Patents by Inventor Shoichi Okamura

Shoichi Okamura 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: 7006599
    Abstract: A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of exponential functions, N in number, with different attenuation time constants. The lag-behind parts are removed by using impulse responses corresponding to variations in the sensor temperature of the FPD. X-ray images are created from corrected radiation detection signals with the lag-behind parts removed therefrom.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: February 28, 2006
    Assignee: Shimadzu Corporation
    Inventors: Shoichi Okamura, Toshinori Yoshimuta
  • Publication number: 20050238249
    Abstract: Signal level differences occurring across a boundary extending vertically are also a type of signal level differences stemming from a distribution of signal levels of pixels. It is therefore possible to reduce the signal level differences of the pixels occurring in the horizontal direction of a pixel arrangement by applying an amount of correction obtained from statistics (mean values) relating to the distribution of signal levels of the pixels to the signal level of each pixel to correct each pixel. The correction is carried out only when a particular condition (condition A or B) that an absolute value of a difference between the mean values is at most a predetermined value is satisfied. It is therefore possible to avoid artifacts being generated by the correction carried out for locations where the absolute value of the difference between the statistics should exceed the predetermined value.
    Type: Application
    Filed: April 15, 2005
    Publication date: October 27, 2005
    Inventor: Shoichi Okamura
  • Publication number: 20050220268
    Abstract: In the radiographic apparatus according to this invention, when a radiographic mode designator 16 designates a non-standard radiographic mode, a signal corrector 15 uses defect information stored in one of non-standard image defect information memories 18B-18E for correcting X-ray detection signals outputted from an FPD 2. Since the pixel defect information for non-standard X-ray images is acquired by a pixel defect information converter 19 through a conversion from defect information for standard X-ray images stored in a standard image defect information memory 18A, it is unnecessary to collect output signals for pixel defect information acquisition from the FPD 2 all over again. As a result, abnormal X-ray detection signals due to defects of radiation detecting elements may be corrected promptly, regardless of how the radiation detecting elements are assigned to the pixels in the X-ray images.
    Type: Application
    Filed: March 24, 2005
    Publication date: October 6, 2005
    Inventors: Keiichi Fujii, Shoichi Okamura, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Shigeya Asai, Akihiro Nishimura
  • Publication number: 20050185755
    Abstract: In a radiographic apparatus according to this invention, when an imaging system scan is performed, a imaging system scanner moves an X-ray tube, which emits a cone-shaped X-ray beam, on one linear track, and an FPD, which detects transmission X-ray images of an object under inspection, on the other linear track synchronously with movement of the X-ray tube. Thus, a non-revolving type imaging system scan is carried out. When an X-ray sectional image reconstruction is performed, a sectional image reconstructing unit reconstructs X-ray sectional image from X-ray detection signals of transmission X-ray images of the object detected by the FPD at different radiographic angles. At this time, a time lag remover uses lag-free X-ray detection signals with lag-behind parts removed from the X-ray detection signals. As a result, the lag-behind parts included in the X-ray detection signals, which would cause a lowering of image quality, are removed in advance of a reconstruction of X-ray sectional images.
    Type: Application
    Filed: February 22, 2005
    Publication date: August 25, 2005
    Inventor: Shoichi Okamura
  • Publication number: 20050063508
    Abstract: An apparatus according to the invention includes a response coefficient to dose relationship memory for storing, in advance, a relationship of correspondence between intensities of an exponential function for impulse response and X-ray doses. The intensities of the exponential function determine conditions relating to an impulse response in a recursive computation performed to remove lag-behind parts from X-ray detection signals outputted from an FPD, thereby to obtain corrected X-ray detection signals. An impulse response coefficient setter sets an impulse response coefficient corresponding to an X-ray dose for an object under examination based on the relationship of correspondence between intensities of the exponential function and radiation doses. A time lag remover performs the recursive computation for time lag removal, with the intensity of an exponential function set to correspond to the X-ray dose for the object under examination.
