WO2017185301A1 - Three-dimensional hair modelling method and device - Google Patents

Abstract

A three-dimensional hair modelling method and device, which are used for solving the problem that hair template reuse is highly complex, and thus the requirements for the rapid reuse of hair templates cannot be met. The method comprises: determining a first coordinate conversion relationship between a 3D head model of hair to be established and a pre-set reference head model, determining a second coordinate conversion relationship between the 3D head model and a pre-set 3D hair template, and registering the 3D head model with the 3D hair template based on the first coordinate conversion relationship and the second coordinate conversion relationship; matching the 3D hair template with a reference head model; and when it is detected that there is an error area in the registered 3D hair template, using a radial basis function (RBF) to deform hair in the error area of the 3D hair template so as to correct the error area, wherein the error area comprises a scalp layer area not completely shielding the 3D head model in the 3D hair template or a non-scalp layer area with a hair root area shielding the 3D head model in the 3D hair template.

Description

Three-dimensional hair modeling method and device Technical field

The present application relates to the field of three-dimensional image processing and computer graphics technology, and in particular, to a three-dimensional hair modeling method and apparatus.

Background technique

With the continuous improvement of the performance of microprocessors (Advanced RISC Machines, ARM for short), high-quality three-dimensional (3D) character reconstruction based on mobile phones has become a reality, and is favored by major mobile phone manufacturers and users. Human hair is a very important part of character portraits and digital character animations. The creation of hair can significantly enhance the realism of virtual characters in avatars and entertainment applications. Therefore, hair modeling for 3D characters has become a key issue to be solved in the 3D character reconstruction process.

The 3D hair modeling scheme is mainly divided into two categories, one is hair styling modeling and the other is hair model reuse. Hair styling modeling is currently the mainstream 3D hair modeling method. This method mainly uses manual to realize the creation of the model. Usually, a hair growth area is selected on the scalp of the existing human head model, and then the hair growth in the area is set. Direction, length, curl, etc. This method creates a hair model that fits exactly with the human head model, but it takes a lot of time and requires complex human intervention. For the 3D face model reconstructed by the mobile phone, if the corresponding 3D hair model is generated manually, the computing resources and time consumed by the mobile phone are unacceptable to the user.

Hair model reuse refers to creating new hairstyles similar to existing hair models on different 3D character models. The prior art performs hair model reuse by pre-storing one or more 3D hair templates, receiving a frontal hair image and a 3D head model, and then deforming the 3D hair template based on the characteristics of the frontal hair image combined with the 3D head model. Processed to produce a realistic 3D hair model.

When morphing a 3D hair template, first define the key points of the 3D hair template and The area divided according to the key points; then the hair shape of the hair image is detected; the detected hair shape is divided into a normal part and a personality part, wherein the common part refers to a similar part of the hair between different individuals, and the personality part refers to the hair in the The part with different differences between different individuals; approximating the divided individual parts, modeling the hair piece of the approximated part of the hair piece; combining the 3D head model, the defined 3D hair model The boundary key points are matched with the boundaries of the divided common parts, and the matching result areas are subjected to 3D data interpolation; the 3D hair pieces modeled by the hair modeling are combined with the 3D data interpolation results to generate real 3D hair. model.

In the prior art, the deformation processing of the 3D hair template requires the 3D hair model to be projected into a 2D form, and the selected key points are in the 2D form, and then the 2D key points are matched with the normal part and the personality part of the front view hair image, so The technique is limited by the detection results of the 2D key points, the matching precision of the 2D key points and the normal part of the face image and the personality part, and the modeling of the hair personality part, so that the hair template reuse complexity is high, and the hair template cannot be satisfied. Fast reuse.

Summary of the invention

The present invention provides a three-dimensional hair modeling method and apparatus for solving the problem that the hair template reused in the prior art has high complexity and cannot satisfy the rapid reuse of the hair template.

In a first aspect, the present application provides a three-dimensional hair modeling method, the method comprising:

Determining a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model, and determining a second coordinate transformation relationship between the 3D head model and the preset 3D hair template, And then registering the 3D head model with the 3D hair template based on the first coordinate transformation relationship and the second coordinate transformation relationship; wherein the preset 3D hair template and the preset reference header The partial models are matched; when it is detected that the registered 3D hair template has an error area, the hair in the wrong area of the 3D hair template is deformed using a radial basis function RBF to correct the error area, Wherein the error area comprises an area of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or a hair root area formed by the root point in the 3D hair template blocks the 3D head model The area of the non-scalp layer.

Through the above scheme, a 3D hair model with a perfect fit effect can be quickly constructed for a 3D head model in a terminal with relatively low storage capacity and relatively low computing power, and the realistic 3D hair model can be compared with the hair style. The hair model generated by the modeling method saves a lot of manual interaction and computing time; compared with the existing hair model reuse technology, the present invention does not need to be limited by the detection result of 2D key points, nor is it limited. The matching accuracy of the 2D key points with the normal part of the hair image and the personality part, without the need to model the hair part, can effectively improve the reusability of the 3D hair template, and the hair model can retain the prototype hair more accurately. Appearance.

In a possible design, determining a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model, and determining the 3D head model and the preset 3D hair template The second coordinate transformation relationship between the two, and the registration of the 3D head model with the 3D hair template based on the first coordinate transformation relationship and the second coordinate transformation relationship may be implemented as follows:

Determining facial key points and scalp key points of the 3D head model of the hair to be created and determining facial key points of the preset reference head model; facial key points of the 3D head model and the reference head model The facial key points are matched to obtain a face matching point pair; then, according to the face matching point pair, a first coordinate transformation relationship between the 3D head model and the reference head model is determined; according to the first Coordinate transformation relationship, obtaining three-dimensional coordinates of the 3D hair template in a target coordinate system, wherein the target coordinate system is a coordinate system in which the 3D head model is located; Matching the rooting point of the 3D hair template with the scalp key points of the 3D head model to obtain a pair of hair root matching points; determining the 3D head model and the 3D hair according to the pair of hair root matching points a second coordinate transformation relationship between the templates; and the 3D hair template is registered with the 3D head model according to the second coordinate transformation relationship.

In the above design, the first coordinate transformation relationship and the second coordinate transformation relationship are determined by the facial key point and the scalp key point of the 3D head model and the facial key point of the reference head model and the root point of the 3D hair template. The amount of calculation is reduced, so that it can be applied to terminal devices with relatively low storage capacity and computing power.

In one possible design, the deformation of the hair in the erroneous region of the 3D hair template using the radial basis function RBF can be achieved as follows:

Each hair in the wrong area of the 3D hair template is respectively performed as follows: at least three three-dimensional coordinate points in each of the hairs are selected as a first key point, and each first is determined by a nearest neighbor algorithm a key point is a nearest neighbor point of the scalp layer of the 3D head model as a matching point of each of the first key points, and each of the first key points and its corresponding matching point constitute a hair matching point pair; Each of the hairs is deformed by matching the hairline matching points as input parameters of a radial basis function.

Wherein, the first key point may include a rooting point and a tip point of each of the hairs.

In the above design, the nearest key algorithm is used to match the selected first key point with the coordinate point in the scalp layer, and the matching is accurate and the calculation amount is small.

