448results about How to "Improve detection distance" patented technology

It is an object of the invention to provide a connection structure for connecting the dielectric strip of an NRD guide with a metal waveguide, in which the conversion loss (connection loss) for high-frequency signals is reduced, and in which the NRD guide as well as the millimeter wave integrated circuit in which the NRD guide is incorporated can be made smaller. A non-radiative dielectric waveguide is made by arranging a dielectric strip for propagating high-frequency signals between parallel planar conductors arranged at a spacing of not more than half the wavelength of a high-frequency signal, a conductive member being arranged at an end face of a terminal end of the dielectric strip. An aperture is formed in at least one of the parallel planar conductors at a location where the electrical field of an LSM mode stationary wave propagating along the dielectric strip becomes largest. An open terminal end of a metal waveguide is connected to this aperture.

A multi-line laser radar comprises a first radar assembly, and the first radar assembly comprises n laser devices, an optical alignment unit, a scanning rotating mirror and a detector, wherein n is larger than 1. Each laser device is used for emitting one way of laser beam to the optical alignment unit; the optical alignment unit is used for aligning the n ways of laser beams, and the aligned n ways of laser beams are shot towards target reflection mirrors of the scanning rotating mirror; the scanning rotating mirror comprises the m reflection mirrors rotating around a rotary shaft, and the rotating plane of the rotary shaft is perpendicular to the arrangement direction of the aligned n ways of laser beams, wherein m is larger than 1; the target reflection mirrors are used for reflecting the received aligned n ways of laser beams to a detection area of the first radar assembly; and the detector is used for receiving reflected echo signals of the n ways of laser beams in the detection area. The multi-line laser radar is of a multi-emit and one-receive structure, signal crosstalk among different detectors is avoided, the working performance is improved, and the cost is lowered.

A sensor apparatus includes a sensor unit, a calculation unit, a switch circuit unit, and a control unit. The sensor unit has a plurality of detection electrodes each having a capacitance changed by proximity of a detection target object. The calculation unit calculates a first distance, which is a distance between the detection target object and the sensor unit. The switch circuit unit is capable of switching the detection electrodes between a first state in which a signal voltage for detecting the capacitance is supplied and a second state which is an electrically floating state, and selects at least two detection electrodes one by one switched from the second state to the first state. The control unit controls the switch circuit unit to cause a second distance, which is a distance between the detection electrodes switched from the second state to the first state, to correspond to the first distance.

The invention discloses a rail damage detection device and method based on magnetostriction and longitudinal ultrasonic guided wave, which are applied in the field of railway traffic nondestructive detection. The rail damage detection device comprises a shell, wherein an inner wire support, an inner coil, an outer wire support, an outer coil, a yoke and a permanent magnet are arranged in the shell; a current input port, an inner coil current input electric wire and an inner coil current output electric wire are arranged at one end of the shell; an outer coil current output electric wire, an outer coil current loop electric wire and a voltage output port are arranged at the other end of the shell; and the upper part of the shell is fixedly connected with a rail detection vehicle. The rail damage detection method comprises the following steps of: exciting induced electromotive force by utilizing magnetostriction and longitudinal ultrasonic guided wave, and indirectly measuring time and strength generated by a defect reflective waveguide signal according to the induced electromotive force, and further determining the destruction position and the destruction size. The rail damage detection device and method can be used for carrying out accurate detection on trace destruction inside and outside the rail, and have the advantages of long detection distance and high detection efficiency.

