JP2957963B2 - Method and apparatus for creating simulated visual field database - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for efficiently creating a database for a model of a simulated field of view.

[0002]

2. Description of the Related Art In creating a database for visually displaying a shape model of a simulated visual field, a binary structure (Binary Space Partition plane) is used as a data structure so that a hidden relationship can be calculated on a video display at a high speed. Is used. It is known to use a separating surface to solve the problem of invisible. FIG. 2 shows an example of a model configured using a separation surface.
FIG. 2A shows data in which a separation plane is defined in advance.
(B) is a view of the assumed scene viewed from above. Separation planes S1, S2, S3, and S4 arrange models A, B, C, D, and E one by one in a space divided by them. It is set as follows. FIG. 2C shows a display example when viewed from a certain viewpoint direction, and FIG. 2D shows models A, B, C, and C which are arranged in the separation planes S1, S2, S3, and S4 and the space divided by them. D,
E is mathematically expressed by a binary tree.

When creating a simulated field of view, it is desired to automatically generate a separation plane. However, the automatic generation of the separation surface has the following difficulties.

(1) As the number of primitives (polygons) as elements constituting a model increases, the total number N of constituent vertices increases. Lower bound of complexity O of separation surface, it has been known to be a function of N ^2, a O (N ^2). Therefore, when the number N of all vertices constituting the model is large, the calculation amount O
(N ² ) increases and it takes time to endure use.

(2) When arranging the primitives, it is desirable to arrange them as evenly as possible on the left and right of the separation surface, but it is difficult to automate them.

[0006] For this reason, there has been a problem that the generation of the separation surface is performed only by "manual creation" and the efficiency of model creation is low.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for rapidly determining a separation plane between models of a simulated field of view.

[0008]

According to the present invention, there is provided a method for creating a simulated view database, comprising: a first step of providing models as a tree structure classified into at least two groups according to a space in which each model in the simulated view exists. From the terminal node of the tree structure to the topmost node in sequence, generation of a convex polyhedron of each model for the terminal node, generation of a convex polyhedron wrapping the models at the node for each node other than the terminal node, Or a second procedure for sequentially generating convex polyhedrons wrapping the convex polyhedrons at the node, and a convex polyhedron at each node generated by the second procedure from the top node to the terminal node of the tree structure sequentially For each interval, the X, Y, and Z axes are assumed to be the normals of the separation plane, and the edges of the convex polyhedron are projected onto the assumed normals. When a separation plane having a distance between the midpoints of end points close to each other is obtained, and the separation plane cannot be obtained, the direction of the edge of the convex polyhedron is assumed to be a normal line of the separation plane and the convex By projecting the edge of the polyhedron onto the assumed normal line, when the projected line segment can be divided into two, a separation plane whose distance is the midpoint of an end point close to each other is obtained, and the separation plane is obtained. When it is impossible, the normal of the surface constituting the convex polyhedron is assumed to be the normal of the separation surface, and the edge of the convex polyhedron is projected on the assumed normal. A separation plane having a distance between the midpoints of the adjacent end points of the minute and a third step of forming each of the models into a binary tree structure from the separation plane obtained from the highest node to the terminal node. is there.

In the database creation method, the convex polyhedron may be a convex polyhedron or a minimum rectangular parallelepiped which wraps the convex polyhedron with edges parallel to the X, Y, and Z axes.

