Patent EP0097044A1 successfully refreshed from Google Patents.
EP0097044A1
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EP
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Diagnostic X-ray apparatus
Assignee: Toshiba Corp
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Filing: 1983-06-10
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Granted: —
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Expires: 2003-06-10
Abstract
Abstract A diagnostic x-ray apparatus emitting pulsed x-ray radiation and including a processor for performing digital x-ray subtraction imaging which includes digitisation of the video signals from an image intensifier-TV chain, digital subtraction and reconversion of the resultant digital difference video signals to analogue signals, wherein the subtraction is performed for two successive difference images with multiplying each image by the respective weighting factor in a predetermined image sequence. The resulting difference image is compared with a standard and reduced to at least the standard before display.
Inventors
- 👤 Kiyoshi C/O Patent Division Okazaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 11:32
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/30; H04N5/32; H04N5/3205
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
309 words
A diagnostic x-ray apparatus for producing visible difference images from x-ray images, obtained from x-ray radiation, comprising: an x-ray generating source for emitting radiation to produce an x-ray image; a television camera for converting said x-ray image into a series of television video signals; synchronising means for generating vertical framing signals at the vertical frame rate of said television camera; exposure control means responsive to said vertical framing signals for generating x-ray exposure control signals to control the exposure of x-ray radiation emitted from said x-ray generating source; analogue-to-digital converter means for selectively causing the analogue video signals corresponding to a television image being selected in a predetermined sequence to be converted into corresponding digital video signals; first weighted subtraction means including first digital memory means for integrating and storing said digital video signals, for producing digital difference video signals by performing a subtraction weighted with a first set of weighting factors between digital video signals recently stored in said digital memory means and preceding digital video signals previously stored in said digital memory means; second weighted subtraction means including second digital memory means for integrating and storing said digital difference video signals from the first weighted subtraction means, for producing digital difference video signals by performing a subtraction weighted with a second set of weighting factors between digital video signals recently stored in said second digital memory means and digital difference video signals previously stored in said digital memory means; comparator means for comparing said digital difference video signals from the second weighted subtraction means with a predetermined standard, and reducing the latter digital difference video signal within the predetermined standard; a digital-to-analogue converter for converting said digital difference video signals from said comparator means into analogue difference video signals; and display or recording means for displaying or recording difference images corresponding to said analogue difference video signals.
Claim 2
Dependent Claim
309 words
A diagnostic x-ray apparatus for producing visible difference images from x-ray images, obtained from x-ray radiation, comprising: an x-ray generating source for emitting radiation to produce an x-ray image; a television camera for converting said x-ray image into a series of television video signals; synchronising means for generating vertical framing signals at the vertical frame rate of said television camera; exposure control means responsive to said vertical framing signals for generating x-ray exposure control signals to control the exposure of x-ray radiation emitted from said x-ray generating source; analogue-to-digital converter means for selectively causing the analogue video signals corresponding to a television image being selected in a predetermined sequence to be converted into corresponding digital video signals; first weighted subtraction means including first digital memory means for integrating and storing said digital video signals, for producing digital difference video signals by performing a subtraction weighted with a first set of weighting factors between digital video signals recently stored in said digital memory means and preceding digital video signals previously stored in said digital memory means; second weighted subtraction means including second digital memory means for integrating and storing said digital difference video signals from the first weighted subtraction means, for producing digital difference video signals by performing a subtraction weighted with a second set of weighting factors between digital video signals recently stored in said second digital memory means and digital difference video signals previously stored in said digital memory means; comparator means for comparing said digital difference video signals from the second weighted subtraction means with a predetermined standard, and reducing the latter digital difference video signal within the predetermined standard; a digital-to-analogue converter for converting said digital difference video signals from said comparator means into analogue difference video signals; and display or recording means for displaying or recording difference images corresponding to said analogue difference video signals.
