Patents by Inventor Xinqiao Liu

Xinqiao Liu 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: 7526120
    Abstract: A sensor system is provided for determining a deployment level of an airbag in a vehicle. A light source of the sensor system emits light onto a region around a vehicle seat. An array of light-sensitive pixels which capture reflected light from the scene, including reflected light that originated from the light source. Processing resources are provided that determine depth information for an object in the scene based on a time-of-flight characteristic of the reflected light from the light source captured on the array. The processing resources may be configured to determine occupancy data for the object based on the captured reflected light from the scene. The processing resources are configured to determine the deployment level of the airbag based at least in part on the occupancy data in when a collision of the vehicle occurs.
    Type: Grant
    Filed: September 11, 2003
    Date of Patent: April 28, 2009
    Assignee: Canesta, Inc.
    Inventors: Salih Burak Gokturk, Cyrus Bamji, Abbas Rafii, Carlo Tomasi, Xinqiao Liu
  • Patent number: 7464351
    Abstract: CMOS implementable three-dimensional silicon sensors are fabricated using a standard fab but using augmented rules that create mask patterns not expressible with existing fab rules. Standard fab rules are not optimized to produce high quality three-dimensional silicon sensors. Accordingly, the normal set of rules does not permit creating the fab mask patterns necessary for high performance such sensors. However, the present invention can use the fab standard mask set with a rich set of fab instructions to express mask patterns from the mask set that would not otherwise be expressible. The resultant method enables high quality silicon sensors for three-dimensional sensing to be readily mass produced from a standard fab.
    Type: Grant
    Filed: December 30, 2004
    Date of Patent: December 9, 2008
    Assignee: Canesta, Inc.
    Inventors: Cyrus Bamji, Xinqiao Liu
  • Publication number: 20080217545
    Abstract: An image sensor having a two-dimensional array of pixel sensors, a layer of scintillation material, and a controller is disclosed. The layer of scintillation material is adjacent to the two-dimensional array, the scintillation material emits light in response to x-rays impinging thereon. The pixel sensors detect this light. The controller reads out data stored in the two-dimensional array of pixel sensors and forms an image therefrom. The controller corrects the data for errors resulting from x-rays that generate electrons that are stored in the pixel sensors in the process of forming the image. In one aspect of the invention, the controller forms the image by causing the two-dimensional array to form a plurality of frames, each frame includes a measurement of a charge stored on each photodiode during a preceding time period. The controller selectively combines data from the frames to form the image.
    Type: Application
    Filed: March 8, 2007
    Publication date: September 11, 2008
    Inventors: XinQiao Liu, Boyd Fowler
  • Publication number: 20080024635
    Abstract: An image sensor having a two-dimensional array of CMOS pixel sensors, a row decoder and a column decoder is disclosed. The two-dimensional array of CMOS pixel sensors is organized as a plurality of rows and columns that are addressed with the aid of row and column decoders. At least one of the column decoder or the row decoder is located between two of the rows or two of the columns, respectively. X-rays are converted to light that is detected by the image sensor by a layer of scintillation material that overlies the two-dimensional array. The internally located decoder or decoders facilitate sensors in which the two-dimensional array includes a rectangular array having a chamfered corner such that rows or columns that extend into the chamfered corner have lengths that are less than rows or columns, respectively, that do not extend into the corners.
    Type: Application
    Filed: July 26, 2006
    Publication date: January 31, 2008
    Inventors: Xinqiao Liu, Boyd Fowler
  • Publication number: 20070015301
    Abstract: A light sensor having a light conversion element between first and second electrodes is disclosed. The light conversion element includes a body of semiconductor material having first and second surfaces. The body of semiconductor material is of a first conductivity type and has doping elements in a concentration gradient that creates a first electrostatic field having a magnitude that varies monotonically from the first surface to the second surface. A bias circuit applies a variable potential between the first and second electrodes to create a second electrostatic field having a direction opposite to that of the first electrostatic field and a magnitude determined by the potential. One of the electrodes is transparent to light in a predetermined band of wavelengths. The body of semiconductor material can include an epitaxial body having a monotonically increasing concentration of a doping element as a function of the distance from one the surfaces.
