US2011038452A1PendingUtilityA1
Image domain based noise reduction for low dose computed tomography fluoroscopy
Est. expiryAug 12, 2029(~3 yrs left)· nominal 20-yr term from priority
G06T 12/20Y10S378/901A61B 6/03
43
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
A method of computed-tomography and a computed-tomography apparatus in which x-ray projection data is acquired at a number of views for a scan of an object. Partial images are created from data for a desired number of said views. Full scan images are created from plural ones of the partial images. Non-overlapping time images are created from the full-scan images. Gradient images are also created. An improved image is created by weighting respective ones of the full scan and non-overlapping time images using the gradient image. The improved image has increased sharpness with reduced noise.
Claims
exact text as granted — not AI-modified1 . A method for generating computed-tomography image, comprising:
exposing an object with x-rays at a plurality of scans at a position of said object to obtain projection data at a plurality of views; generating first images serially in time using the projection data; generating second images by smoothing respective pluralities of said first images; generating a gradient image based on at least one of said first images; and generating a display image by weight blending one said of first images and one of said second images using said gradient image.
2 . A method as recited in claim 1 , comprising:
defining a plurality of said views as a view block; generating consecutive third images from respective consecutive view blocks; and generating each of said first images from a plurality of consecutive third images.
3 . A method as recited in claim 2 , comprising:
using projection data from said view blocks to produce a respective plurality of said third images.
4 . A method as recited in claim 2 , comprising:
generating a first one of said first images using a first plurality of said third images; and generating a second one of said first images by subtracting a first one of said third images from said first one of said first images and adding a next third image subsequent to said plurality of third images to said first one of said first images.
5 . A method as recited in claim 1 , wherein said second images comprise non-overlapping time images (NTA(k)), said first images are given by FS(k), and generating said second images comprises:
NTA
(
k
)
=
1
N
NTA
∑
i
=
1
N
NTA
FS
(
i
·
N
SPR
-
1
)
,
where
N
NTA
>
1
and
k
≥
N
NTA
·
N
SPR
-
1
where: N NTA is a number of NTA images, and
N SPR is a number of sections per rotation of said x-ray source.
6 . A method as recited in claim 1 , wherein first images are given by FS(k) and said gradient images are given by:
Grad k =abs( FS ( k )− FS ( k −1)), where k≧N SPR .
where N SPR is a number of sections per rotation of said x-ray source.
7 . A method as recited in claim 1 , wherein said first images are given by FS(m) and said gradient images are given by:
Grad m =abs( FS ( m )− FS ( m−N SPR )), where m ≧2· N SPR −1
where N SPR is a number of sections per rotation of said x-ray source.
8 . A method as recited in claim 1 , wherein said first images are given by FS(k), said third images are given by NTA p and said gradient images are given by:
Grad p =abs( FS−NTA p ), where p≧N NTA·N SPR −1
where: N NTA is a number of said second images
N SPR is a number of sections per rotation of said x-ray source.
9 . A method as recited in claim 1 , wherein said first images are FS p (n), said second images are NTA p (n) and said display images are given as:
Bl p ( n )=(1−α) NTA p ( n )+α· FS p ( n )
where α is a weighting factor.
10 . A method as recited in claim 9 , wherein a is given as:
1
1
+
-
(
x
-
x
0
)
/
w
.
11 . A method as recited in claim 9 , comprising:
using a blending curve to weight said first and second images.
12 . A method as recited in claim 11 , comprising:
automatically selecting said blending curve.
13 . A computed-tomography apparatus, comprising:
an x-ray source to expose an object with x-rays at a plurality of scans at a position of said object to obtain projection data at a plurality of views; an x-ray detector; a data collection unit; a data processing unit connected to said data collection unit; and a display, wherein: said data processing unit includes a memory storing x-ray projection data for a plurality of scans at a position of the object to obtain projection data at a plurality of views; and said data processing unit generates first images serially in time using the projection data, generates second images by smoothing respective pluralities of said first images, generates a gradient image based on at least one of said first images, and generates a display image by weight blending one said of first images and one of said second images using said gradient image.
14 . An apparatus as recited in claim 13 , wherein said second images comprise non-overlapping time images (NTA(k)), said first images are given by FS(k), and said second images are generated by said data processing unit as:
NTA
(
k
)
=
1
N
NTA
∑
i
=
1
N
NTA
FS
(
i
·
N
SPR
-
1
)
,
where
N
NTA
>
1
and
k
≥
N
NTA
·
N
SPR
-
1
where: N NTA is a number of NTA images, and
N SPR is a number of sections per rotation of said x-ray source.
15 . An apparatus as recited in claim 13 , wherein first images are given by FS(k) and said gradient images are given by:
Grad k =abs( FS ( k )− FS ( k −1)), where k≧N SPR .
where N SPR is a number of sections per rotation of said x-ray source.
16 . An apparatus as recited in claim 13 , wherein said first images are given by FS(m) and said gradient images are given by:
Grad p =abs( FS ( m )− FS ( m−N SPR )), where m ≧2· N SPR −1
where N SPR is a number of sections per rotation of said x-ray source.
17 . An apparatus as recited in claim 13 , wherein said first images are given by FS(k), said second images are given by NTA p and said gradient images are given by:
Grad p =abs( FS−NTA p ), where p≧N NTA ·N SPR −1
where: N NTA is a number of said second images
N SPR is a number of sections per rotation of said x-ray source.
18 . An apparatus as recited in claim 13 , wherein said first images are FS p (n), said second images are NTA p (n) and said display images are given as:
Bl p ( n )=(1−α) NTA p ( n )+α· FS p ( n )
where α is a weighting factor.
19 . An apparatus as recited in claim 18 , wherein α is given as:
1
1
+
-
(
x
-
x
0
)
/
w
.
20 . An apparatus as recited in claim 18 , comprising:
said data collection unit using a blending curve to weight said first and second images.
21 . An apparatus as recited in claim 20 , comprising said data collection unit automatically selecting said blending curve.Join the waitlist — get patent alerts
Track US2011038452A1 — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.