CN118121304A - Error evaluation method and host in operation navigation system - Google Patents

Abstract

An error evaluation method and a host in a surgical navigation system are applied to the surgical navigation system matched with medical image equipment, and the surgical navigation system comprises: a host computer and an end effector mounted with a surgical needle, the method comprising: the method comprises the steps that a host acquires space coordinates of a planning target point in a planning puncture path, and first space coordinates of feature points marked on a surrounding area of the target point on a target planning scanning image where the planning target point is located; acquiring the space coordinates of an actual target point reached by a needle point after the surgical needle punctures according to a planned puncturing path, matching the image features of the region around the feature point on the planning map with a plurality of puncturing scanning maps, and acquiring the second space coordinates of the feature point on the puncturing scanning maps; and calculating the relative error between the planning target point and the actual target point according to all the obtained space coordinates. The embodiment of the application can acquire the relative deviation between the actual and planned paths relative to the focus position by the characteristic points, and improve the effective rate of the evaluation result.

Description

Error evaluation method and host in operation navigation system

Technical Field

The present disclosure relates to data processing technology, and more particularly, to an error assessment method and a host in a surgical navigation system.

Background

Percutaneous puncture surgery is a common means for current diagnosis and treatment, and more percutaneous puncture navigation robots are gradually applied to improve the accuracy and safety of the surgery. How to accurately evaluate the deviation between the actual puncture path and the planned path in the process of performing percutaneous puncture surgery using a navigation robot is a problem faced by most current navigation systems.

In the related art, an absolute error is often calculated, that is, an error between a spatial coordinate of a planned target point and a spatial coordinate of an actual target point in a coordinate system of medical imaging equipment, and the absolute error is used to evaluate a deviation between an actual puncture path and a planned path.

However, the absolute error cannot reveal the relation with the focus position, and the guiding significance for practical application is weak, so that the effective rate of the evaluation result is low.

Disclosure of Invention

The application provides an error evaluation method and a host in a surgical navigation system, which can acquire the relative deviation between an actual puncture path and a planned path relative to the focus position, thereby improving the effective rate of an evaluation result.

In one aspect, the present application provides an error assessment method applied to a surgical navigation system used in cooperation with a medical imaging device, the surgical navigation system comprising: a host computer and an end effector, the end effector having a surgical needle mounted thereon, the error assessment method comprising:

the host acquires the space coordinates of a planning target point in the planning puncture path and the first space coordinates of the characteristic points; the characteristic points are points marked in a first preset size area taking the planning target point as a central point on the target planning scanning diagram in advance;

The host acquires the space coordinates of an actual target point reached by a needle point after the surgical needle actually punctures according to the planned puncturing path, matches the image features of a second preset size area taking the feature point as a central point on the target planning scanning image with a plurality of puncturing scanning images, and acquires the second space coordinates of the feature point on the puncturing scanning image;

and calculating the relative error between the planning target point and the actual target point according to the space coordinates of the planning target point, the first space coordinates of the characteristic points, the space coordinates of the actual target point and the second space coordinates of the characteristic points.

In another aspect, the present application provides a host in a surgical navigation system, comprising: a memory and a processor;

the memory is used for storing executable programs;

The processor is configured to read and execute the executable program to implement the error evaluation method as described above.

Compared with the related art, the method comprises the steps that the host acquires the space coordinates of the planning target point in the planning puncture path and the first space coordinates of the feature points; the characteristic points are points marked in a first preset size area taking the planning target point as a central point on the target planning scanning diagram in advance; acquiring the space coordinates of an actual target point reached by a needle point after the surgical needle completes actual puncture according to the planned puncture path, matching the image features of a second preset size area taking the feature point as a central point on the target planning scanning image with a plurality of puncture scanning images, and acquiring the second space coordinates of the feature point on the puncture scanning image; and calculating the relative error between the planning target point and the actual target point according to the space coordinates of the planning target point, the first space coordinates of the characteristic points, the space coordinates of the actual target point and the second space coordinates of the characteristic points. The embodiment of the application can acquire the relative deviation between the actual puncture path and the planned path relative to the focus position by means of the characteristic points, thereby improving the effective rate of the evaluation result.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. Other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. Other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The accompanying drawings are included to provide an understanding of the principles of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain, without limitation, the principles of the application.

