CN104392492A - Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model - Google Patents

Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model Download PDF

Info

Publication number
CN104392492A
CN104392492A CN 201410680473 CN201410680473A CN104392492A CN 104392492 A CN104392492 A CN 104392492A CN 201410680473 CN201410680473 CN 201410680473 CN 201410680473 A CN201410680473 A CN 201410680473A CN 104392492 A CN104392492 A CN 104392492A
Authority
CN
Grant status
Application
Patent type
Prior art keywords
crown
dental
model
point
boundary line
Prior art date
Application number
CN 201410680473
Other languages
Chinese (zh)
Inventor
廖胜辉
刘石坚
罗雄
梁毅雄
邹北骥
陈再良
王磊
向遥
Original Assignee
中南大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Abstract

The invention discloses a computer interaction type method for segmenting a single tooth crown from a three-dimensional jaw model. The method includes the steps: reading and visually displaying the three-dimensional jaw grid model; detecting anatomic characteristic points and an occlusion plane of upper teeth of a jaw in the three-dimensional jaw grid model; assigning constraint points of harmonic fields of the three-dimensional jaw grid model; calculating the harmonic fields according to constraint conditions to obtain a tooth crown segmenting border line; performing grid cutting according to the obtained tooth crown segmenting border line to obtain a tooth crown model. By the method, a tooth segmenting border can be accurately obtained, the method is simple to use, and a user interactively determines two border points on a visual view of the jaw model for a single tooth to be separated, so that the tooth crown grid model of the tooth can be accurately obtained. The method has important significance for dental orthodontics, virtual jaw surgery simulation and the like.

Description

一种从牙颌三维模型分割单颗牙冠的计算机交互式方法 A method for computer-interactive segmentation of single tooth crowns from Dental cast

技术领域 FIELD

[0001] 本发明涉及一种从牙颌三维模型分割单颗牙冠的计算机交互式方法。 [0001] The present invention relates to a method of interactive computer single tooth dental crown from three-dimensional model divided.

背景技术 Background technique

[0002] 随着3D采集技术的发展,牙颌三维模型目前被广泛应用于牙科相关领域,如口腔医学、法医学、人类学及考古学等。 [0002] With the development of 3D acquisition technology, dental three-dimensional model is widely used in dentistry related areas such as oral medicine, forensic medicine, anthropology and archeology. 对于牙颌模型进行分割、归类等处理是治疗计划制定、虚拟手术等牙科虚拟现实应用中不可或缺的部分。 For dental segmentation model, the classification of treatment is treatment planning, virtual surgery and other dental integral part of virtual reality applications.

[0003] 目前针对牙冠的网格自动分割方法很难得到准确的模型,鲁棒性不强。 [0003] Currently automatic mesh segmentation method for the crown is difficult to get an accurate model, robustness is not strong. 交互式分割方法虽然可以利用人的先验知识,充分体现用户的操作意图,但目前的方法一般都需要用户沿着预想的牙冠分割线指定若干个边界点,这种繁琐、耗时的工序显然不符合智能化的标识。 While interactive segmentation method may utilize a priori knowledge of the person, the operation fully reflect the user's intention, but the methods generally require the user to specify a number of points along the boundary line dividing the expected crown, this tedious, time-consuming step clearly inconsistent with the intelligent identification. 以往的方法要么需要大量手工交互来确定边界,耗时费力,要么得不到准确的牙冠分割结果、鲁棒性差。 Either conventional method requires a lot of manual interaction to determine the boundaries, time-consuming, or not accurate crown segmentation results, poor robustness. 因此,要准确且智能化的从包含复杂牙冠边缘信息的牙颌网格模型中准确分离出所有的牙冠模型是一件具有挑战性的课题。 Therefore, accurate and precise separation of the intelligent object is a model of all the challenging crown from dental crown edge mesh contains complex information.

发明内容 SUMMARY

[0004] 本发明所要解决的技术问题是,针对上述现有技术的不足,提供一种从牙颌三维模型分割单颗牙冠的计算机交互式方法。 [0004] The present invention solves the technical problem, the prior art for less than the above, there is provided a single tooth crown segmentation method of interactive computer three-dimensional model from a dental cast.

[0005] 为解决上述技术问题,本发明所采用的技术方案是:一种从牙颌三维模型分割单颗牙冠的计算机交互式方法,包括以下步骤: [0005] To solve the above technical problem, the technical solution employed in the present invention is: A three-dimensional model divided from a single-tooth dental crown computer interactive method, comprising the steps of:

[0006] 1)读入并可视化显示牙颌三维网格模型; [0006] 1) reads and visualizing dental 3D mesh model;

[0007] 2)检测所述牙颌三维网格模型中牙颌上牙齿的解剖学特征点及咬合平面; [0007] 2) detecting the three-dimensional mesh model of dental anatomical feature point on teeth and dental occlusal plane;

[0008] 3)指定牙颌三维网格模型调和场的约束点; [0008] 3) three constraint points specify the harmonic field of dental mesh model;

[0009] 4)根据约束点计算调和场,获取牙冠分割边界线; [0009] 4) The constraint points is calculated harmonic field, obtaining a crown division boundary line;

[0010] 5)依照获取的牙冠分割边界线进行网格切割,得到牙冠模型。 [0010] 5) in accordance with the cutting crown mesh division boundary line acquired, to give the crown model.