The invention discloses a vehicular visible light wireless digital voice communication system. The vehicular visible light wireless digital voice communication system comprises a sending module and a receiving module. The sending module comprises a digital audio acquisition unit, an RS coding unit, a PWM (pulse width modulation) unit, an LED (light emitting diode) drive unit and an LED transmitting unit, which are connected successively in circuit; the receiving module comprises a PIN photoelectric detection unit, a signal extraction unit, a PWM modulation unit, an RS decoding unit and a digital audio output unit, which are connected successively in circuit. The wireless digital voice communication system realizes instant voice communication between strange vehicles; an LED-based lamp is integrated with automobile lighting and communication without the need of an additional signal emission source installation space and occupation of scarce frequency spectrum resource. The voice signal transmission is high-speed and reliable, high in integration level, strong in anti-interference ability and low in cost, and bigger communication distance and more reliable communication are realized; moreover, a detector has high accuracy, high responsivity, low dark current, higher communication rate, stronger anti-interference ability and high reliability of a transmission channel.

The invention provides a fire detection system and a method thereof. The system comprises a monitoring module which is used for obtaining fire monitoring information of a preset protection area and also comprises a variable-viewing field vidicon, a pretreating module which is connected with the monitoring module and is used for analyzing and processing the fire monitoring information and obtaining a suspected fire occurring area of the preset protection area, a control module which is connected with the pretreating module and the variable-viewing field vidicon and is used for controlling a close-shot image of the suspected fire occurring area obtained by the variable-viewing field vidicon, a fire judgement module which is connected with the variable-viewing field vidicon and is used for judging whether fire occurs in the preset protection area according to the close-shot image of the suspected fire occurring area and obtaining a judgement result and a first warning module which is connected with the fire judgement module and is used for outputting warning information when the judgement result shows that fire occurs in the preset protection area. The fire detection system can obtain the close-shot image of the fire occurring area automatically.

The invention relates to the technical field of artificial intelligence, and in particular relates to a laser radar coaxial optical system. The laser radar optical system comprises a transmitting optical unit and a receiving optical unit; the transmitting optical unit comprises a laser, a collimating lens and an MEMS galvanometer; the receiving optical unit comprises a receiving lens and an aperture reflector, wherein the collimating lens, the aperture reflector and the MEMS galvanometer are sequentially arranged on the subsequent optical path of the light beam transmitted by the laser; afterbeing collimated through the collimating lens, the light beam transmitted by the laser passes through the small hole of the aperture reflector, and enters the MEMS galvanometer; the MEMS galvanometerdeflects and reflects incidence laser onto a target object; and reflected light of the target object is reflected through the MEMS galvanometer, and enters the receiving optical unit. According to thelaser radar coaxial optical system and the laser radar in the invention, coaxial optical path design is adopted; transmitting and receiving optical paths are combined through the aperture reflector;exit laser is scanned from the combined laser through the MEMS galvanometer; the laser radar optical system is convenient to debug; furthermore, due to beam combination, optical signal loss is low; and the detection distance is greatly increased.

Disclosed are a laser transceiver device and a laser radar. The laser transceiver device includes a light-splitting coupling unit that splits original light into first original light and second original light, an emerging unit that forms emergent light according to the first original light, and an acquiring unit that acquires echoed light to form signal light, and further includes at least one ofa first acting surface that reflects part of the first original light to form first local oscillating light and a second acting surface that reflects parts of the second original light to form secondlocal oscillating light. Since the first local oscillating light is formed by the first original light partly reflected by the first acting surface and the second local oscillating light is formed bythe second original light partly reflected by the second acting surface, the first local oscillating light and the second local oscillating light have relatively low power, thus the power of the emergent light can be improved effectively, so as to effectively extend the detection distance of the laser radar and expand the detection range of the laser radar while keeping the process and cost unchanged.

