阅读说明：本技术 一种基于三维ct的脊柱点云提取算法 (Spine point cloud extraction algorithm based on three-dimensional CT ) 是由 伯斯坦·巴勃罗大卫 于 2021-08-02 设计创作，主要内容包括：本发明公开了一种基于三维CT的脊柱点云提取算法,包括如下步骤：S1、移除扫描床；S2、定位病人的中间矢状面MSP,使其与图像的前后轴平行；S3、定位左右PSIS坐标并将左右PSIS坐标假设位于同一张纵向切片上；S4、窗口显示CT上的皮肤；S5、连接PSIS坐标的点云提取；S51、在包含PSIS坐标的纵向切片k中,从左PSIS坐标对应的列出发,到右PSIS坐标对应列j结束；S52、找出每个切片中列的最后的一个像素,并且保存他们的3D坐标；S6、脊柱线的点云提取；S61、在每一帧轴向切片k中搜索；S62、根据MSP在列上寻找最后端的像素,并且保存他们的3D坐标。本发明为后续的电磁坐标系和CT坐标系的校准提供依据。(The invention discloses a spine point cloud extraction algorithm based on three-dimensional CT, which comprises the following steps: s1, removing the scanning bed; s2, positioning the MSP of the midsagittal plane of the patient to be parallel to the front and back axes of the image; s3, positioning the left and right PSIS coordinates and assuming that the left and right PSIS coordinates are positioned on the same longitudinal slice; s4, displaying the skin on the CT through a window; s5, extracting point cloud connected with PSIS coordinates; s51, in the longitudinal slice k containing the PSIS coordinates, starting from the column corresponding to the left PSIS coordinates and ending at the column j corresponding to the right PSIS coordinates; s52, finding the last pixel of the column in each slice and saving their 3D coordinates; s6, extracting point cloud of spinal lines; s61, searching in each frame of axial slice k; s62, find the rearmost pixels on the column according to the MSP, and save their 3D coordinates. The invention provides a basis for the subsequent calibration of the electromagnetic coordinate system and the CT coordinate system.)

1. A spine point cloud extraction algorithm based on three-dimensional CT is characterized in that: the method comprises the following steps:

s1, removing the scanning bed;

s2, positioning the MSP of the midsagittal plane of the patient to be parallel to the front and back axes of the image;

s3, positioning the left and right PSIS coordinates and assuming that the left and right PSIS coordinates are positioned on the same longitudinal slice;

s4, displaying the skin on the CT through a window;

s5, extracting point cloud connected with PSIS coordinates;

s51, in the longitudinal slice k containing the PSIS coordinates, starting from the column corresponding to the left PSIS coordinates and ending at the column j corresponding to the right PSIS coordinates;

s52, finding the last pixel of the column in each slice and saving their 3D coordinates;

s6, extracting point cloud of spinal lines;

s61, searching in each frame of axial slice k;

s62, find the rearmost pixels on the column according to the MSP, and save their 3D coordinates.

2. The three-dimensional CT based spine point cloud extraction algorithm of claim 1, wherein: in step S2, if the MSP is not parallel to the front-to-back axis of the image, then the alignment is rotated.

3. The three-dimensional CT based spine point cloud extraction algorithm of claim 2, wherein: the rotational alignment refers to a counter-rotational alignment.

4. The three-dimensional CT based spine point cloud extraction algorithm of claim 1, wherein: in steps S52 and S62, the coordinate values of the 3D coordinates are represented by i, j, k.

Technical Field

The invention belongs to the technical field of image processing, and particularly relates to a spine point cloud extraction algorithm of spine three-dimensional CT based on three-dimensional CT.

Background

In recent years, medical imaging techniques have been rapidly developed, and Computed Tomography (CT), magnetic resonance imaging (MR), and the like are widely used in clinical diagnosis. CT has a very wide spread because of its fast scanning speed and appropriate price, and is also very important in diagnosis and treatment of the spine.