    Type: Application
    Filed: July 14, 2005
    Publication date: January 18, 2007
    Inventors: David Wen, Xinqiao Liu, Ahn Vu, Steven Onishi
  • Patent number: 7132638
    Abstract: An imaging array having a CCD imaging array that includes a plurality of pixels that accumulate charge when exposed to light and a readout amplifier is disclosed. The readout amplifier includes an operational amplifier having an input and an output port and a feedback capacitor connecting the input and output ports and a variable impedance path between the input and output ports, the path having an impedance controlled by a reset signal. A reset signal generator generates the reset signal in three sequential phases in which the path between the input and output ports has three impedance values to provide a starting voltage at the amplifier input prior to the measurement of charge from each pixel that has reduced noise.
    Type: Grant
    Filed: June 10, 2004
    Date of Patent: November 7, 2006
    Assignee: Fairchild Imaging
    Inventors: Xinqiao Liu, David D. Wen, Anh N. Vu, Steven Kiyoshi Onishi, Charles J. Arduini
  • Patent number: 7061524
    Abstract: Motion/Saturation detection system and method for synthesizing high dynamic range motion blur free images from multiple captures, the system and method utilizing photocurrent estimation to reduce read noise and enhance dynamic range at the low illumination end, saturation detection to enhance dynamic range at the high illumination end, and motion blur detection to ensure the photocurrent estimation is not corrupted by motion. Motion blur detection also makes it possible to extend exposure time and to capture more images, which can be used to further enhance dynamic range at the low illumination end. The present invention operates completely locally, making it well suited for single chip digital camera implementations.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: June 13, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Xinqiao Liu, Abbas El Gamal
  • Patent number: 7009636
    Abstract: The dynamic range and the noise immunity of a digital imaging system are increased by basing an estimate of the illumination on a sensor on a series of measurements of the accumulated illumination at intervals within an exposure period. The measuring may occur destructively, or alternatively the photocurrent of the sensor may continue to accumulate over the exposure period. The estimate may use statistical signal processing of the measurements, based on various noise models and various optimization criteria. The estimate may be computed recursively over the multiplicity of measurements, using a set of recursive values that may include but is not limited to the estimated illumination, a current weighting coefficient, a variance of the current measurement and a variance over the series of measurements.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: March 7, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Xinqiao Liu, Abbas El Gamal
  • Publication number: 20060033826
    Abstract: The present invention includes an imaging apparatus having an imaging array, readout amplifier, and controller. The imaging array includes a plurality of pixels that accumulate charge when exposed to light. The readout amplifier receives charge from the pixels and generates a pixel signal indicative of the amount of charge received. The controller causes the charge from a plurality of the pixels to be added together to form a sum charge that is received by the readout amplifier. The imaging array can include a plurality of columns of pixels, and the controller causes the charge from a plurality of pixels in one of the columns to be added together to form a partial sum charge that is included in the sum charge. The readout amplifier can include a horizontal shift register, and the partial sum charge can be generated in the shift cells.
    Type: Application
    Filed: August 12, 2004
    Publication date: February 16, 2006
    Inventors: Xinqiao Liu, David Wen, Anh Vu, Steven Onishi, Charles Arduini
  • Publication number: 20050274873
    Abstract: An imaging array having a CCD imaging array that includes a plurality of pixels that accumulate charge when exposed to light and a readout amplifier is disclosed. The readout amplifier includes an operational amplifier having an input and an output port and a feedback capacitor connecting the input and output ports and a variable impedance path between the input and output ports, the path having an impedance controlled by a reset signal. A reset signal generator generates the reset signal in three sequential phases in which the path between the input and output ports has three impedance values to provide a starting voltage at the amplifier input prior to the measurement of charge from each pixel that has reduced noise.
