Abstract: This invention relates to a distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry (OFDR) and the related demodulation thereof. The device, adopting OFDR, polarization controlling and analysis techniques, consists of a ultra-narrow linewidth tunable laser source module, polarization generating and polarization splitting balanced detecting module, laser source optical frequency and phase monitoring module, high-speed optical switch and so on to establish a large-scale and long-distance optical sensing network. The demodulation method consists of analysis the polarization information from sensing optical fiber, the method of suppressing and compensating of the non-linear optical frequency and the laser phase noise, super-resolution analyzing, advanced denoising method and the polarization information analysis method based on Jones and Mueller's matrices using distributed wave plate model of optical fiber.

Abstract: The present invention relates to a high stable fiber fabry-perot pressure sensor with glue-free packing and its fabrication method. The sensor includes a sensor head, a sensor body with a through-hole in the axial direction and a optical fiber. The sensor head is a 4-layer structure, which includes the first silicon wafer, the first Pyrex glass wafer, the second silicon wafer and the second Pyrex glass wafer. The rear surface of the first silicon wafer forms the first reflecting surface of the fabry-perot (F-P) cavity, and the second silicon wafer provides the second reflecting surface for the F-P cavity. The second Pyrex glass wafer is welded together with the sensor body. The optical fiber is fixed in the sensor body by a CO2 laser welding to achieve the glue-free packing. When the external pressure is applied to deform the first layer silicon wafer, the F-P cavity length will change.

Abstract: Swing-style demodulation device for measuring displacement information, including (1) a broadband light source, (2) an optical circulator, (3) GRIN lens, (4) a fixed mirror on an object under test, (5) a collimating device, (6) a rotating mirror, (7) f-? lens, (8) a polarizer, (9) a narrow strip shaped birefringent wedge, (10) a polarization analyzer, and (11) a signal acquisition system.

Abstract: Disclosed is a multi-band multiplexing intra-cavity gas sensing system and method. The system consists of a laser resonant cavity subsystem, a gas sensing subsystem and a detection-demodulation subsystem. The laser resonant cavity subsystem consists of the first beam splitter, two ways of gain paths composed of a pump light source, a wavelength division multiplexer, a rare earth doped fiber, an optical isolator and a tunable optical attenuator, a beam combiner and an F-P tunable optical filter. The gas sensing subsystem consists of a gas cell and an optical reflective mirror. The detection-demodulation subsystem consists of an optical coupler, the second beam splitter, two optical detectors, a data acquisition module and a computer. In this invention, different rare-earth doped fibers are multiplexing into one system, in order to cover more maser bands of different rare earth, which greatly expands the scanning range of wavelength, and is capable of detecting various gases simultaneously.

Abstract: The disclosed method calculates video time density functions based on inter-frame mutual information or other similarity measures. The method includes acquiring a video sequence from memory, computing mutual information or other similarity measures between two consecutive frames of the video sequence, and constructing a video temporal density function based on the mutual information or similarity measures. The method enables fast navigation of the video sequence by performing a temporal quantization of the video time density function to determine a set of quanta. The video sequence can be navigated using the nearest neighbor video frames to the set of quanta. The method enables thumbnail extraction of a video sequence using statistical modeling by performing a temporal quantization of the video time density function to segment video sequence in time domain and using mixture (such as Gaussian mixture and ICA mixture) vector quantization to find the sample frames for each temporal segment.

Abstract: The present invention discloses a real-time kernel of open CNC systems and a real-time control method of tool-paths. The real-time kernel translates a real-time control of the tool-paths into sending synchronous pulses into the servo drivers in accordance with the control rhythms ?ti (i=1, . . . , n) in the follow-table and achieves the openness of real-time control method and real-time control process. The real-time kernel has the most simple and reliable multi-axis synchronization capability with high-speed and high-precision, and leads to major changes in the field of digital control method. The real-time kernel no need to configure a real-time operating system and a fieldbus, its core function is only to write the control rhythm into the T-division timer, and to send linkage commands into the servo drivers designated by the state-word, therefore its function and architecture are extremely simple and high reliability.

Abstract: The present invention relates to a high stable fiber fabry-perot pressure sensor with glue-free packing and its fabrication method. The sensor includes a sensor head, a sensor body with a through-hole in the axial direction and a optical fiber. The sensor head is a 4-layer structure, which includes the first silicon wafer, the first Pyrex glass wafer, the second silicon wafer and the second Pyrex glass wafer. The rear surface of the first silicon wafer forms the first reflecting surface of the fabry-perot (F-P) cavity, and the second silicon wafer provides the second reflecting surface for the F-P cavity. The second Pyrex glass wafer is welded together with the sensor body. The optical fiber is fixed in the sensor body by a CO2 laser welding to achieve the glue-free packing When the external pressure is applied to deform the first layer silicon wafer, the F-P cavity length will change.