The invention belongs to the technical field of antenna engineering, and discloses a strong mutual-coupling ultra-wideband wide-angle scanning dual-polarized conformal phased-array antenna. The strong mutual-coupling ultra-wideband wide-angle scanning dual-polarized conformal phased-array antenna comprises a conformal dielectric substrate, conformal dipole units, a circular metal patch, a conformal dielectric layer, a conformal dielectric impedance matching layer, a metal ground matching layer, an unbalance feeding structure, five grounding metallized through holes, a microwave coaxial cable and a metallized frustum-shaped carrier, wherein the conformal dipole units are printed on an upper layer of the conformal dielectric substrate, and placed in a vertical intersection way; the circular metal patch is printed on a lower layer of the conformal dielectric substrate; the conformal dielectric layer is positioned below the conformal dielectric substrate, and subjected to hole digging treatment; the conformal dielectric impedance matching layer is positioned above the conformal dielectric substrate; and the microwave coaxial cable is used for feeding the unbalance feeding structure. The weight of the novel antenna is only 70 percent that of a conventional phased array, so that the requirement on the load carrying of a carrier is lowered greatly. The metal ground matching layer is used, so that an original complex matching circuit is omitted; the machining difficulty is lowered greatly; and the machining cost of the antenna on engineering applications is lowered.

The invention relates to the technical field of radar systems, radio physics, and the like, and in particular relates to a distributed high frequency over-the-horizon radar system. The distributed high frequency over-the-horizon radar system comprises a shore-based high frequency ground wave radar netted subsystem, a fixed / mobile ground wave over-the-horizon radar subsystem in other forms (float type, vehicle-mounted and shipboard ground wave radar), a high frequency sky wave emission subsystem, an environment guarantee subsystem, a control subsystem and a data processing subsystem. The distributed high frequency over-the-horizon radar system can work in a ground wave netted and sky-ground wave hybrid netted mode, by virtue of distributed ground wave radar netted and sky-ground wave integrated netted detection, breaks through the limit that the conventional ground wave radar only can be distributed along coastlines, obtains more comprehensive physical quantity information at the original signal level by organic integration and mutual complementation multiple work modes, can improve accuracy of detection on wind, wave and current to a greater extent, greatly improves detection range of the high frequency radar system, and realizes far-shore ocean dynamics elements detection and near-shore fine detection.

The invention relates to a road construction area safety joint control system and method. The method comprises a safety joint control system is set in advance; a vehicle is continuously monitored by aradar preset in a vehicle monitoring and early warning module, vehicle movement parameters and position parameters are obtained, and prompt information is sent to the vehicle monitoring and early warning module in the safety joint control system, a construction area information prompt module and a vehicle driving state prompt module; the vehicle monitoring and early warning module is used for evaluating a vehicle intrusion risk according to a risk assessment model of a vehicle intrusion construction area, carrying out grading early warning and sending a risk grade wireless signal to an intrusion detection alarm and signal relay unit, a main controller and a remote monitoring unit in the safety joint control system; when the risk is evaluated to be risky, two layers of intrusion detectionequipment including the radar and an intelligent detection track spike are started, and the next step is started; three layers of intrusion detection equipment are started according to the risk gradewireless signal.

The invention discloses a roadway multi-azimuth advance detection method for detecting the water body or other bad geologic bodies at the head and periphery of a roadway when the roadway is excavated. The method comprises the following steps: firstly, cutting off all the commercial power supplies in the roadway and eliminating the metal pieces in the measuring space of the roadway; and then, carrying out the multi-azimuth advance detection on the roadway by adopting a distributed measuring mode by utilizing a transient electromagnetic instrument, wherein the detection azimuth is determined by utilizing a geometric orientation method or a gradient rule orientation method in the detection course. In the method disclosed by the invention, the one-dimensional detection of the conventional advance detection is expanded into the multidimensional detection; the hidden water bursting danger conditions in the excavation sweep range of the roadway can be investigated to the maximum limit, thereby providing geophysical prospecting technical basis for the excavation safety. In the method disclosed by the invention, the detection range and detection distance of the head advance detection of the roadway are expanded; the detection efficiency is greatly enhanced; and the practical significances on the aspects of guaranteeing the excavation safety, coordinating the rapid excavation of high-yield and high-efficiency mines and enhancing the production efficiency are great.

