WO2007004448A1 - Pattern embedding program, pattern embedding device, and pattern embedding method - Google Patents

Abstract

A polygon mesh setting unit sets a polygon mesh representing a surface shape of an object in a virtual 3-dimensional space. A polygon specification unit specifies a region where a concealed pattern is to be embedded in the polygon constituting the polygon mesh and specifies the polygon positioned in the specified region as a specific polygon. A direction modification unit modifies the direction of the specific polygon so that the direct reflection direction of the light from the light ray direction is directed to the direction of the visual line.

Description

 Specification

 Symbol embedding program, symbol embedding device, and symbol embedding method

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a symbol embedding program, a symbol embedding device, and a symbol embedding method using a computer graphics technique, and in particular, a predetermined hidden symbol is applied to a polygon mesh arranged in a virtual three-dimensional space. The present invention relates to a symbol embedding program, a symbol embedding device, and a symbol embedding method.

 Background art

 [0002] In recent years, from the viewpoint of copyright protection, hidden objects have been embedded in the actual objects that are the subject of copyright and the 3D shape model generated in the virtual 3D space to protect these works. Various attempts have been made.

 [0003] For example, Patent Document 1 discloses a step of setting a parameter for embedding watermark processing information, a step of inputting pre-conversion data of a 3D shape model, and each curved mesh of the input 3D shape model. The process of selecting meshes that are transparent and that perform information embedding processing and meshes that are not embedding processing, and for a given mesh in each selected set of curved surface meshes, are specified as embedding parameters. Generating a control point having a divided ratio and generating a divided mesh having the control point on the predetermined curved surface and having the same number of control points as the predetermined curved surface mesh. A technique for embedding electronic permeability in a dimensional shape model is disclosed.

 However, with the technique described in Patent Document 1, the electronic permeability information embedded in the three-dimensional shape model can be obtained if the predetermined restoration process is not performed on the three-dimensional shape model. However, there is a problem that the electronic permeability information cannot be visually recognized directly by the 3D shape model force.

 Patent Document 1: Japanese Patent Laid-Open No. 2003-99805

 Disclosure of the invention

An object of the present invention is to provide a symbol embedding program, a symbol embedding device, and a symbol embedding method capable of embedding a hidden symbol in an actual object or a virtual three-dimensional model. Is Rukoto.

 [0006] A pattern embedding program according to one aspect of the present invention includes a setting unit that sets a polygon mesh representing a surface shape of an object having irregularities repeatedly formed on a surface in a virtual three-dimensional space, and the polygon mesh A means for identifying a polygon located in an area for embedding a predetermined hidden pattern from among the polygons to be specified as a specific polygon, and a regular reflection direction with respect to light from a predetermined ray direction is directed to a predetermined line-of-sight direction Thus, the computer is caused to function as changing means for changing the direction of the specific polygon.

 [0007] A pattern embedding device according to another aspect of the present invention includes a setting unit that sets a polygon mesh representing a surface shape of an object having irregularities repeatedly formed on a surface in a virtual three-dimensional space, and the polygon mesh. A means for identifying a polygon located within an area for embedding a predetermined hidden pattern as a specific polygon, and a regular reflection direction with respect to light from a predetermined ray direction is directed to a predetermined line-of-sight direction And changing means for changing the orientation of the specific polygon.

 [0008] A pattern embedding method according to still another aspect of the present invention includes a setting step in which a computer sets, in a virtual three-dimensional space, a polygon mesh that represents a surface shape of an object on which irregularities are repeatedly formed on a surface. A specific step for specifying a polygon located in an area for embedding a predetermined hidden pattern from among the polygons constituting the polygon mesh as a specific polygon, and a regular reflection direction for light from a predetermined light ray direction are provided. And a changing step of changing the orientation of the specific polygon so as to face a predetermined line-of-sight direction.

 [0009] According to each of the above-described configurations, a polygon mesh representing the surface shape of an object in which irregularities are repeatedly formed on the surface is set in a virtual three-dimensional space, and a specific polygon located in an area where a hidden symbol is embedded The direction of the specific polygon is changed so that the specular reflection direction of the light that is specified and irradiated from the predetermined light ray direction faces the predetermined line-of-sight direction. As a result, only when a portion corresponding to a specific directional force specific polygon is observed by irradiating light from a specific direction, the portion can be visually recognized as a hidden symbol, so that an actual object or virtual 3 Hidden symbols can be embedded in the dimensional model.

 Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of a symbol embedding apparatus according to a first embodiment of the present invention. FIG. 2 is a flowchart for explaining symbol embedding processing by the symbol embedding device shown in FIG. 1.

圆 3] A schematic diagram showing an example of a polygon mesh set in a virtual three-dimensional space. 4) Polygon mesh force is also a diagram showing how a specific polygon is specified.

[5] It is a schematic diagram for explaining how the orientation of a specific polygon is changed.

[6] FIG. 6 is a diagram illustrating an example of a polygon mesh rendered when the light ray direction and the line-of-sight direction are not set to a direction in which a hidden symbol can be visually recognized.

 FIG. 7 is a schematic diagram showing an example of a positional relationship between three light ray directions and a line-of-sight direction.

 FIG. 8 is a diagram illustrating an example of a rendering result of a polygon mesh with respect to a light ray direction.

 FIG. 9 is a diagram showing another example of a polygon mesh rendering result with respect to a light ray direction.