[0011] 所述步骤2)中,利用所述牙颌三维网格模型上顶点的曲率信息及分水岭方法获取牙颌上牙齿的解剖学特征点,利用所述解剖学特征点确定咬合平面。 [0011] step 2), using the acquired tooth on dental anatomical feature point information and the curvature of the apex of the watershed method of dental 3D mesh model, using the anatomical feature point determination occlusal plane.

[0012] 所述步骤3)中,为目标牙冠分别指定1个位于近中牙缝处和1个位于远中牙缝处的约束点。 [0012] step 3) in order to specify a target crown located near the teeth and at a constraint point is located at the distal teeth, respectively.

[0013] 所述步骤4)中,调和场的计算过程为:设牙颌三维网格模型中有m个节点,n个约束点,求解AO=b,得到的解即为牙颌三维网格模型各个顶点对应的调和场值;其中, [0013] step 4), the harmonic field calculation process is as follows: set of dental 3D mesh model has m nodes, n-constraint points, solving AO = b, the resulting solution is the dental 3D mesh corresponding to each vertex of the model harmonic field value; wherein,

Figure CN104392492AD00041

,Li」是mXm阶的拉普拉斯矩阵, , Li "is mXm order Laplace matrix,

Figure CN104392492AD00042

,(i,j)GE,0彡i,j彡m-1, E为牙颌三维网格模型中边的集合; , (I, j) GE, 0 San i, j San m-1, E is a dental 3D mesh model in the set of edges;

Figure CN104392492AD00051

如果Vi或'处为凹点,Vi为牙颌三维网格模型i点处的坐标值,F代表牙颌三维网格模型平均边长,©为常量; Or if Vi 'at the point of a concave, Vi-dimensional coordinate values ​​at the dental model mesh points i, F for dental 3D mesh model average side length, © is a constant;

Figure CN104392492AD00052

»C中的元素Cu= 1,其余为0,0彡p彡ml,p为第r个约束点在牙颌三维网格模型中的序号,r= 0, 1,•••n-1;w= 1000 . »C the elements Cu = 1, p San San remainder 0,0 ml, p is the number of points in the r constraint dental 3D mesh model is, r = 0, 1, ••• n-1; w = 1000.

Figure CN104392492AD00053

»b' 中各元素的取值G{0,0.5, 1}。 »B 'values ​​of G in each element {0, 0.5, 1}.

[0014] 所述步骤4)中,获取牙冠分割边界线的过程为:从所述调和场中抽取若干条等值线作为候选边界线集合,选取评分最高的一条候选边界环作为牙冠牙冠分割边界线。 [0014] step 4), the obtaining of a crown division boundary line process: several pieces of extracted contour as a candidate set from the boundary line harmonic field, select the highest score as a candidate boundaries ring tooth crown crown division boundary line.

[0015] 所述n个约束点包括所述步骤2)获得的解剖学特诊点、步骤3)指定的两个约束点和一系列围绕且不属于目标牙冠的约束点B;所述约束点B的确定方法如下:找到所有解剖学特征点在所述咬合平面上的投影点,找到位于所述咬合平面上、且经过所述投影点的直线;以咬合平面的法线为轨迹,将所述直线朝牙颌底部平移一段距离,所述距离设定为从牙冠尖点到牙颌底部垂直距离的2/3倍;获取直线与牙颌模型的交点,所述交点的集合即为B。 [0015] said n points comprises the anatomic constraint point Laid diagnostic step 2) obtained in step 3) and the two constraint points around a series of constraints specified does not belong to the target point B of the crown; the constraint the method of determining the point B is as follows: find all anatomical feature points of the projected points on the occlusal plane, is located to find the occlusal plane, and a straight line passing through the projection point; normal to the occlusal plane of the track, the the linear translation toward the bottom of dental a distance, the distance is set from the bottom to the crown dental cusp 2/3 times the vertical distance; obtaining intersection of the line with the dental model, the intersection is the set of B.

[0016] 所述步骤4)中,获取所述牙冠分割边界线后,优化所述牙冠分割边界线,优化过程如下:为牙冠分割边界线上各点计算一个标量场,每个点对应的标量值为该点的单位法向量与B中近舌侧点的平均单位法向量的点积,由点积的概念可知,该标量场的值域为[-1,1];选取大于〇的阈值对该标量场进行阈值化,将所述牙冠分割边界线分为近唇侧和近舌侧两部分,舍弃近舌侧部分,保留近唇侧边界线部分;然后,在贴近牙颌近舌侧表面的平面上构造样条线,所述平面由所保留的近唇侧边界线的2个端点以及B中近舌侧的1点确定,将该样条线作为新的近舌侧牙冠边界线;最后,将所述近唇侧边界线部分边界线和所述新的近舌侧牙冠边界线结合起来,成为优化后的完整的牙冠分割边界线。 [0016] step 4), the crown after acquiring the division boundary line, optimizing the crown division boundary line, the optimization process is as follows: calculate a boundary line dividing points scalar field as a crown, each point unit normal vector corresponding to the scalar value for that point B near the lingual side of the dot per unit dot product of vectors, including the concept can be seen by the dot product, the scalar field range is [-1, 1]; select is greater than the threshold value square of the scalar field value of the threshold, the crown division boundary line into two parts near and near labial lingual, lingual portion near discarded, retention portion near the lip border line; then, in close spline configuration on a plane near the lingual side of the dental surface, near the plane defined by the lip border line reserved two endpoints and B near the lingual side of one point is determined, the spline as a new near lingual crown boundary line; Finally, the crown after the complete boundary near the lip portion side of the boundary line and a new boundary line near lingual crown combined to become a boundary line dividing optimization.