In one possible design, the deformation of the hair in the erroneous region of the 3D hair template using the radial basis function RBF can be achieved as follows:

Performing each of the hairs in the wrong area of the 3D hair template as follows: selecting at least three three-dimensional coordinate points in each of the hairs as a second key point, and determining the at least 3 by a nearest neighbor algorithm Each of the second key points is a nearest neighbor point of the scalp layer of the 3D head model as a matching point of each of the second key points, and each of the second key points is corresponding thereto The matching points constitute a pair of hair matching points; the hair matching point pairs are used as radial basis function input parameters, and each of the hairs is deformed; each hair after deformation is divided into at least two parts, Each part of the hair is respectively performed as follows: at least three three-dimensional coordinate points in each part of the hair are taken as a third key point, and each part of the hair is placed in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor of each third key point as a matching point of each third key point, and each of the third key points and their corresponding matching points constitute a segment hairline matching point pair; Segment hairline matching The input parameters is performed as a radial basis function of the deformation of each part of the hair.

Wherein, the second key point may include a hair root point and a hair point point in each of the hairs; and the third key point may include two end points of each part of the hair.

In one possible design, the radial basis function RBF is used to deform the hair in the wrong area of the 3D hair template, including:

Each hair in the wrong area of the 3D hair template is separately performed as follows: each hair is divided into at least two parts, and is performed separately for each part of the hair as follows: at least 3 of each part of the hair is to be The three-dimensional coordinate point is used as the fourth key point, and the nearest neighbor point of each fourth key point in each part of the hair is taken as each fourth key point in the three-dimensional coordinate point of the scalp layer of the 3D head model Matching points, and each of the fourth key points and their corresponding matching points constitute a segment hairline matching point pair; the segment hairline matching point pair is used as a radial basis function input parameter for each Some of the hair is deformed.

Wherein, the third key point may include two end points of each part of the hair.

In a second aspect, the present application provides a three-dimensional hair modeling device, the device comprising:

a first determining unit, configured to determine a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model;

a second determining unit, configured to determine a second coordinate transformation relationship between the 3D head model and a preset 3D hair template, wherein the preset 3D hair template and the preset reference head model Match

a registration unit, configured to determine the first coordinate transformation relationship and the second coordinate transformation relationship based on the determining unit, and register the 3D head model with the 3D hair template;

a detecting unit, configured to detect whether the registered 3D hair template has an error area;

a deformation unit for deforming hair in the erroneous area of the 3D hair template detected by the detecting unit using a radial basis function RBF to correct the erroneous area, wherein the erroneous area includes the 3D hair The area of the scalp layer in the template that does not completely obscure the 3D head model or the hair root point in the 3D hair template obscures the area of the non-skin layer of the 3D head model.

Through the above scheme, a 3D hair model with a perfect fit effect can be quickly constructed for a 3D head model in a terminal with relatively low storage capacity and relatively low computing power, and the realistic 3D hair model can be compared with the hair style. The hair model generated by the modeling method saves a lot of people Work interaction and operation time; compared with the existing hair model reuse technology, the present application does not need to be limited by the detection result of the 2D key point, nor is it limited to the common part of the 2D key point and the front view hair image and the personality part. Matching accuracy, no need to model the hair part, can effectively improve the reusability of 3D hair template, and the hair model can retain the appearance of the prototype hair more accurately.

In a possible design, the first determining unit is specifically configured to: determine a facial key point and a scalp key point of the 3D head model of the hair to be created; and determine a facial key point of the preset reference head model. And matching a facial key point of the 3D head model with a facial key point of the reference head model to obtain a face matching point pair; determining the 3D head model and the Referencing a first coordinate transformation relationship between the head models; the registration unit is configured to obtain three-dimensional coordinates of the 3D hair template in a target coordinate system according to the first coordinate transformation relationship, wherein the target a coordinate system is a coordinate system in which the 3D head model is located; the second determining unit is specifically configured to: a root point of the 3D hair template transformed by the first coordinate transformation relationship, and the 3D head Matching key points of the scalp layer of the model to obtain a pair of hair root matching points; determining a second coordinate transformation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points; Order , According to the second coordinate transformation relationship, the hair 3D template registration with the 3D head model.

In a possible design, the deformation unit is specifically configured to: perform, for each hair in the wrong area of the 3D hair template, respectively: selecting at least three three-dimensional coordinate points in each of the hairs As a first key point, and determining, by a nearest neighbor algorithm, a nearest neighbor point of the first key point in the scalp layer of the 3D head model as a matching point of each of the first key points, and each of the A first key point and its corresponding matching point constitute a hair matching point pair; the hair matching point pair is used as an input parameter of a radial basis function, and each of the hairs is deformed.

Wherein, the first key point may include a rooting point and a tip point of each of the hairs.

In a possible design, the deformation unit is specifically configured to: perform, for each hair in the wrong area of the 3D hair template, respectively: selecting at least three three-dimensional coordinate points in each of the hairs As a second key point, and determining the at least three second levels by a nearest neighbor algorithm Each of the second key points in the key point is the closest neighbor point of the scalp layer of the 3D head model as a matching point of each of the second key points, and each of the second key points and their corresponding matching points Forming a pair of hair matching points; using the hair matching point pair as a radial basis function input parameter, deforming each of the hairs; dividing each deformed hair into at least two parts, for each part of the hair Performing respectively as follows: at least three three-dimensional coordinate points in each part of the hair are taken as a third key point, and each of the part of the hair is placed in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor of the third key point as a matching point of each third key point, and each of the third key points and their corresponding matching points constitute a segment hairline matching point pair; The matching point pairs each of the partial hairs as an input parameter that is a radial basis function.

Wherein, the second key point may include a hair root point and a hair point point in each of the hairs; and the third key point may include two end points of each part of the hair.

In a possible design, the deformation unit is specifically configured to: perform, for each hair in the wrong area of the 3D hair template, as follows: divide each hair into at least two parts, and for each Part of the hair is respectively performed as follows: at least three three-dimensional coordinate points in each part of the hair are taken as a fourth key point, and the three-dimensional coordinate points of the scalp layer of the 3D head model are used in each part of the hair a nearest neighbor point of each fourth key point as a matching point of each fourth key point, and each of the fourth key points and their corresponding matching points constitute a segment hairline matching point pair; The hairline matching point deforms each of the portions of the hair as an input parameter as a radial basis function.

Wherein, the third key point may include two end points of each part of the hair.

In a third aspect, the present application further provides a three-dimensional hair modeling device, comprising: a communication interface, a memory, and a processor. The communication interface is configured to configure a 3D head model of the hair to be created, a preset reference head model, and a preset 3D hair template, and the preset reference head model and the preset 3D hair template phase The memory is used to store the program code executed by the processor; the processor is configured to execute the program code stored in the memory, and specifically perform the operation performed by any one of the first aspects.

In a fourth aspect, the present application also provides a computer readable storage storing one or more programs The medium, the one or more programs comprising instructions that, when executed by an electronic device comprising a plurality of applications, cause the electronic device to perform the operations of any of the designs according to the first aspect.

DRAWINGS

1 is a schematic diagram of facial key points of a selected 3D head model provided by the present application;

2 is a schematic diagram of facial key points of a selected reference head model provided by the present application;

3 is a schematic diagram of key points of a scalp layer of a selected 3D head model provided by the present application;

4 is a schematic diagram of a correspondence between a key point of a 3D hair template and a matching point thereof provided by the present application;

Figure 5 is a schematic view showing the deformation of the hair from the whole to the part provided by the present application;

6 is a flow chart of a three-dimensional hair modeling method provided by the present application;

7 is a flow chart of a 3D hair template and a 3D head model registration method provided by the present application;

FIG. 8 is a schematic diagram of a three-dimensional hair modeling method provided by the present application; FIG.