    Type: Application
    Filed: June 10, 2004
    Publication date: December 15, 2005
    Inventors: Xinqiao Liu, David Wen, Anh Vu, Steven Onishi, Charles Arduini
  • Patent number: 6963370
    Abstract: A method for improving SNR without reducing dynamic range in a CMOS video sensor system under low illumination is described, wherein the CMOS video sensor system employing self-reset DPS architecture includes pixel level A/D conversion and wherein each DPS pixels is capable of resetting itself whenever a corresponding diode reaches saturation during integration time, the method comprising the steps of eliminating global frame reset for the self-reset DPS pixels, capturing and storing a plurality of frames, extending integration time beyond frame readout time, and generating frame images using one or more previously stored frames.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: November 8, 2005
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Jeffrey M. DiCarlo, Xinqiao Liu, Brian Wandell, Abbas El Gamal
  • Patent number: 6927796
    Abstract: A CMOS DPS image sensor architecture for improving SNR and dynamic range is presented. The CMOS DPS architecture includes self-reset digital pixels capable of collecting more charge than the physical well capacity. A method for improving SNR without reducing dynamic range in a CMOS video sensor system under low illumination is described, wherein the CMOS video sensor system employing self-reset DPS architecture includes pixel level A/D conversion and wherein each DPS pixels is capable of resetting itself whenever a corresponding diode reaches saturation during integration time.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: August 9, 2005
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Xinqiao Liu, Suk Hwan Lim, Abbas El Gamal
  • Publication number: 20050156121
    Abstract: Structures and methods for three-dimensional image sensing using high frequency modulation includes CMOS-implementable sensor structures using differential charge transfer, including such sensors enabling rapid horizontal and slower vertical dimension local charge collection. Wavelength response of such sensors can be altered dynamically by varying gate potentials. Methods for producing such sensor structures on conventional CMOS fabrication facilities include use of “rich” instructions to command the fabrication process to optimize image sensor rather than digital or analog ICs. One detector structure has closely spaced-apart, elongated finger-like structures that rapidly collect charge in the spaced-apart direction and then move collected charge less rapidly in the elongated direction. Detector response is substantially independent of the collection rate in the elongated direction.
    Type: Application
    Filed: December 30, 2004
    Publication date: July 21, 2005
    Applicant: Canesta, Inc.
    Inventors: Cyrus Bamji, Xinqiao Liu
  • Patent number: 6919549
    Abstract: Effective differential dynamic range in a differential pixel detector is increased by avoiding saturation effects due to common mode contribution in optical energy to be detected. Photocurrent generated by each photodetector pair is directly integrated by an associated capacitor over an integration time T. Within time T, before either integrated capacitor voltage reaches Vsat for the photodetector, at least one of the capacitors is reset to a voltage such that the desired differential detector signal is still determinable. Reset may be generated externally or internally to the differential pixel detector.
    Type: Grant
    Filed: April 12, 2004
    Date of Patent: July 19, 2005
    Assignee: Canesta, Inc.
    Inventors: Cyrus Bamji, Hakan Yalcin, Xinqiao Liu, Ender Tunc Eroglu
  • Patent number: 6906793
    Abstract: Structures and methods for three-dimensional image sensing using high frequency modulation includes CMOS-implementable sensor structures using differential charge transfer, including such sensors enabling rapid horizontal and slower vertical dimension local charge collection. Wavelength response of such sensors can be altered dynamically by varying gate potentials. Methods for producing such sensor structures on conventional CMOS fabrication facilities include use of “rich” instructions to command the fabrication process to optimize image sensor rather than digital or analog ICs. One detector structure has closely spaced-apart, elongated finger-like structures that rapidly collect charge in the spaced-apart direction and then move collected charge less rapidly in the elongated direction. Detector response is substantially independent of the collection rate in the elongated direction.