[0017] 与现有技术相比,本发明所具有的有益效果为:本发明只需少量的用户交互,就能获取具有准确边界信息的牙冠模型,鲁棒性好,节省时间,操作简单,实现方便;使用本发明公开的方法,可以准确得到牙齿分割边界,且使用简单:对于欲分离的单颗牙齿,一般只需用户在牙颌模型的可视化视图上交互式的确定2个边界点,就能准确得到该牙齿的牙冠网格模型。 [0017] Compared with the prior art, the present invention has beneficial effects: the present invention, only a small amount of user interaction, will be able to obtain accurate crown model with the boundary information, robust, time saving, easy to operate easy to realize; using the method disclosed in the present invention, the dividing boundary can be accurately obtained teeth, and simple to use: for single tooth to be separated, usually only user visualized dental model view interactive two boundary points determined , grid model can accurately obtain the crown of the tooth. 本发明对于牙齿正畸,牙颌虚拟手术模拟等有着重要的意义。 The present invention has important implications for orthodontics, dental surgery virtual simulation.

附图说明 BRIEF DESCRIPTION

[0018] 图1为本发明从上颌网格模型分离牙冠的流程图; [0018] FIG. 1 is a flowchart separated from the upper crown mesh model of the present invention;

[0019] 图2为本发明所使用的牙颌上各牙齿的解剖学特征点示意图; [0019] anatomical feature points of each tooth on dental schematic FIG. 2 of the present invention is used;

[0020] 图3为计算调和场所需约束点的不意图; [0020] FIG. 3 is not intended to calculate the desired harmonic field constraint points;

[0021] 图4为计算所得调和场结果及其等值线的示意图; [0021] FIG. 4 is a schematic view of the resulting harmonic field calculation results and their contours;

[0022] 图5A为需要优化的牙冠分割边界线示意图; [0022] FIG 5A is a schematic view of a boundary line dividing the need to optimize the crown;

[0023] 图5B为分离后所保留的近唇侧边界线及构造近舌侧边界线所依赖平面的示意图; [0023] FIG 5B is a side near the lip line and configured retained after the separation of the tongue near the plane schematic side borderlines dependence;

[0024] 图5C为优化后的牙冠分割边界线的示意图,其中包括了新构造的近舌侧边界线; [0024] FIG 5C is a schematic view of the boundary line is divided into a crown optimized, including nearly tongue side borderlines new configuration;

[0025] 图为依照牙冠分割边界线进行网格切割,最终分离出单颗牙冠的结果。 [0025] The picture shows the division boundary line in accordance with a crown mesh cutting, the final result of the separation of single tooth crowns.

具体实施方式 detailed description

[0026] 本发明的具体实施方式详述如下: [0026] DETAILED DESCRIPTION The present invention is described in detail as follows:

[0027] 如图1所示,本发明所述的从上颌网格模型上交互式分离牙冠的方法,包括步骤: 1读入并可视化显示牙颌三维网格模型;2自动检测牙颌上牙齿的解剖学特征点及咬合平面;3由用户指定网格模型调和场的约束点;4根据约束点计算调和场,获取牙冠分割边界线;5如有必要,优化该边界线;6依照获取的边界线进行网格切割,得到牙冠模型。 [0027] 1, interactive method of separating from the upper crown mesh model according to the present invention, comprising the steps of: a visual display and read dental 3D mesh model; 2 automatically detects edentulous anatomical feature points and the occlusal plane of the teeth; 3 designated by the user constraint points of the grid model harmonic field; 4 calculates harmonic field the constraint points, obtaining a boundary line dividing the crown; 5, if necessary, to optimize the boundary line; 6 in accordance with obtaining a boundary line mesh cut to obtain crown model.

[0028] 1.读入并可视化显示牙颌三维网格模型 [0028] 1. Read in and visualizing dental 3D mesh model

[0029] 从模型文件中载入牙颌通用网格模型数据,该网格模型可以通过三维采集设备(如扫描仪)得到,亦可从CBCT等医学序列图片中重建获得。 [0029] Loading dental generic mesh model from the data file, the three-dimensional mesh model can capture devices (such as scanners) obtained can also be obtained from the reconstructed CBCT and other medical picture sequence. 在计算机中通过通用计算机图形学可视化平台(例如OpenGL)可视化显示以后,用户可以使用鼠标、键盘等设备对该模型进行交互式操作(例如缩放、旋转、平移、选点等)。 Later by a general purpose computer graphics visualization platform (e.g., the OpenGL) visual display, the user can use the device model mouse, keyboard or the like in a computer for interactive operations (e.g., zoom, rotate, pan, etc. setpoint).

