# US 10,482,602 B2 · System and method for image segmentation

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- Number: US 10,482,602 B2
- Document ID: US10482602B2
- Status: Granted
- Kind: B2
- Application number: 16/403,709
- Filed: 2019-05-06
- Published: 2019-08-22
- Granted: 2019-11-19
- Earliest claimed: 2015-05-05
- Assignees: Shanghai United Imaging Healthcare Co., Ltd.
- Applicants: Shanghai United Imaging Healthcare Co., Ltd.
- Inventors: Lilong Wang; Lijia Wang; Yufei Mao; Xiaolin Meng; Xiaodong Wang; Cheng Li
- Web page: https://patentgrep.com/patent/US10482602B2

## CPC

- G06T 7/11: Region-based segmentation
- G06T 7/136: involving thresholding
- G06T 7/143: involving probabilistic approaches, e.g. Markov random field [MRF] modelling
- G06T 7/155: involving morphological operators
- G06T 7/187: involving region growing; involving region merging; involving connected component labelling
- G06T 2200/04: involving 3D image data
- G06T 2207/10072: Tomographic images
- G06T 2207/20156: Automatic seed setting
- G06T 2207/20161: Level set
- G06T 2207/30061: Lung
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A system and method for image segmentation are provided. A three-dimensional image data set representative of a region including at least one airway may be acquired. The data set may include a plurality of voxels. A first-level seed within the region may be identified. A first-level airway within the region may be identified based on the first-level seed. A second-level airway may be identified within the region based on the first-level airway. The first-level airway and the second-level airway may be fused to form an airway tree.

## Claims

### Claim 1

A method of image processing implemented on at least one machine, each of which has at least one processor and at least one storage device, the method comprising:
acquiring a three-dimensional image data set representative of a region including at least one airway, the data set comprising a plurality of voxels;
identifying a first-level seed within the region;
identifying a first-level airway within the region based on the first-level seed;
identifying a second-level airway within the region based on the first-level airway, wherein the identifying a second-level airway includes:
defining a second-level seed based on the first-level airway;
identifying a voxel set based on a level set method and the second-level seed; and
selecting a voxel from the voxel set;
determining a second characteristic value of the voxel, wherein the second characteristic value includes an energy function value; and
marking, when the second characteristic value of the voxel is below a fourth threshold, the voxel as part of the second-level airway; and
fusing the first-level airway and the second-level airway to form an airway tree.

### Claim 2 (depends on 1)

The method of claim 1, the identifying a first-level airway comprising:
selecting, from the plurality of voxels, an adjacent voxel of the first-level seed and neighboring voxels of the adjacent voxel;
determining a characteristic value for the adjacent voxel and a characteristic value for each of the neighboring voxels;
calculating a difference between the characteristic value for the adjacent voxel and the characteristic value for each of the neighboring voxels; and
marking, when the characteristic value of the adjacent voxel is below a first threshold and when, for each of the neighboring voxels, the difference is below a second threshold, the adjacent voxel as part of the first-level airway.

### Claim 3 (depends on 1)

The method of claim 1, the identifying a first-level airway comprising using a morphology based method.

### Claim 4 (depends on 1)

The method of claim 1, the identifying a first-level airway comprising:
determining a voxel set based on a level set method;
selecting a voxel from the voxel set;
determining a first characteristic value of the voxel, wherein the first characteristic value includes a grey level; and
marking, when the first characteristic value of the voxel is below a third threshold, the voxel as part of the first-level airway.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first-level airway includes a low-level bronchus of a lung region, and the second-level airway includes a terminal bronchiole of a lung region.

### Claim 6 (depends on 1)

The method of claim 1 further comprising:
identifying a lung organ;
identifying a lung tissue based on the fused airway and the lung organ; and
labelling, based on the fused airway, the identified lung tissue as a left lung tissue or a right lung tissue.

### Claim 7 (depends on 6)

The method of claim 6, further comprising:
obtaining an image for a 2D layer of the lung organ;
smoothing the image based on a morphology based method; and
labelling a left lung portion of the lung organ including the second-level airway or a right lung portion of the lung organ including the second-level airway based on the smoothed image and the first-level airway.

### Claim 8 (depends on 6)

The method of claim 6, the identifying a lung organ comprising:
determining a lung region based on the plurality of voxels;
removing a background based on the determined lung region;
determining a 2D layer based on area of the 2D layer; and
performing 3D region growing based on the 2D layer.