The invention discloses a security monitoring system which comprises at least one laser radar, a control module and at least one camera module. Each laser radar is provided with a preset target detection area; the laser radar is used for obtaining first point cloud data based on a laser radar coordinate system; the control module is connected with the at least one laser radar, and is used for converting the first point cloud data into second point cloud data under a space coordinate system and carrying out obstacle identification according to the second point cloud data, and determining the coordinates of the obstacle in the space coordinate system according to the third point cloud data of the obstacle in the space coordinate system when the obstacle is identified; the control module is further connected with at least one camera module and used for controlling the camera modules to acquire images of the obstacles according to the coordinates of the obstacles in the space coordinate system. According to the security and protection monitoring system provided by the invention, accurate illegal intrusion monitoring on the perimeter of a large-range area is realized.

The invention discloses a substation patrol robot obstacle avoidance method based on laser radar. A robot scans the surrounding environment through laser radar; an adopted environmental map is a two-dimensional matrix, which is a Boolean matrix of an actual substation, and the position in the substation having a device is defined as Boolean true; the current position coordinate of the robot and heading angle thereof as well as laser radar data obtained after mapping are fused; at the moment, whether the two-dimensional matrix is true or not is judged, if the two-dimensional matrix is true, it is indicated that the corresponding position of the substation has the substation device, and if the two-dimensional matrix is not true, it is indicated that the corresponding position of the substation has an obstacle, and with the coordinate of the robot as an index, corresponding elements are set as true in a new two-dimensional matrix; and a current surrounding navigation data layer of the robot serves as auxiliary information for obstacle avoidance, if a robot planned travel route passes through a corresponding matrix, where the navigation data layer is true, the robot replans a path and utilizes a shortest path algorithm to avoid the obstacle, thereby reducing possibility of the substation patrol robot in colliding with the obstacles.

The invention relates to the field of radar signal processing, in particular to a radio-frequency interference suppression method of a high-frequency ground wave radar. According to the method, on the basis of original high-frequency ground wave radar signal processing, an empirical mode decomposition method is used for decomposing received signals to obtain a plurality of intrinsic mode functions, radio-frequency interference positions are detected through standard deviation and sliding window processing, power spectrum judgment and instantaneous frequency judgment are conducted on sampling points of the radio-frequency interference positions of the intrinsic mode functions, and the amplitude of the sampling points meeting requirements is set to be zero. According to the radio-frequency interference suppression method of the high-frequency ground wave radar, in actual data processing, the application effect is good, signals are not damaged while noise is reduced, the suppression effect is obvious, the radar detection range is expanded, and the radar detection accuracy is increased.

The invention discloses a coherent laser radar based on pulse coding technology. The invention aims at low signal-to-noise ratio (SNR) of echo signals of coherent laser radars, and proposes a method for improving the signal-to-noise ratio of the system and increasing the dynamic range of the system by using the pulse coding technology. The invention outputs the pulse coding sequence codes by an electro-optic modulator, reduces the time-domain cross-correlation between the respective transmit waveforms, reduces auto-correlated side lobes by using the complementary properties of the Golay complementary sequence, and reduces side lobes after the waveform pulse compression. In addition, the present invention performs decoding according to the decoding rule, solves the problem that the pulse peak power of the fiber laser is limited, significantly improves the signal-to-noise ratio of the coherent laser radar, effectively improves the detection range, and does not require pulse accumulationtime, without sacrificing detection time and distance resolution.

The invention, which belongs to the field of laser radar detection, proposes a two-dimensional MEMS scanning galvanometer laser radar system, thereby extending a receiving field of view and increasinga signal-to-noise ratio. A two-dimensional MEMS scanning galvanometer is a scanning mechanism. A control system controls the laser to emit high-frequency pulsed laser; the returned laser signal lightpasses through a filter and a large relative aperture optical lens successively and then is imaged on the incident end face of an image transmission fiber light cone; the image transmission fiber light cone transmits to the surface of an APD array detector. The image transmission fiber light cone is formed by arranging a cone-shaped optical fiber bundle. The APD array detector selects a corresponding APD detector unit to collect signals according to scanning angle of the two-dimensional MEMS scanning galvanometer and the position of a light spot outputted by corresponding echo light at the image transmission fiber light cone. Therefore, , when the caliber, focal length, and detector area of the receiving optical system are certain, the field of view of the MEMS laser radar can be extended, the interference of the ambient background light on the system can be reduced, and the signal-to-noise ratio of the signal receiving can be improved.