FIG. 10 is a diagram showing another example of a rendering result of a polygon mesh with respect to a light ray direction.

 FIG. 11 is a cross-sectional view of an example of a polygon mesh in which a hidden symbol is embedded.

 FIG. 12 is a flowchart for explaining a process in which the texture generation unit shown in FIG. 1 generates a base texture.

[13] FIG. 13 is a schematic diagram showing sample points arranged in a grid in a virtual three-dimensional space. [14] FIG. 14 is a schematic diagram for explaining a light ray direction and a line-of-sight direction.

 FIG. 15 is a schematic diagram when the sample points arranged on the XY plane are viewed from the Z direction.

[16] It is a schematic diagram of a virtual three-dimensional space in which sample points are set.

 FIG. 17 is a diagram showing an example of a base texture when viewed from the heel direction.

 FIG. 18 is a schematic diagram for explaining a state in which a plurality of hidden symbols are embedded in a polygon mesh by the symbol embedding device according to the second embodiment of the present invention.

[19] FIG. 19 is a schematic diagram showing the relationship between the light ray direction and the line-of-sight direction in the second embodiment of the present invention.

[20] This is a schematic surface for explaining how the orientation of a specific polygon is changed.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 [0012] (First embodiment)

 FIG. 1 shows a block configuration diagram of a symbol embedding apparatus according to a first embodiment of the present invention. This symbol embedding device is also configured with a known computer power, and includes a processing unit 10, a storage unit 20, an input unit 30, a display unit 40, and an optical characteristic acquisition device 50. The processing unit 10 is configured with CPU power, and includes a polygon mesh setting unit 11, a polygon specifying unit 12, a target direction calculating unit 13, a direction changing unit 14, a rendering processing unit 15, a texture generating unit 16, and a 3D data output unit 17 It has the function of. The storage unit 20 includes a storage device such as a hard disk, and includes functions of a base texture storage unit 21, a symbol storage unit 22, and an optical characteristic storage unit 23.

 The polygon mesh setting unit 11 to the three-dimensional data output unit 17 and the base texture storage unit 21 to the optical characteristic storage unit 23 execute a symbol embedding program stored in a hard disk as a recording medium by the CPU. This is realized.

 [0014] The optical characteristic acquisition device 50 is a known device invented by the applicant of the present invention, and obtains a sample by photographing the sample while changing the light irradiation direction and the photographing direction with respect to the actual sample. This is a device that generates a BRDF (bidirectional reflection distribution function) from the sample image. Detailed contents are disclosed in JP-A-2005-115645. The optical characteristic acquisition device 50 generates a BRDF of an object (material) that is a base texture creation target (modeling target). The optical property storage unit 23 stores the BRDF generated by the optical property acquisition device 50.

[0015] Here, BRDF is a function that receives the light ray direction and the line-of-sight direction as input, and outputs a reflectance associated with the light ray direction and the line-of-sight direction. In the present embodiment, the BRDF represents the input / output relationship in the LUT (lookup table) format. The reflectance is represented by the ratio of the amount of reflected light to the amount of light emitted from the virtual light source. The BRD F storage unit 21 may store a BRDF other than the BRDF acquired by the optical characteristic acquisition device 50. Here, the BRDF other than the BRDF acquired by the optical characteristic acquisition device 50 is, for example, a BRDF created by inputting numerical values using an application software for setting the BRDF by the user, or a mathematical expression. Contains the represented BRDF. [0016] The texture generation unit 16 reads the BRDF of the object for which the base texture is to be created from the optical property storage unit 23, generates a base texture representing the three-dimensional shape of the object according to the read BRDF, and generates the base texture. Store in storage unit 21. In this way, the base texture storage unit 21 stores a base texture obtained by modeling the surface shape of an object in which fine irregularities (textures) are repeatedly formed in a constant pattern on the surface.

 [0017] The base texture also includes a plurality of sample point forces. Each sample point consists of three components: an X component indicating the X-axis value, a Y component indicating the Y-axis value, and a Z component indicating the Z-axis value set in the virtual three-dimensional space. . In addition, the values of the X and Ύ components at each sample point are determined so that the projections on the XY plane are arranged in a square grid, and the value of the Z component at each sample point is the value of the modeled object. Show height data!

 [0018] The input unit 30 includes a known input device force such as a keyboard and a mouse. The polygon mesh setting unit 11 reads the base texture specified by the user from the base texture storage unit 21 using the input unit 30, and plots each sample point constituting the read base texture in the virtual three-dimensional space. Next, the polygon mesh setting unit 11 connects adjacent sample points with straight lines, and sets a polygon mesh composed of polygons such as triangles or quadrangles in the virtual three-dimensional space. This reproduces the surface shape of an object in which fine irregularities are repeatedly formed in a fixed pattern in a virtual three-dimensional space.

[0019] The symbol storage unit 22 stores in advance hidden symbol data indicating image data of a hidden symbol embedded in the base texture. Here, the hidden symbol data is created in advance by the user using drawing software or the like, captured by the user via the Internet, or previously created by the provider of this symbol embedding program, etc. including.