Fig. 1 is a flow chart of an error evaluation method according to an embodiment of the application.

Detailed Description

The present application has been described in terms of several embodiments, but the description is illustrative and not restrictive, and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the described embodiments. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are possible. Any feature or element of any embodiment may be used in combination with or in place of any other feature or element of any other embodiment unless specifically limited.

The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The disclosed embodiments, features and elements of the present application may also be combined with any conventional features or elements to form a unique inventive arrangement as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive arrangements to form another unique inventive arrangement as defined in the claims. It is therefore to be understood that any of the features shown and/or discussed in the present application may be implemented alone or in any suitable combination. Accordingly, the embodiments are not to be restricted except in light of the attached claims and their equivalents. Further, various modifications and changes may be made within the scope of the appended claims.

Furthermore, in describing representative embodiments, the specification may have presented the method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. Other sequences of steps are possible as will be appreciated by those of ordinary skill in the art. Accordingly, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. Furthermore, the claims directed to the method and/or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the embodiments of the present application.

The embodiment of the application provides an error evaluation method which is applied to a surgical navigation system matched with medical image equipment, wherein the surgical navigation system comprises the following components: a host computer and an end effector having a surgical needle mounted thereon, as shown in fig. 1, the error assessment method comprising:

Step 101, the host acquires the space coordinates of a planning target point in a planning puncture path and the first space coordinates of a feature point; the characteristic points are points marked in a first preset size area taking the planning target point as a central point on the target planning scanning diagram in advance;

102, the host computer obtains the space coordinates of an actual target point reached by a needle point after the surgical needle actually punctures according to the planned puncturing path, and obtains the second space coordinates of the characteristic point on the puncturing scanning image for the image characteristic of the second preset size area taking the characteristic point as the center point on the target planning scanning image and the plurality of puncturing scanning images;

step 103, the host computer calculates a relative error between the planned target point and the actual target point according to the spatial coordinates of the planned target point, the first spatial coordinates of the feature point, the spatial coordinates of the actual target point and the second spatial coordinates of the feature point.

The multiple scan plan is a scan of the patient after scanning, the doctor determines the location of the lesion and plans the puncture path, and the multiple puncture scans are scans of the doctor after determining the planned puncture path in the actual puncture. The coordinates of the multiple scan plans and the multiple puncture scans under the coordinate system of the medical imaging device are usually inconsistent, for example, the scan plans may be-10 mm to scan (a large range needs to be scanned because a doctor does not know the focus position at first), the scan plans are assumed to scan every 5mm, the obtained multiple scan plans are-10 mm, -5mm, 0mm, 5mm and 10mm (Z-axis), the characteristic points are assumed to be made on the scan plan of-5 mm, and the coordinates of the characteristic points on the scan plans are the first space coordinates; when the puncture is actually performed, the scan puncture map may be scanned between-7 mm and 8mm (because the focus position is known, the scan can be performed more accurately), so that the obtained multiple scan puncture maps are-7 mm, -2mm, 3mm and 8mm (Z-axis), the spatial positions of the multiple scan planning map and the multiple scan puncture map are inconsistent, and then the second spatial coordinates of the feature points on the puncture scan map need to be found.

The feature points may specifically be points with significant features, such as points with tumor edge information, points with skeletal features, points with tracheal features, points with vascular features, and the like, marked in a first predetermined-size region on the target planning scan centered on the planning target point.

The error evaluation method provided by the embodiment of the application can acquire the relative deviation between the actual puncture path and the planned path relative to the focus position by means of the characteristic points, thereby improving the effective rate of the evaluation result.

Illustratively, the calculating the relative error between the planned target point and the actual target point according to the spatial coordinates of the planned target point, the first spatial coordinates of the feature point, the spatial coordinates of the actual target point, and the second spatial coordinates of the feature point may be performed by the following formula:

Calculating a relative error between the planned target point and the actual target point; wherein, endPoint (x), endPoint (y), endPoint (z) are the spatial coordinates of the actual target point, targetPoint (x '), targetPoint (y'), targetPoint (z ') are the spatial coordinates of the planned target point, featurePoint (x), featurePoint (y) FeaturePoint (z) are the second spatial coordinates of the feature point, featurePoint (x'), featurePoint (y ') FeaturePoint (z') are the first spatial coordinates of the feature point.