[0030] 2.自动检测上颌牙齿的解剖学特征点及牙颌平面 [0030] The automatic detection of anatomical characteristic points upper teeth and dental plane

[0031] 利用网格模型上顶点的曲率信息及相关算法(例如分水岭算法),可以顺利得到牙冠上的解剖学特征点信息。 [0031] The use of curvature information and related algorithms vertices on the mesh model (e.g. watershed algorithm), to obtain a smooth anatomical feature point information on the crown. 例如图2A所示的切牙切嵴上的2个端点、图2B所示的尖牙上的1个尖点(牙尖)、图2C所示的前磨牙上的2个尖点(舌尖、颊尖)以及图2D所示的磨牙上的4个尖点(远中颊尖、远中舌尖、近中舌尖、近中颊尖)。 For example, two endpoints on the incisors crest shown in FIG. 2A, FIG 2B 1 cuspidal points (cusps) on canine shown, two sharp points (tongue shown on the premolars to Figure 2C, buccal cusp) and FIG. 2D 4 cuspidal points (distal buccal cusp of the upper molars shown, the distal tip of the tongue, near the tip of the tongue, mesial buccal cusp).

[0032] 确定好特征点之后,咬合平面也就可以随之确定下来。 [0032] After determining good feature points, along the occlusal plane may also be determined. 本发明采用通用的定义,即两颗切牙的邻接点、左侧第一磨牙的近中舌尖以及右侧第一磨牙的近中舌尖共三点来确定该咬合平面。 The present invention employs a common definition, i.e. two adjacent points incisor, first molar on the left side and the right side near the tip of the tongue near the tip of the tongue of the first molar to determine the three co-occlusal plane.

[0033] 3.用户指定网格模型调和场的约束点 [0033] 3. The user specifies the constraint points of the grid model harmonic field

[0034] 在本发明所设计的交互式环境下,用户可以使用鼠标、键盘自由选取(通过旋转、 平移、缩放)合适的牙颌模型的可视化视图,并在选定的视图中任意选取网格模型上的顶点并获取其坐标。 [0034] In the present invention, an interactive design environment, the user can use a mouse, keyboard, freely selected (by rotation, translation, scaling) visualizations suitable dental model and view selected arbitrarily selected grid vertex on the model and to obtain the coordinates. 本发明中,需要用户为目标牙冠指定2个分别位于近中和远中牙缝处的约束点。 In the present invention, the user needs to specify two constraint points are located near the teeth and at the distal target crown. 图3所示的牙齿为某下颌左侧第一前磨牙的可视化视图,其中的①标识的小球展示了符合本发明要求的用户指定约束点。 Tooth shown in FIG. 3 is a graphical view of a left first premolar of the lower jaw, wherein the pellets ① shows the identification requirements of this invention, the user can specify a constraint point.

[0035] 4.根据约束点计算调和场,获取牙冠分割边界线 [0035] The constraint point calculating harmonic field, obtaining a crown division boundary line

[0036] 本发明中,我们将寻找分割边界线问题转化为计算网格表面的调和场并选取其某条等值线问题进行解决。 [0036] In the present invention, we will look for a boundary line dividing the problem into the computing grid surface harmonic field and select an article which contours resolve the problem.

[0037] 求解网格表面调和场在数学上即求解泊松方程A〇= 0 (A代表离散拉普拉斯算子)。 [0037] Solving mesh surface harmonic field solving the Poisson equation A〇 i.e. = 0 (A behalf discrete Laplacian) mathematically. 使用最小二乘法可以求解该泊松方程,此时原方程转化为AO=b的形式, The least square method may be solved using the Poisson equation, then the original equation is converted to the form AO = b, and

Figure CN104392492AD00071

[0039] 其中L是拉普拉斯矩阵,如果网格中有m个节点,则L是mXm阶矩阵,对于0 ^i,j^m-1, [0039] where L is the Laplacian matrix, if there are m nodes in the mesh, L is the order matrix mXm, for 0 ^ i, j ^ m-1,

Figure CN104392492AD00072

[0041] 其中,E为牙颌三维网格模型中边的集合;《是拉普拉斯算子的权值,对于调和场的分布有着重要的影响。 [0041] wherein, E is a dental 3D mesh model in the set of edges; "Laplacian is the weight for the harmonic field distribution has an important influence. 这里我们采用 Here we use

[0042] [0042]

Figure CN104392492AD00073

如果Vi或Vj处为凹点 If Vi or Vj is at the pits

[0043] 来捕捉代表分割边界地网格表面凹陷区域,其中Vi为在i点处的坐标值,F代表平均的边长度,©为一个很小的常量(例如0.001)。 [0043] Representative division boundary to capture the mesh surface recessed region, where Vi is the coordinate value at the point i, F represents the average side length, © a small constant (e.g., 0.001).