[0020] The polygon specifying unit 12 reads out the hidden symbol data designated by the user using the input unit 30 from the symbol storage unit 22, and reads out the polygons constituting the polygon mesh set by the polygon mesh setting unit 11. The polygon located in the area where the hidden symbol data is embedded is specified as a specific polygon. The target direction calculation unit 13 calculates, as the target direction, a straight line direction that bisects the angle between the light ray direction and the line-of-sight direction specified by the user using the input unit 30. The direction changing unit 14 extracts a specific polygon whose normal vector angle with respect to the target direction is less than or equal to a specified value from the specific polygon, and specifies the normal vector of the extracted specific polygon so that it matches the target direction. Change the orientation of the polygon.

 The rendering processing unit 15 renders the specific polygon whose direction has been changed by the target direction calculation unit 13 using the BRD F of the object that is the base texture modeling target, and displays it on the display unit 40. The display unit 40 includes a known display device such as a CRT, a liquid crystal panel, or a plasma panel. The rendering processing unit 15 performs rendering according to the line-of-sight direction and the ray direction input by the user using the input unit 30.

 [0023] The three-dimensional data output unit 17 generates NC (Numerical Control) data from the three-dimensional data representing the position of each sample point of the polygon mesh PM in which the direction of the specific polygon has been changed by the direction changing unit 14, Output to stereolithography apparatus 60.

 The stereolithography apparatus 60 is composed of a well-known stereolithography apparatus, and forms the shape of the polygon mesh PM into a grease according to the NC data generated by the three-dimensional data output unit 17. In place of the stereolithography device, a device other than the stereolithography device can be used as long as the device can form the shape on the actual object with a three-dimensional data force representing the shape of the object created on the computer. It may be used.

 In the present embodiment, the polygon mesh setting unit 11 corresponds to an example of a setting unit, the polygon specifying unit 12 corresponds to an example of a specifying unit, and the target direction calculating unit 13 and the direction changing unit 14 are changing units. The rendering processing unit 15 corresponds to an example of a rendering processing unit, the texture generation unit 16 corresponds to an example of a polygon mesh generation unit, and the 3D data output unit 17 corresponds to an example of an output unit. To do.

 Next, the process of the symbol embedding apparatus shown in FIG. 1 will be described using the flowchart shown in FIG. First, in step S1, when the input unit 30 receives an operation command for designating a base texture, the polygon mesh setting unit 11 reads the designated base texture from the base texture storage unit 21 and acquires the base texture. .

[0027] Next, in step S2, the polygon mesh setting unit 11 reads in step S1. Each sample point composing the extracted base texture is plotted in the virtual 3D space, each sample point is connected by a straight line, and a polygon mesh is set in the virtual 3D space.

 FIG. 3 is a schematic diagram showing an example of a polygon mesh set in a virtual three-dimensional space. As shown in FIG. 3, the polygon mesh PM is composed of a plurality of polygons P L having the sample point P as a vertex. When each sample point P is projected onto the XY plane, the X and Y components are arranged so that each projected point SP 'is arranged in a square grid with an interval d of mesoscale (scale of micron order to millimeter order). The value of is determined.

 [0029] The distance d between the projection points is preferably 10 μm or more and 100 μm or less. Polygon mesh PM represents the surface shape of an object with irregularities repeatedly formed on the surface, and it can be seen that the Z component of each sample point P is dispersed.

 [0030] Next, in step S3, the polygon mesh setting unit 11 adds noise to the Z component of each sample point P to further disperse the irregularities on the surface of the polygon mesh PM.

 [0031] Next, in step S4, the polygon specifying unit 12 reads out the hidden symbol data designated by the user from the symbol storage unit 22, sets an area in which the read hidden symbol data is embedded in the polygon mesh PM, Among the polygons constituting the polygon mesh PM, the polygon PL located within the set area is identified as the specific polygon TPL.

 [0032] FIG. 4 is a diagram showing how the specific polygon TPL is specified for the polygon mesh PM force. As shown in Fig. 4, the area D1 where the hidden symbol indicating the alphabet D is embedded is set in the polygon mesh PM. Then, the polygon PL located in the area D1 is specified as the specific polygon TPL.

 [0033] Next, in step S5, the target direction calculation unit 13 sets a light ray direction and a line-of-sight direction in which the hidden symbol G can be visually recognized in accordance with the user force operation command received by the input unit 30. Next, in step S6, the target direction calculation unit 13 calculates, as the target direction OD, the direction of a straight line that equally divides the angle θ 1 formed by the light beam direction LD and the line-of-sight direction VD as shown in FIG.

Next, in step S7, the direction changing unit 14 obtains the normal vector n of the specific polygon TPL as shown in FIG. 5, and the angle φ between the normal vector n and the target direction OD is a predetermined value (10 Extract any specific polygon TPL that is less than or equal to 20 degrees or less). The default value Depending on how scattered the polygon PL is in the normal direction and how much the hidden pattern is visible depending on the BRDF of the material.

[0035] Next, in step S8, the direction changing unit 14 configures the sample point P constituting the specific polygon TPL so that the normal vector n of the specific polygon TPL extracted in step S7 matches the target direction OD. Change the Z component value of and change the direction of the specific polygon TPL

[0036] Next, in step S9, the rendering processing unit 15 renders the polygon mesh PM whose orientation has been changed using the BRDF of the object to be modeled by the polygon mesh PM, and causes the display unit 40 to display it. .

 [0037] Alternatively, in step S10 instead of the process in step S9, the three-dimensional data output unit 17 converts the three-dimensional data of each sample point P of the polygon mesh PM whose direction has been changed into NC data, Output to stereolithography apparatus 60. The optical modeling apparatus 60 forms a resin according to NC data, and forms a texture with a hidden pattern embedded in the resin.

