Patents by Inventor Guangjun Zhang

Guangjun Zhang 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).

  • Publication number: 20090012734
    Abstract: A method for calibration of a digital celestial sensor is disclosed. The method comprises the following steps: firstly, an integrated mathematic model for imaging of a celestial sensor is established according to external and internal parameters of the calibration system of the celestial sensor. Secondly, by rotating two axes of a rotator by different angles, calibration points data are acquired and sent to a processing computer through an interface circuit. Finally, a two-step calibration program is implemented to calculate the calibration parameters by substituting calibration points' data to the integrated mathematic model. The disclosure also relates to an application device of the calibration method, wherein the device comprises: a celestial simulator to provide simulated sunlight or starlight, a two-axis rotator to acquire different the calibration points' data, a processing computer to record the calibration points' data and calculate the calibration parameters.
    Type: Application
    Filed: February 25, 2008
    Publication date: January 8, 2009
    Inventors: Guangjun Zhang, Xinguo Wei, Qiaoyun Fan, Jie Jiang
  • Publication number: 20090012731
    Abstract: A method for calibration of a digital sun sensor is disclosed. The method comprises following steps. First, an integrated mathematic model for imaging of a sun sensor is established according to the external and internal parameters of the calibration system of the sun sensor. Next, the two axis of the rotator are rotated by different angles. Then, calibration points' data are acquired and sent to a processing computer through an interface circuit. Finally, a two-step calibration program is implemented to calculate the calibration parameters by substituting the calibration points' data to the integrated mathematic model. The disclosure also relates to an application device of the calibration method. The device comprises: a sun simulator to provide the incident sunlight, a two-axis rotator to acquire different the calibration points' data, and a processing computer to record the calibration points' data and calculate the calibration parameters.
    Type: Application
    Filed: January 24, 2008
    Publication date: January 8, 2009
    Inventors: Guangjun Zhang, Xinguo Wei, Qiaoyun Fan, Jie Jiang
  • Publication number: 20080317283
    Abstract: The disclosure relates to a signal processing method for multi aperture sun sensor comprising the following steps: reading the information of sunspots in a row from a centroid coordinate memory, judging the absence of sunspots in that row, identifying the row and column index of the sunspots in the complete row, selecting the corresponding calibration parameter based on the row and column index, calculating attitude with the attitude calculation module the corresponding to identified sunspots, averaging the accumulated attitude of all sunspots and outputting the final attitude. At the same time, a signal processing device for multi aperture sun sensor is also presented. It is comprised of a sunspot absence judgment and an identification module and an attitude calculation module. The disclosure implements the integration of sun sensors without additional image processor or attitude processor, reduces field programmable gate array resource and improves the reliability of sun sensors.
    Type: Application
    Filed: December 31, 2007
    Publication date: December 25, 2008
    Inventors: Guangjun Zhang, Jie Jiang, Qiaoyun Fan
  • 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
  • Publication number: 20080131002
    Abstract: The disclosure relates to a rapid and high precision centroiding method for spots image comprising the following steps. First, the method requires convoluting the gray value of a pixel with a Gaussian filter and judging whether the result thereof exceeds a predetermined threshold. If the value exceeds the predetermined threshold, the method requires marking the current pixel with a flag to identify which spot it belongs to, and then accumulating the product of the gray value and a coordinate value of the same spot; and at the same time, accumulating the gray value of the same spot; and saving the results of the accumulation respectively. If the gray value of the pixel does not exceed the predetermined threshold, the method requires marking the current pixel as a background flag.
    Type: Application
    Filed: March 16, 2007
    Publication date: June 5, 2008
    Inventors: Guangjun Zhang, Jie Jiang, Qiaoyun Fan, Xuetao Hao
  • Publication number: 20080050042
    Abstract: The disclosure relates to a hardware-in-the-loop simulation system and method for computer vision. An embodiment of the disclosed system comprises a software simulation and a hardware simulation. The software simulation includes a virtual scene and an observed object that are generated by virtual reality software. The virtual scene images are obtained at different viewpoints. The hardware simulation includes the virtual scene images being projected onto a screen by a projector, wherein the projected scene images are shot by a camera, and where in the direction of the camera is controlled by a pan-tilt.
    Type: Application
    Filed: November 20, 2006
    Publication date: February 28, 2008
    Inventors: Guangjun Zhang, Suqi Li, Zhenzhong Wei, Zhen Liu
  • Publication number: 20080029652
    Abstract: The disclosure relates to an APS based integrated sun sensor comprising: a diaphragm unit, a detection unit, a processing electronics unit and an interface unit. The diaphragm unit is operatively connected with the detection unit for forming a sunspots image. The detection unit is configured for outputting a gray value of each pixel. The processing electronics unit is operatively connected with the detector unit and the interface unit respectively, for evaluating an attitude angle on the basis of the gray value and coordinate of each pixel. The interface unit is operatively connected with a host computer, for transferring the attitude angle to the host computer. This disclosure has such merits as high accuracy, wide FOV (Field of View), low power consumption, low weight, small size and high update rate.
    Type: Application
    Filed: March 16, 2007
    Publication date: February 7, 2008
    Inventors: Guangjun Zhang, Jie Jiang, Qiaoyun Fan
  • Publication number: 20070183631
    Abstract: The present invention relates to a high-performance computer vision system and method for measuring the wings deformation of insects with high flapping-frequency, large stroke-amplitude and excellent mobility during free-flight. A geometrical optic unit composed of a polyhedral reflector with four reflection-planes and four planar reflectors is used to image one high-speed CMOS camera to four virtual cameras, combined with double laser-sheet sources, multiple virtual stereo and structured-light sensors are available to observe the free-flight of insect at different viewpoints simultaneously. In addition, an optoelectronic guiding equipment is included to lead the free-flight of insect and trigger the camera to capture the image sequences of insect-flight automatically. The deformation of insect-wings can be reconstructed by the spatial coordinates of wing-edges and the distorted light-lines projected on the surface of wings.
    Type: Application
    Filed: February 15, 2006
    Publication date: August 9, 2007
    Applicant: BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS
    Inventors: Guangjun ZHANG, Dazhi CHEN, Ying WANG, Fuqiang ZHOU, Zhenzhong WEI
  • Patent number: 6845326
    Abstract: An optical sensor for use in measuring constituents of an agricultural product. An optical sensing window passes a stream of the agricultural product, and a radiation source irradiates the stream as it passes through the optical sensing window. A receiver receives radiation transmitted through the stream and converts it into a corresponding electrical signal using a spectrometer. The electrical signal is digitized to produce a series of data points corresponding to particular wavelengths. A processor normalizes the data points using a reference value in order to generate processed data points that can be used to predict a constituent content of the agricultural product.
    Type: Grant
    Filed: November 7, 2000
    Date of Patent: January 18, 2005
    Assignee: NDSU Research Foundation
    Inventors: Suranjan Panigrahi, Guangjun Zhang