9 is a schematic diagram of a three-dimensional hair modeling device provided by the present application;

10 is a schematic diagram of another three-dimensional hair modeling device provided by the present application;

FIG. 11 is a schematic diagram of a three-dimensional hair modeling effect provided by the present application.

detailed description

The present invention will be further described in detail with reference to the accompanying drawings, in which FIG. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

The present invention provides a three-dimensional hair modeling method and apparatus for solving the problem that the hair template reused in the prior art has high complexity and cannot satisfy the rapid reuse of the hair template. The method and the device are based on the same inventive concept. Since the principles of the method and the device for solving the problem are similar, the implementation of the device and the method can be referred to each other, and the repeated description is not repeated.

The application can be applied to a terminal with relatively low storage capacity and computing power, and of course The electronic device with high storage capacity and high computing capability is not specifically limited in this application.

An embodiment of the three-dimensional hair modeling method provided by the present application includes:

A three-dimensional (3D) head model of the hair to be created may be prepared in advance, and the 3D head model may be divided into a three-dimensional scalp region and a three-dimensional non-hair layer region. All three-dimensional coordinate points constituting this 3D head model constitute a set of 3D head model points. The point set in the 3D head model can be divided into two subsets, including a three-dimensional scalp area point set and a three-dimensional non-hair layer area point set.

The three-dimensional non-scalp region point set includes all facial feature points and an area surrounded by the contours of the faces formed by these points, the ear to the chin area. The information corresponding to the three-dimensional (3D) head model may further include an index number of each facial feature point, and record the index numbers of the facial feature points in the three-dimensional non-scalp region point set. Others are three-dimensional scalp area, and the contours of the three-dimensional scalp area can be marked with the forehead, the horn, and the characteristic points of the ear circumference, which are basically symmetrical. Of course, the scalp layer feature points can also be indexed and recorded in the three-dimensional scalp region point set.

The 3D hair template is prepared in advance in the present application, and corresponds to a reference head model, that is, the 3D hair template is constructed for the reference head model, and the 3D hair template matches the reference head model. The 3D hair template and the reference head model may be ones pre-stored in the 3D hair model library. The 3D hair model library correspondingly stores a plurality of 3D hair templates and reference head models, and one of the 3D hair template libraries can be selected in advance by the user. All three-dimensional coordinate points constituting this reference head model constitute a reference head model point set, and all three-dimensional coordinate points constituting the 3D hair template constitute a 3D hair template point set.

The three-dimensional hair modeling device determines a first coordinate correspondence relationship between the 3D head model of the hair to be created and the preset reference head model.

Specifically, when determining the first coordinate correspondence, first determining a facial key point of the 3D head model of the hair to be created, a scalp key point of the 3D head model, and determining a facial key point of the reference head model And matching the facial key points of the 3D head model with the facial key points of the reference head model to obtain a face matching point pair.

In the present application, when determining the facial key point of the 3D head model of the hair to be created and the key layer of the scalp layer of the 3D head model, the following can be achieved:

The facial key points of the determined 3D head model can be divided into two categories: the first type is a facial key point, which may include an eye area, a nose area, a mouth area, a chin area, and the like; the second type is a key point of the scalp layer, It may include a forehead area, a back of head area, an ear root area, and the like. For example, as shown in FIG. 1, the facial key points of the determined 3D head model include 39, R1 to R39.

In the determination of the key points, the existing feature extraction method can be used, or it can be manually selected. Of course, it is also possible to establish a key point of the face and a key point of the scalp layer that have been determined by the 3D head model, and also in the three-dimensional non-scalp area. A part of the feature points is selected as the face key point in the index number of the facial feature points in the point set, and a part of the feature points is selected as the key point of the scalp layer in the index number of the scalp layer feature points in the point set of the three-dimensional scalp area.

In the present application, in determining the facial key point of the reference head model on which the 3D hair template is based, the facial key point of the reference head model may be determined to include the eye region in the same manner as determining the facial key point of the 3D head model. , nose area, mouth area, chin area, and so on. As shown in FIG. 2, the face key points of the determined reference head model include 39, A1 to A39. The existing feature extraction method may be adopted when determining the key point, or may be manually selected, and may also be a facial key point that has been determined when the reference head model is established.

After determining the facial key points of the 3D head model and the facial key points of the reference head model, the three-dimensional hair modeling device matches the facial key points of the 3D head model with the facial key points of the reference head model. Get a face matching point pair.

Since the face key points of the 3D head model are the same as the face key points of the reference head model, the face matching point pairs may be obtained by matching based on the index numbers, or the face matching point pairs may be manually selected. For example, the key points matching the rear matching point pairs shown in FIG. 1 and FIG. 2 include: R1-A1, R2-A2, R6-A6, R7-A7, R10-A10, R13-A13, R14-A14, R19- A19, R20-A20, R33-A33.

The three-dimensional hair modeling device determines a first coordinate transformation relationship between the 3D head model and the reference head model according to the face matching point pair.

In a specific implementation, the first coordinate transformation relationship between the 3D head model and the reference head model is calculated by using the face matching point pair. The first coordinate transformation relationship s.R.t includes a scaling relationship and a rotation relationship. And translation relationship. The scaling relationship is implemented by s representing a scaling factor s, the rotation relationship is implemented by a rotation matrix R, and the translation relationship is implemented by a translation vector t.

It is assumed in the present application that the center point in the 3D hair model is the origin of the world coordinate system. Then calculate the scaling factor s by the following formula (1):

Wherein, x, y, and z in the formula represent the coordinates of the face key points corresponding to the 3D head model of the face key point pair, in the formula

It represents the coordinates of the face key points corresponding to the reference head model in the face key point pair, and n represents the total number of face key point pairs.

The method of calculating the rotation matrix R and the translation vector t by:

To calculate the uniform scale before R and t, the coordinates of the 3D head model, the reference head model, and all the feature points of the 3D hair template can be normalized. Then use the face key point pair and singular value decomposition (Singular Value Decomposition, SVD) algorithm to calculate R, t.

Assuming that the matching key point pairs are X _i and Y _i , respectively, the essential matrix E is defined as equation (2):

Assume that the external parameter of the 3D head model is P=[I|0], I represents the standard matrix, that is, the standard matrix when no rotation occurs, and 0 means that no translation occurs. The outer parameter of the reference head model is P'=[R|t], then the essential matrix E between the 3D head model and the 3D hair template is as in formula (3):

E=[t] _x R formula (3)

The essential matrix E is subjected to SVD, which is obtained as in formula (4):

E=U diag(1,1,0)V ^T formula (4)

Then the external reference P' of the 3D hair template has the following four possible options:

P'=[UWV ^T |u ₃ ];[UWV ^T |-u ₃ ];[UW ^T V ^T |u ₃ ];[UW ^T V ^T |-u ₃ ];

among them

An optional set of matching facial key points verifies the four possible values of P' to determine the only correct solution from the four different solutions. Assuming P'=[UWV ^T |u ₃ ] is the correct solution, then R=UWV ^T , t=u ₃ .