 FIG. 6 is a diagram illustrating an example of a polygon mesh PM rendered when the light ray direction and the line-of-sight direction are not set to a direction in which a hidden symbol can be visually recognized. In FIG. 6, the ray direction and the line-of-sight direction are set so that the hidden symbol can be seen, so only the surface shape of the object to be modeled is displayed and the hidden symbol G is not displayed.

[0039] Fig. 7 is a schematic diagram showing an example of the positional relationship between the three ray directions LD1 to LD3 and the line-of-sight direction VD. Figs. 8 to 10 show the polygon mesh PM for each ray direction LD1 to LD3. It is a figure which shows an example of a rendering result (rendered image). When the normal vector of a specific polygon matches the target direction that bisects the angle between the light ray direction LD2 and the line-of-sight direction VD, the light directions LD1 and LD3 visually recognize the hidden pattern as shown in Fig. 7. Therefore, even if the polygon mesh PM is rendered with the ray direction set to LD1 or LD3 and the polygon mesh PM is rendered, the hidden symbol G is not displayed as shown in FIG. 8 or FIG. On the other hand, when rendering is performed with the ray direction and line-of-sight direction set to LD2 and VD, as shown in Fig. 9, the hidden symbol G, which is the character power of DFL, is displayed.

[0040] FIG. 11 shows a cross-sectional view of an example of a polygon mesh PM in which a hidden symbol is embedded. The The plane Kl shown in FIG. 11 indicates the polygon surface of the specific polygon TPL whose orientation has been changed in step S8. The specular reflection direction of light on the plane K1 from the light beam direction LD2 is the line-of-sight direction VD. Hidden symbol G will be displayed as a result of directing in line of sight direction VD. On the other hand, when rendering is performed with the ray direction set to a direction other than LD2, for example, LD1, the light in the irregular reflection direction of the plane K1 is directed to the line-of-sight direction VD, so the hidden symbol G is not displayed.

 Next, processing in which the texture generation unit 16 shown in FIG. 1 generates a base texture will be described using the flowchart shown in FIG. First, in step S21, when the input unit 30 receives a user operation command for designating one BRDF from the optical characteristic storage unit 23, the texture generation unit 16 converts the BRDF designated by the user into the optical characteristics. Read from the storage unit 23 to obtain the BRDF.

 [0042] Next, in step S22, the texture generation unit 16 arranges a plurality of sample points in a lattice in the virtual three-dimensional space, and regular reflection of light when light is irradiated to each sample point of the virtual light source power. The direction is calculated using BRDF.

 FIG. 13 is a schematic diagram showing sample points P arranged in a lattice pattern in a virtual three-dimensional space. As shown in Fig. 13, X, Y, and saddle axes that are orthogonal to each other are set in the virtual three-dimensional space. Here, the heel axis indicates the vertical direction, and the heel plane indicates the horizontal plane. The texture generation unit 11 arranges the sample points 格子 in a grid pattern on the ΧΥ plane in the virtual three-dimensional space. Here, the sample points Ρ are arranged on the XY plane at a mesoscale interval d.

[0044] Hereinafter, among the plurality of sample points P arranged on the XY plane, the sample point P to be processed is referred to as a target sample point CP. The texture generation unit 16 obtains the ray direction LD from the virtual light source VL for the target sample point CP, inputs the obtained ray direction LD to the BRDF obtained in step S21, changes the line-of-sight direction VD, and changes each line-of-sight direction VD. Then, the line-of-sight direction that gives the maximum reflectance among the calculated reflectances is calculated as the regular reflection direction of light at the sample point CP of interest. In the example of FIG. 13, since the arrow with the sign of VD becomes longer as the reflectivity increases, the line-of-sight direction VDMAX is calculated as the regular reflection direction RD. The specular reflection direction RD is calculated for other sample points P in the same way. In addition, In FIG. 13, the normal vector n at the sample point CP of interest is displayed exaggerated over the normal vector n at the other sample points P.

 FIG. 14 is a schematic diagram for explaining the light beam direction LD and the line-of-sight direction VD. As shown in Fig. 14, when the sample point of interest CP is the origin, the X 'axis (parallel to the X axis), Y' axis (parallel to the Y axis), and axis (parallel to the Z axis) are set. Is expressed by the angle a between the projection IJT of the ray direction LD onto the XY plane and the X 'axis, and the angle β between the projection and the ray direction LD. The line-of-sight direction VD is expressed by an angle γ formed by the projection VD ′ and the X ′ axis of the line-of-sight direction VD onto the vertical plane, and an angle δ formed by the projection VD and the line-of-sight direction VD.

 Here, the texture generation unit 16 changes the angle δ within a range of 0 to 90 degrees with a predetermined resolution (for example, 5 degrees), and changes the angle γ within a range of −90 to 90 degrees. Change the resolution (eg 10 degrees) and change the line-of-sight direction VD.

 [0047] Referring again to FIG. 12, in step S23, the texture generation unit 16 bisects the angle Θ 2 formed between the specular reflection direction RD and the light ray direction LD of the target sample point CP shown in FIG. Is calculated as a normal vector n with respect to the plane including the sample point of interest CP.

