CN107993277A - Damage location artificial skelecton patch formation model method for reconstructing based on priori - Google Patents

Abstract

The invention discloses a method for reconstructing an artificial bone repair model of a damaged part based on prior knowledge. First, extract the outline of the outer layer of the bone from the medical tomographic CT image, introduce the repair template and resample the contour line from the repair template according to the thickness of the fault layer; secondly, use the eigenvalue method to search for the most matching layer in the repair template The template layer and establish the alignment transformation of the two; then, obtain the isomorphic points on the template layer and the breakpoints of the layer to be repaired by the public angle method, and calculate the fitting equation between the isomorphic points, reversely substitute into the fitting equation to obtain the The point coordinates of the repair layer are interpolated; then, the inner layer contour is generated according to the given bone inner and outer layer thickness; finally, the artificial bone repair model is obtained by using VTK 3D reconstruction. The invention is applied to the actual surgical operation in which the human frontal bone, parietal bone and other parts are severely damaged, resulting in severe fracture of the skull that cannot be repaired directly, and needs to be implanted with personalized artificial bones.

Description

Artificial bone repair model reconstruction method based on prior knowledge

technical field

The invention belongs to the technical field of computer graphics, and is particularly suitable for the three-dimensional design of an artificial bone repair model for repairing damaged parts of the skull.

Background technique

The use of artificial bones to repair skull injuries is suitable for clinical operations where the skull is severely damaged and cannot be directly spliced through existing bone fragments. The design of the three-dimensional artificial bone repair model must be consistent with the location and size of the lesion. For the case of comminuted damage, doctors cannot obtain a rough shape through the repair of broken bones as a reference for artificial bone design. The template is often used as an auxiliary tool in 3D reconstruction. The template here can be the reconstruction result of existing healthy bones, or the averaged virtual reconstruction result. There are many literatures at home and abroad dedicated to using templates to assist in repairing damaged bone contours, such as automatically identifying intersections and breakpoints, and then using the existing templates as a reference, combined with the shortest diagonal linear connection method to repair the extracted fractured contours into closed contours . Due to the difference between the template and the current research case, in order to ensure that the extracted contour line is not distorted, some literatures also introduce a deformation mechanism. For example, in the 3D reconstruction of the spine, a set of statistical models was proposed to represent the average parameterization As a result, the template is affinely aligned with the current research case, and then the template is deformed to obtain a real 3D reconstruction result that matches the current research case. In addition, there are some literatures that start from the template in the process of obtaining the 3D model of the skull, and use iterations to continuously deform it, so as to approach the current research case, and finally obtain a complete 3D skull model with the characteristics of the current research case.

Using the existing bones of the same type as prior knowledge, it is necessary to find the contour line of the same type of bone that best matches the current layer according to the feature description function. Contour start point registration is a very effective method, and the most similar one among different contour start point matches can be obtained by circular shifting. The alignment transformation can realize the spatial coordinate transformation of the feature point image, and establish the corresponding relationship between the current layer and the outline of the same type of bone.

Contents of the invention

In order to solve the above-mentioned defects and deficiencies in the prior art, the present invention provides a method for reconstructing artificial bone repair models of damaged parts based on prior knowledge, aiming at comminuted fractures in the frontal bone, parietal bone and other parts of the human skull after severe trauma If the skull fragmentation is too serious to be directly repaired by surgery, the global similarity of different human skulls and bones can be used; the sequence and local similarity between medical tomographic images; the continuity of the extracted bone contours, etc. As a priori knowledge, the three-dimensional bone model of the fracture site is automatically obtained to provide a data basis for later personalized artificial bone repair surgery. Compared with the existing bone fragment splicing technology, the accuracy and timeliness of repair are improved.