[0044] C和b'分别是代表调和场中约束条件的矩阵和向量。 [0044] C and b 'are representative of field harmonic constraint matrices and vectors. 如果m个节点的网格上有n 个约束点,则C和b'可以表示如下: If there are n m constraint points on the grid nodes, and the C b 'can be expressed as follows:

Figure CN104392492AD00074

[0046] w是一个很大的系数,这里取值为1000。 [0046] w is a big factor, where a value of 1000. 对于第i(i= 0, 1,…n-1)个约束点,其在网格中的序号为P(〇彡P彡m-1),则C中的元素cip = 1,其余为0。 For the first i (i = 0, 1, ... n-1) th constraint points, which number in the grid is P (P San San square m-1), the elements in the cip C = 1, the remaining 0 . b'中元素h的取值G{〇, 〇. 5, 1},即h的取值为0、0. 5、或1,对应于第i个约束点的取值。 b 'values ​​of the elements h G {square, square. 5, 1}, i.e., the value h 0,0. 5, or 1, corresponding to the value of the i-th constraint points. 利用求解带有大型稀疏系数矩阵线性方程AO=b的工具包求出方程的解,即为每个顶点对应的调和场值。 By solving large sparse coefficients AO = b equation solution kit is obtained, i.e. the corresponding values ​​of the vertices of each harmonic field with a matrix of linear equations.

[0047] 为了利用调和场分离牙冠,除了用户指定的2个约束点(记为U,其对应的h值为0.5)以外,其余的约束点可由系统自动获取。 [0047] In order harmonic field than using separate crown, in addition to two constraint points specified by the user (referred to as U, which corresponds to the value of 0.5 h), the rest of the constraint points acquired by the system automatically. 他们分别为步骤2中确定的牙冠上的特征点(记为F,对应的h值为1),以及一系列围绕且不属于目标牙冠的约束点(记为B,对应的h值为0)。 They are characteristic points on the crown determined in step 2 (denoted is F, the corresponding value of h 1), and a series of constraint around the target point does not belong to the crown (referred to as B, the corresponding value of h 0). 以图3为例,其中的②和③所标识的小球分别代表了F和B。 3 as an example, where the identified ② and ③ respectively represent F ball and B.

[0048] 我们采用如下的方法确定B:B中的点由一系列直线与牙颌网格模型的交集所确定。 [0048] We use the following method to determine B: B is determined by the intersection point of the straight line and a series of dental grid model. 这些直线初始化的时候分别经过F中各点在咬合平面上的投影点,且位于咬合平面上。 These lines respectively, after initialization of the nip point F of each point on the projection plane, and located on the occlusal plane. 然后,我们沿着咬合平面的法线作为轨迹,将他们分别朝牙颌底部平移一段距离。 Then, we occlusal plane along the normal trajectory as, respectively, toward their bottom pan dental a distance. 这段距离长度我们一般设定为从牙冠尖点到牙颌底部垂直距离的2/3倍。 This distance is generally set to 2/3 the length of our times from the point to the bottom tip of the crown dental vertical distance.

[0049] 为调和场指定约束条件以后即可求解线性方程AO=b,得到网格上每个节点对应的调和场标量值。 [0049] for solving linear equations AO = b harmonic field specified constraint is later obtained corresponding to each node on the mesh harmonic field scalar value. 我们使用从该调和场中抽取的若干条等值线作为候选边界线集合。 We use several pieces of contours extracted from the harmonic field line set as candidate boundaries. 图4展示了某颗目标牙冠在给定约束条件下的调和场及其等值线。 Figure 4 shows the harmonic field contour and a target crown pieces under the given constraints. 最后,我们采用评分的方式选取候选边界线中最好的一条边界环作为牙冠的分割边界。 Finally, we use the scores to select the way best candidate boundary line as a boundary dividing boundary crown ring.

[0050] 5.如有必要,优化4中所得的边界 [0050] 5. If necessary, the resulting optimization of the boundary 4

[0051] 如果目标牙冠近舌侧边界不明显(如图5所示),则需要对4中所述的边界线进行必要的优化。 [0051] If the target for tooth lingual obvious boundary (shown in FIG. 5), it is necessary for the boundary lines 4, the necessary optimization. 首先,我们为边界线上各点计算一个标量场,。 First, we calculate a scalar field for the point boundary line. 在所述标量场中,每个点对应的标量值为该点的单位法向量与B中近舌侧点的平均单位法向量的点积,由点积的概念可知,该标量场的值域为[-1,1];选取大于〇的某阈值对该标量场进行阈值化,便可将边界线分为近唇侧和近舌侧两部分,我们弃近舌侧部分,保留其余近唇侧的边界线部分(例如图5B相对于图5A来说,其所保留的曲线部分)。 Unit normal vector of the scalar field, each point corresponding to the scalar value for that point B near the lingual side of the dot product of vectors point average unit normal, a concept known dot product, the value of the scalar field domain [-1,1]; select a certain threshold value greater than the square of the scalar field value of the threshold, it will be near the boundary line into two parts near the labial and lingual, lingual portion near we abandoned, leaving the rest near a boundary line portion of the labial side (e.g., FIG. 5B curved portion with respect to FIG. 5A, the reservation it). 然后,我们在贴近牙颌近舌侧表面的特定平面上构造样条线(例如图5C相对于图5B来说,其所添加的曲线部分),将该样条线作为新的近舌侧牙冠边界线。 Then, we close the spline configuration (e.g., FIG. 5C with respect to FIG. 5B, the curved portion which it is added) near a specific plane dental lingual surface, the spline as a new near-lingual crown boundary line. 该平面由所保留的近唇侧边界线的2个端点以及B中近舌侧的1 点唯一的确定(例如图5B相对于图5A来说,其所添加的平面)。 This plane is determined only by the endpoints 1:02 near the reserved line and the B side of the lip near the lingual side (e.g., Figure 5B with respect to the plane of FIG. 5A, the they are added). 最后,将前2步得到的两侧(即近舌侧和近唇侧)边界线结合起来,成为优化后的完整的牙冠分割边界线。 Finally, both sides (i.e., near and near labial lingual) obtained in step 2 before the boundary lines combine into a complete crown optimized division boundary line.