After the first coordinate transformation relationship s.R.t is obtained, the three-dimensional coordinates of the preset 3D hair template in the target coordinate system are obtained according to the first coordinate transformation relationship. The target coordinate system is a coordinate system in which the 3D head model is located.

In a specific implementation, coordinate transformation may be performed on all three-dimensional coordinate points included in the 3D hair template point set by the order of rotation-zoom-translation.

In the present application, since the 3D hair template is made based on the reference head model, the 3D hair template and the reference head model adopt the same coordinate system, and thus can refer to the first between the head model and the 3D head model. The coordinate transformation relationship obtains the three-dimensional coordinates of the preset 3D hair template in the target coordinate system, that is, the three-dimensional coordinates of all the three-dimensional coordinate points included in the 3D hair template point set are converted into the three-dimensional coordinates corresponding to the 3D hair template coordinate system.

The three-dimensional hair modeling device determines a second coordinate transformation relationship between the 3D hair template and the 3D head model transformed by the first coordinate transformation relationship.

Specifically, when determining the second coordinate transformation relationship, determining a root point of the 3D hair template transformed by the first coordinate transformation relationship, and a root point and a root of the 3D hair template transformed by the first coordinate transformation relationship The key points of the scalp layer of the 3D head model are matched to obtain a pair of root matching points.

Among them, the 3D hair template can be divided into two models, one is the hair model, which can also be called the line model; the other is the non-hair model, which can also be called the body model. The hairline model means that the 3D hair template is in the form of a plurality of hairs, each hair being composed of a plurality of dots. There is a hair root point for each hair of the hair model. The non-hair model means that the 3D hair template is present in the form of a plurality of hair regions, that is, the 3D hair template can be divided into a plurality of hair regions, which can be considered to be located in one hair. Each hair in the area has a similar shape shape. For the non-hairline model, the point at which the 3D hair template collides with the scalp layer of the 3D head model can be determined by the collision detection algorithm as the rooting point, and several hair root points of the 3D hair template can be referred to FIG.

In a specific implementation, when the rooting point in the 3D hair template is matched with the scalp key point of the 3D head model to obtain a root matching point pair, the nearest neighbor algorithm may be used in the 3D hair template. The rooting point is matched with the scalp key points of the 3D head model to obtain a root matching point pair. The nearest neighbor algorithm may be any one of the existing algorithms, which is not described herein again.

The three-dimensional hair modeling device determines a second coordinate transformation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points.

In a specific implementation, the second coordinate transformation relationship s.R.t between the 3D head model and the 3D hair template is calculated by using the root matching point pair. The specific calculation method is the same as the above method for calculating the first coordinate transformation relationship, and details are not described herein again.

The three-dimensional hair modeling device registers the 3D hair template with the 3D head model according to the second coordinate transformation relationship.

Due to the difference between the 3D head model and the reference head model, after the 3D hair template is registered with the 3D head model by the second coordinate transformation relationship, the 3D hair may be after registration. There is an error area in the model. The error region includes a region of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or a hair root region of the hair root point in the 3D hair template that obscures the non-skin layer of the 3D head model Area. Therefore, when it is determined that the 3D hair template does not completely obscure the scalp layer of the 3D head model or the hair root region formed by the hair root point in the 3D hair template blocks the non-scalp layer of the 3D head model, The hair in the erroneous region of the 3D hair template is deformed using a radial basis function RBF until the deformed 3D hair template completely obscures the scalp layer of the 3D head model and the rooting point in the 3D hair template The resulting hair root region does not obscure the non-scalp layer of the 3D head model.

When determining the above error area, it can be, but is not limited to, implemented as follows:

Using the ray casting algorithm to emit rays from the geometric center point of the 3D head model to each of the three-dimensional coordinate points constituting the 3D hair template, if the rays directed to a certain area are before the 3D head model is encountered When the 3D hair template area is encountered, the hair in the area of the 3D hair template has an incorrect occlusion relationship.

When the 3D hair template is deformed using the radial basis function RBF, overall deformation, or overall to local deformation, or local deformation may be performed for each hair in the wrong area of the 3D hair template. .

For the deformation from the whole to the local, in the specific implementation, the following operations are performed separately for each hair. In the present application, the hair A is described as an example, and other hairs can be carried out in a manner directed to the hair A.

The overall deformation includes:

1) Select at least three three-dimensional coordinate points in the hairline A as key points. In the present application, three are described as an example, for example, three three-dimensional coordinate points a1 and a5 in the hair A shown in FIG. A9, a1 is the tip point, a9 is the root point, and a5 is any other three-dimensional coordinate point. Determining, by a nearest neighbor algorithm, a nearest neighbor of each key point in the scalp layer of the 3D head model as a matching point of each of the key points, and each key point and its corresponding matching point constitute a hair matching point pair; The key point a1 corresponds to the matching point in the scalp layer of the 3D head model is b1, the key point a5 corresponds to the matching point in the scalp layer of the 3D head model is b5, and the key point a9 corresponds to the matching in the scalp layer of the 3D head model. The point is b9. In Fig. 4, B indicates a portion in the hair A where a1 to a9 match the scalp layer of the 3D head model. The hairline A is deformed using a hairline matching point pair as a radial basis function input parameter.

Local deformation includes:

2), the hairline A is divided into at least two parts. Taking the hairline A into two parts as an example, as shown in FIG. 4, the hairline A is divided into two parts A1 and A2. Select at least 3 three-dimensional coordinate points in each part as the key points, and the three key points in the three key points a1, a3, a5, and A2 in A1 are a5, a7, and a9. And determining, using the nearest neighbor algorithm, the nearest neighbor of each of the at least 3 key points in each of the portions as a matching point in the three-dimensional coordinate point of the scalp layer of the 3D head model, and each A key point and its corresponding matching point constitute a segmented hairline matching point pair. The matching points corresponding to a1, a3, and a5 are b1, b3, and b5, respectively, and the matching points corresponding to a5, a7, and a9 are b5, b7, and b9, respectively. The segment matching point formed by a1, a3, a5 and b1, b3, b5 then deforms the A1 portion of the hair A to the input parameter as a radial basis function. Then with a5, a7, a9 and b5, b7, b9 The resulting segment matching point pairs the A2 portion of the hair A as an input parameter of the radial basis function, as shown in FIG. For convenience of description, numeral 1 in FIG. 5 denotes a1, numeral 2 denotes a2, numeral 3 denotes a3, and so on.

The overall to local deformation includes:

3) After 1) the whole deformation of the hair A, the deformed hair A is divided into at least two parts, and each part is locally deformed by 2).

The radial basis function involved in the present application is a predefined function, and a function which is well-executed by a large number of experiments can be obtained. The radial basis function used in this application can be

Deformation is performed for each hair in a deformed manner for the hair A, and then the 3D hair template is updated to determine whether the updated 3D hair template completely obscures the scalp layer of the 3D head model and the 3D hair template Whether the hair root region formed by the hair root point obscures the non-skin layer of the 3D head model. Determining that the updated 3D hair template does not completely obscure the scalp layer of the 3D head model or the hair root region of the hair root point in the 3D hair template partially obscures the non-scalp layer of the 3D head model, Repeating the operations in 1) or 2) or 3) above for each hair in the wrong area in the 3D hair template until the updated 3D hair template completely obscures the scalp layer of the 3D head model and the 3D hair The hair root region formed by the hair root point in the template does not obscure the non-scalp layer of the 3D head model.