In order to solve the above technical problems, the present invention provides a method for reconstructing the artificial bone repair model of the damaged part based on prior knowledge, which uses the existing repair template contour as the prior knowledge as a guide to automatically obtain the artificial bone used to repair the damaged part of the human bone Repair the model, the specific process is as follows:

(1) preprocessing the bone contour extracted from the medical tomographic image, and searching for the bone contour lines of all unclosed faults, this step includes as follows:

Step S01: Read in the medical tomographic images sequentially, use the Canny method to obtain the bone contour map of the medical tomographic images, and combine the boundary tracking algorithm to obtain several closed or unclosed bone contour lines for each medical tomographic image;

Step S02: Record the layer where the unclosed bone outline appears for the first time, and mark it as A, and similarly mark the layer where the last unclosed bone outline appears as Z;

(2) Establish the corresponding relationship between the repair template and the unclosed contour line, this step includes as follows:

Step S03: recording the coordinates of the interruption points P and Q of the layer A;

Step S04: Set the contour line spacing of the repair template, and resample to obtain a set of closed bone contours;

Step S05: Find the repair template layer A'-1 that best matches the closed contour line layer A-1 in the repair template;

(3) Using the repair template as prior knowledge, obtain the artificial bone contour curve used to repair the damaged part of the human bone at the fault. This step includes the following steps:

Step S06: According to the optimal matching calculated in step S05, obtain the optimal matching layer A' that best matches layer A, construct an alignment transformation equation for the two, and then use the alignment transformation equation to align layers A and A';

Step S07: Use the common included angle to obtain the coordinates of point P' that is isomorphic to breakpoint P in the optimal matching layer A', and obtain the coordinates of point Q' that is isomorphic to another breakpoint Q in the same way, and calculate the sequence Fitting equation X for points P' to Q';

Step S08: use the fitting equation X obtained in step S07 to calculate the interpolation point coordinates in layer A;

Step S09: Calculate the inner contour coordinate points of the artificial bone contour according to the given bone thickness d;

Step S10: record layer A+1 as A;

Step S11: Repeat steps S03 to S11 until A and Z coincide.

(4) Three-dimensional reconstruction artificial bone repair model, this step comprises as follows:

Step S12: Using VTK 3D reconstruction to obtain an artificial bone repair model.

Wherein, in step S01 , the closed or unclosed bone contour line means that the bone contour line on the fault is in a loop or open circuit state.

Wherein, in step S02, record the layer where the unclosed bone outline appears for the first time, and mark it as A, and similarly mark the layer where the unclosed bone outline appears for the last time as Z, and the specific steps are:

Step i01: Start searching from the top layer, and calculate the degree d(v) of each vertex v on each layer by means of undirected edges. If d(v)<2, it means that the point is a hanging point, and the layer is not closed. marked as A;

Step i02: Start searching from the bottom layer, and calculate the degree d(v) of each vertex v on each layer in the form of undirected edges. If d(v)<2, it means that the point is a hanging point, and the layer is not closed. Marked as Z.

Wherein, in the step S03, the coordinates of the interruption points P and Q of the recording layer A, the specific steps are:

Step q01: start searching from the topmost layer and locate to the layer where the contour line marked A is located;

Step q02: Mark the vertex pair whose vertex degree is less than 2 in this layer as breakpoint P, Q.

Wherein, in step S04, the repair template refers to the same average bone data as the current medical tomographic image site and the average bone data can represent all the characteristic information of the damaged part; the contour line refers to the medical tomographic image scanning distance as the repair Template resampling interval; the resampling refers to sampling the repair template according to the scanning distance and direction of the medical tomographic image, and the bone outline obtained is called the repair template layer.

Wherein, in step S05, find the repair template layer A'-1 that matches the closed contour line layer A-1 most in the repair template, and its specific steps are:

Step p01: Locate to the closed contour layer A-1 above and adjacent to layer A;

Step p02: Use the eigenvalue method to make a similarity judgment between layer A-1 and the repair template layer, so as to find the repair template layer that best matches layer A-1, and mark it as A'-1; otherwise, adjust the sampling starting point, Execute step S04 again to obtain new sampling data.

