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227results about How to "Large dynamic range" patented technology

Narrow gap welding monitoring and welding line deviation detecting method based on infrared vision sensing

The invention discloses a narrow gap welding monitoring and welding line deviation detecting method based on infrared vision sensing and belongs to the technical field of welding. An infrared vision sensing system comprises an infrared complementary metal oxide semiconductor (CMOS) camera, a filtering system, an image collecting card, a computer, a display and the like. Narrow gap welding arc light and molten pool radiation light are used as a light source, an infrared narrow belt filtering system is used for filtering interference signals and adjusting light intensity, and the computer collects and displays a welding image obtained through the infrared CMOS camera. An image capturing window is used for capturing an image away from an arc side, the image is processed, welding line deviation information is obtained by extracting a groove single-side edge, and a real-time property of welding line deviation detecting is improved while arc noise is effectively avoided. The system is simple in formation, clear in monitored image, high in welding line deviation detecting precision, strong in anti-interference capacity and good in engineering practicality and can achieve the purposes of real-time monitoring of narrow gap welding and synchronous detecting of welding line deviation.
Owner:JIANGSU UNIV OF SCI & TECH

Vehicle ranging and collision early warning method based on monocular vision

The invention discloses a vehicle ranging and collision early warning method based on monocular vision. Firstly, a target dynamic video is collected through a monocular camera, each frame of the collected video is subjected to image preprocessing, then, the characteristics of an image is compared with positive sample characteristics obtained by training to detect a target, and the target is marked by a rectangular frame. The midpoint coordinate of the bottom edge of the rectangular frame is obtained, and a practical distance between two vehicles can be obtained according to pinhole imaging and the geometric proportion relationship of similar triangles; and according to the distance change of two vehicles within a given time, the relative speed is calculated, the collision time is calculated by combining with the distance, and a voice alarm is given when the time is smaller than the collision safety time so as to prompt a drive to adopt a corresponding measure. The vehicle ranging and collision early warning method only adopts one camera to collect videos, so that equipment is simple, an adopted target detection method has the advantages of being high in accuracy and instantaneity, a ranging method is simple and effective, timely early warning is realized, and traffic accidents are effectively avoided.
Owner:NORTHEASTERN UNIV

Long-distance distributed optical fiber vibration sensing system and method thereof

The invention discloses a long-distance distributed optical fiber vibration sensing system and a method thereof. The system comprises an induction system for inducting outside vibration events and a detecting and controlling system for detecting and controlling vibration signals; the induction system is connected with the detecting and controlling system. The induction system comprises a light source, a pulse modulator, an optical fiber circulator, a first optical fiber amplifier, and a light switch of a first optical fiber filter. The detecting and controlling system comprises a plurality of optical-electrical converters and a system control unit; the system control unit collects output light of the converters, analyzing the collected signals and judges whether the alarm is needed according to the analysis result. The invention adopts the optical switch technology to adopt time-division processing on backward Rayleigh scattering light which is reflected back, the dynamic range of the system is large, and the sensible distance can be tens of kilometers as high as possible, even hundreds of kilometers; and the invention adopts phase detecting technology and optical time domain reflection technology and can greatly improve detecting sensibility of the system and positioning precision.
Owner:SHANGHAI BOOM FIBER SENSING TECH +1

Complex spectral domain optical coherence tomography method and system

The invention provides a tomographic method and a system for coherent optics in complex spectrum frequency domain, comprising a broadband light source, a light source coupling mechanism, a combined interferometer, a fiber-optics imaging probe, a spectrograph, a temperature controller and a computer; the method comprises the following steps of: firstly, measuring three groups of interference spectrum in state of three different phases of reference light; secondly, calculating two groups of differential interference spectrums; thirdly, taking the sum and the remainder of the two groups of differential interference spectrums as a real part and an imaginary part for a complex amplitude so as to reconstruct the interference spectrum of the complex amplitude in a wave number space; finally, making an inverse Fourier transform for the interference spectrum of the complex amplitude and obtaining depth-scanning information of a measured sample along an optical axis, that is chromatogram. Under the condition that a regulating device for the phase of the reference light is not used, the tomographic method and the system eliminate the effect for chromatogram quality caused by a parasitic image and a hetero conjugation image, and can realize the tomography which reflects the real structure of the measured sample with the advantages of simple system structure, wide dynamic scope and deep measurement in full scale.
Owner:SHENZHEN POLYTECHNIC