A simulated view database creating apparatus according to the present invention inputs tree structure data obtained by classifying models into at least two groups according to a space where each model in the simulated view exists, and a node at the end of the tree structure From the top node to the top node in order, generation of a convex polyhedron of each model for the terminal node, generation of a convex polyhedron wrapping the models at the node for each node other than the terminal node,
Or, a convex polyhedron generating section for sequentially generating convex polyhedrons wrapping the convex polyhedrons at the node, and a convex polyhedron at each node generated by the convex polyhedron generating section, from the top node of the tree structure to the terminal node sequentially. For each interval, the length of a line segment where each edge of the convex polyhedron is projected on the X, Y, and Z axes, or the length of a line segment where each edge of the convex polyhedron is projected on an edge of the convex polyhedron, Or, each edge of the convex polyhedron is calculated by the span calculating unit that calculates the length of a line segment projected onto the normal of the surface constituting the convex polyhedron, and each line segment calculated by the span calculating unit is merged and continuously merged. A merging unit for calculating the position of an end point of a line segment to be divided; a separation plane position calculating unit for calculating a midpoint of an end point close to each other when two continuous line segments obtained from the merging unit are provided; Structure from the top to the end For each node follow up over de,
The span calculation unit, the merge unit, and the separation plane position calculation unit are controlled, and for each node, the length of the line segment projected on the X, Y, or Z axis by the span calculation unit, the line segment by the merge unit When the midpoint is obtained by the position calculation of the end point and the midpoint calculation by the separation plane position calculation unit, a plane perpendicular to the axis on which the edge of the convex polyhedron passes through the midpoint is set as the separation plane, and the span calculation is performed. Calculating the length of the line segment projected on the edge of the convex polyhedron by the span calculating unit, when the separation plane cannot be obtained through the calculation of the length of the line segment projected on the X, Y or Z axis by the unit; When the midpoint is obtained by the position calculation of the end point of the line segment by the merging unit and the midpoint calculation by the separation plane position calculation unit, a plane perpendicular to the projected edge of the convex polyhedron passing through the midpoint is separated. And the edge of the convex polyhedron by the span calculation unit. When the separation plane cannot be obtained through the calculation of the length of the line segment projected on the surface, the length calculation of the line segment projected on the normal of the surface constituting the convex polyhedron by the span calculation unit and the merging unit When the midpoint is obtained by the position calculation of the end point of the line segment and the midpoint calculation by the separation plane position calculation unit, a plane perpendicular to the normal line passing through the midpoint and projecting the edge of the convex polyhedron is defined as a separation plane. , And a control unit for converting each model into a binary tree structure.

In the above-mentioned database creation apparatus, the convex polyhedron may be a convex polyhedron or a minimum rectangular parallelepiped wrapping the convex polyhedron with edges parallel to the X, Y, and Z axes.

[0012]

In the method of creating a simulated visual field database, the following operation is performed. In the first procedure, a plurality of models existing in the simulated field of view are classified into at least two groups so as to exist in adjacent spaces. These models are given as tree-structured data.

In the second procedure, a convex polyhedron is generated as follows. First, a convex polyhedron is generated for the terminal node so as to wrap the terminal model. Next, for each node higher than the terminal end, a convex polyhedron enclosing the convex polyhedron generated at a node below the node is sequentially generated up to the highest node. At this time, in addition to the convex polyhedron, a minimum rectangular parallelepiped that wraps the convex polyhedron with edges parallel to the X, Y, and Z axes is generated. The convex polyhedron and the rectangular parallelepiped are used for setting a normal line for generating a separation plane described later.

In a third procedure, a normal to a separation plane is assumed for each node between the convex polyhedrons generated in the second procedure, and it is checked whether a separation plane giving the normal exists. If it exists, its position is determined, separation planes are obtained, and these separation planes and a model occupying one of the spaces divided by the separation planes are connected to a binary tree structure. It is assumed that the X-axis preset in the field of view to be simulated is the normal to the separation plane. The edges of the two convex polyhedrons are projected onto the assumed normal. Since one convex polyhedron has continuous edges, it is projected as one line segment on the normal line. When the two line segments generated by projecting the edges of the two convex polyhedrons become two line segments without overlapping each other, there is a separation surface separating the two convex polyhedrons. Can be confirmed, and by appropriately selecting the surface that gives the normal, the surface can be positioned between the two convex polyhedrons. On the other hand, when the respective two line segments generated by projecting the edges of the two convex polyhedrons overlap each other, the surface that gives the normal cannot be located in the middle of the two convex polyhedrons. There is no separation plane. In this way, it is checked whether a separation plane exists for the X axis. If the existence of the separation plane cannot be confirmed for the X axis at a certain node, the existence of the separation plane is confirmed using the Y axis as a normal line in the same manner as described above. Further, when the existence of the separation surface cannot be confirmed, the existence of the separation surface is similarly confirmed using the Z axis as a normal line.
In this way, it is checked whether a separation plane exists for any of the X, Y, and Z axes at a certain node. Each of the two projected line segments is 2
If it is a line segment of a book and the existence of a separation plane is confirmed,
The midpoint of the end point where the two line segments are close to each other is determined, and that point is defined as the distance d at which the separation plane is located. Therefore, a separation plane determined by the normal line n and the distance d is determined.