Wherein, in step S06, utilize common included angle, obtain the point P ' coordinate that is isomorphic with breakpoint P in layer A ', its concrete steps are:

Step 101: use R, R' to represent the barycenter coordinates of layers A and A' respectively, and P and Q are the interruption points of A;

Step l02: Calculate the angle θ formed by the line PR from P to the center of gravity R and the horizontal line;

Step l03: Starting from R', make a ray with the same angle as θ with the horizontal line, and the ray intersects layer A' at point P', then P' is a point isomorphic to breakpoint P.

Wherein, in step S07, the fitting equation refers to using the least square method curve fitting principle to combine the data sets (P', P+1', P+2',...,P+i',..., Q-j',...,Q-2',Q-1',Q', where i<j) is constructed as an analytic function, and the curve of the function is infinitely close to the discrete point.

Wherein, in step S08, the coordinates of the interpolation points in layer A are calculated using the fitting equation X, and the specific steps are:

Step w01: Insert n uniformly distributed points x ₁ , x ₂ ,...,x _n on the X-axis coordinates of P and Q;

Step w02: Bring the value of x into the fitting equation X, and calculate the values of y ₁ , y ₂ ,...,y _n . The n coordinate points (x _i , y _i ) are the contour points of the artificial bone.

Wherein, in step S09, according to the given bone thickness d, the inner contour coordinate points are calculated, and the specific steps are:

Step h01: Let (x, y) and (x’, y’) be the coordinate points on the outer and inner contours respectively, and (x, y) is known, and (x’, y’) is required;

Step h02: measure the average thickness d of the inner and outer layers of the skull according to the contour map;

Step h03: let dx, dy be x-x', y-y' respectively;

Step h04: Bring d into the equation Where dx=dy, the value of the coordinates (x', y') can be calculated;

Step h05: Repeat step h01-step h04 to calculate and obtain the coordinate values of the outline points of all inner artificial bones in each layer.

Beneficial technical effects achieved by the present invention: the present invention provides a method for reconstructing artificial bone repair models of damaged parts based on prior knowledge, aiming at comminuted fractures and skull fragmentation after severe trauma to the frontal bone and parietal bone of the human skull In severe cases where direct surgical repair is impossible, the global similarity of different human skulls and bones can be used; the sequence and local similarity between medical tomographic images; the continuity of the extracted bone contours, and the existing average bone can be used as prior knowledge Automatically obtain the bone three-dimensional model of the fracture site, and provide the data basis for the later personalized artificial bone repair surgery. Compared with the existing bone fragment splicing technology, the accuracy and timeliness of repair are improved.

Description of drawings

Fig. 1 is the working flow diagram of the artificial bone repair model rebuilding method of damaged part based on prior knowledge in the present invention;

Fig. 2 is a schematic diagram of the bone contour extraction process utilizing the Canny algorithm in the present invention;

Fig. 3 is the schematic diagram of the degree of vertex among the present invention;

Fig. 4 is a schematic diagram of the positional relationship between the current layer and the repair template layer in the present invention;

Fig. 5 is a flow chart of the search optimal matching algorithm in the present invention;

Fig. 6 is a schematic diagram of optimal matching and its feature description function in the present invention;

Fig. 7 is a schematic diagram of aligning and transforming the repair template based on the current layer in the present invention;

Fig. 8 is a schematic diagram of using isomorphic points to obtain a fitting curve in the present invention;

Fig. 9 is a schematic diagram of inner layer contour generated in the present invention;

Fig. 10 is a schematic diagram of the artificial bone repair and reconstruction model of the damaged part obtained by using the repair template as prior knowledge in the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

Below in conjunction with accompanying drawing and embodiment the patent of the present invention is further described.

As shown in Figure 1, the artificial bone repair model reconstruction method based on prior knowledge is characterized in that: using the existing repair template contour as a guide for prior knowledge, for parts of human bones with greater damage, automatically obtain The process of repairing models with artificial bones.

