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    A CALIBRATION METHOD FOR FRINGE PROJECTION SYSTEMS BASED ON PLANE MIRRORS
    11.
    发明申请
    A CALIBRATION METHOD FOR FRINGE PROJECTION SYSTEMS BASED ON PLANE MIRRORS 有权

    公开(公告)号：US20220221270A1

    公开(公告)日：2022-07-14

    申请号：US17631542

    申请日：2020-08-07

    Applicant: Nanjing University of Science and Technology

    Inventor： Chao Zuo ,  Wei Yin ,  Qian Chen ,  Shijie Feng ,  Jiasong Sun ,  Tianyang Tao ,  Yan Hu ,  Liang Zhang ,  Jiaming Qian

    IPC: G01B11/25

    Abstract: A calibration method for fringe projection systems based on plane mirrors. Firstly, two mirrors are placed behind the tested object. Through the reflection of mirrors, the camera can image the measured object from the front and other two perspectives, so as to obtain 360-degree two-dimensional information of the measured object. The projector projects three sets of phase-shifting fringe patterns with frequencies of 1, 8, and 64. The camera captures the fringe image to obtain an absolute phase map with a frequency of 64 by using the phase-shifting method and the temporal phase unwrapping algorithm. By using the calibration parameters between the projector and the camera, the absolute phase map can be converted into three-dimensional information of the measured object. Then, the mirror calibration is realized by capturing a set of 3D feature point pairs, so that the 3D information from different perspectives is transformed into a unified world coordinate system. The calibration method does not need to artificially fix the feature pattern on plane mirrors, only needs to capture a set of 3D feature point pairs by the camera to directly realize the mirror calibration that it avoids the loss of measurement accuracy and realizes high-precision panoramic three-dimensional measurement.

    Method for vehicle detection based on single-axis geomagnetic sensor
    12.
    发明授权
    Method for vehicle detection based on single-axis geomagnetic sensor 有权

    公开(公告)号：US11373523B2

    公开(公告)日：2022-06-28

    申请号：US16969896

    申请日：2018-10-16

    Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY

    Inventor： Yong Qi ,  Xian Lv ,  PengZhen Du ,  WeiBin Zhang

    IPC: G08G1/04 ,  G08G1/042 ,  G08G1/052 ,  G08G1/065

    Abstract: A method for vehicle detection based on single-axis geomagnetic sensor is disclosed. The method includes the following: arranging two geomagnetic sensors in tandem at a fixed distance in the same lane, and acquiring, by the two geomagnetic sensors, data when a vehicle passes by; performing data cleansing and denoising on the data acquired by the geomagnetic sensors; detecting, by the geomagnetic sensors, the vehicle by using an state machine algorithm based on a fixed threshold, and extracting moments when the vehicle enters and leaves detection ranges of the sensors; and collecting statistics on traffic flow in a predetermined period of time, and calculating the velocity and length of the vehicle. The presently disclosed method and apparatus can be independently used to obtain vehicle parameters at important traffic sections or intersections, or can be used in combination with other traffic detection devices to obtain more comprehensive traffic information. The presently disclosed method and apparatus has low power consumption, high detection sensitivity, is easy to install and resists the impact of a harsh environment.

    A MICROSCOPIC IMAGING METHOD OF PHASE CONTRAST AND DIFFERENTIAL INTERFERENCE CONTRAST BASED ON THE TRANSPORT OF INTENSITY EQUATION
    13.
    发明申请
    A MICROSCOPIC IMAGING METHOD OF PHASE CONTRAST AND DIFFERENTIAL INTERFERENCE CONTRAST BASED ON THE TRANSPORT OF INTENSITY EQUATION 有权

    公开(公告)号：US20220011563A1

    公开(公告)日：2022-01-13

    申请号：US17294019

    申请日：2019-07-05

    Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY

    Inventor： Chao ZUO ,  Qian CHEN ,  Jiasong SUN ,  Yuzhen ZHANG ,  Guohua GU

    IPC: G02B21/36 ,  G02B27/12 ,  H04N5/225

    Abstract: The invention claims a microscopic imaging method of phase contrast (PC) and differential interference contrast (DIC) based on the transport of intensity equation (TIE). Firstly, three intensity images are captured along the optical axis; secondly, TIE is solved by deconvolution to obtain the quantitative phase; then, the intensity image under the DIC imaging mode is obtained according to the DIC imaging principle; finally, the corresponding phase image of PC imaging mode is obtained according to the PC imaging principle. The proposed approach can endow the bright-field microscope with the ability to realize PC and DIC imaging without complex modification of the traditional bright-field microscope. In other words, this method only needs to use the traditional bright-field microscope without adding any complex hardware. Through the PC and DIC algorithms, this method has the advantages of quantitative, high-speed, low-cost, simple structure, and less external interference. In addition, it has the same imaging performance as the phase contrast microscope and differential interference contrast microscope, which are expensive, complex-structure, and has strict environmental conditions.