 [0048] Next, in step S24, the texture generation unit 16 calculates the unevenness information of the sample point P as follows. FIG. 15 is a schematic diagram when the sample points P arranged on the XY plane are viewed from the Z direction, and FIG. 16 is a schematic diagram of a virtual three-dimensional space in which the sample points P are set.

 First, as shown in FIG. 15, the texture generating unit 16 specifies the polygon PL1 located at the lower left of the two polygons constituting the lower left grid K1 as the target polygon. Next, as shown in FIG. 16, among the three sample points P constituting the polygon PL1, the sample points P2, P3 are set so that the direction of the polygon PL1 is orthogonal to the normal vector nl of the lower left sample point P1. Is moved in the Z direction, and the value of the Z component of the sample points P2 and P3 after the movement is calculated as the unevenness information of the sample points P2 and P3.

[0050] Next, as shown in FIG. 15, the texture generation unit 16 identifies the polygon PL2 located at the lower left of the polygons constituting the grid K2 adjacent to the grid K1 as the target polygon, as shown in FIG. Of the polygon PL2, the sample points P4, P so as to be orthogonal to the normal vector n2 of the sample point P2 in the lower left of the three sample points P constituting the polygon PL2 5 is moved in the Z direction, and the value of the Z component of the sample points P4 and P5 after the movement is calculated as the unevenness information of the sample points P4 and P5.

Next, as shown in FIG. 15, the texture generation unit 16 identifies the polygon PL3 in the lattice K3 adjacent to the upper side of the lattice K1 as the target polygon, and the orientation of the polygon PL3 as shown in FIG. Force The sample point P6 is moved in the Z direction so as to be orthogonal to the normal vector n3 of the sample point P3, and the value of the Z component of the sample point P6 after the movement is calculated as the unevenness information of the sample point P6.

 Thereafter, in the same manner as described above, the texture generation unit 16 identifies the polygon PL4 in the lattice K4 adjacent to the right side of the lattice K2 as the target polygon, and changes the orientation of the polygon PL4 in the same manner as the polygon PL2. . In this way, the texture generation unit 16 sequentially identifies the target polygon from the polygon PL1 of the lower left grid K1 so as to meander diagonally upward to the right, and the orientation of the identified target polygon is as described above. Change and calculate the Z component value of each sample point after the change as unevenness information of each sample point to generate a 3D texture.

 FIG. 17 is a diagram illustrating an example of a texture generated by the texture generation unit 16.

 As shown in Fig. 17, it can be seen that the surface shape of the object is realistically reproduced. Note that the texture generation unit 16 sequentially identifies the target polygon from the polygons in the lower right, upper left, and upper right grids other than the lower left so as to meander to the upper left, lower right, and lower left. A little.

 [0054] As described above, according to the present design embedding device, the specific polygon located in the region where the hidden design is embedded is specified, and the regular reflection direction of the light irradiated from the specific light ray direction is specified. The direction of the specific polygon is changed so as to face the viewing direction. As a result, when a polygon mesh is rendered using BRDF of the object to be modeled, a hidden pattern is displayed only when rendering is performed with the ray direction, line-of-sight direction, specific ray direction, and line-of-sight direction set. Can do.

[0055] Therefore, a person who does not know the specific light ray direction and line-of-sight direction cannot display the embedded hidden symbol and can hide the hidden symbol from the polygon mesh. On the other hand, a person who knows a specific ray direction and line-of-sight direction can display a hidden pattern by setting the ray direction and line-of-sight direction and rendering the polygon mesh. Even without performing the restoration process as in Patent Document 1, it is possible to immediately recognize the hidden symbol embedded in the polygon mesh.

 [0056] Further, according to the present design embedding apparatus, it is possible to embed a hidden design in the wrinkles formed with wrinkles, and light is applied to the wrinkles formed with wrinkles from a specific direction (light beam direction). However, when observing from a specific direction (line-of-sight direction), a hidden symbol appears. On the other hand, when a third party imitates a wrinkle and forms a resin, the hidden pattern is not embedded in this resin, so even if it is irradiated from a specific direction and observed from a specific direction, the hidden pattern does not appear. It will not appear. Thereby, imitation of the grain by a third party can be prevented.

 [0057] It should be noted that in step S3 in FIG. 2, the force applied noise to the Z component is not limited to this, and the processing shown in step S3 may be omitted. Further, in the above description, the force that prevents imitation of the wrinkles is not limited to this, and the object is a three-dimensional or two-dimensional decorated object, and the entire surface of the object or a part thereof. By embedding a hidden pattern in the area where the wrinkles are displayed, it is possible to protect the decorations from imitation by third parties.

 [0058] (Second Embodiment)

 The symbol embedding device according to the second embodiment embeds a plurality of types of hidden symbols in the polygon mesh compared to the symbol embedding device according to the first embodiment that embeds one type of hidden symbol in the polygon mesh PM. It is characterized by. Since the symbol embedding device according to the second embodiment has substantially the same configuration as the symbol embedding device according to the first embodiment, the symbol embedding device according to the first embodiment shown in FIG. This will be described with reference to the block diagram.

 [0059] Hereinafter, a case where three types of hidden symbols G1 to G3 are embedded in the polygon mesh PM will be described as an example. FIG. 18 is a schematic diagram for explaining how the hidden symbols G1 to G3 are embedded in the polygon mesh, and FIG. 19 is a schematic diagram showing the relationship between the light ray direction and the line-of-sight direction in the second embodiment. is there.

