Patents by Inventor Junhua Sun

Junhua Sun has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8964027
    Abstract: The present disclosure provides a global calibration method based on a rigid bar for a multi-sensor vision measurement system, comprising: step 1, executing the following procedure for at least nine times: placing, in front of two vision sensors to be calibrated, a rigid bar fasten with two targets respectively corresponding to the vision sensors; capturing images of the respective targets by their corresponding vision sensors; extracting coordinates of feature points of the respective targets in their corresponding images; and computing 3D coordinates of each feature points of the respective targets under their corresponding vision sensor coordinate frames; and Step 2, computing the transformation matrix between the two vision sensors, with the constraint of the fixed position relationship between the two targets. The present disclosure also provides a global calibration apparatus based on a rigid bar for a multi-sensor vision measurement system.
    Type: Grant
    Filed: August 9, 2011
    Date of Patent: February 24, 2015
    Assignee: Beihang University
    Inventors: Guangjun Zhang, Zhen Liu, Zhenzhong Wei, Junhua Sun, Meng Xie
  • Publication number: 20120162414
    Abstract: The present disclosure provides a global calibration method based on a rigid bar for a multi-sensor vision measurement system, comprising: step 1, executing the following procedure for at least nine times: placing, in front of two vision sensors to be calibrated, a rigid bar fasten with two targets respectively corresponding to the vision sensors; capturing images of the respective targets by their corresponding vision sensors; extracting coordinates of feature points of the respective targets in their corresponding images; and computing 3D coordinates of each feature points of the respective targets under their corresponding vision sensor coordinate frames; and Step 2, computing the transformation matrix between the two vision sensors, with the constraint of the fixed position relationship between the two targets. The present disclosure also provides a global calibration apparatus based on a rigid bar for a multi-sensor vision measurement system.
    Type: Application
    Filed: August 9, 2011
    Publication date: June 28, 2012
    Applicant: BEIHANG UNIVERSITY
    Inventors: Guangjun Zhang, Zhen Liu, Zhenzhong Wei, Junhua Sun, Meng Xie
  • Patent number: 8180101
    Abstract: This disclosure provides a calibration method for structure parameters of a structured-light vision sensor, which includes setting up the coordinate frames of a camera, image plane and target for calibration. The calculation of coordinates in the camera coordinate frame of stripes, projected by structured-light, on the planar target and a structured-light equation fitting according to the coordinates in the camera coordinate frame of the stripes on the planar target, by moving the planar target arbitrarily multiple times. The calibration method of the structured-light vision sensor provided by the disclosure is easy to operate and no auxiliary apparatus is needed, which can not only promote the efficiency of the calibration of structured-light, but also extend the application scope of calibration of structured-light.
    Type: Grant
    Filed: January 30, 2008
    Date of Patent: May 15, 2012
    Assignee: Beihang University
    Inventors: Junhua Sun, Guangjun Zhang, Zhenzhong Wei
  • Patent number: 8078025
    Abstract: The invention discloses a vehicle dynamic measurement device for comprehensive parameters of rail wear, which comprises a vision sensor, a computer and a milometer. A high-speed image acquisition card and a measurement module are installed in the computer. The vision sensor comprises imaging system for rail cross-section and a raster projector which can project more than one light plane perpendicular to the measured rail. The measurement module is used for calculating vertical wear, horizontal wear, the amplitude and wavelength of corrugation wear. The invention also discloses a vehicle dynamic measurement method for comprehensive parameters of rail wear. The invention can increase the sampling rate of image sensing and acquisition hardware equipment with no need of improving the performance of it, thereby satisfy high-speed on-line dynamic measurement requirements for corrugation wear, and the amplitude and wavelength of corrugation wear can be calculated more precisely.