CMOS asynchronous time domain image sensor capable of achieving real-time time stamp

The invention relates to the integrated circuit design filed and the digital image processing field of microelectronics. A CMOS asynchronous time domain image sensor capable of achieving real-time time stamp aims to solve the event-time mismatching problem caused by an AER asynchronous output mode, achieve accurate stamp output of image time among rows, and improve the accuracy of obtained images in a time domain. In order to achieve the purposes, according to the technical scheme, the CMOS asynchronous time domain image sensor capable of achieving the real-time time stamp comprises a light intensity change detector circuit CD and a double-sampling pulse width modulation circuit PWM and further comprises a row/column reset control circuit, a row arbiter circuit, a row level time stamp circuit and a row/column address coding circuit, wherein the column address coding circuit receives row selected signals transmitted by a row weighted arbiter structure and outputs a selected row address, and the row address coding circuit is triggered by the output signals of the CD circuit outputting pixels. The CMOS asynchronous time domain image sensor capable of achieving the real-time time stamp is mainly applied to the design and the manufacturing of image sensors.
Owner:TIANJIN UNIV

CMOS image sensor reading circuit and reading method

The invention relates to a CMOS image sensor reading circuit, which comprises an analog-to-digital converter, and also comprises a variable gain amplifier, a comparator and a gain adjusting device, wherein the variable gain amplifier is suitable for receiving and adjusting pixel exposing voltage of the image sensor, and outputting the voltage to the analog-to-digital converter; the comparator is suitable for judging the pixel exposing voltage; and the gain adjusting device is suitable for receiving a judgment result output by the comparator, and adjusting an amplification factor of the variable gain amplifier according to an exposing voltage section where the exposing voltage is positioned. The invention also relates to a method for reading digital signals from pixels by the CMOS image sensor, which comprises the following steps: adjusting the pixel exposing voltage by the variable gain amplifier; converting analog voltage signals output by the variable gain amplifier into digital signals for output; judging the pixel exposing voltage; and adjusting the amplification factor of the variable gain amplifier according to the exposing voltage section where the exposing voltage is positioned. Under the conditions of different light intensities, both the reading circuit and the method can obtain clear images to meet the requirement of human eye on image quality.
Owner:BRIGATES MICROELECTRONICS KUNSHAN

Low-power mixed-mode echo/crosstalk cancellation in wireline communications

A signal processing system is disclosed. The signal processing system comprises an AGC and pre-echo cancellation system for receiving an analog signal, boosting it up (over all frequencies) to a pre-determined range by AGC, and removing the immediate transmit pulse from this received signal by pre-echo canceller to provide a second analog signal. The signal processing system further comprises a summer for receiving the analog signal; a feed forward equalization (FFE) unit for receiving a signal from the summer; and a slicer for receiving a signal from the FFE unit and providing an output signal. The signal processing system also comprises an Echo and NEXT cancellation system for receiving the output signal and for providing a signal to the summer for canceling the echo and crosstalk in the signal processing system. Accordingly, in a system and method in accordance with the present invention the Echo and crosstalk components associated with a signal processing system can be subtracted prior to the FFE. This allows for a practical analog implementation which has a good dynamic range of the signal through the FFE and subsequent analog elements. This system can be utilized to great advantage in low power CMOS designs where supply voltages are limited.
Owner:MARVELL ASIA PTE LTD

Double-closed loop locking technology-based resonant optical gyro

The invention discloses a double-closed loop locking technology-based resonant optical gyro. The double-closed loop locking technology-based resonant optical gyro comprises an optical system composed of a tunable laser, an optical shunt, two frequency shifters of a first frequency shifter and a second frequency shifter, two modulators, an optical resonant cavity and a photoelectric conversion module, and a processing circuit composed of a modulation-demodulation module and three feedback locking modules. Main components of the optical system comprise the tunable laser as a double-closed loop feedback terminal and the two frequency shifters. A first signal extracted by the modulation-demodulation module can respectively change frequency shift amounts of the tunable laser and the first frequency shifter through two of the threes feedback locking modules. A second signal extracted by the modulation-demodulation module can change a frequency shift amount of the second frequency shifter through another feedback locking module. A rotation signal is obtained according to the difference between frequency shift amounts of the first frequency shifter and the second frequency shifter. The double-closed loop locking technology-based resonant optical gyro has a completely reciprocal resonant optical gyro structure, and is beneficial for elimination of reciprocal noise of a system, improvement of system linearity, broadening of a system dynamic scope, and reduction of optical Kerr noise.
Owner:ZHEJIANG UNIV