This application can quickly construct a 3D hair model with perfect fit for the 3D head model in the terminal with relatively low storage capacity and computing power. The realistic 3D hair model can be compared with the hair modeling model. The hair model generated by the method saves a lot of manual interaction and computing time; compared with the existing hair model reuse technology, the present application does not need to be limited by the detection result of 2D key points, and is not limited to the 2D key. The matching accuracy of the point and the normal part of the hair image and the personality part, without the need to model the hair part, can effectively improve the reusability of the 3D hair template, and the hair model constructed can more accurately retain the appearance of the prototype hair. .

Referring to FIG. 6, a flow chart of a three-dimensional hair modeling method provided by the present application is provided.

S601, determining a third between a 3D head model of the hair to be created and a preset reference head model a coordinate transformation relationship, and determining a second coordinate transformation relationship between the 3D head model and a preset 3D hair template, and the 3D head based on the first coordinate transformation relationship and the second coordinate transformation relationship The model is registered with the 3D hair template. The above S601 can be referred to as a rigid registration process.

The preset 3D hair template matches the preset reference head model.

S602. When it is detected that the registered 3D hair template has an error area, the hair in the wrong area of the 3D hair template is deformed by using a radial basis function RBF to correct the error area.

Wherein the error area comprises an area of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or a hair root area formed by the root point in the 3D hair template blocks the 3D head model The area of the non-scalp layer.

Alternatively, the rigid registration process can be implemented as follows, as shown in FIG.

S701. Determine a facial key point and a scalp key point of the 3D head model of the hair to be created, and determine a facial key point of the preset reference head model.

S702. Match a facial key point of the 3D head model with a facial key point of the reference head model to obtain a face matching point pair.

S703. Determine a first coordinate transformation relationship between the 3D head model and the reference head model according to the face matching point pair.

S704. Obtain a three-dimensional coordinate of the 3D hair template in a target coordinate system according to the first coordinate transformation relationship.

The target coordinate system is a coordinate system in which the 3D head model is located.

S705. Match a root point of the 3D hair template transformed by the first coordinate transformation relationship with a key point of the scalp layer of the 3D head model to obtain a root matching point pair.

S706. Determine a second coordinate transformation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points.

S707. Register the 3D hair template with the 3D head model according to the second coordinate transformation relationship.

Based on the embodiments described in FIG. 6 and FIG. 7, in the rigid registration process, the first coordinate transformation relationship may include a rotation relationship, a scaling relationship, and a translation relationship. The first coordinate transformation relationship s.R.t includes a scaling relationship, a rotation relationship, and a translation relationship. The scaling relationship is implemented by a scaling factor s1, the rotation relationship is implemented by a rotation matrix R1, and the translation relationship is implemented by a translation vector t1. For the calculation method of the scaling factor s1, the rotation matrix R1, and the translation vector t1, refer to the corresponding description above, and the present application will not be repeated here. Referring to FIG. 8, a schematic diagram of a three-dimensional hair modeling method provided by the present application is provided.

First, a 3D head model and a face matching point pair of the reference head model are obtained based on steps S701 and S702.

In S703, determining a first coordinate transformation relationship between the 3D head model and the reference head model according to the face matching point pair may be implemented as follows:

Determining a rotation relationship, a scaling relationship, and a translation relationship between the 3D head model and the reference head model according to the face matching point pair.

Specifically, s1, R1, and t1 are calculated according to the face matching point pair.

In S704, according to the first coordinate transformation relationship, the three-dimensional coordinates of the three-dimensional coordinate point of the 3D hair template in the coordinate system of the 3D head model are obtained, which can be implemented as follows:

The three-dimensional coordinates of the 3D hair template in the coordinate system in which the 3D head model is located are obtained by sequentially rotating, scaling, and translating the three-dimensional coordinate points of the 3D hair template using the rotation relationship, the zoom relationship, and the translation relationship. The 3D hair template is converted into a coordinate system of the 3D head model.

Similarly, the second coordinate transformation relationship may include a rotation relationship, a scaling relationship, and a translation relationship; wherein the first coordinate transformation relationship s.R.t includes a scaling relationship, a rotation relationship, and a translation relationship. The scaling relationship is implemented by a scaling factor s2, the rotation relationship is implemented by a rotation matrix R2, and the translation relationship is implemented by a translation vector t2.

Then, through S705, a 3D head model and a root matching point pair of the 3D hair template are obtained. In S706, determining a second coordinate transformation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points may be implemented as follows:

Determining a rotation relationship, a scaling relationship, and a translation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points.

Specifically, s2, R2, and t2 are calculated according to the pair of root-matching points.

In S707, registering the 3D hair template with the 3D head model according to the second coordinate transformation relationship may be implemented as follows:

The 3D hair template is registered with the 3D head model by sequentially rotating, scaling, and translating the three-dimensional coordinate points of the 3D hair template using the rotation relationship, the zoom relationship, and the translation relationship.

Optionally, the radial basis function RBF is used to deform the hair in the wrong area of the 3D hair template, and specifically, the hair in the wrong area of the 3D hair template may be integrally deformed using a radial basis function RBF. Or from the whole to the local deformation, or local deformation.

The overall deformation for each hair includes:

Each hair in the wrong area of the 3D hair template is performed as follows:

Selecting at least three three-dimensional coordinate points in each of the hairs as a first key point, and determining, by a nearest neighbor algorithm, a nearest neighbor point of each first key point in the scalp layer of the 3D head model as the Matching points of each first key point, and each of the first key points and their corresponding matching points constitute a pair of hair matching points;

Each of the hairs is deformed using a hairline matching point pair as a radial basis function input parameter.

Optionally, the first key point includes a hair root point and a hair point of each of the hairs. Other first key points can select other three-dimensional coordinate points in each hair. Specifically, three-dimensional coordinate points close to the root point and the midpoint of the tip point can be selected.

The overall to local deformation for each hair includes:

A1, each hair in the wrong area of the 3D hair template is performed as follows:

Selecting at least three three-dimensional coordinate points in each of the hairs as a second key point, and determining, by the nearest neighbor algorithm, each of the at least three second key points in the 3D head The nearest neighbor of the model scalp layer serves as a matching point for each of the second key points, and each of the The two key points and their corresponding matching points constitute a pair of hair matching points; the hair matching point pairs are used as radial basis function input parameters, and each of the hairs is deformed;

A2, divide each hair after deformation into at least two parts, and perform the following for each part of hair separately:

Taking at least 3 three-dimensional coordinate points in each part of the hair as a third key point, and each third key point in each part of the hair in the three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor point as a matching point of each third key point, and each of the third key points and their corresponding matching points constitute a segment hairline matching point pair; The input parameters of the radial basis function deform the hair of each portion.

Optionally, the second key point includes a rooting point and a tip point in each of the hairs;

The third key point includes two endpoints of each portion of the hair.

Local deformations for each hair include:

Each hair in the wrong area of the 3D hair template is performed as follows:

Divide each hair into at least two parts and perform the following for each part of the hair:

Taking at least 3 three-dimensional coordinate points in each part of the hair as a fourth key point, and each fourth key point in each part of the hair in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor as a matching point for each of the fourth key points, and each of the fourth key points and their corresponding matching points constitute a segmented hair matching point pair; The input parameters of the radial basis function deform the hair of each portion.

Optionally, the third key point comprises two endpoints of the hair of each portion.