[0060] As shown in FIG. 18, the hidden symbol G1 is a symbol indicating the letter “D”, the hidden symbol G2 is a symbol indicating the letter “F”, and the hidden symbol G3 is a symbol indicating the letter “L”. And Further, the light ray directions in which the respective hidden patterns G1 to G3 can be visually recognized are shown as light ray directions LD1 to LD3 shown in FIG. 19, respectively. In this case, the polygon identification unit 12 As shown, the regions D1 to D3 in which the hidden symbols G1 to G3 are embedded are identified from the polygon mesh PM, and the polygons located in the regions D1 to D3 are identified as the specific polygons TPL1 to TPL3.

 [0061] As shown in FIG. 18, the target direction calculation unit 13 calculates a direction that bisects the angle formed by the light beam direction LD1 and the line-of-sight direction VD as the target direction OD1, and calculates the light beam direction LD2 and the line-of-sight direction VD The target direction OD2 is calculated as the direction that divides the angle formed by halving the target direction OD3.

 The direction changing unit 14 extracts the specific polygon TPL 1 whose angle between the normal vector nl and the target direction OD 1 is less than the specified value from the specific polygon TPL1 as shown in FIG. Among them, a specific polygon TPL2 whose angle between the normal vector n2 and the target direction OD2 is less than the specified value is extracted, and among the specific polygon TPL3, the angle between the normal vector n3 and the target direction OD3 is less than the specified value. Extract specific polygon TPL3. Then, the direction of the specific polygon TPL 1 is changed so that the normal vector nl of the extracted specific polygon TPL1 matches the target direction OD1, and the normal vector n2 of the extracted specific polygon TPL2 matches the target direction OD2 As described above, the direction of the specific polygon TPL2 is changed, and the direction of the specific polygon TPL3 is changed so that the normal vector n3 of the extracted specific polygon TPL3 matches the target direction OD3.

 [0063] When the rendering processing unit 15 sets the ray direction to LD1 to LD3, sets the line-of-sight direction to VD, and renders the polygon mesh PM using BRDF, as shown in FIG. A hidden symbol G1, a hidden symbol G2 of “F”, and a hidden symbol G3 of “L” are displayed on the display unit 40. On the other hand, when the rendering processing unit 15 renders the polygon mesh PM with the ray direction set to LD1 and the line-of-sight direction set to VD, only the hidden symbol “D” is displayed on the display unit 40 in FIG. Hidden symbols G2 and G3 of “F” and “L” are not displayed on the display unit 40. Further, when the rendering processor 15 sets the light beam direction in a direction other than the light beam directions LD1 to LD3 and renders the polygon mesh PM, the hidden symbols G1 to G3 are not displayed.

[0064] As described above, according to the symbol embedding apparatus according to the second embodiment, a plurality of hidden symbols are embedded in the polygon mesh PM, and each hidden symbol can be visually recognized. Because of the different directions, it is more difficult for a third party to visually recognize the hidden symbol embedded in the polygon mesh.

In each of the above embodiments, the directions of the specific polygons TPL and TPL1 to TPL3 are changed so that the normal vectors n and nl to n3 of the specific polygon TPL match the target directions OD and OD1 to OD3. However, it is not limited to this. For example, as shown in FIG. 20, the Z component of the sample point SP is corrected so that the normal vector to the sample point SP matches the target direction OD, and each specific polygon TPL1 to TPL5 sharing the sample point SP is corrected. You may change the orientation. In this case, the normal vector η 平均 of the sample point SP can be calculated by taking the average of the normal vectors nl to n5 of the specific polygons TPL1 to TPL5 including the sample point SP.

 In the second embodiment, the rendering processing unit 15 performs rendering by setting the colors of the light beam directions LD1 to LD3 to different colors, respectively, “D”, “F”, The letters “L” can be displayed in different colors. Further, in the second embodiment, the hidden symbol is a force in which three types of hidden symbol forces are also configured. The present invention is not limited to this, and two types or four or more types of hidden symbols may be used. In the second embodiment, the number of the line-of-sight directions VD is one, but the present invention is not limited to this, and a plurality of line-of-sight directions VD may be set.

 [0067] As described above, the design embedding program according to an aspect of the present invention sets the polygon mesh representing the surface shape of the object formed by repeatedly forming the unevenness on the surface in the virtual three-dimensional space. And a means for specifying a polygon located in an area for embedding a predetermined hidden pattern from among the polygons constituting the polygon mesh as a specific polygon, and a regular reflection direction for light from a predetermined light ray direction The computer is caused to function as changing means for changing the orientation of the specific polygon so that is directed in a predetermined line-of-sight direction.

[0068] A pattern embedding device according to another aspect of the present invention includes a setting unit that sets a polygon mesh representing a surface shape of an object having uneven surfaces repeatedly formed in a virtual three-dimensional space; A specifying means for specifying a polygon located in an area for embedding a predetermined hidden pattern as a specific polygon from the constituent polygons, and a regular reflection direction with respect to light from a predetermined ray direction is directed to a predetermined line-of-sight direction As described above, a change means for changing the orientation of the specific polygon is provided. [0069] In the symbol embedding method according to another aspect of the present invention, the computer sets a polygon mesh representing a surface shape of an object having irregularities repeatedly formed on a surface in a virtual three-dimensional space; A specific step for specifying a polygon located in an area for embedding a predetermined hidden pattern as a specific polygon from among the polygons constituting the polygon mesh, and a specular reflection direction for light from a predetermined ray direction is a predetermined line of sight Changing the direction of the specific polygon so as to face the direction.

