Mark point automatic registration method based on model matching

Abstract

The invention discloses a mark point automatic registration method based on model matching. The method comprises the following steps of (1)obtaining image data containing mark points; (2) constructing a mark point model; (3) reading in the obtained image data, conducting anisotropic diffusion filtering on images, and automatically extracting a skin three-dimensional grid from the images; (4) adopting an ICP algorithm to be matched with the mark point model and the skin three-dimensional grid, and obtaining the coordinate of the center of each mark point on the skin three-dimensional grid in an image space coordinate system; (5) adopting the ICP algorithm to be matched with the center of each mark point of the image space and the center of each mark point of the actual space, obtaining a rotating matrix R and a translational vector quantity T between the image space coordinate system and the actual space coordinate system, and completing registration of the mark points. According to the mark point registration method, the multiple mark points can be rapidly registered, the obtained rotating matrix R and the obtained translational vector quantity T of the image coordinate system and the actual coordinate system are more accurate, manual interference is reduced, the precision of the registration of the mark points is improved, and the mark point automatic registration method has good robustness.

Description

technical field [0001] The invention relates to a method for automatic registration of marking points, in particular to a method for automatic registration of marking points based on model matching, which belongs to the technical field of surgical navigation. Background technique [0002] The surgical navigation system can help doctors observe the internal structure of the human body and precise surgical instruments, making complex and delicate operations possible. The surgical navigation system combines medical images to locate surgical instruments in three-dimensional space during the operation, guide the operation, reduce surgical trauma, and improve the safety, accuracy and effectiveness of the operation. Therefore, it is necessary to register before the operation to obtain the actual location of the surgical instrument. The registration accuracy directly determines the navigation accuracy. If the registration accuracy is low, the navigation system may not be usable. ...

AI Technical Summary

Problems solved by technology

The surgical navigation system combines medical images to locate surgical instruments in three-dimensional space during the operation, guide the operation, reduce surgical trauma, and improve the safety, accuracy and effectiveness of the operation. Therefore, it is necessary to register before the operation to obtain the actual location of the surgical instrument. The corresponding relationship between the space and the image space where the image is located, the registration accuracy directly determines the navigation accuracy, if the registration accuracy is low, it may make the navigation system unusable

[0003] At present, the commonly used registration methods are surface-based and mark-based. The surface registration method does not require mark points. The optical method is used to obtain the actual space surface information and match the surface extracted in the image space. Although this method is simple to operate, but The algorithm process is complex and the registration accuracy is low, so it is rarely used; the registration method of marker points is highly accurate and is currently the most used registration method. During registration, the tip of the surgical tool is inserted into the gap in the middle of the marker point, and the positioning system tracks the tip of the surgical instrument Determine the center of the gap, that is, the coordinates of the center of the marked point in the actual space coordinate system, combined with the coordinates of the center of the corresponding marked point in the image coordinate system, the rotation matrix R and translation between the actual space coordinate system and the image space coordinate system can be calculated Vector T, complete the registration process

[0004] The current marker point registration method mainly uses manual methods to extract the coordinates of the marker point center in the image coordinate system, but due to the influence of factors such as the pixel distance in the image and the layer thickness of the image, coupled with individual differences in manual positioning , using the center coordinates extracted by this method to register will produce a large error, and this error will always exist in the tracking and positioning process as a system error, seriously affecting the tracking and positioning accuracy

In addition, the process of manually extracting the center coordinates is complicated, and when there are many marker points, the registration speed is slow. Many doctors will give up using the surgical navigation system for these reasons

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