The present application also provides a three-dimensional hair modeling device, as shown in FIG. 9, the device includes:

a first determining unit 901, configured to determine a first coordinate transformation relationship between a 3D head model of the hair to be created and a preset reference head model;

a second determining unit 902, configured to determine a second coordinate transformation relationship between the 3D head model and a preset 3D hair template, wherein the preset 3D hair template and the preset reference header The models match;

a registration unit 903, configured to determine, according to the first determining unit 901, the first coordinate transformation off And the second coordinate transformation relationship determined by the second determining unit 902, registering the 3D head model with the 3D hair template;

The detecting unit 904 is configured to detect whether the registered 3D hair template has an error area;

a deformation unit 905, configured to deform the hair in the wrong area of the 3D hair template by the detecting unit 904 using the radial basis function RBF when the detecting unit 904 detects the wrong area, to correct the An error area, wherein the error area includes an area of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or a hair root area formed by the root point in the 3D hair template blocks the 3D The area of the non-scalp layer of the head model.

This application can quickly construct a 3D hair model with perfect fit for the 3D head model in the terminal with relatively low storage capacity and computing power. The realistic 3D hair model can be compared with the hair modeling model. The hair model generated by the method saves a lot of manual interaction and computing time; compared with the existing hair model reuse technology, the present application does not need to be limited by the detection result of 2D key points, and is not limited to the 2D key. The matching accuracy of the point and the normal part of the hair image and the personality part, without the need to model the hair part, can effectively improve the reusability of the 3D hair template, and the hair model constructed can more accurately retain the appearance of the prototype hair. .

Optionally, the first determining unit 901 is specifically configured to:

Determining a facial key point and a scalp key point of the 3D head model of the hair to be created; determining a facial key point of the preset reference head model; a facial key point of the 3D head model and the reference head model The facial key points are matched to obtain a face matching point pair; and the first coordinate transformation relationship between the 3D head model and the reference head model is determined according to the face matching point pair;

The registration unit 903 is configured to obtain, according to the first coordinate transformation relationship, three-dimensional coordinates of the 3D hair template in a target coordinate system, where the target coordinate system is a coordinate of the 3D head model system;

The second determining unit 902 is specifically configured to: match a root point of the 3D hair template transformed by the first coordinate transformation relationship with a key point of the scalp layer of the 3D head model to obtain a root matching a pair of points; determining a second coordinate transformation relationship between the 3D head model and the 3D hair template according to the pair of hair root matching points;

The registration unit 903 is configured to register the 3D hair template with the 3D head model according to the second coordinate transformation relationship.

In a possible implementation, the deformation unit 905 is specifically configured to:

Each hair in the wrong area of the 3D hair template is performed as follows:

Selecting at least three three-dimensional coordinate points in each of the hairs as a first key point, and determining, by a nearest neighbor algorithm, a nearest neighbor point of each first key point in the scalp layer of the 3D head model as the Matching points of each first key point, and each of the first key points and their corresponding matching points constitute a pair of hair matching points;

Each of the hairs is deformed by matching the hairline matching points as input parameters of a radial basis function.

Optionally, the first key point includes a rooting point and a tip point of each of the hairs.

In a possible implementation, the deformation unit 905 is specifically configured to:

Each hair in the wrong area of the 3D hair template is performed as follows:

Selecting at least three three-dimensional coordinate points in each of the hairs as a second key point, and determining, by the nearest neighbor algorithm, each of the at least three second key points in the 3D head The nearest neighbor of the model scalp layer serves as a matching point of each of the second key points, and each of the second key points and its corresponding matching point constitute a pair of hair matching points;

Deforming each of the hairs using a hairline matching point pair as a radial basis function input parameter; dividing each deformed hair into at least two portions, respectively performing the following for each portion of the hair: At least 3 three-dimensional coordinate points in each part of the hair as a third key point, and the nearest neighbor of each third key point in each part of the hair in the three-dimensional coordinate point of the scalp layer of the 3D head model a point as a matching point of each third key point, and each of the third key points and their corresponding matching points constitute a segment hairline matching point pair; the segment hairline matching point pair is used as a radial basis The input parameters of the function deform each of the portions of the hair.

Optionally, the second key point may include a hair root point and a hair point in each of the hairs; and the third key point includes two end points of each part of the hair.

In a possible implementation, the deformation unit 905 is specifically configured to:

Each of the hairs in the wrong area of the 3D hair template is performed as follows: each hair is divided into at least two parts, and the hair is separately executed for each part as follows:

Taking at least 3 three-dimensional coordinate points in each part of the hair as a fourth key point, and each fourth key point in each part of the hair in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor as a matching point for each of the fourth key points, and each of the fourth key points and their corresponding matching points constitute a segmented hair matching point pair; The input parameters of the radial basis function deform the hair of each portion.

Optionally, the third key point may include two endpoints of each portion of the hair.

The division of the unit in the present application is schematic, and is only a logical function division. In actual implementation, there may be another division manner. In addition, each functional unit in each embodiment of the present application may be integrated into one processor. It can also be physically present alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software function module.

Wherein, when the integrated unit can be implemented in the form of hardware, the first determining unit 901, the second determining unit 902, the registering unit 903, the detecting unit 904, and the deforming unit 905 are corresponding to the physical hardware of the three-dimensional hair modeling device. It may be the processor 1001 as shown in FIG. The 3D hair modeling device may further include a memory 1002 for storing program code executed by the processor 1001.

The memory 1002 may be a volatile memory (English: volatile memory), such as a random access memory (English: random-access memory, abbreviation: RAM); the memory may also be a non-volatile memory (English: non-volatile memory). For example, read-only memory (English: read-only memory, abbreviation: ROM), flash memory (English: flash memory), hard disk (English: hard disk drive, abbreviation: HDD) or solid state drive (English: solid-state drive, Abbreviations: SSD), or memory, are any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto. The memory can be a combination of the above memories.

The 3D hair modeling device may further include a communication interface 1003, configured to configure a 3D head model of the hair to be created, a preset reference head model, and a preset 3D hair template, the preset The reference head model and the preset 3D hair template are matched. After the configuration is completed, it is saved in the memory 1002.

The 3D hair modeling device can also include a display 1004 due to the 3D head model displaying the hair to be created, the preset reference head model, and the preset 3D hair template.

The processor 1001, the memory 1002, the communication interface 1003, and the display 1004 may be connected by a bus 1005. The manner of connection between other components is merely illustrative and not limited. The bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 10, but it does not mean that there is only one bus or one type of bus.

The processor 1001 is configured to execute the program code stored by the memory 1002, and specifically perform the following operations:

Determining a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model, and determining a second coordinate transformation relationship between the 3D head model and the preset 3D hair template, And registering the 3D head model with the 3D hair template based on the first coordinate transformation relationship and the second coordinate transformation relationship. The above S601 can be referred to as a rigid registration process.

The preset 3D hair template matches the preset reference head model.

When it is detected that the registered 3D hair template has an erroneous area, the hair in the erroneous area of the 3D hair template is deformed using a radial basis function RBF to correct the erroneous area.

Wherein the error area comprises an area of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or a hair root area formed by the root point in the 3D hair template blocks the 3D head model The area of the non-scalp layer.