In an exemplary embodiment, the acquiring, according to the image features of the second predetermined size area on the target planning scan and the plurality of puncture scans, the second spatial coordinates of the feature points on the puncture scan includes:

Firstly, taking a feature point on the target planning scanning image as the center of a feature extraction window, determining the size of a first feature extraction window capable of acquiring not less than a preset number of key points, and extracting all first key points and first image feature descriptors of the first key points in the first feature extraction window;

Secondly, determining the size of a second feature extraction window for extracting key points on a plurality of puncture scans according to the size of the first feature extraction window;

Thirdly, sequentially acquiring reference points of a plurality of second feature extraction windows on the plurality of puncture scans according to a preset rule; each time a reference point is obtained, the following operations are performed: setting the second feature extraction window with the datum point as a center, extracting all second key points and second image feature descriptors of the second key points in the set second feature extraction window, and calculating feature matching degrees between all second key points corresponding to the datum point and all first key points according to the second image feature descriptors of the second key points corresponding to the datum point and the first image feature descriptors;

And finally, acquiring the maximum feature matching degree from the feature matching degrees, acquiring a key point matching pair output by the maximum feature matching degree, and calculating second space coordinates of the feature points according to the key point matching pair and the first space coordinates of the feature points.

Wherein, the feature matching degree is calculated by adopting BFMatcher feature matching algorithm.

For example, assuming that all first key points are designated as point a, point B, point C, point D, and point E, all second key points corresponding to the reference point are designated as point a1, point a2, point a3, point a4, point a5, point a6, and point a7, calculating feature matching degrees between all second key points corresponding to the reference point and all first key points means: feature matching degrees between the points a, B, C, D and E and the points a1, a2, a3, a4, a5, a6 and a7 are calculated.

In an exemplary embodiment, the calculating the second spatial coordinate of the feature point according to the key point matching pair corresponding to the maximum feature matching degree and the first spatial coordinate of the feature point includes:

Firstly, obtaining second target key points forming the key point matching pair from all second key points corresponding to the maximum feature matching degree, and obtaining first target key points forming the key point matching pair from all first key points corresponding to the maximum feature matching degree;

and secondly, acquiring the space coordinates of each first target key point and the space coordinates of each second target key point, and calculating the second space coordinates of the characteristic points according to the space coordinates of the first target key points, the first space coordinates of the characteristic points and the space coordinates of the second target key points.

For example, assuming that the feature matching degree between the points a, B, C, D and E and the points a1, a2, a3, a4, a5, a6 and a7 is highest, 4 points of the points a, B, C, D and E are matched, since the feature matching degree will output the key point matching pair accordingly, the maximum feature matching degree outputs the key point matching pair accordingly, assuming that the key point matching pair is as follows: point a-point a3, point B-point a5, point D-point a2, point E-point a7, then the second target keypoints are: the first target key points are point a3, point a5, point a2 and point a 7: point a, point B, point D, point E.

Because the first spatial position relation between the first target key point and the feature point is consistent with the second spatial position relation between the second target key point and the feature point, the second spatial coordinate of the feature point can be obtained through calculation according to the spatial coordinate of the first target key point, the first spatial coordinate of the feature point and the spatial coordinate of the second target key point.

In an exemplary embodiment, the determining, with the feature points on the target planning scan as the centers of the feature extraction windows, the size of the feature extraction window capable of obtaining not less than a preset number of key points includes:

Taking the feature points as the center, taking a feature extraction window with a preset size as a current feature extraction window, and executing the following window size adjustment operation:

Firstly, acquiring the number of extracted key points in a current feature extraction window;

And secondly, when the number of the extracted key points is smaller than a first preset number, enlarging the size of the current feature extraction window, taking the feature extraction window with enlarged size as a new current feature extraction window, continuing to execute the key point acquisition operation until the number of the key points extracted by the new current feature extraction window is not smaller than the first preset number, and taking the size of the obtained new current feature extraction window as the size of the feature extraction window capable of acquiring not less than the preset number of key points.

In one illustrative example, the expanding the size of the current feature extraction window includes:

enlarging the size of the current feature extraction window according to a first preset size enlargement value;

In an illustrative example, the determining the size of the second feature extraction window for keypoint extraction on the plurality of puncture scans based on the size of the first feature extraction window includes:

And determining the size of a second feature extraction window for extracting key points on the plurality of puncture scans according to the size of the first feature extraction window and a second preset size expansion value.

