US5233989A
Expired / Lapsed
US
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Method for discriminating x-ray contrast image from non-contrast image and x-ray imaging system including contrast image discriminating function
Assignee: Toshiba Corp
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Filing: 1991-10-17
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Granted: 1993-08-10
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Expires: 2011-10-17
Abstract
Abstract To discriminate a contrast image from a non-contrast image, an X-ray imaging method is characterized by comprising the steps of: acquiring a plurality of X-ray images of a biological body under medical examination; subtracting at least two sets of the X-ray images with each other acquired at temporally different timings to obtain a subtraction image; subdividing one subtraction image into a plurality of image blocks; calculating an averaged value of image concentration with respect to each of the image blocks, thereby obtaining a plurality of averaged values for the subdivided image blocks; calculating a difference between at least two averaged values of image concentration with respect to the image blocks acquired within substantially same temporal timing period; and, judging whether or not the X-ray image is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.
Inventors
- 👤 Michitaka Honda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:48
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/50
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
144 words
An X-ray imaging method comprising the steps of: acquiring a plurality of X-ray images of a biological body under medical examination; subtracting at least two of the X-ray images from each other acquired at temporally different timings to obtain a subtraction image; subdividing one subtraction image into a plurality of image blocks; calculating an averaged value of image concentration with respect to each of the image blocks, thereby obtaining a plurality of averaged values for each of the plurality of image blocks; calculating a difference between at least two of said charged values of image concentration with respect to the image blocks acquired within substantially same temporal timing period; and, judging whether one of said plurality of X-ray images is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.
Claim 2
Dependent Claim
144 words
An X-ray imaging method comprising the steps of: acquiring a plurality of X-ray images of a biological body under medical examination; subtracting at least two of the X-ray images from each other acquired at temporally different timings to obtain a subtraction image; subdividing one subtraction image into a plurality of image blocks; calculating an averaged value of image concentration with respect to each of the image blocks, thereby obtaining a plurality of averaged values for each of the plurality of image blocks; calculating a difference between at least two of said charged values of image concentration with respect to the image blocks acquired within substantially same temporal timing period; and, judging whether one of said plurality of X-ray images is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.
Claim 3
Dependent Claim
65 words
An X-ray imaging method as claimed in claim 1, further comprising the step of: coding said averaged value of image concentration for the image blocks by comparing said averaged value with a threshold value to obtain coded-image data, whereby it is judged whether the X-ray image is acquired under such a condition that an X-ray contrast medium appears therein based n the coded image data.
Claim 4
Dependent Claim
18 words
An X-ray imaging method as claimed in claim 2, wherein at least two different threshold values are employed.
Claim 5
Dependent Claim
22 words
An X-ray imaging method as claimed in claim 1, wherein said one subtraction image is subdivided into at least four image blocks.
Claim 6
Dependent Claim
157 words
An X-ray imaging system comprising: means for producing a plurality of X-ray images of a biological body under medical examination; subtraction means for subtracting at least two of the X-ray images with each of the produced at temporally different timings to obtain a subtraction image; subdividing means or subdividing said subtraction image into a plurality of image blocks; averaging means for obtaining an averaged value of image concentration for each of image blocks subdivided from one subtraction image, thereby obtaining a plurality of averaged values for the image blocks; calculating means for calculating a difference between at least two of said averaged values of image concentration with respect to the image blocks acquired within substantially same temporal timing period; and judging means for judging whether one of the plurality of X-ray times is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.
Claim 7
Dependent Claim
157 words
An X-ray imaging system comprising: means for producing a plurality of X-ray images of a biological body under medical examination; subtraction means for subtracting at least two of the X-ray images with each of the produced at temporally different timings to obtain a subtraction image; subdividing means or subdividing said subtraction image into a plurality of image blocks; averaging means for obtaining an averaged value of image concentration for each of image blocks subdivided from one subtraction image, thereby obtaining a plurality of averaged values for the image blocks; calculating means for calculating a difference between at least two of said averaged values of image concentration with respect to the image blocks acquired within substantially same temporal timing period; and judging means for judging whether one of the plurality of X-ray times is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.
Claim 8
Dependent Claim
48 words
An X-ray imaging system as claimed in claim 5, wherein said averaging means is constructed of at least accumulating means for accumulating said plurality of X-ray images, and subtracting means for performing a subtraction among the accumulated X-ray images, whereby said averaged values of image concentration are obtained.
Claim 9
Dependent Claim
66 words
An X-ray imaging system as claimed in claim 5, wherein said calculating means includes: threshold value generating means for generating at least a first threshold value and a second threshold value; and, comparing means for comparing at least two image blocks based upon said first and second threshold values so as to obtain coded-image data reflecting said difference in said two averaged values of image concentration.
Claim 10
Dependent Claim
39 words
An X-ray imaging system as claimed claim 7, further comprising: a plurality of frame memories each having a plurality of memory regions coupled to said comparing means for storing a plurality of coded-image data derived from said comparing means.
Claim 11
Dependent Claim
164 words
An X-ray imaging system as claimed in claim 8, wherein said judging means includes: address generating means for generating a plurality of address data; first table memory means having a first conversion table, for converting the coded-image data read from each of said plurality of memory regions of each of said plurality of frame memories simultaneously addressed by the same address data into a plurality of code signals based upon the first conversion table; plural counting means for counting a total number of each of said code signals, while reading all of said plurality of said memory regions of said plurality of frame memories; and second gable memory means having a second conversion table, for converting said total number o the code signals into a contrast-image present signal based upon the second conversion able, whereby a judgement is made whether or not the X-ray image is acquired under such a condition that the X-ray contrast medium appears therein based upon said contrast-image present signal.
Claim 12
Dependent Claim
27 words
An X-ray imaging system as claimed in claim 8, further comprising: one frame memory coupled to said comparing means for storing one piece of said coded-image data.
Claim 13
Dependent Claim
117 words
An X-ray imaging system as claimed in claim 10, wherein said judging means includes: address generating means for sequentially generating address data; code distributing means for distributing code signals reflecting said coded-image data; plural counting means for counting a total number of each of said code signals while reading an entire memory region of said single frame memory; and, a table memory having a conversion table coupled to said counting means, for converting said total numbers of code signals into a contrast-image present signal based upon the conversion table, whereby a judgement is established whether the X-ray image is acquired under such a condition that the X-ray contrast medium appears therein based upon the contrast-image present signal.
Claim 14
Dependent Claim
40 words
An X-ray imaging system as claimed in claim 7, wherein said threshold value generating means of said calculating means further generates a third threshold value and a fourth threshold value, which are different from said first and second threshold values.
Claim 15
Dependent Claim
104 words
An X-ray imaging system as claimed in claim 5, further comprising a peak trace unit including: X-ray image frame memory means for sequentially receiving said plurality of X-ray image to be stored therein; and, comparator means for comparing said X-ray images with each other which are successively produced by said producing means and derived from said X-ray image frame memory means, so as to obtain X-ray image data having a lowest concentration value from concentration values for all of the compared image data, whereby a plurality of said X-ray image data having the lowest concentration value are continuously derived from said peak trace unit.
References Cited (Backward Citations)
US4483342A
Cited
US4437161A
Cited
US4436095A
Cited
US4459990A
Cited
JPS59110293A
Cited
US4636953A
Cited
US4688175A
Cited
US4816681A
Cited
JPS60185481A
Cited
JPS61252779A
Cited
JPS62167540A
Cited
JPS6478241A
Cited
US5029586A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |