Virtual image rendering method, apparatus, and electronic device

Abstract

The present disclosure provides a virtual figure rendering method and device and electronic equipment, relates to the technical field of artificial intelligence, in particular to the technical field of computer vision, augmented reality, virtual reality, deep learning and the like, and can be applied to the scene of metaverse, digital person and the like. The specific scheme is: obtaining an input image, the input image containing a target object; performing three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual figure of the target object, the first three-dimensional virtual figure comprising a plurality of figure blocks; determining rendering coefficients of the plurality of figure blocks based on the difference information between the first three-dimensional virtual figure and a preset reference three-dimensional virtual figure; calculating bone coefficients of bone nodes in a bone tree based on the rendering coefficients of the plurality of figure blocks; and performing three-dimensional virtual figure rendering according to the bone coefficients of the bone nodes in the bone tree to obtain a second three-dimensional virtual figure of the target object. The present disclosure can reduce the maintenance resource overhead of the three-dimensional virtual figure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of artificial intelligence, in particular to the technical field of computer vision, augmented reality, virtual reality, deep learning and the like, which can be applied to metaverse, digital human and the like, and in particular to a virtual image rendering method and device and electronic equipment. BACKGROUND

[0002] With the development of artificial intelligence technology, there are more and more application scenarios of three-dimensional virtual images, such as metaverse, digital human and the like. At present, the main technical means for rendering three-dimensional virtual images is to render based on the grid data of three-dimensional virtual images. SUMMARY

[0003] The present disclosure provides a virtual image rendering method, device and electronic equipment.

[0004] According to an aspect of the present disclosure, a virtual image rendering method is provided, comprising:

[0005] obtaining an input image containing a target object;

[0006] performing three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual image of the target object, the first three-dimensional virtual image comprising a plurality of image blocks, each image block being associated with a plurality of bone nodes in a bone tree, the bone tree matching a preset reference three-dimensional virtual image;

[0007] determining rendering coefficients of the plurality of image blocks based on the difference information between the first three-dimensional virtual image and the preset reference three-dimensional virtual image;

[0008] calculating bone coefficients of the bone nodes in the bone tree based on the rendering coefficients of the plurality of image blocks;

[0009] performing three-dimensional virtual image rendering according to the bone coefficients of the bone nodes in the bone tree to obtain a second three-dimensional virtual image of the target object.

[0010] According to another aspect of the present disclosure, a virtual image rendering device is provided, comprising:

[0011] an acquisition module configured to acquire an input image containing a target object;

[0012] a reconstruction module configured to perform three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual image of the target object, the first three-dimensional virtual image comprising a plurality of image blocks, each image block being associated with a plurality of bone nodes in a bone tree, the bone tree matching a preset reference three-dimensional virtual image;

[0013] determining a rendering coefficient of the plurality of avatar blocks based on the difference information between the first three-dimensional avatar and the preset reference three-dimensional avatar;

[0014] calculating a bone coefficient of a bone node in the bone tree based on the rendering coefficient of the plurality of avatar blocks;

[0015] rendering a three-dimensional avatar according to the bone coefficient of the bone node in the bone tree to obtain a second three-dimensional avatar of the target object.

[0016] According to another aspect of the present disclosure, an electronic device is provided, comprising:

[0017] at least one processor; and

[0018] a memory in communication connection with the at least one processor; wherein

[0019] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the virtual avatar rendering method provided by the present disclosure.

[0020] According to another aspect of the present disclosure, a non-transitory computer readable storage medium storing computer instructions is provided, wherein the computer instructions are used to enable the computer to perform the virtual avatar rendering method provided by the present disclosure.

[0021] According to another aspect of the present disclosure, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the virtual avatar rendering method provided by the present disclosure.

[0022] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are used to better understand the present scheme, and do not constitute a limitation on the present disclosure. Among them:

[0024] Figure 1 is a flowchart of a virtual avatar rendering method provided by the present disclosure;

[0025] Figure 2 is a schematic diagram of a bone tree provided by the present disclosure;

[0026] Figures 3a to 3g is a structural diagram of a virtual avatar rendering device provided by the present disclosure;

[0027] Figure 4 is a block diagram of an electronic device for implementing an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure are described herein below with reference to the accompanying drawings, in which various details of embodiments of the present disclosure are set forth in order to provide an adequate understanding of the present disclosure. It should be understood that these details are merely exemplary and do not limit the scope of the present disclosure. It will be readily understood to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Also, for the sake of brevity and clarity, descriptions of well-known functions and constructions are omitted herein.

[0029] Referring to Figure 1 , Figure 1 is a flowchart of a virtual avatar rendering method provided by the present disclosure, as shown in Figure 1 , comprising the following steps:

[0030] Step S101, an input image is acquired, the input image containing a target object.

[0031] The above acquisition of the input image can be that an electronic device performing the above method receives an input image sent by another device, or can be that an electronic device performing the above method receives an input image input by a user.

[0032] The above target object can be one or more parts corresponding to a virtual avatar, such as a face, a hand, a foot, etc.

[0033] Step S102, a three-dimensional reconstruction is performed on the target object contained in the input image, obtaining a first three-dimensional virtual avatar of the target object, the first three-dimensional virtual avatar comprising a plurality of avatar blocks, each avatar block being associated with a plurality of bone nodes in a bone tree, the bone tree matching a preset reference three-dimensional virtual avatar.

[0034] The above three-dimensional reconstruction of the target object contained in the input image can be that a first three-dimensional virtual avatar of the target object is generated based on the target object.

[0035] In the present disclosure, a three-dimensional virtual avatar can be all or part of a three-dimensional virtual human avatar, such as a three-dimensional virtual avatar of a face, or a three-dimensional virtual avatar of a whole human. In addition, in the present disclosure, a three-dimensional virtual avatar can also be referred to as a three-dimensional virtual model.

[0036] The above preset reference three-dimensional virtual avatar can be a basic three-dimensional virtual avatar or a standard three-dimensional virtual avatar obtained in advance, such as a base three-dimensional virtual model (base model).

[0037] The skeleton tree can include a plurality of skeleton nodes of a preset reference three-dimensional virtual image and a positional relationship between the skeleton nodes, for example, a skeleton tree 201 as shown in FIG. 8. Figure 2

[0038] The plurality of image blocks can represent a plurality of local regions of the first three-dimensional virtual image, and each local region is an image block. In addition, in the present disclosure, the plurality of image blocks can also be referred to as a plurality of sliders, and each slider is associated with a different skeleton node. In addition, each image block can correspond to a corresponding semantic, for example, "high nose bridge, large eyes, thin chin" are the semantics of the image blocks of the nose, eyes, and chin, respectively.

[0039] In the present disclosure, a plurality of image blocks of a three-dimensional virtual image can be predefined, and each three-dimensional virtual image includes the same number of image blocks.

[0040] In step S103, rendering coefficients of the plurality of image blocks are determined based on the difference information between the first three-dimensional virtual image and the preset reference three-dimensional virtual image.

[0041] The difference information can be used to represent the difference between the first three-dimensional virtual image and the preset reference three-dimensional virtual image, which includes but is not limited to overall difference, local difference, parameter difference, etc.

[0042] The rendering coefficients of the plurality of image blocks can be coefficients used for rendering a three-dimensional virtual image, and the rendering coefficient of each image block is used to represent the rendering shape of the image block.

[0043] In step S104, the skeleton coefficients of the skeleton nodes in the skeleton tree are calculated based on the rendering coefficients of the plurality of image blocks.

[0044] Since each image block is associated with a plurality of skeleton nodes, according to the correspondence between the skeleton nodes and the image blocks, the skeleton coefficients of each skeleton node in the skeleton tree can be calculated based on the rendering coefficients of the plurality of image blocks.

[0045] In step S105, a three-dimensional virtual image is rendered according to the skeleton coefficients of the skeleton nodes in the skeleton tree to obtain a second three-dimensional virtual image of the target object.

[0046] The three-dimensional virtual image can be rendered according to the skeleton coefficients of the skeleton nodes in the skeleton tree to obtain a second three-dimensional virtual image of the target object, which can be inputting the skeleton coefficients of the skeleton nodes in the skeleton tree to a rendering system to drive a three-dimensional virtual image to obtain the second three-dimensional virtual image, for example, driving a face to display a specific shape to obtain a three-dimensional virtual face corresponding to the target object.

[0047] ​In the present disclosure, the bone coefficients of the bone nodes in the bone tree are calculated through the rendering coefficients of the plurality of image blocks, and then the second three-dimensional virtual image of the target object is rendered according to the bone coefficients of the bone nodes in the bone tree, so that the three-dimensional virtual image can be rendered based on the rendering coefficients of the plurality of image blocks, thereby only the rendering system of the plurality of image blocks needs to be maintained for one three-dimensional virtual image, and the maintenance resource consumption of the three-dimensional virtual image is reduced.

[0048] For example, when the application displays the three-dimensional virtual image, only the rendering coefficients of the plurality of image blocks need to be maintained, and then the bone coefficients of the bone nodes in the bone tree are calculated in the above manner to obtain the three-dimensional virtual image through the bone coefficients, so that the rendering coefficients of each mesh in the three-dimensional virtual image do not need to be maintained, thereby reducing the maintenance resources of the application. When the target object is a face, the face mesh generally has 10000+ meshes, and 10000+ rendering coefficients need to be maintained, while the image blocks of the face are usually a few, a dozen or dozens, thereby reducing the maintenance resources of the application.

[0049] In the present disclosure, the above method is executed by an electronic device, that is, all steps included in the method are executed by the electronic device, which can be a server, a computer, a mobile phone, a tablet computer, a vehicle-mounted terminal or the like.

[0050] In one embodiment, the target object includes a face.

[0051] In this embodiment, the input image can be a face image.

[0052] In this embodiment, the rendering of the three-dimensional virtual face can be implemented, and the method can be applied to the face shaping scene, so that only one set of image block coefficients needs to be maintained in the entire face shaping system, thereby reducing the maintenance cost of the face shaping system.

[0053] It should be noted that the present disclosure does not limit the target object to be a face, for example, in some embodiments, the target object can be a hand, a foot, an animal or the like.

[0054] In one embodiment, the rendering coefficients of the plurality of image blocks are determined based on the difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image, including:

[0055] The difference information of a plurality of three-dimensional virtual objects is linearly fitted based on the change amount of the plurality of image blocks to obtain the rendering coefficients of the plurality of image blocks, the change amount of the plurality of image blocks is a preconfigured change amount, and the difference information of the plurality of three-dimensional virtual objects includes the difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image.

[0056] The linear fitting of the difference information of the plurality of three-dimensional virtual objects based on the change amount of the plurality of image blocks can be that the rendering coefficients of the plurality of image blocks are calculated in the process of linear fitting of the difference information of the plurality of three-dimensional virtual objects.

[0057] The difference information of the plurality of three-dimensional virtual objects includes the difference information of the first three-dimensional virtual image and other three-dimensional virtual images in addition to the difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image. The other three-dimensional virtual images can be three-dimensional virtual images obtained by changing the preset reference three-dimensional virtual image.

[0058] In this embodiment, the rendering coefficients of the plurality of image blocks are determined by linear fitting, which can improve the accuracy of the rendering coefficients.

[0059] It should be noted that the rendering coefficients of the plurality of image blocks are not limited to be determined by linear fitting in the present disclosure. For example, in the present disclosure, the rendering coefficients of each image block in the preset reference three-dimensional virtual image are set in advance. Then, for each image block, the difference of the rendering coefficient of the image block compared with the rendering coefficient of the image block in the preset reference three-dimensional virtual image is calculated based on the difference information of the image block, and the rendering coefficient of the image block is calculated based on the difference of the rendering coefficient of the image block. For example, if the difference between an image block and the image block in the preset reference three-dimensional virtual image is small, the rendering coefficient of the image block in the preset reference three-dimensional virtual image can be directly used. If the difference between an image block and the image block in the preset reference three-dimensional virtual image is large, the rendering coefficient of the image block in the preset reference three-dimensional virtual image can be adjusted based on the difference to obtain the rendering coefficient of the image block.

[0060] In one embodiment, the linear fitting of the difference information of the plurality of three-dimensional virtual objects based on the change amount of the plurality of image blocks to obtain the rendering coefficients of the plurality of image blocks comprises:

[0061] performing N rounds of linear fitting, in a case that i is equal to 1, the i-th round of linear fitting comprises: linear fitting, based on the change amount of the plurality of image blocks in the i-th round, difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image, to obtain a weighting coefficient of the plurality of image blocks in the i-th round; in a case that the i is greater than 1, the i-th round of linear fitting comprises: linear fitting, based on the change amount of the plurality of image blocks in the i-th round, difference information of the first three-dimensional virtual image and a three-dimensional virtual image in an (i-1)-th round, to obtain a weighting coefficient of the plurality of image blocks in the i-th round, the three-dimensional virtual image in the (i-1)-th round being a three-dimensional virtual image obtained based on the weighting coefficient of the plurality of image blocks in the (i-1)-th round, the i taking a value of 1 to N, and N being an integer greater than 1;

[0062] for each of the plurality of image blocks, adding the N weighting coefficients of the image block obtained in the N rounds of linear fitting to obtain a rendering coefficient of the image block.

[0063] wherein the change amount of the plurality of image blocks in each round is a preconfigured change amount, which can be a slight deformation change amount.

[0064] For example: the first three-dimensional virtual image (such as a face shape + facial expression) is represented as M, the preset reference three-dimensional virtual image (base model base) is represented as B, the preset image blocks S1, …, image block Sn, n is a positive integer greater than 1, and the N rounds of linear fitting can be as follows:

[0065] In the first round, the change amounts B11, …, B1n corresponding to the slight deformation of the image blocks are prepared, and then the B11, …, B1n are used to linearly fit the deformation deviation M-B to obtain the weighting coefficients coeff11, …, coeff1n. The weighting coefficients are used to drive the sliders S1, …, Sn to obtain the deformation result M1, which is the three-dimensional virtual image in the first round.

[0066] In the second round, the change amounts B21, …, B2n corresponding to the slight deformation of the sliders are prepared, and then the B21, …, B2n are used to linearly fit the deformation deviation M-M1 to obtain the weighting coefficients coeff21, …, coeff2n. On the basis of the deformation of M1, the weighting coefficients are used to drive the sliders S1, …, Sn to obtain the deformation result M2, which is the three-dimensional virtual image in the second round.

[0067] By analogy, until the deformation deviation is less than a given error, the rendering coefficients of the plurality of image blocks can be obtained.

[0068] The rendering coefficient of each of the plurality of image blocks can be obtained by adding the N weighted coefficients of the image block obtained in the N linear fitting processes.

[0069] In this embodiment, the rendering coefficients of the plurality of image blocks can be more accurate through the plurality of linear fitting processes.

[0070] It should be noted that the rendering coefficients of the plurality of image blocks are not limited to be determined by performing the N linear fitting processes. For example, in some scenarios, the rendering coefficients of the plurality of image blocks can be determined by performing one linear fitting process.

[0071] In one embodiment, the method further includes:

[0072] In a case where the linear fitting of the i-th round ends, the image difference represented by the difference information between the first three-dimensional virtual image and the three-dimensional virtual image of the (i-1)-th round is compared with a preset difference. In a case where the image difference is greater than or equal to the preset difference, the next linear fitting process is performed. In a case where the image difference is less than the preset difference, the linear fitting ends.

[0073] In this embodiment, at the end of each linear fitting process, the difference between the three-dimensional virtual image corresponding to the weighted coefficients of the plurality of image blocks obtained in the linear fitting process and the first three-dimensional virtual image is calculated. If the difference is less than the preset difference, the linear fitting ends. The number of times of the linear fitting is the value of N.

[0074] In this embodiment, the linear fitting ends in a case where the image difference is less than the preset difference. This can reduce the difference between the second three-dimensional virtual image and the first three-dimensional virtual image, thereby further improving the accuracy of the rendering coefficients of the image blocks.

[0075] It should be noted that the value of N is not limited to be determined by comparing the image difference with the preset difference in this embodiment. For example, in some embodiments, the value of N can also be a preset empirical value.

[0076] In one embodiment, the linear fitting of the difference information between the first three-dimensional virtual image and the three-dimensional virtual image of the (i-1)-th round based on the change amount of the plurality of image blocks of the i-th round to obtain the weighted coefficients of the plurality of image blocks of the i-th round includes:

[0077] constructing a fitting linear equation, in which a weighted product of the plurality of image blocks added up equals difference information of the first three-dimensional virtual image and the three-dimensional virtual image of the i-1th round, and the weighted product of each image block equals a product of a change amount of the image block of the i th round and a weighting coefficient of the image block of the i th round;

[0078] solving the fitting linear equation by a least square method to obtain the weighting coefficients of the plurality of image blocks of the i th round.

[0079] In some embodiments, the fitting linear equation can be expressed as follows:

[0080] coeff11*B11 + coeff12*B12 + …… + coeff1n*B1n = M-B

[0081] wherein B21, …, B2n respectively represent change amounts of the n image blocks, coeff11, …, coeff1n respectively represent weighting coefficients of the n image blocks, and M represents the first three-dimensional virtual image, and B represents the preset reference three-dimensional virtual image.

[0082] In some embodiments, the fitting linear equation can be expressed as follows:

[0083] coeff11*B11 + coeff12*B12 + …… + coeff1n*B1n = M- M i-1

[0084] wherein M represents the first three-dimensional virtual image, and M i-1 represents the three-dimensional virtual image of the i-1th round.

[0085] In this embodiment, by constructing the fitting linear equation and solving by the least square method, the accuracy of the weighting coefficients of the image blocks can be improved, and thus the rendering accuracy of the image blocks can be improved.

[0086] It should be noted that the disclosure does not limit the calculation of the weighting coefficients of the image blocks by constructing the fitting linear equation and solving by the least square method. For example, a set of weighting coefficients can be configured for each image block according to empirical values in advance, and in each linear fitting process, the most suitable weighting coefficient is selected from the set of weighting coefficients for each image block, so as to obtain the weighting coefficient of each image block in each linear fitting.

[0087] In one embodiment, the calculation of the bone coefficients of the bone nodes in the bone tree based on the rendering coefficients of the plurality of image blocks comprises:

[0088] obtain a coefficient mapping relationship, the coefficient mapping relationship comprising a mapping relationship between a rendering coefficient of a target avatar block and a skeleton coefficient of a plurality of skeleton nodes associated with the target avatar block, the target avatar block being any one of the plurality of avatar blocks;

[0089] convert, based on the coefficient mapping relationship, the rendering coefficients of the plurality of avatar blocks into the skeleton coefficients of the skeleton nodes in the skeleton tree.

[0090] The coefficient mapping relationship can be preconfigured, and the mapping relationship between each skeleton node and the corresponding avatar block is a linear relationship, for example: b = f(a), where b is the skeleton coefficient of the skeleton node, a is the rendering coefficient of the avatar block, and f() is a preconfigured linear function. Each skeleton node corresponds to a linear function that is preconfigured according to an empirical value. For example, the linear function corresponding to a certain skeleton node is b = ka + d, where k and d are constants, and the specific values of k and d are preconfigured according to an empirical value. The values of k and d for different skeleton nodes can be different, or partially different, or the values of k and d for some skeleton nodes can be the same.

[0091] In this embodiment, the mapping relationship can improve the accuracy of the skeleton coefficients of the skeleton nodes.

[0092] It should be noted that the disclosure does not limit the calculation of the skeleton coefficients of the skeleton nodes in the skeleton tree through the above mapping relationship. For example, in some scenarios, the skeleton coefficients of the skeleton nodes in the skeleton tree can be obtained through a lookup table. For example, the table stores a plurality of rendering coefficients of each avatar block, and stores the skeleton coefficients of each skeleton node under each rendering coefficient. In this way, the skeleton coefficients of the skeleton nodes can also be obtained through the lookup table.

[0093] In one embodiment, the method further comprises:

[0094] outputting the second three-dimensional virtual avatar and the rendering coefficients of the plurality of avatar blocks;

[0095] receiving a first input, the first input being used to adjust the rendering coefficient of at least one avatar block in the plurality of avatar blocks;

[0096] adjusting the rendering coefficient of the at least one avatar block in response to the first input to obtain an updated rendering coefficient of the at least one avatar block;

[0097] updating the second three-dimensional virtual avatar based on the updated rendering coefficient of the at least one avatar block to obtain a third three-dimensional virtual avatar.

[0098] The outputting can be transmitting the second three-dimensional virtual image to another device, such as a user terminal, or the outputting can be displaying the second three-dimensional virtual image.

[0099] The receiving the first input can be receiving a user input or receiving an input from another receiving device.

[0100] The adjusting the rendering coefficient of the at least one image block can be adjusting a value of the rendering coefficient of the at least one image block.

[0101] The updating the second three-dimensional virtual image based on the updated rendering coefficient of the at least one image block can be re-rendering a three-dimensional virtual model based on the updated rendering coefficient to obtain a third three-dimensional virtual image.

[0102] In this embodiment, the rendering coefficient of the image block can be adjusted to adjust the three-dimensional virtual image, so that the three-dimensional virtual image is adjusted more conveniently. For example, in the face pinching process, a user can customize a face based on the image block.

[0103] In one embodiment, the method further includes:

[0104] Outputting a shape set of virtual image local region shapes, each virtual image local region shape in the shape set including at least one image block, and the rendering coefficient of the image block of each virtual image local region shape being pre-stored;

[0105] Receiving a second input, the second input being used to select a plurality of virtual image local region shapes in the shape set;

[0106] In response to the second input, generating a fourth three-dimensional virtual image based on the rendering coefficient of the image block of the plurality of virtual image local region shapes.

[0107] The shape set can include a plurality of virtual image local region shapes, such as a plurality of different virtual image face region shapes, a plurality of different virtual image chin region shapes, a plurality of different virtual image eye region shapes, and a plurality of different virtual image head region shapes.

[0108] In some embodiments, the virtual image local region shapes in the shape set can be pre-adjusted by the rendering coefficient of the image block.

[0109] The outputting can be transmitting the shape set to another device, such as a user terminal, or the outputting can be displaying the shape set.

[0110] The second input can be a user input or an input from another receiving device.

[0111] The second input can be a selection of a plurality of virtual image partial region shapes from the shape set, the plurality of virtual image partial region shapes being used to form a three-dimensional virtual image.

[0112] In this embodiment, the three-dimensional virtual image can be directly selected from the shape set, and the rendering coefficients of the image blocks of each virtual image partial region shape are stored, so that the three-dimensional virtual image can be directly selected while reducing storage costs.

[0113] In one embodiment, the method further comprises:

[0114] obtaining a plurality of virtual image partial region shapes included in the second three-dimensional virtual image;

[0115] adding the plurality of virtual image partial region shapes included in the second three-dimensional virtual image to the shape set, and recording the image blocks of the plurality of virtual image partial region shapes included in the second three-dimensional virtual image and the rendering coefficients of the image blocks.

[0116] The plurality of virtual image partial region shapes included in the second three-dimensional virtual image can be obtained after the second three-dimensional virtual image is rendered or the rendering coefficients of the plurality of image blocks of the second three-dimensional virtual image are obtained, and the corresponding rendering coefficients are stored.

[0117] In this embodiment, the shape set can be updated in a timely manner.

[0118] In one embodiment, the method further comprises:

[0119] outputting the second three-dimensional virtual image;

[0120] receiving a third input, the third input being used to select at least one virtual image partial region shape from the shape set and select at least one virtual image partial region shape in the second three-dimensional virtual image;

[0121] in response to the third input, replacing the at least one virtual image partial region shape selected in the second three-dimensional virtual image with the at least one virtual image partial region shape selected from the shape set.

[0122] The outputting can be sending the second three-dimensional virtual image to another device, such as a user terminal, or the outputting can be displaying the second three-dimensional virtual image.

[0123] The third input can be a user input or an input sent by another receiving device.

[0124] In this embodiment, the three-dimensional virtual image generated based on the input image can be replaced by the user, thereby improving the flexibility of the three-dimensional virtual image generation. For example, in the face pinching scene, the generated three-dimensional virtual face can be replaced by the user.

[0125] In some embodiments, the three-dimensional virtual image in the present disclosure can be a digital person in a metaverse, a digital person, or a digital animal.

[0126] In the present disclosure, the bone coefficients of the bone nodes in the bone tree are calculated based on the rendering coefficients of the multiple image blocks, and the second three-dimensional virtual image of the target object is rendered based on the bone coefficients of the bone nodes in the bone tree. This can render a three-dimensional virtual image based on the rendering coefficients of multiple image blocks, so that only the rendering system of multiple image blocks needs to be maintained for one three-dimensional virtual image, thereby reducing the maintenance resource overhead of the three-dimensional virtual image.

[0127] Please refer to Figure 3a , Figure 3a The virtual image rendering device provided by the present disclosure is shown in Figure 3a The virtual image rendering device 300 includes:

[0128] The acquisition module 301 is configured to acquire an input image, wherein the input image contains a target object.

[0129] The reconstruction module 302 is configured to perform three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual image of the target object, wherein the first three-dimensional virtual image includes multiple image blocks, each image block is associated with multiple bone nodes in a bone tree, and the bone tree is matched with a preset reference three-dimensional virtual image.

[0130] The determination module 303 is configured to determine rendering coefficients of the multiple image blocks based on difference information between the first three-dimensional virtual image and the preset reference three-dimensional virtual image.

[0131] The calculation module 304 is configured to calculate bone coefficients of the bone nodes in the bone tree based on the rendering coefficients of the multiple image blocks.

[0132] The rendering module 305 is configured to perform three-dimensional virtual image rendering based on the bone coefficients of the bone nodes in the bone tree to obtain a second three-dimensional virtual image of the target object.

[0133] In one embodiment, the determination module 303 is configured to:

[0134] linearly fit difference information of the plurality of three-dimensional virtual objects based on the change amount of the plurality of image blocks, to obtain rendering coefficients of the plurality of image blocks, the change amount of the plurality of image blocks being a preconfigured change amount, and the difference information of the plurality of three-dimensional virtual objects including difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image.

[0135] In one embodiment, as shown in FIG. 3, Figure 3b The determination module 301 includes:

[0136] The fitting unit 3031 is configured to perform N rounds of linear fitting. In a case where i is equal to 1, the i-th round of linear fitting includes: linearly fitting the difference information of the first three-dimensional virtual image and the preset reference three-dimensional virtual image based on the change amount of the plurality of image blocks in the i-th round, to obtain the weighting coefficients of the plurality of image blocks in the i-th round. In a case where i is greater than 1, the i-th round of linear fitting includes: linearly fitting the difference information of the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round based on the change amount of the plurality of image blocks in the i-th round, to obtain the weighting coefficients of the plurality of image blocks in the i-th round, the three-dimensional virtual image in the (i-1)-th round being a three-dimensional virtual image obtained based on the weighting coefficients of the plurality of image blocks in the (i-1)-th round, and i being an integer from 1 to N, N being an integer greater than 1.

[0137] The calculation unit 3032 is configured to, for each image block in the plurality of image blocks, add the N weighting coefficients of the image block obtained in the N rounds of linear fitting, to obtain the rendering coefficient of the image block.

[0138] In one embodiment, as shown in FIG. 3, Figure 3c The apparatus further includes:

[0139] The comparison module 306 is configured to, in a case where the i-th round of linear fitting is completed, compare an image difference represented by the difference information of the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round with a preset difference; in a case where the image difference is greater than or equal to the preset difference, perform the next round of linear fitting, and in a case where the image difference is less than the preset difference, end the linear fitting.

[0140] In one embodiment, the linearly fitting the difference information of the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round based on the change amount of the plurality of image blocks in the i-th round, to obtain the weighting coefficients of the plurality of image blocks in the i-th round, includes:

[0141] constructing a fitting linear equation, in which a weighted product of the plurality of image blocks added up equals difference information of the first three-dimensional virtual image and the three-dimensional virtual image of the i-1th round, and the weighted product of each image block equals a product of a change amount of the image block of the i th round and a weighting coefficient of the image block of the i th round;

[0142] solving the fitting linear equation by a least square method to obtain the weighting coefficients of the plurality of image blocks of the i th round.

[0143] In one embodiment, as Figure 3d , the computing module 304 comprises:

[0144] The obtaining unit 3041 is configured to obtain a coefficient mapping relationship, the coefficient mapping relationship comprising a mapping relationship between a rendering coefficient of a target image block and bone coefficients of a plurality of bone nodes associated with the target image block, the target image block being any image block in the plurality of image blocks.

[0145] The converting unit 3042 is configured to convert, based on the coefficient mapping relationship, the rendering coefficients of the plurality of image blocks into the bone coefficients of the bone nodes in the bone tree.

[0146] In one embodiment, as Figure 3e , the apparatus further comprises:

[0147] The first output module 307 is configured to output the second three-dimensional virtual image and the rendering coefficients of the plurality of image blocks.

[0148] The first receiving module 308 is configured to receive a first input, the first input being used to adjust a rendering coefficient of at least one image block in the plurality of image blocks.

[0149] The first response module 309 is configured to adjust the rendering coefficient of the at least one image block in response to the first input to obtain an updated rendering coefficient of the at least one image block.

[0150] The updating module 310 is configured to update the second three-dimensional virtual image based on the updated rendering coefficient of the at least one image block to obtain a third three-dimensional virtual image.

[0151] In one embodiment, as Figure 3f , the apparatus further comprises:

[0152] The second output module 311 is configured to output a shape set of virtual image local area shapes, each virtual image local area shape in the shape set comprising at least one image block, and the rendering coefficients of the image blocks of each virtual image local area shape being pre-stored.

[0153] The second receiving module 312 is configured to receive a second input, where the second input is used to select a plurality of virtual local region shapes from the shape set.

[0154] The second response module 313 is configured to generate a fourth three-dimensional virtual image based on rendering coefficients of image blocks of the plurality of virtual local region shapes in response to the second input.

[0155] In one embodiment, as Figure 3g The apparatus further includes:

[0156] The third output module 314 is configured to output the second three-dimensional virtual image.

[0157] The third receiving module 315 is configured to receive a third input, where the third input is used to select at least one virtual local region shape from the shape set and select at least one virtual local region shape in the second three-dimensional virtual image.

[0158] The third response module 316 is configured to replace the at least one virtual local region shape selected in the second three-dimensional virtual image with the at least one virtual local region shape selected from the shape set in response to the third input.

[0159] In one embodiment, the target object includes a human face.

[0160] The virtual image rendering apparatus provided by the present disclosure can implement each process of the virtual image rendering method provided by the present disclosure and achieve the same technical effects. To avoid repetition, details are not repeated here.

[0161] In the technical solution of the present disclosure, the acquisition, storage, and application of user personal information comply with relevant laws and regulations and do not violate public order and good customs.

[0162] According to the embodiments of the present disclosure, the present disclosure further provides an electronic device, a readable storage medium, and a computer program product.

[0163] The electronic device includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to perform the virtual image rendering method provided by the present disclosure.

[0164] The readable storage medium stores computer instructions. The computer instructions are used to enable the computer to perform the virtual image rendering method provided by the present disclosure.

[0165] The computer program product described above comprises a computer program which, when executed by a processor, implements the virtual figure rendering method provided by the present disclosure.

[0166] Figure 4 A schematic block diagram of an example electronic device 400 that can be used to implement embodiments of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the present disclosure described and / or claimed in this document.

[0167] As shown, Figure 4 The device 400 includes a computing unit 401 that can perform various appropriate actions and processes in accordance with a computer program stored in a read-only memory (ROM) 402 or a computer program loaded into a random access memory (RAM) 403 from a storage unit 408. Various programs and data required for the operation of the device 400 can also be stored in the RAM 403. The computing unit 401, the ROM 402, and the RAM 403 are connected to each other through a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0168] Various components in the device 400 are connected to the I / O interface 405, including an input unit 406, such as a keyboard, a mouse, etc.; an output unit 407, such as various types of displays, speakers, etc.; the storage unit 408, such as a magnetic disk, an optical disk, etc.; and a communication unit 409, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 409 allows the device 400 to exchange information / data with other devices through a computer grid, such as the Internet, and / or various telecommunication grids.

[0169] The computing unit 401 can be various general and / or special purpose processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The computing unit 401 performs various methods and processes described above, such as the avatar rendering method. For example, in some embodiments, the avatar rendering method can be implemented as a computer software program tangibly embodied in a machine-readable medium, such as the storage unit 408. In some embodiments, part or all of the computer program can be loaded and / or installed onto the device 400 via the ROM 402 and / or the communication unit 409. When the computer program is loaded onto the RAM 403 and executed by the computing unit 401, one or more steps of the avatar rendering method described above can be performed. Alternatively, in other embodiments, the computing unit 401 can be configured to perform the avatar rendering method by any other appropriate means, such as by means of firmware.

[0170] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0171] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, produces a means for implementing the functions / operations specified in the flowchart and / or block diagram block or blocks. The program code can be retrieved from the storage system and / or the storage system can be implemented as a storage system that is remotely located from the processor or controller. The program code can be executed by one or more programmable processors or controllers to produce a computer-implemented process such that the program code, when executed by the one or more programmable processors or controllers, cause the functionality described herein to be performed, at least incrementally. The program code can be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a specific machine or

[0172] In the context of this disclosure, a machine-readable medium can be a tangible medium that contains or stores a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include but is not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine-readable storage medium would include a lined- based system, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0173] To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0174] The systems and techniques described here can be implemented in a computing system that includes a back-end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0175] The computer system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0176] It should be understood that the various forms of flow shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, in series, or in a different order, as long as the desired results of the technology disclosed in the present disclosure can be achieved, which is not limited herein.

[0177] The above detailed description does not constitute a limitation on the protection scope of the present disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for rendering a virtual figure, comprising: obtaining an input image, the input image containing a target object; performing three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual figure of the target object, the first three-dimensional virtual figure comprising a plurality of figure blocks, each of the plurality of figure blocks being associated with a plurality of bone nodes in a bone tree, the bone tree matching a preset reference three-dimensional virtual figure; determining rendering coefficients of the plurality of figure blocks based on difference information between the first three-dimensional virtual figure and the preset reference three-dimensional virtual figure; calculating bone coefficients of the bone nodes in the bone tree based on the rendering coefficients of the plurality of figure blocks; performing three-dimensional virtual figure rendering according to the bone coefficients of the bone nodes in the bone tree to obtain a second three-dimensional virtual figure of the target object; wherein the determining of the rendering coefficients of the plurality of figure blocks based on the difference information between the first three-dimensional virtual figure and the preset reference three-dimensional virtual figure comprises: performing N rounds of linear fitting, in a case where i is equal to 1, the i-th round of linear fitting comprising: linearly fitting the difference information between the first three-dimensional virtual figure and the preset reference three-dimensional virtual figure based on a change amount of the plurality of figure blocks in the i-th round to obtain a weighting coefficient of the plurality of figure blocks in the i-th round; in a case where the i is greater than 1, the i-th round of linear fitting comprising: linearly fitting the difference information between the first three-dimensional virtual figure and a three-dimensional virtual figure in an (i-1)-th round based on a change amount of the plurality of figure blocks in the i-th round to obtain a weighting coefficient of the plurality of figure blocks in the i-th round, the three-dimensional virtual figure in the (i-1)-th round being a three-dimensional virtual figure obtained based on the weighting coefficient of the plurality of figure blocks in the (i-1)-th round, i taking a value from 1 to N, N being an integer greater than 1; for each of the plurality of figure blocks, adding the N weighting coefficients of the figure block obtained in the N rounds of linear fitting to obtain a rendering coefficient of the figure block; wherein the change amount of the plurality of figure blocks is a preconfigured change amount.

2. The method of claim 1, wherein, The method further comprises: in a case where the i-th round of linear fitting is ended, comparing a figure difference represented by the difference information between the first three-dimensional virtual figure and the three-dimensional virtual figure in the (i-1)-th round with a preset difference; in a case where the figure difference is greater than or equal to the preset difference, performing a next round of linear fitting; in a case where the figure difference is less than the preset difference, ending the linear fitting.

3. The method of claim 2, wherein, The linearly fitting of the difference information between the first three-dimensional virtual figure and the three-dimensional virtual figure in the (i-1)-th round based on the change amount of the plurality of figure blocks in the i-th round to obtain the weighting coefficient of the plurality of figure blocks in the i-th round comprises: constructing a fitting linear equation, in the fitting linear equation, a weighted product of the plurality of figure blocks is added up to equal the difference information between the first three-dimensional virtual figure and the three-dimensional virtual figure in the (i-1)-th round, and a weighted product of each figure block is equal to a product of the change amount of the figure block in the i-th round and the weighting coefficient of the figure block in the i-th round; solving the fitting linear equation by a least square method to obtain the weighting coefficient of the plurality of figure blocks in the i-th round.

4. The method of any one of claims 1 to 3, wherein, The method further comprises: obtaining a coefficient mapping relationship, the coefficient mapping relationship comprising a mapping relationship between a rendering coefficient of a target image block and a skeleton coefficient of a plurality of skeleton nodes associated with the target image block, the target image block being any one of the plurality of image blocks; based on the coefficient mapping relationship, converting the rendering coefficients of the plurality of image blocks into the skeleton coefficients of the skeleton nodes in the skeleton tree.

5. The method of any one of claims 1 to 3, the method further comprising: outputting the second three-dimensional virtual image and the rendering coefficients of the plurality of image blocks; receiving a first input, the first input being for adjusting a rendering coefficient of at least one of the plurality of image blocks; in response to the first input, adjusting the rendering coefficient of the at least one image block to obtain an updated rendering coefficient of the at least one image block; based on the updated rendering coefficient of the at least one image block, updating the second three-dimensional virtual image to obtain a third three-dimensional virtual image.

6. The method of any one of claims 1 to 3, wherein, The method further comprises: outputting a shape set of virtual image local region shapes, each virtual image local region shape in the shape set comprising at least one image block, and the rendering coefficients of the image blocks of each virtual image local region shape being pre-stored; receiving a second input, the second input being for selecting a plurality of virtual image local region shapes in the shape set; in response to the second input, generating a fourth three-dimensional virtual image based on the rendering coefficients of the image blocks of the plurality of virtual image local region shapes.

7. The method of claim 6, wherein, The method further comprises: outputting the second three-dimensional virtual image; receiving a third input, the third input being for selecting at least one virtual image local region shape in the shape set and selecting at least one virtual image local region shape in the second three-dimensional virtual image; in response to the third input, replacing the at least one virtual image local region shape selected in the second three-dimensional virtual image with the at least one virtual image local region shape selected in the shape set.