When performing the rigid registration process operation, the processor 1001 can be implemented as follows:

Determining a facial key point and a scalp key point of the 3D head model of the hair to be created, and determining a facial key point of the preset reference head model; a facial key point of the 3D head model and the reference head Matching facial key points of the model to obtain a face matching point pair; determining, according to the face matching point pair, a first coordinate transformation relationship between the 3D head model and the reference head model; according to the first coordinate transformation Relation, obtaining a three-dimensional coordinate of the 3D hair template in a target coordinate system; wherein the target coordinate system is a coordinate system in which the 3D head model is located; Matching the root point of the 3D hair template and the key point of the 3D head model to obtain a root matching point pair; determining the 3D head according to the root matching point pair a second coordinate transformation relationship between the part model and the 3D hair template; and the 3D hair template is registered with the 3D head model according to the second coordinate transformation relationship.

When the facial key points and the scalp key points of the 3D head model of the hair to be created are determined as described above, and the facial key points of the preset reference head model are determined, the face may be selected by the 3D head model displayed on the display 1004. Key points and scalp key points, through the user input selected face key points and scalp key points, and then the processor 1001 determines the facial key points and scalp key of the 3D head model of the hair to be created after receiving the user input point. The same method can also be used in determining the facial key points of the preset reference head model.

Optionally, the processor 1001 deforms the hair in the wrong area of the 3D hair template using a radial basis function RBF, and specifically may use the radial basis function RBF to make the hair in the wrong area of the 3D hair template as a whole. Deformation, or deformation from whole to local, or local deformation.

The overall deformation for each hair includes:

Each hair in the wrong area of the 3D hair template is performed as follows:

Selecting at least three three-dimensional coordinate points in each of the hairs as a first key point, and determining, by a nearest neighbor algorithm, a nearest neighbor point of each first key point in the scalp layer of the 3D head model as the Matching points of each first key point, and each of the first key points and their corresponding matching points constitute a pair of hair matching points;

Each of the hairs is deformed using a hairline matching point pair as a radial basis function input parameter.

Optionally, the first key point includes a hair root point and a hair point of each of the hairs. Other first key points can select other three-dimensional coordinate points in each hair. Specifically, three-dimensional coordinate points close to the root point and the midpoint of the tip point can be selected.

The overall to local deformation for each hair includes:

For each hair in the wrong area of the 3D hair template, respectively, the following is performed: selecting at least three three-dimensional coordinate points in each of the hairs as the second key point, and adopting the nearest neighbor algorithm Determining, at each of the at least 3 second key points, a nearest neighbor point of the scalp layer of the 3D head model as a matching point of each of the second key points, and each of the The two key points and their corresponding matching points constitute a pair of hair matching points; the hair matching point pairs are used as radial basis function input parameters, and each of the hairs is deformed;

Dividing each of the deformed hairs into at least two parts, respectively, for each part of the hair is performed as follows: at least three three-dimensional coordinate points in each part of the hair are regarded as a third key point, and in the 3D head a three-dimensional coordinate point of the scalp layer of the model, a nearest neighbor point of each third key point in each part of the hair as a matching point of each third key point, and corresponding to each third key point The matching points constitute a segmented hairline matching point pair; the segment hairline matching point pair is deformed as an input parameter of a radial basis function.

Optionally, the second key point includes a rooting point and a tip point in each of the hairs;

The third key point includes two endpoints of each portion of the hair.

Local deformations for each hair include:

Each hair in the wrong area of the 3D hair template is separately performed as follows: each hair is divided into at least two parts, and is performed separately for each part of the hair as follows: at least 3 of each part of the hair is to be The three-dimensional coordinate point is used as the fourth key point, and the nearest neighbor point of each fourth key point in each part of the hair is taken as each fourth key point in the three-dimensional coordinate point of the scalp layer of the 3D head model Matching points, and each of the fourth key points and their corresponding matching points constitute a segment hairline matching point pair; the segment hairline matching point pair is used as a radial basis function input parameter for each Some of the hair is deformed.

Optionally, the third key point comprises two endpoints of the hair of each portion.

As shown in FIG. 11, in the present application, the rigid matching of the pre-built 3D head model with the pre-stored 3D hair template is first completed. After the rigid matching operation is completed, the 3D hair template is aligned with the scalp layer of the 3D head model, and some areas may have an incorrect occlusion relationship, such as the area marked by the ring in FIG. The key points of the 3D head model scalp are then used to guide the 3D hair model from overall to local deformation. Deformation eliminates false occlusion relationships and results in a 3D hair template that fits well with the 3D head model.

This application can quickly construct a 3D hair model with perfect fit for the 3D head model in the terminal with relatively low storage capacity and computing power. The realistic 3D hair model can be compared with the hair modeling model. The hair model generated by the method saves a lot of manual interaction and computing time; compared with the existing hair model reuse technology, the present application does not need to be limited by the detection result of 2D key points, and is not limited to the 2D key. The matching accuracy of the point and the normal part of the hair image and the personality part, without the need to model the hair part, can effectively improve the reusability of the 3D hair template, and the hair model constructed can more accurately retain the appearance of the prototype hair. .

Those skilled in the art will appreciate that embodiments of the present application can be provided as a method, system, or computer program product. Thus, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment in combination of software and hardware. Moreover, the application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the present application. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. Instructions are provided for implementation in the flowchart The steps of a process or a plurality of processes and/or block diagrams of a function specified in a block or blocks.

While the preferred embodiment of the present application has been described, those skilled in the art can make further changes and modifications to these embodiments once they are aware of the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and the modifications and

It will be apparent to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit and scope of the application. Thus, it is intended that the present invention cover the modifications and variations of the present invention.

Claims (17)

1. A three-dimensional hair modeling method, comprising:

   Determining a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model, and determining a second coordinate transformation relationship between the 3D head model and the preset 3D hair template, And registering the 3D head model with the 3D hair template based on the first coordinate transformation relationship and the second coordinate transformation relationship; wherein the preset 3D hair template and the preset reference header The model is matched;

   When it is detected that the registered 3D hair template has an error area, the hair in the wrong area of the 3D hair template is deformed using a radial basis function RBF to correct the error area, wherein the error area Including the region of the 3D hair template that does not completely obscure the scalp layer of the 3D head model or the hair root region of the 3D hair template obscures the non-skin layer region of the 3D head model .
2. The method of claim 1 , wherein determining a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model, and determining the 3D head model and the preset Corresponding to the second coordinate transformation relationship between the 3D hair templates, and registering the 3D head model with the 3D hair template based on the first coordinate transformation relationship and the second coordinate transformation relationship, including:

   Determining facial key points and scalp key points of the 3D head model of the hair to be created;

   Determining a facial key point of the preset reference head model;

   Matching a facial key point of the 3D head model with a facial key point of the reference head model to obtain a face matching point pair;

   Determining, according to the pair of face matching points, a first coordinate transformation relationship between the 3D head model and the reference head model;

   Obtaining a three-dimensional coordinate of the 3D hair template in a target coordinate system according to the first coordinate transformation relationship, wherein the target coordinate system is a coordinate system in which the 3D head model is located;

   a root point of the 3D hair template transformed by the first coordinate transformation relationship and the 3D The key points of the scalp layer of the head model are matched to obtain a pair of root matching points;

   Determining, according to the pair of hair root matching points, a second coordinate transformation relationship between the 3D head model and the 3D hair template;