The CT system utilizes the precisely collimated X-ray and a detector with extremely high sensitivity to receive signals penetrating through a human body, and data acquired by scanning form a tomographic image through an image reconstruction algorithm. With the development of multi-slice helical CT technology in recent years, the number of detector rows has been from the first 4 rows, 64 rows, to the present 256 rows CT. This in turn brings a huge amount of data to be interpreted by the physician, so the work of computer-aided analysis becomes very important. For example, in a CT scan of the spine, a scout image of the spine is typically scanned, and then the physician manually frames the position and orientation of each spine to facilitate the CT system scanning the spine along the spine. For another example, in spine orthopedics, a doctor is usually required to identify the position of each spine and regenerate tomographic images according to the spatial direction of each spine, so as to diagnose the health condition of the spine of a patient, and in the process, a person is usually required to interpret information such as the degree and direction of bending. When the computer-aided analysis is performed, a precise electromagnetic coordinate system and a precise CT coordinate system need to be established so as to facilitate the implementation of the aided analysis.

Disclosure of Invention

The invention aims to solve the problems and provides a spine point cloud extraction algorithm based on three-dimensional CT. And (3) extracting registration point cloud by utilizing CT bony information, wherein the point cloud can be matched with a sagittal line and a transverse line of a spine of a patient, and the two lines are connected with left and right PSIS points, so that a basis is provided for subsequent calibration of an electromagnetic coordinate system and a CT coordinate system.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a spine point cloud extraction algorithm based on three-dimensional CT comprises the following steps:

s1, removing the scanning bed;

s2, positioning a midsagittal plane (MSP) of the patient to be parallel to the front-back axis of the image;

s3, positioning the left and right PSIS coordinates and assuming that the left and right PSIS coordinates are positioned on the same longitudinal slice;

s4, displaying the skin on the CT through a window;

s5, extracting point cloud connected with PSIS coordinates;

s51, in the longitudinal slice k containing the PSIS coordinates, starting from the column corresponding to the left PSIS coordinates and ending at the column j corresponding to the right PSIS coordinates;

s52, finding the last pixel of the column in each slice and saving their 3D coordinates;

s6, extracting point cloud of spinal lines;

s61, searching in each frame of axial slice k;

s62, find the rearmost pixels on the column according to the MSP, and save their 3D coordinates.

As an improvement to the above technical solution, in step S2, if the MSP cannot be parallel to the front-back axis (anterior-posterior axis) of the image, the MSP is rotationally aligned.

As an improvement to the above technical solution, the rotational alignment refers to a reverse rotational alignment.

As a modification of the above, in step S52 and step S62, the coordinate values of the 3D coordinates are represented by i, j, k.

Compared with the prior art, the invention has the advantages and positive effects that:

according to the spine point cloud extraction algorithm based on the three-dimensional CT, the registration point cloud is extracted by utilizing the bony information of the CT, the point cloud can be matched with the sagittal line and the transverse line of the spine of the patient, and the two lines are connected with the left PSIS point and the right PSIS point, so that a basis is provided for the subsequent calibration of an electromagnetic coordinate system and a CT coordinate system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of an original CT slice with a couch beneath a patient's body;

FIG. 2 is a schematic drawing of a slice containing left and right PSIS, with the left cross indicated as the left PSIS slave, the right cross indicated as the right PSIS slave, the vertical line indicating the MSP plane, and the horizontal line being the top of the bed;

FIG. 3 is a schematic diagram of the result of extracting the spinal point cloud according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived from the embodiments of the present invention by a person skilled in the art without any creative effort, should be included in the protection scope of the present invention.

As shown in fig. 1 to 3, the present embodiment discloses a spine point cloud extraction algorithm based on three-dimensional CT, which includes the following steps:

s1, removing the scanning bed.

S2, positioning the midsagittal plane (MSP) of the patient, and rotationally aligning if the MSP is not parallel to the antero-posterior axis of the image.

S3, locating the left and right PSIS coordinates (assuming they are in the same longitudinal slice).

S4, conventionally, the window displays the skin on the CT.

S5, point cloud extraction of connecting PSIS:

in the vertical slice k containing the PSIS, starting from the column corresponding to the left PSIS and ending to the column j corresponding to the right PSIS.

The last pixel of the column in each slice is found and their 3D coordinates (i, j, k) are saved.

S6, point cloud extraction of spinal lines:

search in each frame axial slice k.

The rearmost pixels are found on the column according to msp (j) and their 3D coordinates (i, j, k) are saved.

S7, reverse rotation if necessary (from step 2a to both point clouds).