully for the first time to study the dynamics of developmental processes in mouse preimplantation lives. Label-free 3-D subcellular time-lapse images are demonstrated to investigate 3-D spatial relationship between the second polar body (2PB) and the first cleavage plane. By using FF-OCT together with quantitative study, we show that only 25% of the predicted first cleavage planes, defined by the apposing plane of two ...

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    13. Feature Of The Week 7/22/12: Label-Free Subcellular 3D Live Imaging of Preimplantation Mouse Embryos With Full-Field Optical Coherence Tomography

      Feature Of The Week 7/22/12: Label-Free Subcellular 3D Live Imaging of Preimplantation Mouse Embryos With Full-Field Optical Coherence Tomography

      arly patterning and polarity is of fundamental interest in preimplantation embryonic development. Label-free subcellular 3D live imaging is very helpful to its related studies. We have developed a novel system of full-field optical coherence tomography (FF-OCT) for noninvasive 3D subcellular live imaging of preimplantation mouse embryos with no need of dye labeling. 3D digitized embryos can be obtained by image processing. Label-free 3D live imaging is demonstrated for the mouse embryos at various typical preimplantation stages with a spatial resolution of 0.7 µm and imaging rate of 24 fps. Factors that relate to early patterning and polarity, such as ...

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    14. Compressed sensing with linear-in-wavenumber sampling in spectral-domain optical coherence tomography

      Compressed sensing with linear-in-wavenumber sampling in spectral-domain optical coherence tomography

      We propose a novel method called compressed sensing with linear-in-wavenumber sampling (k -linear CS) to retrieve an image for spectral-domain optical coherence tomography (SD-OCT). An array of points that is evenly spaced in wavenumber domain is sampled from an original interferogram by a preset k -linear mask. Then the compressed sensing based on l1 norm minimization is applied on these points to reconstruct an A-scan data. To get an OCT image, this method uses less than 20% of the total data as required in the typical process and gets rid of the spectral calibration with numerical interpolation in traditional CS-OCT ...

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    15. Label-free subcellular 3D live imaging of preimplantation mouse embryos with full-field optical coherence tomography

      Label-free subcellular 3D live imaging of preimplantation mouse embryos with full-field optical coherence tomography

      Early patterning and polarity is of fundamental interest in preimplantation embryonic development. Label-free subcellular 3D live imaging is very helpful to its related studies. We have developed a novel system of full-field optical coherence tomography (FF-OCT) for noninvasive 3D subcellular live imaging of preimplantation mouse embryos with no need of dye labeling. 3D digitized embryos can be obtained by image processing. Label-free 3D live imaging is demonstrated for the mouse embryos at various typical preimplantation stages with a spatial resolution of 0.7 µm and imaging rate of 24 fps. Factors that relate to early patterning and polarity, such as ...

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    16. Spectral-domain optical coherence tomography with a Fresnel spectrometer

      Spectral-domain optical coherence tomography with a Fresnel spectrometer

      We propose a novel spectral-domain optical coherence tomography (SD-OCT) equipped with a Fresnel spectrometer, which utilizes a Fresnel zone plate (FZP) as both dispersion and focusing optics and thus spreads the spectral interferogram evenly in wavenumber domain because of the proportional relation between the focal length of the FZP and the wavenumber. With no need of the conversion calculation from wavelength to wavenumber in conventional SD-OCT, this new design is favorable for fast imaging with high resolution. As only a FZP and CCD are used, the Fresnel spectrometer is simple and compact. It is experimentally shown that its performance is ...

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    1-16 of 16
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  2. Topics in the News

    1. (13 articles) Tsinghua University
    2. (13 articles) Tianyuan Chen
    3. (13 articles) Ping Xue
    4. (12 articles) Chengming Wang
    5. (10 articles) Jing-gao Zheng
    6. (10 articles) Ning Zhang
    7. (3 articles) UC Irvine
    8. (3 articles) Zhongping Chen
    9. (2 articles) Peking University
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    Spectral-domain optical coherence tomography with a Fresnel spectrometer Label-free subcellular 3D live imaging of preimplantation mouse embryos with full-field optical coherence tomography Compressed sensing with linear-in-wavenumber sampling in spectral-domain optical coherence tomography Feature Of The Week 7/22/12: Label-Free Subcellular 3D Live Imaging of Preimplantation Mouse Embryos With Full-Field Optical Coherence Tomography Understanding three-dimensional spatial relationship between the mouse second polar body and first cleavage plane with full-field optical coherence tomography Tiny endoscopic optical coherence tomography probe driven by a miniaturized hollow ultrasonic motor Feature Of The Week 10/13/13: Tsinghua University Demonstrates a Tiny OCT Endoscopic Probe Using a Hollow Ultrasonic Motor Linear-in-wavenumber swept laser with an acousto-optic deflector for optical coherence tomography Feature Of The Week 2/2/14: Tsinghua University.Demonstrates Linear-in-Wavenumber Swept Laser with an Acousto-Optic Deflector for OCT Feature Of The Week 11/26/2016: Tsinghua University Demonstrates Optical Computing Technique and Achieves High Speed OCT of 10 Mega-A-Scans/Second. Direct inverse linearization of piezoelectric actuator’s initial loading curve and its applications in full-field optical coherence tomography (FF-OCT) Peripapillary Retinal and Choroidal Perfusion in Nonarteritic Ischemic Optic Neuropathy Using Optical Coherence Tomography Angiography