[0052] 6.依照获取的边界线进行网格切割,得到牙冠模型 [0052] 6. The mesh boundary line cut in accordance with the acquired model obtained crown

[0053] 得到满意的牙冠分割边界线以后,我们使用网格切割的方法将目标牙冠从牙颌上分离下来。 After the [0053] crown satisfactory division boundary line, we use a method of cutting the target grid is separated from the dental crown. 具体方法是计算边界线上的各点到邻近的网格顶点的距离。 The specific method is the distance of the mesh vertices calculated for each point adjacent to the boundary line. 利用该局部距离场,即便分割边界线不能完全贴合于牙颌网格表面上(例如新构造的近舌侧样条边界线), 网格切割也能够顺利的进行。 By using the local distance field, even if the division boundary line can not be completely attached to the dental surface of the grid (e.g., near the lingual side of the newly constructed spline boundary lines), grid cutting can be performed smoothly. 图®显示了根据边界线切割后的牙冠模型。 FIG ® crown model shows the cut according to the boundary line.

Claims (7)

  1. 1. 一种从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,包括以下步骤: 1) 读入并可视化显示牙颌三维网格模型; 2) 检测所述牙颌三维网格模型中牙颌上牙齿的解剖学特征点及咬合平面; 3) 指定牙颌三维网格模型调和场的约束点; 4) 根据约束点计算调和场,获取牙冠分割边界线; 5) 依照获取的牙冠分割边界线进行网格切割,得到牙冠模型。 A three-dimensional model is divided from the single-tooth dental crown interactive computer method comprising the following steps: 1) reading and visualizing a three-dimensional dental model mesh; 2) detecting the three-dimensional dental cast grid model of dental anatomical feature points on the tooth and the occlusal plane; 3) specify the constraint of dental point of the 3D mesh model harmonic field; 4) is calculated according to the harmonic field constraint points, obtaining a boundary line dividing the crown; 5) in accordance with a boundary line dividing the acquired crown mesh cut to obtain crown model.
  2. 2. 根据权利要求1所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述步骤2)中,利用所述牙颌三维网格模型上顶点的曲率信息及分水岭方法获取牙颌上牙齿的解剖学特征点,利用所述解剖学特征点确定咬合平面。 According to claim dividing three-dimensional model from the single-tooth dental crown computer interactive method of claim 1 wherein 2) said step of using the curvature information on vertices dental 3D mesh model and watershed method for obtaining dental anatomical feature points on the teeth, with the occlusal plane determined anatomical feature point.
  3. 3. 根据权利要求2所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述步骤3)中,为目标牙冠分别指定1个位于近中牙缝处和1个位于远中牙缝处的约束点。 3. From the three-dimensional model into single tooth dental crown interactive computer method, wherein according to claim 2, in the step 3), to specify a target located near the crown of the teeth, respectively and a distal teeth located at the point of constraint.
  4. 4. 根据权利要求3所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述步骤4)中,调和场的计算过程为:设牙颌三维网格模型中有m个节点,η个约束点,求解ΑΦ = b,得到的解即为牙颌三维网格模型各个顶点对应的调和场值;其中, 4. From the three-dimensional model into single tooth dental crown interactive computer method, wherein according to claim 3, said step 4), the harmonic field calculation process is as follows: set of dental 3D mesh model has m nodes, constraint point [eta], solving ΑΦ = b, the resulting solution is the harmonic field value of each vertex of the mesh model corresponding to the three-dimensional dental cast; wherein,
    Figure CN104392492AC00021
    ^ ? ^ ' ' 一 ^? ^ '' A
    Figure CN104392492AC00022
    Lij是mXm阶的拉普拉斯矩阵, (i, j) e E,0彡i, j彡m-1, i PE为牙颌三维网格模型中边的集合; Lij is the Laplacian matrix mXm order, (i, j) e E, 0 San i, j San m-1, i PE dental 3D mesh model is a set of edges;
    Figure CN104392492AC00023
    如果Vi或\处为凹点,Vi为牙颌三维网格模型i点处的坐标值,F代表牙颌三维网格模型平均边长,〇为常量; If Vi or \ at a concave point, Vi-dimensional coordinate values ​​at the dental model mesh points i, F for dental 3D mesh model average side length of constant square;
    Figure CN104392492AC00024
    C中的元素= 1,其余为0,0彡p彡m-1,p为第r个约束点在牙颌三维网格模型中的序号, C 1 = the elements, the remainder being 0,0 San San p m-1, p is the number of points in the r constraint 3D mesh model in the dental,
    Figure CN104392492AC00025
    中各元素的取值e {0,0.5, 1}。 The value of each element e {0, 0.5, 1}.