 [0070] According to each of the above-described configurations, a polygon mesh representing the surface shape of an object in which irregularities are repeatedly formed on the surface is set in a virtual three-dimensional space, and a specific polygon located in a region where a hidden symbol is embedded The direction of the specific polygon is changed so that the specular reflection direction of the light that is specified and irradiated from the predetermined light ray direction faces the predetermined line-of-sight direction.

 [0071] Therefore, when 3D data of a polygon mesh whose polygon orientation has been changed is output to an optical modeling apparatus, and the shape defined by this polygon mesh is formed on an object such as a resin, It is possible to observe a hidden symbol only when irradiating light from a specific direction and observing from a specific direction, and it is possible to embed a hidden symbol in an object

[0072] In addition, it is possible to observe a hidden symbol only when rendering a polygon mesh whose orientation of the polygon has been changed from a specific ray direction and line-of-sight direction, and it is possible to embed a hidden symbol in a virtual 3D model. It becomes possible.

 [0073] Therefore, when a third party imitates the irregularities on the surface of an object and forms it on another object, the hidden pattern cannot be visually recognized on the object, so the third party imitations on the irregularities on the surface of the object Can be prevented. Alternatively, it is possible to embed hidden symbols in a virtual 3D model that represents the irregularities on the surface of the object, preventing third-party imitations on the virtual 3D model.

 [0074] Further, if a person who knows the light ray direction and the line-of-sight direction in which the hidden symbol can be visually recognized sets the light ray direction and the line-of-sight direction and renders the polygon mesh, the hidden symbol is directly visually recognized. Thus, the hidden symbol embedded in the polygon mesh can be immediately recognized without performing the restoration process as in Patent Document 1.

[0075] Further, a cubic that defines the shape of the polygon mesh whose orientation has been changed by the changing means. It is preferable to further cause the computer to function as output means for outputting the original data to the three-dimensional modeling apparatus. In this case, it is possible to embed a hidden symbol in an actual object having irregularities repeatedly formed on the surface.

[0076] Further, an acquisition unit that acquires the optical characteristics of the object, and a rendering processing unit that renders the polygon mesh whose orientation has been changed by the change unit using the optical characteristics acquired by the acquisition unit. It is preferable to make a computer function. In this case, it is possible to embed a hidden symbol in a virtual three-dimensional model of an object with irregularities repeatedly formed on the surface.

 [0077] Further, it is preferable that the acquisition unit acquires a bidirectional reflectance distribution function as the optical characteristic. In this case, since the polygon mesh is rendered using the bidirectional reflectance distribution function, the surface shape of the object can be realistically reproduced.

 [0078] In addition, it is preferable that the changing unit changes the direction of only the specific polygon whose direction change amount is equal to or less than a predetermined angle among the specific polygons. In this case, since the orientation of the polygon that has to be changed greatly does not change, it is possible to embed a hidden pattern that does not greatly change the original shape of the polygon mesh. In addition, if there are many polygons whose orientation has been changed greatly, there is a possibility that hidden symbols can be seen from directions other than the predetermined line-of-sight direction, but by adopting the above configuration, directions other than the predetermined line-of-sight direction can be observed. Therefore, it is possible to prevent the hidden symbol from being visually recognized.

 [0079] Further, the changing unit sets a direction that bisects the angle between the predetermined ray direction and the predetermined line-of-sight direction as a target direction, and a normal vector of the specific polygon matches the target direction It is preferable to change the direction of the specific polygon.

 [0080] In this case, the direction that bisects the angle between the predetermined ray direction and the line-of-sight direction is set as the target direction, and the direction of the specific polygon is set so that the normal vector of the specific polygon coincides with the target direction. Because it is changed, it is possible to accurately change the direction of the specific polygon to the target direction.

[0081] Further, the hidden symbol is also configured with n (n is an integer of 2 or more) types of hidden symbol forces, the specifying unit specifies a specific polygon corresponding to each hidden symbol, and the changing unit includes The specular reflection direction with respect to light from a predetermined ray direction corresponding to the hidden symbol is the predetermined line of sight. It is preferable to change the orientation of the specific polygon corresponding to each hidden symbol so that it faces the direction.

 [0082] In this case, the hidden symbol is composed of n types of hidden symbol powers, and a light beam directional light that can be visually recognized for each hidden symbol is irradiated to illuminate the hidden symbol. Only when observing from the line of sight that can be recognized, the hidden symbol can be visually recognized. Therefore, the entire hidden symbol cannot be visually recognized unless the line-of-sight direction in which the symbols for all the n types of hidden symbols are visible is known. As a result, the probability that the entire hidden symbol is visually recognized can be reduced, and the possibility that the hidden symbol is visually recognized by a third party can be further reduced.

 [0083] Further, the hidden symbol is also configured with n (n is an integer of 2 or more) types of hidden symbol forces, the specifying unit specifies a specific polygon corresponding to each hidden symbol, and the changing unit includes: The direction of the specific polygon corresponding to each hidden symbol is changed so that the specular reflection direction with respect to light from a predetermined ray direction corresponding to the hidden symbol is directed to the predetermined line-of-sight direction. It is also possible to render the polygon mesh whose direction is changed by the changing means by setting the color of the light from the light ray direction corresponding to the hidden symbol to a different color. In this case, n types of hidden symbols can be represented by different colors.

