Method for characterizing an intraoral organ
A method for characterizing an intraoral organ. Modelling the organ as a digital three-dimensional model to be characterized (MTBC), including a mesh of points defining a surface. Placing the MTBC in a standardized configuration with respect to a digital three-dimensional initial reference model (IRM), including a mesh of points, called initial reference points (IRPs), the number of IRPs being less than 20% of the MTBC. Then, determining a final reference point (FRP), for each IRP, by a deformation algorithm. Then, determining a set of values determining the position of the FRP and/or a final elementary surface depending on the FRP, the algorithm determining the positions of the FRPs so that a final reference model consisting of a mesh of the final reference points matches the model to be characterized as closely as possible. Generating a characteristic vector grouping, in an ordered manner, the values determined for all the IRPs.
1 . A method for characterizing an intraoral organ to be characterized, said method comprising the following steps:
1) modelling the intraoral organ to be characterized in the form of a digital three-dimensional model, or “model to be characterized”, comprising a mesh of points defining a surface;
2) placing said model to be characterized in a standardized configuration with respect to a digital three-dimensional model, called “initial reference model”, comprising a mesh of points, called “initial reference points”, the number of initial reference points being less than 20% of the number of points of the model to be characterized; then
3) determining a final reference point, for each initial reference point, by means of a deformation algorithm, then
determining a set of values determining the position of the final reference point and/or a final elementary surface depending on the final reference point, the deformation algorithm determining the positions of the final reference points so that a final reference model consisting of a mesh of the final reference points matches the model to be characterized as closely as possible;
4) generating a characteristic vector grouping, in an ordered manner, the values determined in step 3) for all said initial reference points.
2 . A method for generating a database of characteristic vectors, said method comprising, for each intraoral organ to be characterized of a set of intraoral organs comprising more than 500 intraoral organs, characterizing said intraoral organ to be characterized according to a method as claimed in claim 1 , then according to the following step 5′):
5′) adding the characteristic vector to the database of characteristic vectors.
3 . A method for generating a model of an intraoral organ, said method comprising generating a characteristic vector according to a method as claimed in claim 1 , then, on the basis of the characteristic vector and of said initial reference model, deforming the initial reference model by moving the initial reference points as a function of said characteristic vector.
4 . A method for detecting a shape anomaly of an intraoral organ to be tested, said method comprising the following steps:
c) characterizing the intraoral organ to be tested according to a characterization method as claimed in claim 1 , so as to acquire a characteristic vector “to be tested”;
d) comparing, for at least one parameter of the characteristic vector to be tested, the value of said parameter with a pre-defined range of “acceptable” values;
e) generating, if said value to be tested does not belong to said range, a notification indicating the existence of a shape anomaly.
5 . A method for generating a database of indexed historical models, called “indexed historical library”, said method comprising, for each intraoral organ of a set of intraoral organs comprising more than 500 intraoral organs:
characterizing according to a method as claimed in claim 1 so as to determine a model of the intraoral organ, or “historical model”, and a characteristic vector, called “historical characteristic vector”; then
forming a record, called “historical record”, comprising said historical characteristic vector and said historical model; then
adding said historical record to the indexed historical library.
6 . The method as claimed in claim 5 , implemented for a plurality of said sets of intraoral organs, said intraoral organs being teeth and each set containing only teeth with the same number or of the same type and the initial reference model used when characterizing the teeth of said set being a model of a reference tooth having said number or being of said type, respectively.
7 . The method as claimed in claim 5 , wherein said intraoral organs are teeth, said set contains teeth with different numbers or of different types, and the initial reference model used when characterizing the teeth of said set is the same, irrespective of the tooth that is the subject of said characterization.
8 . A method for identifying an individual, said method comprising the steps of:
i) generating, at a first time, an indexed historical library according to a method for generating a database of indexed historical models, called “indexed historical library”, said method comprising, for each intraoral organ of a set of intraoral organs comprising more than 500 intraoral organs:
characterizing according to a method as claimed in claim 1 so as to determine a model of the intraoral organ, or “historical model”, and a characteristic vector, called “historical characteristic vector”; then
forming a record, called “historical record”, comprising said historical characteristic vector and said historical model; then
adding said historical record to the indexed historical library or, a database of characteristic vectors according to a method for generating a database of characteristic vectors, said method comprising, for each intraoral organ to be characterized of a set of intraoral organs comprising more than 500 intraoral organs, characterizing said intraoral organ to be characterized according to a method as claimed in claim 1 , then according to the following step 5′):
5′) adding the characteristic vector to the database of characteristic vectors; and
associating each characteristic vector, the indexed historical library or the database of characteristic vectors, resulting from the processing of a model of an intraoral organ, with an identifier of the individual wearing said intraoral organ,
ii) at a second time after the first time:
characterizing a target intraoral organ of a target individual to be identified, according to a method as claimed in claim 1 , so as to determine a digital three-dimensional model, or “target model”, of the intraoral organ, and a corresponding target characteristic vector; then
searching, in the indexed historical library or in the database of characteristic vectors, for a characteristic vector corresponding to the target characteristic vector and having the identifier associated with said characteristic vector corresponding to the target characteristic vector.