At a certain node, the X axis, Y axis, Z
If the existence of the separation plane cannot be confirmed for any of the axes, the direction of one edge forming the convex polyhedron at that node is assumed to be the normal of the separation plane at that node. The edges of the two convex polyhedrons are projected onto the assumed normal. As described above, each of two line segments generated by projecting the edges of the two convex polyhedrons is
Whether or not there is a separation plane with the direction of one edge as a normal line is determined based on whether or not they overlap each other. If it is not possible to confirm the existence of the separation plane in the direction of one edge at a certain node, the existence of the separation plane is confirmed in the same manner as described above using the direction of the other edge as a normal line. In this way, it is confirmed whether or not a separation plane exists at a certain node in the direction of any one of the edges constituting the convex polyhedron at the node. When the projected two line segments do not overlap each other and become two line segments, and the existence of the separation plane is confirmed, the midpoint of the end point where the two line segments are close to each other is determined. This point is defined as the distance d at which the separation plane is located. Therefore, a separation plane determined by the normal line n and the distance d is determined. If a separation plane exists, the existence of the separation plane is confirmed from the next node with respect to the X axis, the Y axis, or the Z axis.

At a certain node, the X axis, Y axis, Z
If none of the axes can confirm the existence of a separation surface and none of the edges that make up the convex polyhedron can confirm the existence of a separation surface, then if one of the surfaces that make up the convex polyhedron at that node, The normal is assumed to be the normal of the separation plane. The edges of the two convex polyhedrons are projected onto the assumed normal. As described above, it is determined whether or not a separation plane having the assumed normal exists by checking whether or not each of two line segments generated by projecting the edges of the two convex polyhedrons overlap each other. At one node,
If it is not possible to confirm the existence of the separation surface with respect to the normal line of a certain surface, the existence of the separation surface is confirmed in the same manner as described above using the normal line of the other surface as the normal line. In this way, it is confirmed whether or not a separation plane exists at a certain node in the normal direction of any one of the surfaces constituting the convex polyhedron at the node. When the projected two line segments do not overlap each other and become two line segments, and the existence of the separation plane is confirmed, the midpoint of the end point where the two line segments are close to each other is determined. This point is defined as the distance d at which the separation plane is located. Therefore, a separation plane determined by the normal line n and the distance d is determined.
If there is a separation plane, the next node starts with the X axis or Y
Confirm the existence of the separation plane about the axis or the Z axis.

In this manner, the confirmation of the separation plane is performed sequentially from the highest node to the last node.

By making the convex polyhedron generated in the second procedure a minimum rectangular parallelepiped wrapped by edges parallel to the X, Y, and Z axes, it becomes easy to confirm the existence of separation planes in the X, Y, and Z axes.

The simulated visual field database creating device operates as follows. In advance, tree-structured data in which the models are classified into at least two groups according to the space where each model exists in the simulated field of view is created.

The convex polyhedron generating unit receives the data of the tree structure, and uses the data to generate and generate a convex polyhedron of each model from the terminal node to the top node of the tree structure. For each of the other nodes, generation of a convex polyhedron wrapping the models at the node or generation of a convex polyhedron wrapping the convex polyhedrons at the node are sequentially performed.

The span calculation unit calculates, for each of the convex polyhedrons at each node of the tree structure from the top node to the terminal node of the tree structure, each edge of the convex polyhedron as X,
The length of a line segment projected on the Y and Z axes, or the length of a line segment where each edge of the convex polyhedron is projected on the edge of the convex polyhedron, or each edge of the convex polyhedron constitutes the convex polyhedron Calculate the length of the line segment projected on the normal of the surface to be drawn.

The merging unit merges the edges calculated by the span calculating unit and calculates the position of the end point of the continuous line segment.

The separation plane position calculation unit calculates the midpoint of end points that are close to each other when there are two continuous line segments obtained from the merge unit.

The control unit controls the span calculation unit, the merge unit, and the separation plane position calculation unit for each node by sequentially tracing the tree structure from the top to the bottom. This control is divided as follows by the projection to the normal by the span calculation. For each node, the length calculation of the line segment projected on the X, Y or Z axis by the span calculation unit, the calculation of the position of the end point of the line segment by the merge unit, and the calculation of the midpoint by the separation plane position calculation unit When the midpoint is obtained, a plane passing through the midpoint and perpendicular to the axis on which the edge of the convex polyhedron is projected is defined as a separation plane for the node. When a separation plane cannot be obtained through the span calculation unit, the span calculation unit calculates the length of the line segment projected on the edge of the convex polyhedron, the merge unit calculates the position of the end point of the line segment, and performs the separation. When the midpoint is obtained by the midpoint calculation by the surface position calculation unit, a plane passing through the midpoint and perpendicular to the edge on which the edge of the convex polyhedron is projected is set as a separation plane for the node. When a separation plane cannot be obtained through the span calculation unit, the span calculation unit calculates the length of the line segment projected to the normal of the surface constituting the convex polyhedron, and calculates the end point of the line segment by the merge unit. When the midpoint is obtained by the position calculation and the midpoint calculation by the separation plane position calculation unit, a plane passing through the midpoint and perpendicular to the normal on which the edge of the convex polyhedron is projected is defined as a separation plane for the node. These controls are sequentially performed from the highest node to the last node, and the obtained separation plane and each of the models are formed into a binary tree structure.