First, the bone contours extracted from all medical tomographic images are preprocessed to search for the bone contour lines of all unclosed faults. This step includes the following steps:

Step S01: Read in the medical tomographic images sequentially, use the Canny method to obtain the bone contour map of the medical tomographic images, and combine the boundary tracking algorithm to obtain several closed or unclosed bone contours for each medical tomographic image;

Step S02: Record the layer where the unclosed bone outline appears for the first time, and mark it as A, and similarly mark the layer where the last unclosed bone outline appears as Z;

Secondly, establish the corresponding relationship between the repair template and the current unclosed contour line, this step includes the following steps:

Step S03: recording the coordinates P and Q of the interruption point of layer A;

Step S04: Set the contour line spacing of the repair template, and resample to obtain a set of closed bone contours;

Step S05: Find the repair template layer A'-1 that best matches the closed contour line layer A-1 adjacent to layer A in the repair template;

Then, using the repair template as prior knowledge, obtain the artificial bone contour curve used for repair on this fault, and this step includes the following steps:

Step S06: According to the optimal matching calculated in step S05, it can be seen that the optimal matching layer with layer A is A', construct the alignment transformation equation of both, and then use the alignment transformation equation to align layers A and A';

Step S07: Using the common included angle, obtain the coordinates of point P' that is isomorphic to breakpoint P in layer A', and similarly obtain the coordinates of point Q' that is isomorphic to another breakpoint Q, and calculate the sequence point P' Fit equation X to Q';

Step S08: use the fitting equation X obtained in step S07 to calculate the interpolation point coordinates in layer A;

Step S09: Calculate the inner contour coordinate points according to the given bone thickness d;

Step S10: record layer A+1 as A;

Step S11: Repeat steps S03 to S09 until A and Z coincide.

Finally, three-dimensional reconstruction of artificial bone repair model, this step includes the following steps:

Step S12: Using VTK 3D reconstruction to obtain an artificial bone repair model.

The process of obtaining the outer contour line of the medical tomographic image is shown in FIG. 2 . Figure 2-① is a medical tomographic image; Figure 2-② is a skeleton pixel that remains after filtering out the skin, brain tissue, eyes and ears and other organ pixels in the original image after setting the binarization threshold for the medical tomographic image; 2-③ is the bone contour map obtained by using the Canny edge detection method, including the inner bone contour; Figure 2-④ is the outer bone contour obtained by using the boundary tracking algorithm.

As shown in Figure 3, the degree d(v) refers to the number of edges associated with the vertex v. As an embodiment of the present invention, as shown in Figure 3-①, it is the outline of the 25th layer of bone outer layer, which is the layer where the unclosed outline appears for the first time, where point v _j is a continuous point, and degree d(v _j )=2; points v _i and v _k are breakpoints respectively, and degree d(v _i )=d(v _k )=2; as shown in Figure 3-②, it is the contour line of the 74th layer bone, the dotted frame Represents a local enlargement, wherein points v _m and v _n are intersection points respectively, and degree d(v _m )=d(v _n )=3.

As shown in Figure 4, it represents the positional relationship between the current layer and the repaired template layer. Among them, Fig. 4-① and Fig. 4-③ respectively represent the layer A (25) where the unclosed bone contour line appears for the first time and its adjacent closed layer A-1 (24); Fig. 4-② and 4-④ respectively represent the repair Template layer A'(78) and layer A'-1(77).

As shown in Figure 5, find the patch template layer A'-1 that best matches the layer A-1 in the patch template, and the specific steps are:

Step p01: Locate to the closed contour layer A-1 above and adjacent to layer A;

Step p02: Use the eigenvalue method to make a similarity judgment between layer A-1 and the repair template, so as to find the repair template layer that best matches layer A-1, and mark it as A'-1; otherwise, adjust the sampling starting point and execute again Step S04 obtains new sampling data.

