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US4562586A Expired / Lapsed US ⏱️ 0.0 years remaining

X-Ray image pick-up device

Assignee: Toshiba Corp
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Filing: 1984-05-16
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Granted: 1985-12-31
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Expires: 2004-05-16
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Abstract

Abstract An X-ray image pick-up device includes an X-ray source for radiating X-rays onto an object including a region of interest, an image intensifier for converting to an optical image an X-ray image obtained when the X-rays radiated from the X-ray source are transmitted through the object, an image pick-up camera for converting to an image pick-up signal the optical image which is generated from the image intensifier, and an optical diaphragm arranged between the image intensifier and the image pick-up camera for adjusting an amount of optical image light incident on the image pick-up camera. The X-ray image pick-up device further includes an exposure controller for detecting both the maximum value of image pick-up signals from the pick-up camera and the average value of the image pick-up signals in the region of interest at a time of fluoroscopic examination, for calculating the density resolutions of the output pick-up signals from the image pick-up camera with respect to the various combinations of tube voltages, tube currents and optical diaphragm values, and for determining a tube voltage and a tube current of an X-ray source, along with an optical diaphragm value so as to provide a maximum density resolution which permits the device to always operate under optimal exposure conditions.

Inventors

  • 👤 Michitaka Honda
  • 👤 Osamu Takami

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 03:27
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H04; H04N; H04N23/00; H04N23/30; H05G1/30; H05G1/46; H05G1/60

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 183 words
An X-ray image pick-up device comprising: an X-ray source for radiating X-rays onto an object including a region of interest; means for converting to an optical image an X-ray image obtained when the X-rays irradiate the object and are transmitted therethrough; image pick-up means for converting to an image pick-up signal the optical image which is generated from said converting means; optical diaphragm means, disposed between said converting means and said image pick-up means, for adjusting an amount of light incident on said image pick-up means; and exposure control means for detecting a maximum value of image pick-up signals from said image pick-up means and an average value of the image pick-up signals in the region of interest when a single image pick-up operation is performed, calculating density resolutions of output pick-up signals of said image pick-up means with respect to various combinations of tube voltages and tube currents of said X-ray source and optical diaphragm values of said optical diaphragm means, and determining the tube voltage and the tube current, along with the optical diaphragm value which determine a maximum density resolution.
Claim 2
Dependent Claim 183 words
An X-ray image pick-up device comprising: an X-ray source for radiating X-rays onto an object including a region of interest; means for converting to an optical image an X-ray image obtained when the X-rays irradiate the object and are transmitted therethrough; image pick-up means for converting to an image pick-up signal the optical image which is generated from said converting means; optical diaphragm means, disposed between said converting means and said image pick-up means, for adjusting an amount of light incident on said image pick-up means; and exposure control means for detecting a maximum value of image pick-up signals from said image pick-up means and an average value of the image pick-up signals in the region of interest when a single image pick-up operation is performed, calculating density resolutions of output pick-up signals of said image pick-up means with respect to various combinations of tube voltages and tube currents of said X-ray source and optical diaphragm values of said optical diaphragm means, and determining the tube voltage and the tube current, along with the optical diaphragm value which determine a maximum density resolution.
Claim 3
Dependent Claim 43 words
A device according to claim 1, in which said exposure control means determines the tube voltage and the tube current and the optical diaphragm value in accordance with the output pick-up signal from said image pick-up means at the time of fluoroscopic examination.
Claim 4
Dependent Claim 57 words
A device according to claim 1, in which said exposure control means sequentially calculates the optical diaphragm value in accordance with a saturation level of the output pick-up signal generated from said image pick-up means and density resolutions at respective tube voltages, and detects the maximum density resolution among the density resolutions at the respective tube voltages.
Claim 5
Dependent Claim 41 words
A device according to claim 1, in which the density resolution is defined by a signal-to-noise ratio of a level difference of the image pick-up signals respectively obtained from the region of interest and a region of noninterest of the object.
Claim 6
Dependent Claim 40 words
A device according to claim 4, in which the density resolution is defined by the number of photons of the X-ray radiated from said X-ray source and by the saturation level of the output signal from said image pick-up means.

References Cited (Backward Citations)

US4423521A Cited
US4479231A Cited
US4473843A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-12-30 1989-07-01 1989-12-31 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-12-30 1993-07-01 1993-12-31 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-12-30 1997-07-01 1997-12-31 $7700.00 Window Closed / Lapsed

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