   And registering the 3D hair template with the 3D head model according to the second coordinate transformation relationship.
3. The method according to claim 1 or 2, wherein said deforming the hair in the erroneous region of said 3D hair template using a radial basis function RBF comprises:

   Each hair in the wrong area of the 3D hair template is performed as follows:

   Selecting at least three three-dimensional coordinate points in each of the hairs as a first key point, and determining, by a nearest neighbor algorithm, a nearest neighbor point of each first key point in the scalp layer of the 3D head model as the Matching points of each first key point, and each of the first key points and their corresponding matching points constitute a pair of hair matching points;

   Each of the hairs is deformed by matching the hairline matching points as input parameters of a radial basis function.
4. The method of claim 3 wherein said first key point comprises a root point and a tip point of said each hair.
5. The method according to claim 1 or 2, wherein said deforming the hair in the erroneous region of said 3D hair template using a radial basis function RBF comprises:

   Each hair in the wrong area of the 3D hair template is performed as follows:

   Selecting at least three three-dimensional coordinate points in each of the hairs as a second key point, and determining, by the nearest neighbor algorithm, each of the at least three second key points in the 3D head The nearest neighbor of the model scalp layer serves as a matching point of each of the second key points, and each of the second key points and its corresponding matching point constitute a pair of hair matching points;

   Deforming each of the hairs using a hairline matching point pair as a radial basis function input parameter;

   Divide each hair after deformation into at least two parts, and perform the following for each part of the hair separately:

   Taking at least 3 three-dimensional coordinate points in each part of the hair as a third key point, and each third key point in each part of the hair in the three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor point as a matching point of each third key point, and each of the third key points and its corresponding matching point constitute a segment hairline matching point pair;

   Each of the portions of hair is deformed by the segmented hairline matching point pair as an input parameter to a radial basis function.
6. The method according to claim 5, wherein said second key point comprises a hair root point and a hair point in said each hair;

   The third key point includes two endpoints of each portion of the hair.
7. The method according to claim 1 or 2, wherein said deforming the hair in the erroneous region of said 3D hair template using a radial basis function RBF comprises:

   Each hair in the wrong area of the 3D hair template is performed as follows:

   Divide each hair into at least two parts and perform the following for each part of the hair:

   Taking at least 3 three-dimensional coordinate points in each part of the hair as a fourth key point, and each fourth key point in each part of the hair in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor point as a matching point of each fourth key point, and each of the fourth key points and their corresponding matching points constitute a segment hairline matching point pair;

   Each of the portions of hair is deformed by the segmented hairline matching point pair as an input parameter to a radial basis function.
8. The method of claim 7 wherein said third key point comprises two endpoints of said each portion of hair.
9. A three-dimensional hair modeling device, comprising:

   a first determining unit, configured to determine a first coordinate transformation relationship between the 3D head model of the hair to be created and the preset reference head model;

   a second determining unit, configured to determine a second coordinate transformation relationship between the 3D head model and a preset 3D hair template, wherein the preset 3D hair template and the preset reference head model Match

   a registration unit, configured to determine the first coordinate transformation relationship and the second coordinate transformation relationship based on the determining unit, and register the 3D head model with the 3D hair template;

   a detecting unit, configured to detect whether the registered 3D hair template has an error area;

   a deformation unit for deforming hair in the erroneous area of the 3D hair template detected by the detecting unit using a radial basis function RBF to correct the erroneous area, wherein the erroneous area includes the 3D hair The area of the scalp layer in the template that does not completely obscure the 3D head model or the hair root point in the 3D hair template obscures the area of the non-skin layer of the 3D head model.
10. The device according to claim 9, wherein the first determining unit is specifically configured to:

    Determining a facial key point and a scalp key point of the 3D head model of the hair to be created; determining a facial key point of the preset reference head model; a facial key point of the 3D head model and the reference head model The facial key points are matched to obtain a face matching point pair; and the first coordinate transformation relationship between the 3D head model and the reference head model is determined according to the face matching point pair;

    The registration unit is configured to obtain, according to the first coordinate transformation relationship, three-dimensional coordinates of the 3D hair template in a target coordinate system, where the target coordinate system is a coordinate system in which the 3D head model is located ;

    The second determining unit is specifically configured to: match a root point of the 3D hair template transformed by the first coordinate transformation relationship with a key point of the scalp layer of the 3D head model to obtain a root matching point Determining, according to the pair of hair root matching points, determining a second coordinate transformation relationship between the 3D head model and the 3D hair template;

    The registration unit is configured to register the 3D hair template with the 3D head model according to the second coordinate transformation relationship.
11. The device according to claim 9 or 10, wherein the deformation unit is specifically configured to:

    Each hair in the wrong area of the 3D hair template is performed as follows:

    Selecting at least 3 three-dimensional coordinate points in each of the hairs as the first key point and passing The nearest neighbor algorithm determines a nearest neighbor point of the first key point in the scalp layer of the 3D head model as a matching point of each of the first key points, and corresponding each of the first key points The matching points constitute a pair of hair matching points;

    Each of the hairs is deformed by matching the hairline matching points as input parameters of a radial basis function.
12. The device of claim 11 wherein said first key point comprises a root point and a tip point of said each hair.
13. The device according to claim 9 or 10, wherein the deformation unit is specifically configured to:

    Each hair in the wrong area of the 3D hair template is performed as follows:

    Selecting at least three three-dimensional coordinate points in each of the hairs as a second key point, and determining, by the nearest neighbor algorithm, each of the at least three second key points in the 3D head The nearest neighbor of the model scalp layer serves as a matching point of each of the second key points, and each of the second key points and its corresponding matching point constitute a pair of hair matching points;

    Deforming each of the hairs using a hairline matching point pair as a radial basis function input parameter;

    Divide each hair after deformation into at least two parts, and perform the following for each part of the hair separately:

    Taking at least 3 three-dimensional coordinate points in each part of the hair as a third key point, and each third key point in each part of the hair in the three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor point as a matching point of each third key point, and each of the third key points and its corresponding matching point constitute a segment hairline matching point pair;

    Each of the portions of hair is deformed by the segmented hairline matching point pair as an input parameter to a radial basis function.
14. The device according to claim 13, wherein said second key point includes a hair root point and a hair point in said each hair;

    The third key point includes two endpoints of each portion of the hair.
15. The device according to claim 9 or 10, wherein the deformation unit is specifically configured to:

    Each hair in the wrong area of the 3D hair template is performed as follows:

    Divide each hair into at least two parts and perform the following for each part of the hair:

    Taking at least 3 three-dimensional coordinate points in each part of the hair as a fourth key point, and each fourth key point in each part of the hair in a three-dimensional coordinate point of the scalp layer of the 3D head model a nearest neighbor point as a matching point of each fourth key point, and each of the fourth key points and their corresponding matching points constitute a segment hairline matching point pair;

    Each of the portions of hair is deformed by the segmented hairline matching point pair as an input parameter to a radial basis function.
16. The device of claim 15 wherein said third key point comprises two endpoints of said each portion of hair.
17. A three-dimensional hair modeling device, comprising:

    Communication interface, memory, and processor;

    The communication interface is configured to configure a 3D head model of the hair to be created, a preset reference head model, and a preset 3D hair template, and the preset reference head model and the preset 3D hair template phase match;

    The memory is configured to store program code executed by the processor;

    The processor is configured to execute the program code stored in the memory, and specifically execute the method according to any one of claims 1 to 8.

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