As shown in Figure 6, Figure 6-① is layer A-1; Figure 6-② shows the layer A'-1 that best matches layer A-1 in the repair template; Figure 6-③ and Figure 6-④ are utilization features Value method calculation layer A-1, the characteristic description function of repair template layer A'-1: f _M (n) and f _(A-1) (n), and its specific steps are:

Step u01: Aggregate the non-significant feature points on the patched template and the contour points on the patched template using the method of minimum average error, and use the threshold to retain the same number of feature points on the two templates;

Step u02: use the eigenvalue method to obtain the matching starting point;

Step u03: If the optimal match can be obtained, the contour of the repaired template that best matches the contour of the adjacent non-repaired template can be found in the same direction; otherwise, adjust the starting point of contour line sampling of the repaired template, and continue to step S04;

Step u04: Repeat steps t01 to t03 to find all patched templates that can match the non-patched template.

As shown in Figure 7, layer A is aligned with patch layer A' using the alignment transformation. Figure 7-① is layer A'-1; Figure 7-② is the result after layer A'-1 is rotated clockwise by α around the center of gravity R'; Figure 7-③ is layer A'-1 translated by d Figure 7-④ is layer A, wherein the center of gravity R is the vertical mapping of layer A'-1 center of gravity coordinate R; Figure 7-⑤ is layer A' centered on center of gravity R', and the same The result diagram after rotating α clockwise; Figure 7-⑥ is the result diagram after translating layer A' by d(dx,dy). The specific steps of rotation and translation are as follows:

Step k01: Calculate the barycentric coordinates of layers A-1 and A'-1: R, R';

Step k02: Record the matching starting point pair coordinates obtained according to step u02: S, S';

Step k03: Calculate the angle θ between the line segment RS and the horizontal line and the angle θ' between R'S' and the horizontal line;

Step k04: calculating R, displacement difference dx, dy between R';

Step k04: Bring α=θ-θ' into the rotation matrix, and dx and dy into the translation matrix to obtain the alignment transformation equation.

As shown in Figure 8, it means that the fitting curve is obtained by using isomorphic points.

Figure 8-① shows the affine alignment results of layers A and A', where the black is the layer A where the unclosed bone outline is located, and the gray is a certain layer A' in the repair template, and layer A' matches layer A best. P and Q are the interruption points of A, and P’ and Q’ are the points in A’ that are isomorphic to P and Q, and the specific calculation steps are as follows:

Step 101: use R, R' to represent the barycenter coordinates of layers A and A' respectively, and P and Q are the interruption points of A;

Step l02: Calculate the angle θ formed between the line PR from P to the center of gravity R and the horizontal line;

Step l03: Create a ray from R' with the same angle as θ with the horizontal line, the ray intersects layer A' at point P', then P' is a point isomorphic to breakpoint P.

The curve between the vertices P' and Q' in Figure 8-② is the fitting curve X. The specific implementation method is: the data set on the discrete point (P', P+1', P+2',...,P+i ',...,Q-j',...,Q-2',Q-1',Q', where i<j) is constructed as an analytical function, so that the function curve is as close as possible to the original discrete point.

The curve PQ in Figure 8-③ is to calculate the coordinates of the interpolation points in layer A through the equation of the fitting curve X, and the specific steps are:

Step w01: Insert n uniformly distributed points x ₁ , x ₂ ,...,x _n on the X-axis coordinates of P and Q;

Step w02: Bring the value of x into the fitting equation X, and calculate the values of y ₁ , y ₂ ,...,y _n . The n coordinate points (x _i , y _i ) are the contour points of the patched artificial bone.

As shown in Figure 9, according to the given bone thickness d, the inner contour coordinate points are calculated.