Rock quartz accelerometer servo-circuit

The invention discloses a servo circuit of quartz accelerometer, comprising an integrated part and a divided part wherein the integrated part comprises a triangle generator, a differential capacitance detector, an integrating amplifier and a transconductance amplifier; and the divided part comprises a negative feedback circuit, an outer timing capacitor, an outer timing resistance and outer offset resistance. The triangle generator outputs the triangular wave to the differential capacitance detector by an emitter follower. The differential capacitance detector charges and discharges the differential capacitor of the swinging subassembly of the accelerometer the detected differential capacitance signal is converted into the corresponding error current signal and the error current signal is output to the integrating amplifier. After the slowly varying pressure signal is obtained after integrate demodulation by the integrating amplifier, the transconductance amplifier is pushed. The slowly varying pressure signal is added on the electromagnetic torquer of the quartz accelerometer through the transconductance output terminal to form the restoring torque, so as to recover the swing slice at the balance position. The negative feedback circuit is mounted between the inverted input terminal of the integrating amplifier and the output feedback terminal of the transconductance amplifier to form a complete closed loop test system with deep negative feedback.
Owner:CHINA AEROSPACE TIMES ELECTRONICS CORP NO 771 RES INST

Interferometry-based optical fiber Verdet constant measuring system

The invention discloses an interferometry-based optical fiber Verdet constant measuring system. The system comprises an ASE (amplified spontaneous emission) light source, a single-mode optical fiber coupler, a Y-waveguide integrated optical modulator, 1/4 wave plates, Faraday rotator mirrors, a solenoid, a sine alternating-current driving circuit, matching fluid, a probe, an information processing module, a computer and measured optical fibers. The ASE light source, the single-mode optical fiber coupler, the Y-waveguide integrated optical modulator, the measured optical fibers and the Faraday rotator mirrors are connected through optical fibers in sequence. Each 1/4 wave plate is arranged between the Y-waveguide integrated optical modulator and the corresponding measured optical fiber. A signal processing portion comprises a feedback servo circuit, an FPGA (field programmable gate array) module and a phase modulation driving circuit. The system is of an all-optical-fiber structure and simple and convenient to set up; by the aid of the Faraday rotator mirrors, influences of linear birefringence of the optical fibers on measurement can be eliminated, and measurement accuracy is improved; and Verdet constants of various optical fibers can be measured by the system.
Owner:BEIHANG UNIV

Distributed optical fiber sound sensing device and method based on dual-polarization double-sideband modulation

The invention discloses a distributed optical fiber sound sensing device and method based on dual-polarization double-sideband modulation. The distributed optical fiber sound sensing device comprisesa narrow linewidth laser source (1), a polarization-maintaining optical fiber isolator (2), a dual-polarization four-parallel Mach-zehnder electro-optic modulator (3), an arbitrary waveform generator(4) for drive in an X polarization direction, an arbitrary waveform generator (5) for drive in a Y polarization direction, an electro-optic modulator bias control panel (6), a 1*2 polarization-maintaining optical fiber coupler (7), an optical fiber polarization beam splitter (8), a first erbium-doped optical fiber amplifier (9), a first optical fiber (10), an optical fiber circulator (11), a second erbium-doped optical fiber amplifier (13), a second optical fiber (14), a four-way output-type 90-degree light mixer (15), a balance photoelectric detector (16), a data acquisition card (17) and a processing unit (18). The distributed optical fiber sound sensing device integrates the advantages of time-domain reflection and frequency-domain reflection, is free from electromagnetic interference,is electrically passive and can achieve distributed sound sensing with a large dynamic range and high spatial resolution.
Owner:TIANJIN UNIV
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