    Type: Grant
    Filed: June 17, 2003
    Date of Patent: June 14, 2005
    Assignee: Canesta, Inc.
    Inventors: Cyrus Bamji, Xinqiao Liu
  • Publication number: 20050051707
    Abstract: Effective differential dynamic range in a differential pixel detector is increased by avoiding saturation effects due to common mode contribution in optical energy to be detected. Photocurrent generated by each photodetector pair is directly integrated by an associated capacitor over an integration time T. Within time T, before either integrated capacitor voltage reaches Vsat for the photodetector, at least one of the capacitors is reset to a voltage such that the desired differential detector signal is still determinable. Reset may be generated externally or internally to the differential pixel detector.
    Type: Application
    Filed: April 12, 2004
    Publication date: March 10, 2005
    Inventors: Cyrus Bamji, Hakan Yalcin, Xinqiao Liu, Ender Eroglu
  • Publication number: 20040153229
    Abstract: A sensor system is provided for determining a deployment level of an airbag in a vehicle. A light source of the sensor system emits light onto a region around a vehicle seat. An array of light-sensitive pixels which capture reflected light from the scene, including reflected light that originated from the light source. Processing resources are provided that determine depth information for an object in the scene based on a time-of-flight characteristic of the reflected light from the light source captured on the array. The processing resources may be configured to determine occupancy data for the object based on the captured reflected light from the scene.
    Type: Application
    Filed: September 11, 2003
    Publication date: August 5, 2004
    Inventors: Salih Burak Gokturk, Cyrus Bamji, Abbas Rafii, Carlo Tomasi, Xinqiao Liu
  • Patent number: 6642543
    Abstract: A functional block for a CMOS circuit within the core of an integrated circuit chip and a method of making the same is disclosed. The functional block uses both thick and thin gate oxide transistors which reduces the leakage current and increases the voltage swing while permitting the device scaling in circuits made in CMOS technology. Within the functional block, the distance between a thick oxide transistor and a thin oxide transistor is chosen based on a transistor stability criterion. The thick and thin oxide transistors can be connected to identical or different voltage sources. Further, a transistor within a functional block can be chosen to be thick or thin oxide transistor based on a leakage current threshold or a voltage swing threshold.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: November 4, 2003
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Abbas El Gamal, Xinqiao Liu, Sukhwan Lim
  • Publication number: 20030098919
    Abstract: The dynamic range and the noise immunity of a digital imaging system are increased by basing an estimate of the illumination on a sensor on a series of measurements of the accumulated illumination at intervals within an exposure period. The measuring may occur destructively, or alternatively the photocurrent of the sensor may continue to accumulate over the exposure period. The estimate may use statistical signal processing of the measurements, based on various noise models and various optimization criteria. The estimate may be computed recursively over the multiplicity of measurements, using a set of recursive values that may include but is not limited to the estimated illumination, a current weighting coefficient, a variance of the current measurement and a variance over the series of measurements.
    Type: Application
    Filed: November 13, 2001
    Publication date: May 29, 2003
    Inventors: Xinqiao Liu, Abbas El Gamal
  • Publication number: 20030095189
    Abstract: Motion/Saturation detection system and method for synthesizing high dynamic range motion blur free images from multiple captures, the system and method utilizing photocurrent estimation to reduce read noise and enhance dynamic range at the low illumination end, saturation detection to enhance dynamic range at the high illumination end, and motion blur detection to ensure the photocurrent estimation is not corrupted by motion. Motion blur detection also makes it possible to extend exposure time and to capture more images, which can be used to further enhance dynamic range at the low illumination end. The present invention operates completely locally, making it well suited for single chip digital camera implementations.
    Type: Application
    Filed: November 13, 2001
    Publication date: May 22, 2003
    Inventors: Xinqiao Liu, Abbas El Gamal