Sequence points P,...,P+m,...,Q-n,...,Q in Figure 9-①, m<n is the interpolation point set obtained by fitting the equation according to step w01-step w02;

Figure 9-② is an illustration of the results of the inner contour coordinate points calculated based on the existing outer contour coordinate points and the given bone thickness. The specific calculation steps are:

Step h01: Let (x, y) and (x’, y’) be the coordinate points on the outer and inner contours respectively, and (x, y) is known, and (x’, y’) is required;

Step h02: measure the average thickness d of the inner and outer layers of the skull according to the contour map;

Step h03: let dx, dy be x-x', y-y' respectively;

Step h04: Bring d into the equation Among them let dx=dy, calculate and obtain the value of coordinate (x', y');

Step h05: Repeat step h01-step h04 to calculate and obtain the coordinate values of all the repaired contour points in the inner layer.

Figure 9-③ is the effect diagram of embedding the obtained inner and outer outlines of the artificial bone into layer A.

The process of reconstructing the artificial bone repair model of the injured part based on the prior knowledge by the method of the present invention is as follows.

Embodiment one:

As shown in Figure 10, Figure 10-① is a three-dimensional reconstruction effect diagram of the injured skull; Figure 10-② is a three-dimensional reconstruction effect diagram of the artificial bone repair model obtained by the method of the present invention; Figure 10-③ and Figure 10-④ are respectively the Different perspective renderings of the artificial bone repair model embedded in the damaged part.

The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent replacement or equivalent transformation schemes fall within the protection scope of the present invention.

Claims (10)

1. the damage location artificial skelecton patch formation model method for reconstructing based on priori, it is characterised in that：To have repaired mould Web wheel is wide to be guided for priori, automatic to obtain the artificial skelecton patch formation model for being used for repairing skeleton damage location, tool Body process is as follows：

(1) bone contours extracted from Medical Slice Images are pre-processed, and search for all damage locations, that is, the wheel obtained Exterior feature is fracture shape.It is inc bone contours line to define this contour line for occurring damaging, which includes as follows：

Step S01：Medical Slice Images are read in successively, and the bone contours map of Medical Slice Images is obtained using Canny methods, Some closures of every Medical Slice Images or inc bone contours line are obtained with reference to edge following algorithm；

Step S02：There is layer where not closing bone contours line for the first time in record, and is labeled as A, similarly last time occurs Layer where not closing bone contours line is labeled as Z；

(2) repairing template and the correspondence of not closed contour are established, which includes as follows：

Step S03：The coordinate of the recording layer A points of interruption P, Q；

Step S04：Setting repairing template contour interval, resampling obtain one group of closure bone contours；

Step S05：Found in repairing complementary modulus plate and closed contour layer A_-1Most matched repairing template layer A '_-1；

(3) to repair template as priori, obtain and be used for the artificial skelecton repairing for repairing skeleton damage location at tomography Model silhouette curve, the step include as follows：

Step S06：The Optimum Matching being calculated according to step S05, obtains and the most matched Optimum Matching layer A ' of layer A, structure Both alignment transformation equations, then using the transformation equation that aligns, make registration process by layer A, A '；

Step S07：Using public angle, the point P ' coordinates with breakpoint P-isomorphism are tried to achieve in Optimum Matching layer A ', are similarly tried to achieve another Point Q ' the coordinates of the isomorphism of one breakpoint Q, sequence of calculation point P ' arrive the fit equation X of Q '；

Step S08：Interpolation point coordinates in the fit equation X computation layers A obtained using step S07；

Step S09：According to given bone thickness d, the internal layer profile coordinate points of calculating artificial skelecton patch formation model contour curve；

Step S10：By layer A₊₁It is denoted as A；

Step S11：Repeat step S03 to step S11, until A and Z is overlapped.

(4) three-dimensional reconstruction artificial skelecton patch formation model, the step include as follows：

Step S12：Artificial skelecton patch formation model is obtained using VTK three-dimensional reconstructions.

2. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：Closure or inc bone contours line refer to that the bone contours line on tomography is in circuit or disconnected in step S01 The state on road.

3. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S02, there is layer where not closing bone contours line for the first time in record, and is labeled as A, similarly by last Layer where secondary appearance does not close bone contours line is labeled as Z, it is concretely comprised the following steps：

Step i01：Searched for since top, the degree d (v) of every layer of upper each vertex v is calculated in a manner of nonoriented edge, if d (v)<2 It is hitch point to represent the point, which not closing phenomenon occurs, labeled as A；

Step i02：Searched for since the bottom, the degree d (v) of every layer of upper each vertex v is calculated in a manner of nonoriented edge, if d (v)<2 It is hitch point to represent the point, which not closing phenomenon occurs, labeled as Z.

4. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S03, the coordinate of the recording layer A points of interruption P, Q, it is concretely comprised the following steps：

Step q01：Searched for since top and position layer where to the contour line labeled as A；

Step q02：It is P, Q to mark by vertex of the degree of vertex in this layer less than 2.

5. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S04, repairing template refers to the average skeleton data identical with Medical faultage image position and this is average Skeleton data can represent complete whole characteristic informations when damage location；Contour refers to make Medical Slice Images sweep span To repair the spacing of template resampling；The resampling refers to repairing template according to Medical Slice Images sweep span, direction Sampled, the bone contours line of acquisition is known as repairing template layer.

6. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S05, found in repairing complementary modulus plate and most matched repairing template layer A ' -1 of closed contour layer A-1, its tool Body step is：

Step p01：Positioning is to above layer A and the closed contour layer A-1 adjacent with layer A；

Step p02：Make similitude judgement in layer A-1 and repairing template interlayer using method of characteristic, so as to find with layer A-1 most The repairing template layer matched somebody with somebody, labeled as A ' -1；Otherwise, first sampling point is adjusted, step S04 is performed again and obtains new hits According to.

7. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S06, using public angle, the point P ' coordinates with breakpoint P-isomorphism are tried to achieve in layer A ', it is concretely comprised the following steps：

Step l01：With R, R ' expression layers A, A respectively ' barycentric coodinates, P, Q are the A points of interruption；

Step l02：Calculate the angle theta that the line PR from P to center of gravity R is formed with horizontal line；

Step l03：From R ' do one with horizontal line angle be all θ ray, ray and layer A ' intersect at point P ', then P ' is i.e. For the point with breakpoint P-isomorphism.

8. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S07, fit equation refers to utilize least square curve fit principle, by the data set on discrete point (P ', P+1 ', P+2 ' ..., P+i ' ..., Q-j ' ..., Q-2 ', Q-1 ', Q ', wherein i<J) analytical function is configured to, and makes the letter Several curve infinite approach discrete points.

9. the damage location artificial skelecton patch formation model method for reconstructing according to claim 1 based on priori, it is special Sign is：In step S08, using interpolation point coordinates in fit equation X computation layers A, it is concretely comprised the following steps：

Step w01：N equally distributed point x are inserted on the X-axis coordinate of P and Q₁,x₂,…,x_n；

Step w02：Bring the value of x into fit equation X, y is calculated₁,y₂,…,y_nValue.This n coordinate points (x_i,y_i) be Point on artificial skelecton contour curve.

10. the damage location artificial skelecton patch formation model method for reconstructing according to claim 9 based on priori, it is special Sign is：In step S09, according to given bone thickness d, internal layer profile coordinate points are calculated, it is concretely comprised the following steps：

Step h01：It is respectively the coordinate points on outer layer and internal layer profile to make (x, y), (x ', y '), and (x, y) it is known that demand (x’,y’)；

Step h02：According to thickness average value d inside and outside every layer of skull of profile geographic survey；

Step h03：It is respectively x-x ', y-y ' to make dx, dy；

Step h04：Bring d into equationsWherein make dx=dy, you can the value of coordinate (x ', y ') is calculated；

Step h05：Repeat step h01- step h04, calculate and obtain every layer of all internal layer artificial skelecton profile point coordinate value.