The invention discloses laser radar. The laser radar adopts a multi-channel laser transmitter and a multi-channel photoelectric detector, the positions of the multi-channel laser transmitter and the multi-channel photoelectric detector are fixed, a laser pulse and a laser pulse echo signal are horizontally scanned at the same time by means of rotating a scanning module, an instantaneous view fieldfor receiving the laser pulse echo signal can be very small, the background light noise is relatively low, the relatively large detection range is achieved, no slip ring is needed, no functional modules with functions like wireless power supply and wireless communication are needed, the laser transmitter and the photoelectric detector do not need to be adjusted repeatedly, and the laser radar hasthe advantages of being low in cost, convenient to adjust and install, compact in structure, easy to realize volume production, etc.

The invention discloses brace porcelain insulator ultrasonic flaw detection method. It includes the following steps: emitting SH wave to detected surface; using transversal wave couplant for the probe and the detected surface; using the probe to check the detected surface; using porcelain insulator test piece to adjust probe reference sensitivity and checking sensitivity; detecting the reflection wave of the detected surface, recording the one which reaches defect setting value as defect signal; measuring the defect length; judging the work piece recorded with defect signal as waste. The invention also discloses the defect detecting probe of which emitted ultrasonic is SH type transverse wave. The method has high sensitivity, reliability, and large detecting range. Meanwhile the special probe has little size which can ensure detecting sensitivity and increase porcelain vase retrievable rate at the same time.

The invention relates to a whole day photon counting laser radar device and a method, which comprises an emission system consisting of a laser, an expander and a reflector, a receiving system consisting of a telescope, an optics filter and a photoelectric detector, and a central control device connected with the photoelectric detector with a software. The invention is characterized in that the wavelength of the laser and the optics filter are chosen to match with the fraunhofer absorption line wavelength of the solar spectrum; the intense absorption is adopted to reduce the intensity of a solar back light by 80 to 90 percent and to lead the laser radar to have good photon counting ability under the back light condition in days. The invention is characterized in that the day detection signal-noise ratio and the detection distance are greatly improved, which effectively improves the whole day high-performance working ability. Besides, the invention is widely suitable for the laser radarof detecting weak signal such as Mie dispersion, Rayleigh dispersion, Raman dispersion and atom resonance fluorescence, etc.

The invention relates to a medium wave infrared continuous zooming optical system with high zoom ratio, belongs to the technical field of optic lens, and aims to solve the existent problems of long zooming stroke, large F value and more lens in the prior art. The system comprises a front fixing group, a lens A of a time changing group, a lens C of a compensation group, a lens B of the time changing group, a lens D of the compensation group, a back fixing group, a secondary image formation group and a probe, coaxially arranged from left to right in sequence, wherein the continuous zooming of the system is realized through the axial movement of the time changing group and the compensation group. Through adopting the structure that the lens A and the lens B of the time changing group and the lens C and the lens D of the compensation group are arranged in a crossing manner to move, the continuous zooming is realized, the zooming stroke is short, the curve is smooth, 100% cold light stop efficiency is satisfied, the F value is constant to be 2, the continuous zooming can be carried out within the range of 10 mm to 300 mm of focal distance, and the image formation quality is sound in the whole focal distance range.