### Claim 9 (depends on 8)

The method of claim 8, the determining a lung region comprising:
selecting, from the plurality of voxels, a voxel; and
determining, based on a comparison between a characteristic value of the voxel and a seventh threshold, whether the voxel belongs to the lung region.

### Claim 10 (depends on 8)

The method of claim 8, the removing a background comprising:
identifying a background send near an edge of the lung region; and
performing region growing based on the background seed.

### Claim 11

A system comprising:
at least one processor, and
executable instructions that, when executed by the at least one processor, cause the at least one processor to effectuate a method comprising:
acquiring a three-dimensional image data set representative of a region including at least one airway, the data set comprising a plurality of voxels;
identifying a first-level seed within the region;
identifying a first-level airway within the region based on the first-level seed;
identifying a second-level airway within the region based on the first-level airway, wherein the identifying a second-level airway includes:
defining a second-level seed based on the first-level airway;
identifying a voxel set based on a level set method and the second-level seed; and
selecting a voxel from the voxel set;
determining a second characteristic value of the voxel, wherein the second characteristic value includes an energy function value; and
marking, when the second characteristic value of the voxel is below a fourth threshold, the voxel as part of the second-level airway; and
fusing the first-level airway and the second-level airway to form an airway tree.

### Claim 12 (depends on 11)

The system of claim 11, the identifying a first-level airway comprising:
selecting, from the plurality of voxels, an adjacent voxel of the first-level seed and neighboring voxels of the adjacent voxel;
determining a characteristic value for the adjacent voxel and a characteristic value for each of the neighboring voxels;
calculating a difference between the characteristic value for the adjacent voxel and the characteristic value for each of the neighboring voxels; and
marking, when the characteristic value of the adjacent voxel is below a first threshold and when, for each of the neighboring voxels, the difference is below a second threshold, the adjacent voxel as part of the first-level airway.

### Claim 13 (depends on 11)

The system of claim 11, the identifying a first-level airway comprising:
determining a voxel set based on a level set method;
selecting a voxel from the voxel set;
determining a first characteristic value of the voxel, wherein the first characteristic value includes a grey level; and
marking, when the first characteristic value of the voxel is below a third threshold, the voxel as part of the first-level airway.

### Claim 14 (depends on 11)

The system of claim 11, wherein the first-level airway includes a low-level bronchus of a lung region, and the second-level airway includes a terminal bronchiole of a lung region.

### Claim 15 (depends on 11)

The system of claim 11, further comprising:
identifying a lung organ;
identifying a lung tissue based on the fused airway and the lung organ; and
labelling, based on the fused airway, the identified lung tissue as a left lung tissue or a right lung tissue.

### Claim 16 (depends on 15)

The system of claim 15, further comprising:
obtaining an image for a 2D layer of the lung organ;
smoothing the image based on a morphology based method; and
labelling a left lung portion of the lung organ including the second-level airway or a right lung portion of the lung organ including the second-level airway based on the smoothed image and the first-level airway.

### Claim 17 (depends on 15)

The system of claim 15, the identifying a lung organ comprising:
determining a lung region based on the plurality of voxels;
removing a background based on the determined lung region;
determining a 2D layer based on area of the 2D layer; and
performing 3D region growing based on the 2D layer.

### Claim 18 (depends on 17)

The system of claim 17, the determining a lung region comprising:
selecting, from the plurality of voxels, a voxel; and
determining, based on a comparison between a characteristic value of the voxel and a seventh threshold, whether the voxel belongs to the lung region.

### Claim 19 (depends on 17)

The system of claim 17, the removing a background comprising:
identifying a background send near an edge of the lung region; and
performing region growing based on the background seed.

### Claim 20

A non-transitory computer readable medium comprising executable instructions that, when executed by at least one processor, cause the at least one processor to effectuate a method comprising:
acquiring a three-dimensional image data set representative of a region including at least one airway, the data set comprising a plurality of voxels;
identifying a first-level seed within the region;
identifying a first-level airway within the region based on the first-level seed;
identifying a second-level airway within the region based on the first-level airway, wherein the identifying a second-level airway includes:
defining a second-level seed based on the first-level airway;
identifying a voxel set based on a level set method and the second-level seed; and
selecting a voxel from the voxel set;
determining a second characteristic value of the voxel, wherein the second characteristic value includes an energy function value; and
marking, when the second characteristic value of the voxel is below a fourth threshold, the voxel as part of the second-level airway; and
fusing the first-level airway and the second-level airway to form an airway tree.