8. The method of any one of claims 1 to 3, wherein, The target object comprises a human face.

9. A virtual image rendering apparatus, comprising: an obtaining module configured to obtain an input image, the input image containing a target object; a reconstruction module configured to perform three-dimensional reconstruction on the target object contained in the input image to obtain a first three-dimensional virtual image of the target object, the first three-dimensional virtual image comprising a plurality of image blocks, each image block being associated with a plurality of skeleton nodes in a skeleton tree, the skeleton tree matching a preset reference three-dimensional virtual image; a determination module configured to determine rendering coefficients of the plurality of image blocks based on difference information between the first three-dimensional virtual image and the preset reference three-dimensional virtual image; a calculation module configured to calculate skeleton coefficients of the skeleton nodes in the skeleton tree based on the rendering coefficients of the plurality of image blocks; a rendering module configured to perform three-dimensional virtual image rendering according to the skeleton coefficients of the skeleton nodes in the skeleton tree to obtain a second three-dimensional virtual image of the target object. The determining module comprises: The fitting unit is configured to perform N rounds of linear fitting. In a case where i is equal to 1, the i-th round of linear fitting comprises: performing linear fitting on difference information between the first three-dimensional virtual image and the preset reference three-dimensional virtual image based on a change amount of the plurality of image blocks in the i-th round, to obtain a weighting coefficient of the plurality of image blocks in the i-th round. In a case where i is greater than 1, the i-th round of linear fitting comprises: performing linear fitting on difference information between the first three-dimensional virtual image and a three-dimensional virtual image in an (i-1)-th round based on a change amount of the plurality of image blocks in the i-th round, to obtain a weighting coefficient of the plurality of image blocks in the i-th round, wherein the three-dimensional virtual image in the (i-1)-th round is a three-dimensional virtual image obtained based on the weighting coefficient of the plurality of image blocks in the (i-1)-th round, and i is an integer from 1 to N, and N is an integer greater than 1. The calculating unit is configured to add the N weighting coefficients of each image block in the plurality of image blocks obtained in the N rounds of linear fitting, to obtain a rendering coefficient of the image block. The change amount of the plurality of image blocks is a preconfigured change amount.

10. The apparatus of claim 9, wherein, The device further comprises: The comparing module is configured to, in a case where the i-th round of linear fitting is completed, compare an image difference represented by the difference information between the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round with a preset difference. In a case where the image difference is greater than or equal to the preset difference, performing a next round of linear fitting. In a case where the image difference is less than the preset difference, ending the linear fitting.

11. The apparatus of claim 10, wherein, The performing linear fitting on the difference information between the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round based on the change amount of the plurality of image blocks in the i-th round comprises: Constructing a fitting linear equation, wherein in the fitting linear equation, a weighted product of the plurality of image blocks is added up to be equal to the difference information between the first three-dimensional virtual image and the three-dimensional virtual image in the (i-1)-th round, and a weighted product of each image block is equal to a product of the change amount of the image block in the i-th round and the weighting coefficient of the image block in the i-th round. Solving the fitting linear equation by a least square method to obtain the weighting coefficient of the plurality of image blocks in the i-th round.

12. The apparatus of any one of claims 9-11, wherein, The calculating module comprises: The obtaining unit is configured to obtain a coefficient mapping relationship, the coefficient mapping relationship comprising a mapping relationship between a rendering coefficient of a target image block and a skeletal coefficient of a plurality of skeletal nodes associated with the target image block, the target image block being any one of the plurality of image blocks. The converting unit is configured to convert, based on the coefficient mapping relationship, the rendering coefficient of the plurality of image blocks into the skeletal coefficient of the skeletal node in the skeletal tree.

13. The apparatus according to any one of claims 9 to 11, further comprising: The first output module is configured to output the second three-dimensional virtual image and the rendering coefficient of the plurality of image blocks. The first receiving module is configured to receive a first input, the first input being used to adjust a rendering coefficient of at least one image block in the plurality of image blocks. The first response module is configured to adjust the rendering coefficients of the at least one image block in response to the first input to obtain updated rendering coefficients of the at least one image block. The updating module is configured to update the second three-dimensional virtual image based on the updated rendering coefficients of the at least one image block to obtain a third three-dimensional virtual image.

14. The apparatus of any one of claims 9-11, wherein, The device further comprises: The second output module is configured to output a shape set of virtual image partial region shapes, each virtual image partial region shape in the shape set including at least one image block, and the rendering coefficients of the image blocks of each virtual image partial region shape being pre-stored; The second receiving module is configured to receive a second input, the second input being used to select a plurality of virtual image partial region shapes in the shape set; The second response module is configured to generate a fourth three-dimensional virtual image based on the rendering coefficients of the image blocks of the plurality of virtual image partial region shapes in response to the second input.

15. The apparatus of claim 14, wherein, The device further comprises: The third output module is configured to output the second three-dimensional virtual image; The third receiving module is configured to receive a third input, the third input being used to select at least one virtual image partial region shape in the shape set and select at least one virtual image partial region shape in the second three-dimensional virtual image; The third response module is configured to replace the at least one virtual image partial region shape selected in the second three-dimensional virtual image with the at least one virtual image partial region shape selected in the shape set in response to the third input.

16. The apparatus of any one of claims 9-11, wherein, The target object includes a human face. 17.An electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-8.

18. A non-transitory computer readable storage medium having stored thereon computer instructions, wherein, The computer instructions are used to enable the computer to perform the method of any one of claims 1-8. 19.A computer program product comprising a computer program which, when executed by a processor, implements the method of any one of claims 1-8.

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