9 . A method for correcting a digital three-dimensional model, called “analysis model”, modelling an intraoral organ, called “intraoral analysis organ”, said method comprising the following steps:
generating an indexed historical library according to a method for generating a database of indexed historical models, called “indexed historical library” said method comprising, for each intraoral organ of a set of intraoral organs comprising more than 500 intraoral organs:
characterizing according to a method as claimed in claim 1 so as to determine a model of the intraoral organ, or “historical model”, and a characteristic vector, called “historical characteristic vector”; then
forming a record, called “historical record”, comprising said historical characteristic vector and said historical model; then
adding said historical record to the indexed historical library;
characterizing the intraoral analysis organ, according to a method as claimed in claim 1 , so as to generate said analysis model and a corresponding characteristic vector, called “analysis characteristic vector”;
searching, in the indexed historical library, for a historical record comprising a historical characteristic vector that optimally matches the analysis characteristic vector, and correcting the analysis model with the historical model of said historical record, with the correction being able to involve replacing the analysis model with the historical model.
10 . The method as claimed in the claim 9 , wherein the method for generating a database of indexed historical models is implemented for a plurality of said sets of intraoral organs, said intraoral organs being teeth and each set containing only teeth with the same number or of the same type and the initial reference model used when characterizing the teeth of said set being a model of a reference tooth having said number or being of said type, respectively, and wherein all the historical models of the indexed historical library, the initial reference model and the analysis model teeth with the same number or of the same type.
11 . The method as claimed in claim 9 , wherein, for said search, the following steps are carried out:
e1) defining a filter relating to one or more parameters of the historical characteristic vectors;
e2) filtering the indexed historical library with said filter so as to retain a subset of the indexed historical library;
e3) modifying the filter, by making the filtering conditions stricter by increasing the number of parameters involved in the filter and/or by enhancing the filtering conditions of said filter;
e4) filtering said subset with the modified filter so as to define a new subset, with the cycle of steps e3) and e4) being repeated until the subset acquired in step e3) comprises less than 5 historical records;
e5) correcting the analysis model with the historical model of one of said historical records derived from step e4).
12 . The method as claimed in claim 9 , wherein, after searching the historical model for the historical record, a white area of the analysis model is filled and/or errors in the analysis model are deleted, and/or part of the analysis model representing an intraoral organ is replaced with a surface of said historical model, and/or the analysis model is replaced with said historical model.
13 . A method for assessing an attribute on the basis of a three-dimensional representation, called “assessment representation”, of an intraoral organ, called “intraoral assessment organ”, of an individual, called “assessment individual”, said method comprising the following steps:
creating a learning database comprising more than 1,000 historical structures, each historical structure comprising:
a three-dimensional representation, called “historical representation”, of a “historical” intraoral organ of a “historical” individual; and
a “historical” descriptor containing a “historical” value, relating to the historical individual, for said attribute;
training at least one neural network by means of the training database;
submitting the assessment representation to said neural network so that it determines, for said assessment representation, at least one “assessment” value for said attribute;
the method comprising characterizing, according to a method as claimed in claim 1 , historical intraoral organs and the assessment intraoral organ in order to generate, as historical representations and an assessment representation, respectively, historical characteristic vectors and an “assessment characteristic vector”, respectively.
14 . The method as claimed in claim 1 , wherein the deformation algorithm is a constraint deformation algorithm of the mesh of the initial reference model or a projection algorithm of the initial reference points on the surface of the model to be characterized.
15 . The method as claimed in claim 1 , wherein all said intraoral organs are teeth, or wherein all said intraoral organs are teeth and all the teeth have the same tooth number or are of the same type.
16 . The method as claimed in claim 1 , wherein the initial reference model is a digital three-dimensional model of a reference intraoral organ and/or represents a population of individuals and/or represents a population of individuals and is a model of a typodont.
17 . The method as claimed in claim 1 , wherein the number of initial reference points is greater than 10 and/or less than 10% of the number of points of the model to be characterized, or wherein the number of initial reference points is less than 1% of the number of points of the model to be characterized.
18 . The method as claimed in claim 1 , wherein each characteristic vector comprises more than 10 and less than 1,000 values.
19 . The method as claimed in claim 1 , wherein the initial reference points are evenly distributed over the surface of the initial reference model.
20 . The method as claimed in claim 1 , wherein a value determined in step 3) is a value of:
a parameter of the movement vector, the origin of which is the initial reference point and the end of which is the respective final reference point; or
a parameter of a function determining said position of the final reference point on the basis of said position of the initial reference point.
21 . The method as claimed in claim 1 , wherein, in step 4), said characteristic vector comprises parameterizations of an interpolation function determined so that said interpolation function, parameterized with said parameterization, generates a final elementary surface for an initial reference point.
22 . The method as claimed in claim 21 , wherein said interpolation function is a radial basis function and/or wherein, in step 4), said characteristic vector comprises only values of the parameterization of said interpolation function.