Image processing apparatus, method, and program

Patent metadata

Field	Value
Publication number	US-9307948-B2
Application number	US-201414481741-A
Country	US
Kind code	B2
Filing date	Sep 9, 2014
Priority date	Mar 13, 2012
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The filtering unit calculates an evaluation matrix by performing filtering on each pixel position of an image representing a hollow structure using a second order partial differential of a function representing a hollow sphere. The evaluation unit calculates an evaluation value of at least one or more of point-like structureness, line-like structureness, and plane-like structureness at the pixel position based on the calculated evaluation matrix.

First claim

What is claimed is:

1. An image processing apparatus, comprising:
a filter that is configured to calculate a Hessian matrix on each pixel position of an image representing a hollow structure by convoluting a filter kernel representing a second order partial differential of a function representing a hollow sphere; and
an evaluation unit that is configured to calculate an evaluation value of at least one or more of hollow-point-like structureness, hollow-line-like structureness, and hollow-plane-like structureness at the pixel position based on the calculated Hessian matrix.

2. An image processing apparatus, comprising:
a filter that is configured to calculate an evaluation Hessian matrix by performing filtering on each pixel position of an image representing a hollow structure using by convoluting a filter kernel representing a second order partial differential of a function representing a hollow sphere; and
a direction discrimination unit that is configured to calculate eigenvalues and eigenvectors by performing eigenvalue analysis on the calculated Hessian matrix and discriminates, based on directions of the calculated eigenvectors, a principal axis direction of a hollow-line-like structure or a normal direction of a hollow-plane-like structure.

3. The image processing apparatus as claimed in claim 1 , wherein the function representing the hollow sphere is expressed by Formula (3) given below:

f
⁡

(
r
)

=

δ
⁡

(

r
-
R

)

r
=

x
2

+

y
2

+

z
2

}

(
3
)

where, x, y, z are three-dimensional coordinates in real space and R is the radius of the hollow sphere.

4. The image processing apparatus as claimed in claim 1 , wherein the filter calculates respectively, with respect to functions representing the hollow sphere in a plurality of sizes, Hessian matrixes by using filters representing a second order partial differential of the function representing each hollow sphere.

5. The image processing apparatus as claimed in claim 1 , wherein the filter calculates the Hessian matrix in Fourier space.

6. The image processing apparatus as claimed in claim 1 , wherein the image is a medical image, and the hollow structure is a bronchus.

7. An image processing method performed by a computer having a processor and a memory, comprising:
calculating a Hessian matrix by performing filtering on each pixel position of an image representing a hollow structure by convoluting a filter kernel representing a second order partial differential of a function representing a hollow sphere; and
calculating an evaluation value of at least one or more of hollow-point-like structureness, hollow-line-like structureness, and hollow-plane-like structureness at the pixel position based on the calculated Hessian matrix.

8. A non-transitory computer readable recording medium on which is recorded an image processing program that causes a computer to function as, comprising:
a filter that is configured to calculate a Hessian matrix on each pixel position of an image representing a hollow structure by convoluting a filter kernel representing a second order partial differential of a function representing a hollow sphere; and
an evaluation unit that is configured to calculate an evaluation value of at least one or more of hollow-point-like structureness, hollow-line-like structureness, and hollow-plane-like structureness at the pixel position based on the calculated Hessian matrix.

9. The image processing apparatus as claimed in claim 2 , wherein the function representing the hollow sphere is expressed by Formula (3) given below:

f
⁡

(
r
)

=

δ
⁡

(

r
-
R

)

r
=

x
2

+

y
2

+

z
2

}

(
3
)

Assignees

• Fujifilm Corp

Inventors

• Kitamura Yoshiro

Classifications

• G06T2207/10081

  Computed x-ray tomography [CT] · CPC title

• G06T2207/30061

  Lung · CPC title

• A61B6/505

  for diagnosis of bone · CPC title

• A61B6/504

  for diagnosis of blood vessels, e.g. by angiography · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title