Abstract: This invention relates to a distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry (OFDR) and the related demodulation thereof. The device, adopting OFDR, polarization controlling and analysis techniques, consists of a ultra-narrow linewidth tunable laser source module, polarization generating and polarization splitting balanced detecting module, laser source optical frequency and phase monitoring module, high-speed optical switch and so on to establish a large-scale and long-distance optical sensing network. The demodulation method consists of analysis the polarization information from sensing optical fiber, the method of suppressing and compensating of the non-linear optical frequency and the laser phase noise, super-resolution analyzing, advanced denoising method and the polarization information analysis method based on Jones and Mueller's matrices using distributed wave plate model of optical fiber.

Abstract: This invention provides a swing-style and high signal-to-noise ratio low coherence interference demodulation devices and the corresponding demodulation method for the measurement of displacement. In the displacement sensing method, the optical path difference, which is built by the light reflections from the reference surface and the test object, varies with the displacement of the test object. When the reflected signal lights is sent to a low coherence polarization interference system, the birefringent wedge formulates a spatial distribution of optical path difference, from which the optical path difference of the reflection signals thus can be demodulated. In the displacement scanning method, the reflected signal lights are collimated and transferred to a time scanner consisting of a rotating mirror and a f-? lens, to perform thin light beam scanning along the longitudinal direction of a birefringent wedge.

Abstract: The disclosed method calculates video time density functions based on inter-frame mutual information or other similarity measures. The method includes acquiring a video sequence from memory, computing mutual information or other similarity measures between two consecutive frames of the video sequence, and constructing a video temporal density function based on the mutual information or similarity measures. The method enables fast navigation of the video sequence by performing a temporal quantization of the video time density function to determine a set of quanta. The video sequence can be navigated using the nearest neighbor video frames to the set of quanta. The method enables thumbnail extraction of a video sequence using statistical modeling by performing a temporal quantization of the video time density function to segment video sequence in time domain and using mixture (such as Gaussian mixture and ICA mixture) vector quantization to find the sample frames for each temporal segment.

Abstract: The disclosed method calculates video time density functions based on inter-frame mutual information or other similarity measures. The method includes acquiring a video sequence from memory, computing mutual information or other similarity measures between two consecutive frames of the video sequence, and constructing a video temporal density function based on the mutual information or similarity measures. The method enables fast navigation of the video sequence by performing a temporal quantization of the video time density function to determine a set of quanta. The video sequence can be navigated using the nearest neighbor video frames to the set of quanta. The method enables thumbnail extraction of a video sequence using statistical modeling by performing a temporal quantization of the video time density function to segment video sequence in time domain and using mixture (such as Gaussian mixture and ICA mixture) vector quantization to find the sample frames for each temporal segment.

Abstract: A method is provided for measuring polarization dependent loss in an optical transmission system. In the method, a first optical signal is generated, and a polarization of the first optical signal is altered over time. The first optical signal is combined with a second optical signal from the optical transmission system to yield a combined optical signal, which is coherently detected to yield a radio frequency signal. A power of the radio frequency signal is measured. The measured power of the radio frequency signal is processed to generate an indication of the polarization dependent loss of the optical transmission system.

Abstract: A method and apparatus for estimating available throughput of a fixed node in a mobile node of a communication network. The communication network includes fixed nodes connected to a router connected to at least one foreign network and mobile nodes connected to the fixed nodes. A second mobile node is selected from among mobile nodes connected to a fixed node whose available throughput is estimated in a first mobile node. An idle slot interval of the second mobile node connected to the fixed node is set. A transmission probability is measured in one slot interval of the second mobile node through an average of set idle slot intervals. Transmission information of the second mobile node is acquired using the measured transmission probability. The available throughput of the fixed node is estimated using the acquired transmission information.

Abstract: A method and apparatus for estimating available throughput of a fixed node in a mobile node of a communication network. The communication network includes fixed nodes connected to a router connected to at least one foreign network and mobile nodes connected to the fixed nodes. A second mobile node is selected from among mobile nodes connected to a fixed node whose available throughput is estimated in a first mobile node. An idle slot interval of the second mobile node connected to the fixed node is set. A transmission probability is measured in one slot interval of the second mobile node through an average of set idle slot intervals. Transmission information of the second mobile node is acquired using the measured transmission probability. The available throughput of the fixed node is estimated using the acquired transmission information.