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EP0126434A2 Expired / Lapsed EP ⏱️ 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: —
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Expires: 2004-05-16
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Abstract

Abstract (9 An X-ray image pick-up device includes an X-ray source (34) for radiating X-rays onto an object (32) including a region of interest, an image intensifier (36) for converting to an optical image an X-ray image obtained when the X-rays radiated from the X-ray source (34) are transmitted through the object (32), an image pick-up camera (40) for converting to an image pick-up signal the optical image which is generated from the image intensifier (36), and an optical diaphragm (38) arranged between the image intensifier (36) and the image pick-up camera (40) for adjusting an amount of optical image light incident on the image pick-up camera (40). The X-ray image pick-up device further includes an exposure controller (46) for detecting both the maximum value of image pick-up signals from the pick-up camera (40) 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 (40) 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 (34), 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 C/O Patent Division Honda
  • 👤 Osamu C/O Patent Division Takami

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 21:51
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 204 words
An X-ray image pick-up device comprising: an X-ray source (34) for radiating X-rays onto an object (32) including a region of interest; means (36) for converting to an optical image an X-ray image obtained when the X-rays irradiate the object (32) and are transmitted therethrough; image pick-up means (40) for converting to an image pick-up signal the optical image which is generated from said converting means (36); and optical diaphragm means (38), disposed between said converting means (36) and said image pick-up means (40), for adjusting an amount of light incident on said image pick-up means (40), characterized in that said device further comprises exposure control means (46) for detecting a maximum value of image pick-up signals from said image pick-up means (40) 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 (40) with respect to various combinations of tube voltages, tube currents of said X-ray source (34) and optical diaphragm values of said optical diaphragm means (38), 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 204 words
An X-ray image pick-up device comprising: an X-ray source (34) for radiating X-rays onto an object (32) including a region of interest; means (36) for converting to an optical image an X-ray image obtained when the X-rays irradiate the object (32) and are transmitted therethrough; image pick-up means (40) for converting to an image pick-up signal the optical image which is generated from said converting means (36); and optical diaphragm means (38), disposed between said converting means (36) and said image pick-up means (40), for adjusting an amount of light incident on said image pick-up means (40), characterized in that said device further comprises exposure control means (46) for detecting a maximum value of image pick-up signals from said image pick-up means (40) 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 (40) with respect to various combinations of tube voltages, tube currents of said X-ray source (34) and optical diaphragm values of said optical diaphragm means (38), 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 46 words
A device according to claim 1, characterized in that said exposure control means (46) 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 (40) at the time of fluoroscopic examination.
Claim 4
Dependent Claim 60 words
A device according to claim 1, characterized in that said exposure control means (46) 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 (40) 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 42 words
A device according to claim 1, characterized in that 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 43 words
A device according to claim 4, characterized in that the density resolution is defined by the number of photons of the X-ray radiated from said X-ray source (34) and by the saturation level of the output signal from said image pick-up means (40).

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