In a vehicle radar device, a predetermined number of received light signals output based on a predetermined number of laser beams radiated from a radar sensor are integrated by an integrator to produce an integrated signal. Integration of the predetermined number of received light signals helps amplify the received light signal components corresponding to the waves reflected by reflecting objects, making it possible to improve the sensitivity for detecting the waves reflected by the reflecting object. There are set a plurality of ranges of the received light signals to be integrated, each being shifted by one received light signal. This minimizes a drop in the angular resolution based on the integrated signals.

The invention discloses an all-weather active type panoramic sensing device which comprises a mobile object laser light source, a multi-element output all-around visual sensor and a micro processor, wherein a mirror surface with double curved surfaces and two camera units are arranged in the multi-element output all-around visual sensor; a polarization splitting prism is arranged on a refraction and reflection light path of the mirror surface with double curved surfaces is used for splitting the refraction and reflection light of the mirror surface with double curved surfaces into light containing a certain polarized component and light not containing a certain polarized component; the two camera units are respectively positioned on reflection and refraction light paths of the polarization splitting prism, and are used for respectively acquiring a first panoramic video image containing polarized light information and a second panoramic video image containing light intensity information; the micro processor is used for fusing point cloud geometrical information in the first panoramic video image with the color information in the second panoramic video image, and constructing a panoramic 3D model. The invention further discloses a 3D panoramic modeling approach adopting the all-weather active type panoramic sensing device.

The invention relates to a continuous zooming infrared lens, and the lens can improve the imaging quality. The lens comprises a first lens group serving as a front fixed group; a second lens group serving as a zooming group; a third lens group serving as a compensation group; a fourth lens group serving as a rear fixed group; a fifth lens group serving as a focusing group which is used for compensating the offset of an image plane under the condition of different object distances and different temperatures; and a zooming drive cam. The beneficial effects of the lens are that the lens remarkably prolongs the detection operation distance and improves the imaging quality, reduces the cost, and can achieve a good imaging effect. The zooming drive cam which employs the technology of curve fitting to design the curve of the zooming drive cam effectively solve a problem of the offset of the image plane in a zooming process.

The invention provides a collision distance calculation method and system based on fusion of an ultrasound wave and a camera. On the basis of obstacle detection based on ultrasound and camera fusion,different types of obstacles such as vehicles and pedestrians, pure ultrasound waves are obtained; collision distances are calculated respectively according to vehicle parameters, turning radiuses, vehicle speeds, and different types of obstacle information; areas of interest are selected in different driving directions and turning directions; and distance of all obstacles in the areas of interest are minimized to obtain the fused collision distances. According to the invention, with the existing ultrasonic sensor, all-around CMOS camera, integrated parking controller and all-around controller in a current vehicle, the relative position accuracy of detection is improved and the obstacle detection reliability and detection distances are enhanced. The collision distance calculation methodand system have advantages of reliable detection, high accuracy, high scene adaptability, and moderate cost; and the adaptability of the low-speed auxiliary system is improved effectively.

The invention relates to an unmanned aerial vehicle monitoring system and a monitoring method thereof. The unmanned aerial vehicle monitoring method comprises the following steps: step 1, acquiring animage in a scanning area; step 2, forming a three-dimensional vision to determine whether a suspicious object exists in the image or not through a first camera and a second camera; step 3, if yes, calculating the standard position of the suspicious target, and tracking and shooting the suspicious target. A plurality of servo holders are arranged in the area to be detected, the first camera and the second camera are arranged on the two side end faces of each servo holder, after the unmanned aerial vehicle is found, the unmanned aerial vehicle is tracked and monitored through binocular vision according to the position information, the finding, identifying and disposing of the low-altitude low-speed small targets can be realized, the unmanned aerial vehicle is detected through the two cameras, the concept that the unmanned aerial vehicle is detected by radar is changed, and the detection cost of the unmanned aerial vehicle is reduced.