  5. 5. 根据权利要求4所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述步骤4)中,获取牙冠分割边界线的过程为:从所述调和场中抽取若干条等值线作为候选边界线集合,选取评分最高的一条候选边界环作为牙冠牙冠分割边界线。 According to claim dividing three-dimensional model from the single-tooth dental crown computer interactive method of claim 4 wherein said step 4), the process of obtaining a crown division boundary line is: from the harmonic field extracted several pieces of contour boundary line as a candidate set, select a highest score as candidate boundaries crown crown ring division boundary line.
  6. 6. 根据权利要求4或5所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述η个约束点包括所述步骤2)获得的解剖学特诊点、步骤3)指定的两个约束点和一系列围绕且不属于目标牙冠的约束点B ;所述约束点B的确定方法如下:找到所有解剖学特征点在所述咬合平面上的投影点,找到位于所述咬合平面上、且经过所述投影点的直线;以咬合平面的法线为轨迹,将所述直线朝牙颌底部平移一段距离,所述距离设定为从牙冠尖点到牙颌底部垂直距离的2/3倍;获取所述直线与牙颌三维网格模型的交点,所述交点的集合即为Β。 6. The computer-interactive method of dividing a single tooth from dental crown 4 or three-dimensional model according to claim 5, wherein said η anatomical constraints, VIP points comprising the step 2) obtained in point , step 3) of the two specified points and a set of constraint around the crown does not belong to the target point B constraints; method of determining the constraint point B as follows: find all anatomical feature points of the projected points on the occlusal plane, , locate the occlusal plane, and a straight line passing through the projection point; occlusal plane normal to the trajectory, the linear translation toward the bottom of dental a distance, the distance is set from the crown cusp 2/3 the vertical distance to the bottom of dental; obtaining the point of intersection of the straight line and dental 3D mesh model, the intersection is the set Β.
  7. 7. 根据权利要求6所述的从牙颌三维模型分割单颗牙冠的计算机交互式方法,其特征在于,所述步骤4)中,获取所述牙冠分割边界线后,优化所述牙冠分割边界线,优化过程如下:为牙冠分割边界线上各点计算一个标量场,每个点对应的标量值为该点的单位法向量与B中近舌侧点的平均单位法向量的点积,由点积的概念可知,该标量场的值域为[_1,1]; 选取大于〇的阈值对该标量场进行阈值化,将所述牙冠分割边界线分为近唇侧和近舌侧两部分,舍弃近舌侧部分,保留近唇侧边界线部分;然后,在贴近牙颌近舌侧表面的平面上构造样条线,所述平面由所保留的近唇侧边界线的2个端点以及B中近舌侧的1点确定,将该样条线作为新的近舌侧牙冠边界线;最后,将所述近唇侧边界线部分边界线和所述新的近舌侧牙冠边界线结合起来,成为优化后的完整的牙冠 7. Dental cast from the interactive computer method of dividing a single tooth crown according to claim 6, wherein,) in step 4, after acquiring the division boundary line of the crown, optimize the dental crown division boundary line, the optimization process is as follows: each point of a boundary line dividing crown calculating a scalar field, each point corresponding to a scalar value for the average unit normal vector and the unit normal vector of the point B near the lingual side of the point dot product of the dot product of the concept can be seen, the range of the scalar field is [selected, 1]; greater than a selected threshold value square of the scalar field value of the threshold, the division boundary line into crown near the labial and portions near two lingual, lingual portion near discard reserved line side near the lip portion; then, a spline configuration on a plane close to the near-lingual surface of the dental, the near side of the plane defined by the lip retained two endpoints, and B is near the lingual side of the boundary of one point is determined, the spline as a new boundary line near lingual crown; Finally, the near-side boundary portion of the lip and the new boundary line after almost a complete crown lingual crown boundary line combination, be optimized 割边界线。 Cut boundary line.
CN 201410680473 2014-11-24 2014-11-24 Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model CN104392492A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201410680473 CN104392492A (en) 2014-11-24 2014-11-24 Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201410680473 CN104392492A (en) 2014-11-24 2014-11-24 Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model

Publications (1)

Publication Number Publication Date
CN104392492A true true CN104392492A (en) 2015-03-04

Family

ID=52610390

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 201410680473 CN104392492A (en) 2014-11-24 2014-11-24 Computer interaction type method for segmenting single tooth crown from three-dimensional jaw model

Country Status (1)