Claim 3
Dependent Claim
27 words
The apparatus of claim 1 wherein said two weighted subtraction means including multipliers for multiplying digital video signals from digital memory means by sets of weighting factors.
Claim 4
Dependent Claim
45 words
The apparatus of claim 2 wherein, said sets of weighting factors are generated from a micro-processor incorporating a read only memory, at least a portion of said factors being determined in accordance with ratio of amplitudes of digital video signals used in the subtraction process.
Claim 5
Dependent Claim
143 words
A diagnostic x-ray apparatus for producing visible difference images from x-ray images comprising, means for producing x-ray images, analogue-to-digital means for converting the analogue video signals of the x-ray images into corresponding digital video signals; means for storing said digital video signals representing first and second images of the same objective; means for subtracting the digital video signals representing one of said first and second images from the other to produce digital video signals of a difference image; means for comparing the value of said digital video signals of the difference image with a predetermined standard; means for reducing said value at least to said predetermined standard if the value exceeds the standard; digital-to-analogue means for converting said digital video signals of the difference image within said standard to analogue video signals; and means for displaying or recording said latter analogue video signals.
Claim 6
Dependent Claim
143 words
A diagnostic x-ray apparatus for producing visible difference images from x-ray images comprising, means for producing x-ray images, analogue-to-digital means for converting the analogue video signals of the x-ray images into corresponding digital video signals; means for storing said digital video signals representing first and second images of the same objective; means for subtracting the digital video signals representing one of said first and second images from the other to produce digital video signals of a difference image; means for comparing the value of said digital video signals of the difference image with a predetermined standard; means for reducing said value at least to said predetermined standard if the value exceeds the standard; digital-to-analogue means for converting said digital video signals of the difference image within said standard to analogue video signals; and means for displaying or recording said latter analogue video signals.
Claim 7
Dependent Claim
128 words
A diagnostic x-ray apparatus of claim 4 also including; means for storing said digital video signals of said difference image; means for storing digital video signals as converted by said analogue-to-digital means representing a third image of the same objective; means for subtracting said digital video signals representing said first image from the digital video signals representing said third image to obtain digital video signals representing second difference image; means for subtracting said digital signals representing said first difference image from the digital video signals representing said second difference image to produce digital video signals representing a third difference image; and wherein said comparing means, said reducing means, said digital-to-analogue means and said displaying means are successively applied to said digital video signals representing said third difference image.
Claim 8
Dependent Claim
80 words
A diagnostic x-ray apparatus for producing video signals representing difference images from x-ray images of the same objective, the improvement comprising: means for comparing the value of the video signals of a difference image with a predetermined standard, and means for reducing said value at least to said predetermined standard, if said value exceeds said standard, whereby any signal values representing unwanted background images developed as the result of time differentials between relevant x-ray images are removed or substantially reduced.
Claim 9
Dependent Claim
80 words
A diagnostic x-ray apparatus for producing video signals representing difference images from x-ray images of the same objective, the improvement comprising: means for comparing the value of the video signals of a difference image with a predetermined standard, and means for reducing said value at least to said predetermined standard, if said value exceeds said standard, whereby any signal values representing unwanted background images developed as the result of time differentials between relevant x-ray images are removed or substantially reduced.
Claim 10
Independent Claim
63 words
A method for producing video signals representing difference images from x-ray images of the same objective, an improvement for removing unwanted background images arising during the time differential between x-ray images comprising: comparing the value of the video signals of a difference image with a predetermined standard; and reducing said value at least to said predetermined standard, if said value exceeds said standard.
Claim 11
Independent Claim
63 words
A method for producing video signals representing difference images from x-ray images of the same objective, an improvement for removing unwanted background images arising during the time differential between x-ray images comprising: comparing the value of the video signals of a difference image with a predetermined standard; and reducing said value at least to said predetermined standard, if said value exceeds said standard.
References Cited (Backward Citations)
US4210812A
Cited
US4204226A
Cited
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