Apparatus For Determining a Modification of a Size of an Object

• US 20110142322A1
• Filed: 08/24/2009
• Published: 06/16/2011
• Est. Priority Date: 08/28/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kabus, Sven, Wiemker, Rafael
• Granted Patent: US 8,559,758 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: G06T 2207/10081 Computed x-ray tomography [CT]
• CPC Class Codes: G06T 2207/20104 Interactive definition of region of interest [ROI]
• CPC Class Codes: G06T 2207/30064 Lung nodule
• CPC Class Codes: G06T 3/147 using affine transformations
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/38 Registration of image sequences

Abstract

The present invention relates to an apparatus for determining a modification of a size of an object. The apparatus comprises a registration unit (13) for registering with respect to each other a first region of interest in a first image data set showing an object at a first time and a second region of interest in a second image data set showing the object at a second time being different from the first time, wherein the registration unit is adapted to generate a scaling value by performing at least a scaling transformation for registering the first region of interest and the second region of interest with respect to each other. The apparatus further comprises a modification value determination unit (14) for determining a modification value, which indicates the modification of the size of the object, depending on the generated scaling value.

Claims

1. An apparatus for determining a modification of a size of an object (23, 24), the apparatus comprising:

an image data set providing unit (18) for providing a first image data set (20) showing the object (23) at a first time and for providing a second image data set (21) showing the object (24) at a second time being different from the first time,

a region of interest providing unit (12) for providing a first region of interest (22), in which the object (23) shown in the first image data set (20) is located, in the first image data set (20) and for providing a second region of interest (25), in which the object (24) shown in the second image data set (21) is located, in the second image data set (21),

a registration unit (13) for registering the first region of interest (22) and the second region (25) of interest with respect to each other, wherein the registration unit (13) is adapted to generate a scaling value by performing at least a scaling transformation for registering the first region of interest (22) and the second region of interest (25) with respect to each other,

a modification value determination unit (14) for determining a modification value, which indicates the modification of the size of the object (23, 24), depending on the generated scaling value.

2. The apparatus as claimed in claim 1, wherein the registration unit (13) is adapted to generate several scaling values for different dimensions by performing the scaling transformation in different dimensions.

3. The apparatus as claimed in claim 2, wherein the modification value determination unit (14) is adapted to determine a modification value depending on the several scaling values generated for different dimensions.

4. The apparatus as claimed in claim 3, wherein the modification value determination unit (14) is adapted to determine a modification value depending on a product of the several scaling values.

5. The apparatus as claimed in claim 1, wherein the registration unit (13) is adapted to perform an affine transformation, which includes the scaling transformation, for registering the first region of interest (22) and the second region of interest (25) with respect to each other.

6. The apparatus as claimed in claim 1, wherein the region of interest providing unit (12) comprises:

a first position providing unit (30) for providing a first position (35) of the object in the first image data set (20),

a positioning region providing unit (32) for providing a positioning region (36) including the first position (35) of the object and the object (23) shown in the first image data set (20),

an aligning unit (31) for aligning the positioning region (36) with the second image data set (21), wherein the center of the aligned positioning region defines a second position (37) of the object in the second image data set (21),

wherein the region of interest providing unit (12) is adapted to provide the first region of interest (22) around the first position (35) of the object and to provide the second region of interest (25) around the second position (37) of the object.

7. The apparatus as claimed in claim 6, wherein the aligning unit (31) is adapted to determine a geometrical position of the first position (35) of the object with respect to a coordinate system, which is common to the first image data set (20) and the second image data set (21), to determine an intermediate second position of the object by determining the geometrical position in the second image data set (21) by using the coordinate system, and to start aligning the positioning region (36) with the second image data set (21) by positioning the positioning region in the second image data set (21) such that the center of the positioning region is the intermediate second position of the object.

8. The apparatus as claimed in claim 1, wherein

the registration unit (13) is adapted to perform a first registration for registering the first region of interest (22) onto the second region of interest (25), wherein the registration unit (13) is adapted to generate a first scaling value by performing at least a scaling transformation for registering the first region of interest (22) onto the second region of interest (25),

the modification value determination unit (14) is adapted to determine a first modification value, which indicates the modification of the size of the object, depending on the generated first scaling value,

the registration unit (13) is adapted to perform a second registration for registering the second region of interest (25) onto the first region of interest (22), wherein the registration unit (13) is adapted to generate a second scaling value by performing at least a scaling transformation for registering the second region of interest (25) onto the first region of interest (22),

the modification value determination unit (14) is adapted to determine a second modification value, which indicates the modification of the size of the object, depending on the generated second scaling value.

9. The apparatus as claimed in claim 8, further comprising:

a similarity determination unit (15) for determining whether one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are similar with respect to a similarity measure,

an output unit (11) for outputting a signal if the similarity determination unit (15) has determined that one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are not similar with respect to the similarity measure.

11. A computer program for determining a modification of a size of an object, the computer program comprising program code means for causing an apparatus as defined in claim 1 to carry out the steps of the method as defined in claim 10, when the computer program is run on a computer controlling the apparatus.

10. A method of determining a modification of a size of an object (23, 24), the method comprising the following steps:

providing a first image data set (20) showing the object (23) at a first time and providing a second image data set (21) showing the object (24) at a second time being different from the first time,

providing a first region of interest (22), in which the object (23) shown in the first image data set (20) is located, in the first image data set (20) and providing a second region of interest (25), in which the object (24) shown in the second image data set (21) is located, in the second image data set (21),

registering the first region of interest (22) and the second region of interest (25) with respect to each other, wherein a scaling value is generated by performing at least a scaling transformation for registering the first region of interest (22) and the second region of interest (25) with respect to each other,

determining a modification value, which indicates the modification of the size of the object, depending on the generated scaling value.