The convex polyhedron generated by the convex polyhedron generating section has X,
By using a minimum rectangular parallelepiped wrapped by edges parallel to the Y and Z axes, it becomes easy to confirm the existence of a separation plane for the X, Y and Z axes.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
1A is a flowchart illustrating a method for creating a simulated view database according to the present invention, FIG. 1B is a diagram illustrating a polytope tree, FIG. 1C is a diagram illustrating a binary tree, FIG.
(D) is a diagram illustrating the spatial arrangement of the separation surface. FIG.
In (a), the processing name of Gen_SO_All is given. This Gen_SO_All processing is performed by inputting a predetermined source shown in FIG. 3A and inputting a binary tree structure data as shown in FIG. 3B in which a model is connected to a final end with a separation surface corresponding to a node. What you get. FIG. 1A is roughly divided into a procedure for generating a polytope (convex polyhedron) indicated by 11 “Gen_Polytope” and a procedure for generating a separation plane indicated by 12 “Gen_SO”.

FIG. 4 is a functional block diagram illustrating an apparatus for creating a simulated visual field database according to the present invention. In FIG. 4, reference numeral 41 denotes a convex polyhedron generator, 42 denotes a span calculator,
3 is a merge unit, 44 is a separation plane position calculation unit, 45 is a control unit that controls the entire apparatus, and 46 is a storage unit.

First, a tree structure of a model existing in a simulated field of view is created in advance. This creation method will be described. First, classify the model at a large level. That is, the space in which the model exists is divided into two adjacent spaces, and the same number of models are selected to be connected to the respective nodes by branches. For example, consider obtaining a separation plane for the scene of FIG. 2C used in the description of the conventional technique. As shown in FIG. 3 (a), the nodes corresponding to the building layer and the terrain (terrain) layer are connected by two branches at the node of the highest hierarchy,
The nodes in the building layer connect models A, B, and C, and terr
The nodes of the ain (terrain) layer have a tree structure such that the models D and E are connected. The hierarchy and components are defined in accordance with the syntax shown in FIG. 5, and data described as source data is created. In the example, CPO
(Complex Object) indicates the beginning of the hierarchy. In FIG. 3A, the model group A,
B and C are, for example, buildings, and the model groups D and E are, for example, terrain. Since the model groups A, B, and C and the model groups D and E were arranged in such a positional relationship that they could be relatively easily divided into two, the hierarchy is defined by building (building) and terrain (terrain) in FIG. The components that belong to each level of the building layer and the terrain layer are specified in each model.

The present invention is to confirm whether a separation plane can exist corresponding to a predetermined node of the tree structure defined as above, and to define the separation plane. When it is not possible to confirm the existence of a separation plane in a predetermined direction at the node, assuming a separation plane in another predetermined direction,
When the separation surface is confirmed, the separation surface is set, and FIG.
Data of a binary tree structure is obtained as shown in FIG.