 [0084] In addition, a plurality of sample points are arranged in a virtual three-dimensional space, and the regular reflection direction of light emitted from the virtual light source to each of the arranged sample points is represented by the bidirectional reflectance distribution function of the object. The normal vector of each sample point is calculated from the calculated regular reflection direction and the incident direction of the light of the virtual light source power, and the height data of each sample point is calculated based on the calculated normal vector By doing so, it is preferable that the computer further function as polygon mesh generating means for generating the polygon mesh.

 [0085] In this case, the user can obtain a polygon mesh representing the surface shape of the object simply by giving the bidirectional reflectance distribution function of the object without modeling the polygon mesh.

[0086] The object is preferably an object having a texture. In this case, since the polygon mesh represents the surface shape of the object having the texture, the orientation of the polygons other than the specific polygon is dispersed, so that the hidden symbol can be expressed more clearly. Also hidden in wrinkles It becomes possible to embed a design and prevent imitation of a wrinkle by a third party. Industrial applicability

 The symbol embedding device according to the present invention can embed a hidden symbol in an actual object or a virtual three-dimensional model, and thus is useful as a symbol embedding device using computer graphics technology. .

Claims

The scope of the claims  [1] A setting means for setting a polygon mesh representing a surface shape of an object having uneven surfaces repeatedly formed in a virtual three-dimensional space;  A specifying means for specifying, as a specific polygon, a polygon located in an area for embedding a predetermined hidden pattern from among the polygons constituting the polygon mesh;  A symbol embedding program for causing a computer to function as changing means for changing the direction of the specific polygon so that a specular reflection direction with respect to light from a predetermined ray direction is directed to a predetermined line-of-sight direction. [2] The computer according to claim 1, wherein the computer is further caused to function as output means for outputting the 3D data defining the shape of the polygon mesh whose orientation has been changed by the changing means to the 3D modeling apparatus. Design embedding program. [3] an acquisition means for acquiring optical characteristics of the object;  3. The computer is further made to function as a rendering processing unit that renders a polygon mesh whose orientation has been changed by the changing unit, using the optical characteristics acquired by the acquiring unit. Design embedding program. 4. The design embedding program according to claim 3, wherein the acquisition unit acquires a bidirectional reflectance distribution function as the optical characteristic. [5] The design according to any one of [1] to [4], wherein the changing unit changes the direction of only the specific polygon whose direction change amount is a predetermined angle or less among the specific polygon. Embedded program. [6] The changing unit sets a direction that bisects the angle between the predetermined ray direction and the predetermined line-of-sight direction as a target direction, so that a normal vector of the specific polygon matches the target direction. The design embedding program according to claim 1, wherein the orientation of the specific polygon is changed. [7] The hidden symbol includes n (n is an integer of 2 or more) types of hidden symbol powers,  The specifying means specifies a specific polygon corresponding to each hidden symbol, The changing means includes a specific polygon corresponding to each hidden symbol so that a normal reflection direction with respect to light from a predetermined light direction corresponding to each hidden symbol is directed to the predetermined line-of-sight direction. The design embedding program according to any one of claims 1 to 6, wherein the orientation is changed.  [8] The hidden symbol includes n (n is an integer of 2 or more) types of hidden symbol powers,  The specifying means specifies a specific polygon corresponding to each hidden symbol,  The changing means changes the direction of the specific polygon corresponding to each hidden symbol so that the normal reflection direction with respect to light from the predetermined light direction corresponding to each hidden symbol is directed to the predetermined line-of-sight direction,  The rendering processing means sets the color of light from the light ray direction corresponding to each hidden symbol to a different color, and renders the polygon mesh whose direction has been changed by the changing means. 3. The pattern embedding program described in 3.  [9] A plurality of sample points are arranged in a virtual three-dimensional space, and the regular reflection direction of the light irradiated with the virtual light source force to each arranged sample point is calculated using the bidirectional reflectance distribution function of the object. The normal vector of each sample point is calculated from the calculated regular reflection direction and the incident direction of the light of the virtual light source power, and the height data of each sample point is calculated based on the calculated normal vector. 9. The design embedding program according to claim 1, further comprising a computer functioning as a polygon mesh generation means for generating the polygon mesh by calculation.  10. The design embedding program according to claim 1, wherein the object is an object having a wrinkle.  [11] A setting means for setting a polygon mesh representing a surface shape of an object having uneven surfaces repeatedly formed in a virtual three-dimensional space;  A specifying means for specifying, as a specific polygon, a polygon located in an area for embedding a predetermined hidden pattern from among the polygons constituting the polygon mesh;  A pattern embedding device comprising: changing means for changing the direction of the specific polygon so that a specular reflection direction with respect to light from a predetermined light direction is directed to a predetermined line-of-sight direction [12] a setting step in which a computer sets a polygon mesh representing a surface shape of an object having uneven surfaces repeatedly formed in a virtual three-dimensional space; A step of specifying a polygon located in an area for embedding a predetermined hidden pattern from among the polygons constituting the polygon mesh as a specific polygon; and a specular reflection direction with respect to light from a predetermined ray direction is a predetermined line of sight A design embedding method comprising: a change step for changing the orientation of the specific polygon so as to face the direction.