Country Link
CN (1) CN104392492A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104867131A (en) * 2015-04-24 2015-08-26 杭州一牙数字口腔有限公司 Dental crown data extraction method based on digital model
CN105046750A (en) * 2015-08-24 2015-11-11 杭州美齐科技有限公司 Method for automatically segmenting whole dental triangular mesh model
CN105748163A (en) * 2016-02-05 2016-07-13 杭州美齐科技有限公司 Design method for computer-aided bracket-free concealed teeth correcting equipment
CN105931291A (en) * 2016-05-16 2016-09-07 杭州美齐科技有限公司 Digitalized complete tooth and jaw modeling method
CN106228550A (en) * 2016-07-19 2016-12-14 上海爱圣美科技有限公司 Recognition method of dental crown part in three-dimensional teeth model
CN106228549A (en) * 2016-07-14 2016-12-14 嘉兴学院 Triangular grid tooth segmentation method based on path planning

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6049743A (en) * 1996-09-06 2000-04-11 Technology Research Association Of Medical And Welfare Appartus Method of designing dental prosthesis model and computer program product therefor
CN103700103A (en) * 2013-12-05 2014-04-02 嘉兴学院 Method for automatically extracting gingiva curves of three-dimensional digital dentition model
CN103871097A (en) * 2014-02-26 2014-06-18 南京航空航天大学 Tooth preparation-based data flexible fusion method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6049743A (en) * 1996-09-06 2000-04-11 Technology Research Association Of Medical And Welfare Appartus Method of designing dental prosthesis model and computer program product therefor
CN103700103A (en) * 2013-12-05 2014-04-02 嘉兴学院 Method for automatically extracting gingiva curves of three-dimensional digital dentition model
CN103871097A (en) * 2014-02-26 2014-06-18 南京航空航天大学 Tooth preparation-based data flexible fusion method

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
BEI-JI ZOU 等: "Interactive tooth partition of dental mesh base on tooth-target harmonic field", 《WWW.SCIENCEDIRECT.COM/SCIENCE/ARTICLE/PII/S001048251400287X》 *
HAO WANG 等: "Spectral 3D mesh segmentation with a novel single segmentation field", 《GRAPHICAL MODELS》 *
OSCAR KIN-CHUNG AU 等: "Mesh Segmentation with Concavity-Aware Fields", 《IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS》 *
朱赴东 等: "数字化全牙列下颌骨三维解剖建模", 《解剖学报》 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104867131A (en) * 2015-04-24 2015-08-26 杭州一牙数字口腔有限公司 Dental crown data extraction method based on digital model
CN104867131B (en) * 2015-04-24 2017-11-03 杭州牙数字口腔有限公司 Data extraction method based on the digital crown model
CN105046750B (en) * 2015-08-24 2017-08-15 杭州美齐科技有限公司 A method for automatic segmentation whole jaw teeth triangular mesh model
CN105046750A (en) * 2015-08-24 2015-11-11 杭州美齐科技有限公司 Method for automatically segmenting whole dental triangular mesh model
CN105748163A (en) * 2016-02-05 2016-07-13 杭州美齐科技有限公司 Design method for computer-aided bracket-free concealed teeth correcting equipment
CN105931291A (en) * 2016-05-16 2016-09-07 杭州美齐科技有限公司 Digitalized complete tooth and jaw modeling method
CN106228549A (en) * 2016-07-14 2016-12-14 嘉兴学院 Triangular grid tooth segmentation method based on path planning
CN106228550A (en) * 2016-07-19 2016-12-14 上海爱圣美科技有限公司 Recognition method of dental crown part in three-dimensional teeth model

Similar Documents

Publication Publication Date Title
Motohashi et al. A 3D computer-aided design system applied to diagnosis and treatment planning in orthodontics and orthognathic surgery
US6767208B2 (en) System and method for positioning teeth
Plooij et al. Digital three-dimensional image fusion processes for planning and evaluating orthodontics and orthognathic surgery. A systematic review
US6371761B1 (en) Flexible plane for separating teeth models
US6665570B2 (en) Efficient data representation of teeth model
US6632089B2 (en) Orthodontic treatment planning with user-specified simulation of tooth movement
US7474307B2 (en) Clinician review of an orthodontic treatment plan and appliance
US7063532B1 (en) Subdividing a digital dentition model
US7373286B2 (en) Efficient data representation of teeth model
US20060147872A1 (en) Custom orthodontic appliance system and method
US6409504B1 (en) Manipulating a digital dentition model to form models of individual dentition components
US20050089822A1 (en) Dental computer-aided design (CAD) methods and systems
US6688886B2 (en) System and method for separating three-dimensional models
US6633789B1 (en) Effiicient data representation of teeth model
US20060263739A1 (en) Method and system for finding tooth features on a virtual three-dimensional model
Hublin et al. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens
US20080248443A1 (en) Clinician review of an orthodontic treatment plan and appliance
US7717708B2 (en) Method and system for integrated orthodontic treatment planning using unified workstation
Xia et al. Three-dimensional virtual-reality surgical planning and soft-tissue prediction for orthognathic surgery
US20040175671A1 (en) Subdividing a digital dentition model
Kondo et al. Tooth segmentation of dental study models using range images
US7156655B2 (en) Method and system for comprehensive evaluation of orthodontic treatment using unified workstation
US6227850B1 (en) Teeth viewing system
US20120095732A1 (en) System and method for effective planning, visualization, and optimization of dental restorations
US20090148809A1 (en) System and method for improved dental geometry representation

Legal Events

Date Code Title Description
C06 Publication
C10 Entry into substantive examination