# US 8,787,647 B2 · Image matching device and patient positioning device using the same

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- Number: US 8,787,647 B2
- Document ID: US8787647B2
- Status: Granted
- Kind: B2
- Application number: 13/256,551
- Filed: 2010-06-07
- Published: 2012-05-10
- Granted: 2014-07-22
- Earliest claimed: 2009-06-10
- Assignees: Mitsubishi Electric Corporation
- Applicants: Kosuke Hirasawa; Hidenobu Sakamoto; Ryoichi Yamakoshi; Yasuo Kitaaki; Shinjiro Kawato; Haruhisa Okuda; Hiroshi Kage; Kazuhiko Sumi
- Inventors: Kosuke Hirasawa; Hidenobu Sakamoto; Ryoichi Yamakoshi; Yasuo Kitaaki; Shinjiro Kawato; Haruhisa Okuda; Hiroshi Kage; Kazuhiko Sumi
- Web page: https://patentgrep.com/patent/US8787647B2

## CPC

- A61B 6/0487: {Motor-assisted positioning}
- A61B 90/36: {Image-producing devices or illumination devices not otherwise provided for}
- G06T 7/33: using feature-based methods
- G06T 7/337: {involving reference images or patches}
- A61B 2090/364: {Correlation of different images or relation of image positions in respect to the body}
- G06T 2207/10081: Computed x-ray tomography [CT]
- G06T 2207/30004: Biomedical image processing
- G06T 2207/30008: Bone
- G06T 2207/30096: Tumor; Lesion
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

An image matching device in which, in automatic positioning calculation using an ICP method, a solution is converged to an optimal solution while avoiding reaching a local solution, and a patient positioning device using this matching device. The device includes a CT image data reading unit reading first and second CT image data, a point group data generation unit generating first and second point group data in a three-dimensional space by binarization processing and edge-extraction processing on sliced images of the first and second CT image data, respectively, a point group data resolution conversion unit thinning-out point group data so as to extend a point-group-data array pitch, and an ICP calculation unit obtaining, using an ICP method, a conversion amount for the second point group data so that an error function of the first point group data and the second point group data outputted from the point group data resolution conversion unit is minimized.

## Claims

### Claim 1

An image matching device comprising:
a CT image data reading unit for reading first CT image data and second CT image data;
a point group data generation unit for generating first point group data and second point group data in a three-dimensional space from sliced images of the first CT image data and the second CT image data, respectively;
a point group data resolution conversion unit for thinning-out at least one of the first point group data and the second point group data so as to extend a point-group-data array pitch; and
an ICP (iterative closest point) calculation unit for obtaining, using an ICP method, a conversion amount for the second point group data so that an error function of the first point group data and the second point group data outputted from the point group data resolution conversion unit is minimized.

### Claim 2 (depends on 1)

An image matching device as recited in claim 1 further comprising
a region division unit for dividing the first point group data into a plurality of regions, and the second point group data into a plurality of regions corresponding thereto, wherein
the ICP calculation unit calculates only between each of the regions of the first point group data and each of the corresponding regions of the second point group data.

### Claim 3 (depends on 1)

An image matching device as recited in claim 1 further comprising
a point group data noise removal unit for removing, from at least one of the first point group data and the second point group data, noise data in a portion other than a region where image matching is performed, wherein
the ICP calculation unit calculates using the first point group data and the second point group data where the noise data has been removed.

### Claim 4 (depends on 1)

An image matching device as recited in claim 1 further comprising:
an MPR processing unit for creating from the second CT image data, using oblique-section creation parameters based on the conversion amount obtained by the ICP calculation unit, an MPR section group which can be compared with the first CT image data;
a template setting unit for registering as a template image a characteristic region selected from the MPR section group; and
a template matching unit for obtaining, by matching the sliced images of the first CT image data and the template image, a place where a correlation value is highest, and then obtaining a conversion-amount compensation value for the second point group data so as to translate the characteristic region to this place.

### Claim 5 (depends on 4)

An image matching device as recited in claim 4 wherein
the template setting unit registers as a plurality of template images a plurality of characteristic regions existing in respective consecutive MPR sections selected from the MPR section group, and
the template matching unit obtains, by matching the sliced images of the first CT image data and the plurality of template images, a place where the sum of correlation values for the respective template images is highest, and a conversion amount compensation value for the second point group data so as to translate the plurality of characteristic regions to this place.

### Claim 6

A patient positioning device comprising:
an image matching device including:
a CT image data reading unit for reading first CT image data and second CT image data;
a point group data generation unit for generating first point group data and second point group data in a three-dimensional space from sliced images of the first CT image data and the second CT image data, respectively;
a point group data resolution conversion unit for thinning-out at: Least one of the first point group data and the second point group data so as to extend a point-group-data array pitch; and
an ICP (iterative closest point) calculation unit for obtaining, using an ICP method, a conversion amount for the second point group data so that an error function of the first point group data and the second point group data outputted from the point group data resolution conversion unit is minimized; and
a treatment table control parameter calculation unit for calculating parameters for controlling driving axes of a treatment table according to the conversion amount obtained by the ICP calculation unit.

### Claim 7 (depends on 6)

A patient positioning device as recited in claim 6, wherein
the image matching device further includes a region division unit for dividing the first point group data into a plurality of regions, and the second point group data into a plurality of regions corresponding thereto, and
the ICP calculation unit calculates only between each of the regions of the first point group data and each of the corresponding regions of the second point group data.

### Claim 8 (depends on 6)

A patient positioning device as recited in claim 6, wherein
the image matching device further includes a point group data noise removal unit for removing, from at least one of the first point group data and the second point group data, noise data in a portion other than a region where image matching is performed, and
the ICP calculation unit calculates using the first point group data and the second point group data where the noise data has been removed.

### Claim 9 (depends on 6)

A patient positioning device as recited in claim 6,
wherein the image matching device further includes:
an MPR processing unit for creating from the second CT image data, using oblique-section creation parameters based on the conversion amount obtained by the ICP calculation unit, an MPR section group which can be compared with the first CT image data;
a template setting unit for registering as a template image a characteristic region selected from the MPR section group; and
a template matching unit for obtaining, by matching the sliced images of the first CT image data and the template image, a place where a correlation value is highest, and then obtaining a conversion-amount compensation value for the second point group data so as to translate the characteristic region to this place; and
the treatment table control parameter calculation unit calculates the parameters for controlling the driving axes of the treatment table according to the conversion amount obtained by the ICP calculation unit and the conversion amount compensation value obtained by the template matching unit.

### Claim 10 (depends on 9)

A patient positioning device as recited in claim 9, wherein
the template setting unit registers as a plurality of template images a plurality of characteristic regions existing in respective consecutive MPR sections selected from the MPR section group, and
the template matching unit obtains, by matching the sliced images of the first CT image data and the plurality of template images, a place where the sum of correlation values for the respective template images is highest, and a conversion amount compensation value for the second point group data so as to translate the plurality of characteristic regions to this place.