The tree-structured data is used by the convex polyhedron generator 41 to generate a convex polyhedron. The generation of this convex polyhedron is indicated by the “Gen_Polytope” 11 in FIG.
FIG. 6 shows the details of the procedure. When the tree structure of FIG. 3A is traced downward from the top and reaches the terminal node specified by the building layer (FIG. 6, 62), each of the models A and B belonging to the terminal node , Model C, a polytope (POLYTOPE, a convex polyhedron wrapping the polygons constituting the model, also simply referred to as a “convex polyhedron”) and a cuboid (BOUNDING BOX) are created (63). Next, the polytopes of the models A, B, and C connected to the building nodes are read out (64), and “MERGEPOLYTO” is read.
A new polytope is generated to include all of these polytopes in the “PE” (65).
turn ", the tree structure shown in FIG. 3A is traced downward, and when reaching the terminal node defined by the terrain (terrain) layer, the polytope for each of the models D and E belonging to the terminal node is determined. Next, the polytopes of the models D and E connected to the terrain node are read out (FIGS. 6, 63 and 64), and "MERGE P
A new polytope is generated so as to include the entirety of these polytopes in "OLYTOPE" (65). Further, recursive processing is performed by "Return", but all elements are completed only at the terminal node in the processing so far. 6, the process proceeds to “Polytope output” at 67 in “All elements end” at 61. In the embodiment, the layering is performed.
It is performed by a building layer and a terrain layer, and these are the end nodes. For example, when these layers are further classified and hierarchized, 62 in FIG.
In the “end node” determination process of “Gen_Polytop” in 66, it is determined that the node is not the end node.
e ", a recursive process is performed to generate a polytope in the same manner as described above. A schematic diagram of each of the polytope and the rectangular parallelepiped is shown in FIG.
(A) and (b) show. The data of the models A to E include the positions of vertices for each face of the polygon representing the geometric shape. Therefore, when each of the models A to E is not a convex polyhedron, a vertex of a surface that becomes a convex polyhedron is newly created from these data. The rectangular parallelepiped is a box that surrounds the convex polyhedron of each model with a minimum rectangular parallelepiped having edges parallel to the X, Y, and Z axes, and is created from the data of each of the models A to E or the data of the polytope. The X, Y, and Z axes are set in advance to a simulated field of view.

FIG. 8 (a) shows a detailed flow chart of the procedure of "POLYTOPE" 63 in FIG. 6, and FIG. 8 (b) shows a schematic diagram of polytope generation. In FIG. 8A, 8
For example, when two surfaces A and B forming a part of a model are in contact with each other as shown in FIG. 8B, spatial information of the surface A (a set of vertices forming the surface) ) And surface B
Is a process of reading the spatial information (a set of vertices constituting the surface). Reference numeral 82 denotes a process of generating a new surface C1 and a new surface C2 based on the information and generating a polytope C.

Also, 65 "MERGE POL" in FIG.
9 (a) shows a detailed flow chart of the YTOPE "procedure, and FIG. 9 (b) shows a schematic diagram of the polytope merge. In FIG. 9 (a), reference numeral 91 denotes, for example, two polytopes A and a polytope. When B and B are arranged as shown in FIG. 9B, a process of reading out information on the polytope A (a set of vertices forming the surface) and information on the polytope B (a set of vertices forming the surface) Reference numeral 92 denotes a process of generating a polytope C by generating new planes C1, C2, and C3 so that the polytope A and the polytope B wrap each other based on the information.

In this manner, "G" of 11 in FIG.
The polytope generated in “en_Polytope” is arranged at a position indicated by a black circle in each hierarchy as shown in FIG. 1B in accordance with the data of the tree structure to form a polytope tree. Next, FIG. 12 “Gen_SO”
In the process of the above, each node of the polytope tree is traced from top to bottom to generate a separation plane (SO plane) for each node, and these are connected to form a binary tree. FIG. 10 shows details of the process of “Gen_SO”. “Gen_SOX” 101 in FIG. 10
Then, the existence of a separation plane (SO plane) for each node is confirmed and its position is determined. In “SO_EXIS” of 102, SO
When it is determined that there is no plane,
When an error is caused by “r_EXIT” and the SO plane can be obtained at a certain node, “En” in 104
If it is not the last node in “d of Node”, 1
05 in “Gen_SO” by recursive processing
The processing of "en_SO" is performed, and the processing exits from this processing when the processing of the final node is completed. The processing reaches "End" in FIG. 1A and the processing ends.