The invention provides a method for carrying out transient electromagnetic forecasting on a long-distance water-containing target body in front of a tunnel face. The method provided by the invention comprises the following steps: carrying out detection on the long-distance water-containing target body in front of the tunnel face by using a medium-power transient electromagnetic instrument, thereby obtaining observation data of the long-distance water-containing target body in front of the tunnel face; by using a damped least-square algorithm, completing an inversion process of apparent resistivity data, thereby obtaining an apparent resistivity parameter of the long-distance water-containing target body in front of the tunnel face; by using a genetic algorithm, obtaining an electric conductivity parameter of the long-distance water-containing target body in front of the tunnel face; according to the apparent resistivity parameter and the electric conductivity parameter, carrying out explanation on the observation data so as to obtain information of the long-distance water-containing target body in front of the tunnel face. By using the method disclosed by the invention, the information of the long-distance water-containing target body in front of the tunnel face can be obtained, thereby implementing a process of carrying out forecasting on the long-distance water-containing target body in front of the tunnel face by using a transient electromagnetic method.

The invention relates to a long-wave infrared two-speed viewing field tracking measurement lens comprising a main lens cone. The long-wave infrared two-speed viewing field tracking and measuring lens is characterized in that the main lens cone is internally provided with a just crescent fixed lens A, a switching lens group B and a just crescent focusing lens C along an incident direction of infrared light from left to right, wherein the just crescent focusing lens C is driven by a focusing mechanism arranged in the main lens cone; the switching lens group B is divided into a long-focus lens group B (long) used during a long lens focus and a short-focus lens group B (short) used during a short lens focus, and the long-focus lens group B (long) or the short-focus lens group B (short) is driven by a switching rotation mechanism arranged in the main lens cone to be on a same light path with the just crescent fixed lens A and the just crescent focusing lens C. The invention has long designed focus of the lens, can conveniently switch the two-speed viewing field lens and enable a thermal imaging system to carry out tracking measurement on a long-distance target, can not only carry out large-area low-magnification approximate observation on the long-distance target, but also carry out small-area high-magnification detailed observation on the long-distance target.

The invention discloses an infrared medium-long wave double wave band imaging optical system which is mainly used for an infrared focal plane imaging system. The invention puts forward a tetra-sheet optical system. A light beam coming from an infinite distance object space in order passes through a first lens, a second lens, a third lens, a fourth lens, a Dewar window and a aperture diaphragm to form an imagining on an image plane. The aperture diaphragm of the system superposes the Dewar cold diaphragm of a refrigeration photoconductor. According to the system, medium-long wave infrared (MWIR, 3 to 5 [mu] m) and long wave infrared (LWIR, 8 to 12 [mu] m) wave bands form imaginings on a same focal plane. In the system, the relative aperture is 1 to 3, the focal length is 300 millimeters and the field of view is 8 degree. The structure of the invention is mainly characterized by double wave band work, common infrared materials used in the system, 100 percent diaphragm efficiency, simple structure and easy assembling.

The invention provides a phi-OTDR quadrature phase demodulation system and phase demodulation method. Laser of a narrow linewidth laser device is split by an optical fiber coupler, a large beam is connected into an acoustic optical modulator as sensing light, a modulated frequency shift is delivered into sensing optical fiber, a small beam is used as reference light, sensing light returned by a circulator is subjected to heterodyne coherence in a 2*2 optical fiber coupler, is then split into two beams of identical signal light to be converted into an electric signal through a balanced probe and is divided into two circuits through a power divider after being filtered, and after one circuit is delayed by an electric adjustable delay chip, the two circuits of electric signals are mixed with a sinusoidal signal with the frequency of fc sent by a signal generating module in a mixer separately and are then sent into a control center through a low-pass filter and an analog-digital conversion module to obtain phase information of a sensor light signal. According to the Phi-OTDR quadrature phase demodulation system and phase demodulation method, an interferometer does not need to be introduced, and additional environment noise cannot be introduced; complex high-speed data acquisition and processing are not needed, the system is simple, the price is low, and the system and method are more suitable for engineering application.