In an exemplary embodiment, the acquiring the reference points of the plurality of second feature extraction windows sequentially on the plurality of puncture scans according to a predetermined rule includes:

For each puncture scan, the following operations are performed:

Firstly, determining all setting positions of a second feature extraction window on a puncture scanning image according to the principle that the second feature extraction window can cover the puncture scanning image at all different positions;

Next, a center point of the second feature extraction window at each of the determined setting positions is acquired as the reference point.

For example, all the setting positions of the second feature extraction window on the puncture scan map may be determined according to the principle that the second feature extraction window is set at all different positions so as to cover the puncture scan map, and the number of setting positions is the smallest.

In an exemplary embodiment, the acquiring the reference points of the plurality of second feature extraction windows sequentially on the plurality of puncture scans according to a predetermined rule includes:

Firstly, determining a first target point closest to a characteristic point in a plurality of puncture scans according to the relation between the position of the target planning scan under a coordinate system of medical imaging equipment and the positions of the plurality of puncture scans under the coordinate system of the medical imaging equipment and the first space coordinates of the characteristic point;

secondly, taking the first target point as a starting point, and respectively acquiring a plurality of second target points along the positive direction and the negative direction of the X axis, the positive direction and the negative direction of the Y axis and the positive direction and the negative direction of the Z axis in a uniform and outwards divergent mode under a coordinate system of medical imaging equipment;

Finally, the obtained first target point and the second target point are taken as the datum points.

In an illustrative example, the acquiring a plurality of second target points along the X-axis positive and negative directions, the Y-axis positive and negative directions, and the Z-axis positive and negative directions includes:

Acquiring a plurality of second target points along the positive and negative directions of the X axis, the positive and negative directions of the Y axis and the positive and negative directions of the Z axis, and judging whether an acquisition stopping condition is reached or not;

the acquisition stop condition includes:

and sequentially reducing the matching degree of the second preset number of features obtained continuously.

The error evaluation method provided by the embodiment of the application can greatly reduce the acquisition number of the datum points on the premise of finding the maximum characteristic matching degree, thereby reducing the resource expenditure.

The embodiment of the application also provides a host in the operation navigation system, which comprises a memory and a processor;

the memory is used for storing executable programs;

The processor is configured to read and execute the executable program to implement the error evaluation method according to any one of the foregoing embodiments.

The host in the surgical navigation system provided by the embodiment of the application can acquire the relative deviation between the actual puncture path and the planned path relative to the focus position by means of the characteristic points, so that the effective rate of the evaluation result is improved.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, functional modules/units in the apparatus, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between the functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed cooperatively by several physical components. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

Claims (9)

1. An error evaluation method is applied to a surgical navigation system matched with medical image equipment, and the surgical navigation system comprises: a host computer and an end effector, the end effector having a surgical needle mounted thereon, the error assessment method comprising:

the host acquires the space coordinates of a planning target point in the planning puncture path and the first space coordinates of the characteristic points; the characteristic points are points marked in a first preset size area taking the planning target point as a central point on the target planning scanning diagram in advance;

The host acquires the space coordinates of an actual target point reached by a needle point after the surgical needle actually punctures according to the planned puncturing path, matches the image features of a second preset size area taking the feature point as a central point on the target planning scanning image with a plurality of puncturing scanning images, and acquires the second space coordinates of the feature point on the puncturing scanning image;

And the host calculates the relative error between the planning target point and the actual target point according to the spatial coordinates of the planning target point, the first spatial coordinates of the characteristic points, the spatial coordinates of the actual target point and the second spatial coordinates of the characteristic points.

2. The method of claim 1, wherein the obtaining second spatial coordinates of the feature points on the puncture scan from the image features and the plurality of puncture scans of the second predetermined size region centered on the feature points on the target planning scan comprises:

The method comprises the steps of taking a feature point on a target planning scanning chart as the center of a feature extraction window, determining the size of a first feature extraction window capable of acquiring not less than a preset number of key points, and extracting all first key points and first image feature descriptors of the first key points in the first feature extraction window;

Determining the size of a second feature extraction window for extracting key points on a plurality of puncture scans according to the size of the first feature extraction window;

Sequentially acquiring reference points of a plurality of second feature extraction windows on the plurality of puncture scans according to a preset rule; each time a reference point is obtained, the following operations are performed: setting the second feature extraction window with the datum point as a center, extracting all second key points and second image feature descriptors of the second key points in the set second feature extraction window, and calculating feature matching degrees between all second key points corresponding to the datum point and all first key points according to the second image feature descriptors of the second key points corresponding to the datum point and the first image feature descriptors;

And acquiring the maximum feature matching degree from the plurality of feature matching degrees, acquiring a key point matching pair output by the maximum feature matching degree, and calculating second space coordinates of the feature points according to the key point matching pair and the first space coordinates of the feature points.