    Type: Application
    Filed: October 6, 2004
    Publication date: March 24, 2005
    Inventor: Shoichi Okamura
  • Publication number: 20050031070
    Abstract: A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants. When a single attenuation time constant and intensity are provisionally set, checking is made whether an attenuation to a noise level of X-ray detection signals occurs in an X-ray non-emission state following an X-ray emission state. When the set attenuation time constant and intensity are found appropriate (OK), the impulse response having the single exponential function is determined valid. Corrected radiation detection signals are obtained by removing the lag-behind parts using the impulse response determined.
    Type: Application
    Filed: July 29, 2004
    Publication date: February 10, 2005
    Inventors: Shoichi Okamura, Keiichi Fujii, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Shigeya Asai, Akihiro Nishimura
  • Publication number: 20050031088
    Abstract: A subtraction image is obtained, by a subtraction process (DSA process), from a live image and a mask image. A lag-behind part included in each X-ray detection signal is considered due to an impulse response formed of exponential functions. The lag-behind part is removed from each X-ray detection signal by a recursive computation to obtain a corrected X-ray detection signal. The live image and mask image are obtained from such corrected detection signals.
    Type: Application
    Filed: July 12, 2004
    Publication date: February 10, 2005
    Inventors: Shoichi Okamura, Keiichi Fujii, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Shigeya Asai, Akihiro Nishimura
  • Publication number: 20050031079
    Abstract: A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants. The lag-behind parts are removed by using impulse responses of the FPD corresponding, for example, to an X-ray dose used in a fluoroscopic image pickup and an X-ray dose used in a radiographic image pickup. X-ray images are created from corrected radiation detection signals with the lag-behind parts removed therefrom.
    Type: Application
    Filed: July 8, 2004
    Publication date: February 10, 2005
    Inventors: Shoichi Okamura, Keiichi Fujii, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Shigeya Asai, Akihiro Nishimura
  • Publication number: 20040258207
    Abstract: A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of exponential functions, N in number, with different attenuation time constants. The lag-behind parts are removed by using impulse responses corresponding to variations in the sensor temperature of the FPD. X-ray images are created from corrected radiation detection signals with the lag-behind parts removed therefrom.
    Type: Application
    Filed: May 26, 2004
    Publication date: December 23, 2004
    Inventors: Shoichi Okamura, Toshinori Yoshimuta
  • Publication number: 20040156481
    Abstract: A radiographic apparatus obtains lag-free radiation detection signals with lag-behind parts removed from radiation detection signals taken from a flat panel X-ray detector as X rays are emitted from an X-ray tube. The lag-behind parts are removed by a recursive computation on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of exponential functions, N in number, with different attenuation time constants. X-ray images are created from the lag-free radiation detection signals.
    Type: Application
    Filed: January 16, 2004
    Publication date: August 12, 2004
    Inventors: Shoichi Okamura, Keiichi Fujii, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Masatomo Kaino, Hiroshi Koyama
  • Patent number: 5752514
    Abstract: A biomagnetism measuring method and apparatus for determining a positional relationship of an examinee with fluxmeters in a short time. A current supply unit simultaneously supplies alternating currents of different frequencies to a plurality of oscillator coils attached to the examinee, respectively. The fluxmeters detect magnetic fields simultaneously formed by the oscillator coils supplied with the currents. Field data thereby obtained are applied through a data collecting unit to a field analyzer for frequency analysis to recognize field strengths due to the respective oscillator coils for the respective fluxmeters. The field analyzer computes positions of the oscillator coils relative to the fluxmeters from the field strengths recognized for the respective oscillator coils and known values of the currents supplied to the respective oscillator coils.
    Type: Grant
    Filed: August 15, 1996
    Date of Patent: May 19, 1998
    Assignee: Shimadzu Corporation
    Inventors: Shoichi Okamura, Akira Arakawa, Shigeki Kajihara