    METHOD FOR VEHICLE DETECTION BASED ON SINGLE-AXIS GEOMAGNETIC SENSOR
    14.
    发明申请
    METHOD FOR VEHICLE DETECTION BASED ON SINGLE-AXIS GEOMAGNETIC SENSOR 有权

    公开(公告)号：US20210118291A1

    公开(公告)日：2021-04-22

    申请号：US16969896

    申请日：2018-10-16

    Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY

    Inventor： Yong Qi ,  Xian Lv ,  PengZhen Du ,  WeiBin Zhang

    IPC: G08G1/042 ,  G08G1/065 ,  G08G1/052

    Abstract: A method for vehicle detection based on single-axis geomagnetic sensor is disclosed. The method includes the following: arranging two geomagnetic sensors in tandem at a fixed distance in the same lane, and acquiring, by the two geomagnetic sensors, data when a vehicle passes by; performing data cleansing and denoising on the data acquired by the geomagnetic sensors; detecting, by the geomagnetic sensors, the vehicle by using an state machine algorithm based on a fixed threshold, and extracting moments when the vehicle enters and leaves detection ranges of the sensors; and collecting statistics on traffic flow in a predetermined period of time, and calculating the velocity and length of the vehicle. The presently disclosed method and apparatus can be independently used to obtain vehicle parameters at important traffic sections or intersections, or can be used in combination with other traffic detection devices to obtain more comprehensive traffic information. The presently disclosed method and apparatus has low power consumption, high detection sensitivity, is easy to install and resists the impact of a harsh environment.

    SUPER-RAPID THREE-DIMENSIONAL TOPOGRAPHY MEASUREMENT METHOD AND SYSTEM BASED ON IMPROVED FOURIER TRANSFORM CONTOUR TECHNIQUE
    15.
    发明申请
    SUPER-RAPID THREE-DIMENSIONAL TOPOGRAPHY MEASUREMENT METHOD AND SYSTEM BASED ON IMPROVED FOURIER TRANSFORM CONTOUR TECHNIQUE 有权

    公开(公告)号：US20210102801A1

    公开(公告)日：2021-04-08

    申请号：US16496815

    申请日：2018-02-26

    Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY

    Inventor： Qian CHEN ,  Chao ZUO ,  Shijie FENG ,  Jiasong SUN ,  Yuzhen ZHANG ,  Guohua GU

    IPC: G01B11/25

    Abstract: A super-rapid three-dimensional measurement method and system based on an improved Fourier transform contour technique is disclosed. The method comprises: firstly calibrating a measurement system to obtain calibration parameters, then cyclically projecting 2n patterns into a measured scene using a projector, wherein n patterns are binary sinusoidal fringes with different high frequency, and the other n patterns are all-white images with the values of 1, and projecting the all-white images between every two binary high-frequency sinusoidal fringes, and synchronously acquiring images using a camera; and then performing phase unwrapping on wrapped phases to obtain initial absolute phases, and correcting the initial absolute phases, and finally reconstructing a three-dimensional topography of the measured scene by exploiting the corrected absolute phases and the calibration parameters to obtain 3D spatial coordinates of the measured scene in a world coordinate system, thereby accomplishing three-dimensional topography measurement of an object. In this way, the precision of three-dimensional topography measurement is ensured, and the speed of three-dimensional topography measurement is improved.

    Highly efficient three-dimensional image acquisition method based on multi-mode composite encoding and epipolar constraint
    16.
    发明授权
    Highly efficient three-dimensional image acquisition method based on multi-mode composite encoding and epipolar constraint 有权

    公开(公告)号：US10911672B2

    公开(公告)日：2021-02-02

    申请号：US16496845

    申请日：2018-02-26

    Applicant: Nanjing University of Science and Technology

    Inventor： Qian Chen ,  Chao Zuo ,  Shijie Feng ,  Jiasong Sun ,  Yuzhen Zhang ,  Guohua Gu

    IPC: H04N13/246 ,  H04N5/232 ,  H04N13/239 ,  G01B11/25

    Abstract: A highly efficient three-dimensional image acquisition method based on multi-mode composite encoding and epipolar constraint, respectively using a fast imaging mode or a high-precision imaging mode, wherein in the fast imaging mode, two phase maps having different frequencies are obtained by four stripe gratings, and a high-frequency absolute phase is obtained by means of the epipolar constraint and a left-right consistency check, and the three-dimensional image is obtained by means of a mapping relationship between the phase and three-dimensional coordinates; and in the high precision imaging mode, two phases having different frequencies are obtained by means of N+2 stripe gratings, a low-frequency absolute phase is obtained by the epipolar constraint, and the unwrapping of a high-frequency phase is assisted by means of the low-frequency absolute phase, so as to obtain the high-frequency absolute phase, and finally, the three-dimensional image is obtained by the mapping relationship between the phase and the three-dimensional coordinates. In this way, the imaging efficiency is ensured, and the imaging precision is improved.

    A SILICON-BASED MICRO-MACHINED VIBRATORY GYROSCOPE WITH AN I-SHAPED STRUCTURE
    17.
    发明申请
    A SILICON-BASED MICRO-MACHINED VIBRATORY GYROSCOPE WITH AN I-SHAPED STRUCTURE 审中-公开

    公开(公告)号：US20190017822A1

    公开(公告)日：2019-01-17

    申请号：US16066634

    申请日：2016-09-26

    Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY

    Inventor： Qin SHI ,  Anping QIU ,  Guoming XIA ,  Yang ZHAO

    IPC: G01C19/5621

    Abstract: The invention relates to a silicon-based micro-machined vibratory gyroscope with an I-shaped structure, which is a measuring instrument used for measuring the angular rate perpendicular to a base, and comprises a top monocrystalline silicon, a middle monocrystalline silicon, and a bottom monocrystalline silicon; the top monocrystalline silicon being arranged with signal input and output lines is the silicon micro gyroscope packaged cover plate; the middle monocrystalline silicon is where the gyroscope mechanical structures are fabricated; the bottom monocrystalline silicon is a gyroscope substrate with fixed pedestals; the middle monocrystalline silicon layer is sealed in a closed cavity formed by top and bottom monocrystalline silicon layers. The invented gyroscope has properties of small error, high mechanical sensitivity, low vibration sensitivity, and low temperature sensitivity, and can implement motion decoupling of a driving mode and a detection mode, large amplitude vibration, and detection output decoupling.

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