3. The method according to claim 2, wherein the calculating the second spatial coordinates of the feature points according to the key point matching pair corresponding to the maximum feature matching degree and the first spatial coordinates of the feature points includes:

Obtaining second target key points forming the key point matching pair from all second key points corresponding to the maximum feature matching degree, and obtaining first target key points forming the key point matching pair from all first key points corresponding to the maximum feature matching degree;

And acquiring the space coordinates of each first target key point and the space coordinates of each second target key point, and calculating the second space coordinates of the feature points according to the space coordinates of the first target key points, the first space coordinates of the feature points and the space coordinates of the second target key points.

4. The method according to claim 2, wherein determining the size of the feature extraction window in which no less than a preset number of key points can be acquired with the feature points on the target planning scan as the centers of the feature extraction window includes:

Taking the feature points as the center, taking a feature extraction window with a preset size as a current feature extraction window, and executing the following window size adjustment operation:

Acquiring the number of the extracted key points in the current feature extraction window;

and when the number of the extracted key points is smaller than a first preset number, enlarging the size of the current feature extraction window, taking the feature extraction window with enlarged size as a new current feature extraction window, continuing to execute the key point acquisition operation until the number of the key points extracted by the new current feature extraction window is not smaller than the first preset number, and taking the obtained size of the new current feature extraction window as the size of the feature extraction window capable of acquiring not less than the preset number of key points.

5. The method of claim 4, wherein expanding the size of the current feature extraction window comprises:

enlarging the size of the current feature extraction window according to a first preset size enlargement value;

the determining the size of the second feature extraction window for extracting key points on the plurality of puncture scans according to the size of the first feature extraction window comprises the following steps:

And determining the size of a second feature extraction window for extracting key points on the plurality of puncture scans according to the size of the first feature extraction window and a second preset size expansion value.

6. A method according to claim 3, wherein the sequentially acquiring the reference points of the plurality of second feature extraction windows on the plurality of puncture scans according to a predetermined rule comprises:

For each puncture scan, the following operations are performed:

Determining all setting positions of the second feature extraction window on the puncture scanning map according to the principle that the second feature extraction window can cover the puncture scanning map in all different positions;

And acquiring a center point of the second feature extraction window at each determined setting position as the reference point.

7. A method according to claim 3, wherein the sequentially acquiring the reference points of the plurality of second feature extraction windows on the plurality of puncture scans according to a predetermined rule comprises:

Determining a first target point closest to the characteristic point in the plurality of puncture scans according to the relation between the position of the target planning scan under the coordinate system of the medical imaging device and the positions of the plurality of puncture scans under the coordinate system of the medical imaging device and the first space coordinate of the characteristic point;

Taking the first target point as a starting point, and acquiring a plurality of second target points along the positive direction and the negative direction of the X axis, the positive direction and the negative direction of the Y axis and the positive direction and the negative direction of the Z axis respectively in a uniform outwards divergent mode under a coordinate system of medical imaging equipment;

And taking the obtained first target point and the obtained second target point as the reference points.

8. The method of claim 7, wherein the acquiring the plurality of second target points along the X-axis positive and negative directions, the Y-axis positive and negative directions, and the Z-axis positive and negative directions comprises:

Acquiring a plurality of second target points along the positive and negative directions of the X axis, the positive and negative directions of the Y axis and the positive and negative directions of the Z axis, and judging whether an acquisition stopping condition is reached or not;

the acquisition stop condition includes:

and sequentially reducing the matching degree of the second preset number of features obtained continuously.

9. A host computer in a surgical navigation system, comprising: a memory and a processor;

the memory is used for storing executable programs;

The processor is configured to read and execute the executable program to implement the error assessment method according to any one of claims 1 to 8.