    Type: Grant
    Filed: October 25, 2008
    Date of Patent: December 13, 2011
    Assignee: Beihang University
    Inventors: Guangjun Zhang, Junhua Sun, Zhenzhong Wei, Fuqiang Zhou, Qingbo Li, Zhen Liu, Qianzhe Liu
  • Patent number: 8019147
    Abstract: The present disclosure is directed to a three-dimensional data registration method for vision measurement in flow style based on a double-sided target. An embodiment of the disclosed method that comprises A. Setting up two digital cameras which can observe the entire measured object; B. Calibrating intrinsic parameters and a transformation between the two digital camera coordinate frames; C. A double-sided target being placed near the measured area of the measured object, the two digital cameras and a vision sensor taking images of at least three non-collinear feature points of the double-sided target; D. Removing the target, measuring the measured area by using the vision sensor; E. Respectively computing the three dimensional coordinates of the feature points in the global coordinate frame and in the vision sensor coordinate frame; F.
    Type: Grant
    Filed: February 4, 2008
    Date of Patent: September 13, 2011
    Assignee: Beihang University
    Inventors: Guangjun Zhang, Junhua Sun, Zhenzhong Wei, Qianzhe Liu
  • Publication number: 20090112487
    Abstract: The invention discloses a vehicle dynamic measurement device for comprehensive parameters of rail wear, which comprises a vision sensor, a computer and a milometer. A high-speed image acquisition card and a measurement module are installed in the computer. The vision sensor comprises imaging system for rail cross-section and a raster projector which can project more than one light plane perpendicular to the measured rail. The measurement module is used for calculating vertical wear, horizontal wear, the amplitude and wavelength of corrugation wear. The invention also discloses a vehicle dynamic measurement method for comprehensive parameters of rail wear. The invention can increase the sampling rate of image sensing and acquisition hardware equipment with no need of improving the performance of it, thereby satisfy high-speed on-line dynamic measurement requirements for corrugation wear, and the amplitude and wavelength of corrugation wear can be calculated more precisely.
    Type: Application
    Filed: October 25, 2008
    Publication date: April 30, 2009
    Applicant: BEIHANG UNIVERSITY
    Inventors: Guangjun Zhang, Junhua Sun, Zhenzhong Wei, Fuqiang Zhou, Qingbo Li, Zhen Liu, Qianzhe Liu
  • Publication number: 20090059011
    Abstract: This disclosure provides a calibration method for structure parameters of a structured-light vision sensor, which includes setting up the coordinate frames of a camera, image plane and target for calibration. The calculation of coordinates in the camera coordinate frame of stripes, projected by structured-light, on the planar target and a structured-light equation fitting according to the coordinates in the camera coordinate frame of the stripes on the planar target, by moving the planar target arbitrarily multiple times. The calibration method of the structured-light vision sensor provided by the disclosure is easy to operate and no auxiliary apparatus is needed, which can not only promote the efficiency of the calibration of structured-light, but also extend the application scope of calibration of structured-light.
    Type: Application
    Filed: January 30, 2008
    Publication date: March 5, 2009
    Inventors: Junhua Sun, Guangjun Zhang, Zhenzhong Wei
  • Publication number: 20080298673
    Abstract: The present disclosure is directed to a three-dimensional data registration method for vision measurement in flow style based on a double-sided target. An embodiment of the disclosed method that comprises A. Setting up two digital cameras which can observe the entire measured object; B. Calibrating intrinsic parameters and a transformation between the two digital camera coordinate frames; C. A double-sided target being placed near the measured area of the measured object, the two digital cameras and a vision sensor taking images of at least three non-collinear feature points of the double-sided target; D. Removing the target, measuring the measured area by using the vision sensor; E. Respectively computing the three dimensional coordinates of the feature points in the global coordinate frame and in the vision sensor coordinate frame; F.
    Type: Application
    Filed: February 4, 2008
    Publication date: December 4, 2008
    Inventors: Guangjun Zhang, Junhua Sun, Zhenzhong Wei, Qianzhe Liu