First, a layer in which a polytope created by merging three models A, B, and C and a polytope created by merging two models D and E exists (for example, FIG. 1 ( b) In the layer where the black circles are arranged at the upper stage), SO planes are generated for those polytopes, and it is confirmed that the SO plane exists between the polytopes, and the SO plane is used as the first plane S1 to form a binary tree. In the storage unit 46 of FIG. Next, an SO plane is generated for the polytope of the models A, B, and C in the layer where the three models are present, and the existence thereof is confirmed. At that time, since there are three models A, B, and C, three faces may be generated. Due to the nature of the binary tree, no more than two branches are connected to one node, so if the existence of a surface between models A and B can be confirmed, it corresponds to the node that connects that surface to the previously generated plane S1. Is assumed to be a plane S2. If you can't confirm, use Model BC
Alternatively, the existence of a surface is confirmed between ACs. If the existence of a surface between two certain models, for example, the model AB, can be confirmed, it is confirmed whether a surface exists between the models AC or BC. Following confirmation of the plane between models AB, model A
When a plane is confirmed between C, the plane is defined as S3. In this case, what is connected to the plane S2 is the model B
And a plane S3 as a node. The model AC is connected to the plane S3. If a plane cannot be confirmed between the models AC following the confirmation of the plane between the models AB and a plane can be confirmed between the models BC, the plane is defined as S3. In this case, what is connected to the plane plane S2 is the model A and a plane S3 as a node, and the model BC is connected to the plane S3. If no plane exists between the models AB for the plane S2 as described above, the model BC or the model A
The existence of the plane S2 is confirmed between C, and the plane S3 and the model connected to the plane S2 and the model connected to the plane S3 are set as a binary tree. Next, it is confirmed whether the SO plane exists between the polytopes of the model in the layer where the model DE exists. When an SO plane exists, the plane S4 is made to correspond to a node connected to the plane S1, and is made to correspond to a binary tree. When the planes S2 and S3 are generated for the polytopes of the models A, B and C, the polytope tree of FIG. 1B includes the polytopes of the models D and E. 104 from “End of Node” to 105 from “Gen_S”
Move to O "and perform recursive processing. Models A, B, C, D, E
Are connected to a binary tree as shown in FIG. 1C with respect to the plane, the “End of No.” 104 in FIG.
de ”exits“ EXIT. ”In this way, the data of the models A, B, C, D, and E are formed into a binary tree, and
The data is stored in the storage unit 46 of FIG. 4 and is used as a database for simulating the visual field.

The procedure for confirming the existence of one plane, that is, the details of “SO_EXIS” 102 in FIG.
It is shown in FIG. The control unit 45 generates an SO plane with the X, Y, and Z axes virtually existing in the simulated field of view as normals (111). The span calculator 42 determines which of these axes is the normal n. First, it is assumed that the X axis is the normal (114, 117). Now, when processing is performed on each of the polytopes of the hierarchy for which the existence of the SO plane is to be confirmed, that is, the polytopes of the two models A and B are sequentially processed from the top and reach the lowest hierarchy. The distance djk from the origin when each vertex of each polytope is projected on the normal is obtained for each polytope (FIGS. 11, 118, 119, and 1110). When the distance djk of all vertices is obtained for one polytope, a set (span (SPAN)) of the longest distance djMIN and the shortest distance djMAX from the origin is obtained (1111). FIG. 12 (a)
Shows the span generation. The longest distance djM when all polytopes are projected to the normal for a certain hierarchy
When IN and the shortest distance djMAX are obtained, the shortest distance djMIN of the span
The spans are sorted in order (1112). Then, the arranged spans are considered as line segments. Minimum shortest distance drM
When another shortest distance dsMIN is arranged next to IN, since the line segment having the shortest distance dsMIN overlaps with the line segment having another shortest distance drMIN, the number of the shortest distance is sequentially determined from the shortest distance to the shortest distance. When the numbers of the longest distances are counted and they are the same, it can be said that the position is the end of the line segment having the overlapping portion. When the longest distance follows the shortest distance, the line segments do not overlap, and the projection of the polytope to the normal does not overlap. Therefore, the merging unit 5 merges the spans so that each span having an overlapping portion becomes one continuous span (1113). FIG. 12B shows the result of span merging. When the shortest distance appears next to the longest distance between the spans as a result of merging, it is known that these do not overlap each other when the polytope is projected to the normal line, and the two-minute division is possible (1114). Next, the separation plane position calculation unit 44 determines, in the merge unit 43, adjacent end points of each span determined to be bisected, that is, the smaller longest distance DmMAX.
Intermediate distance d = (D
mMAX + Dm + 1MIN) / 2, the distance d is defined as the position on the SO plane, and the normal line n is defined as the normal line np. FIG. 12C shows the derivation of the midpoint.

As a result of merging the spans at 1113 in FIG. 11, the shortest distance DMIN and the longest distance DMAX are each one at one location, so that it is determined at 1114 that two minutes are not possible. In this case, the process returns to step 111, and since the X axis is used based on the history of the previous processing, a normal is generated using the Y axis, and processing is performed in the same manner as described above. If it is determined that it is not possible to perform two minutes in this process, the process returns to step 111, and since the X-axis and Y-axis are used from the history of the previous process, a normal is generated using the Z-axis, and the process is performed in the same manner as described above. . If it is determined that it is not possible to perform two minutes in this process, the process returns to step 111, and since the X axis, Y axis, and Z axis are used based on the history of the previous process, no normal is generated using the axis. Then, proceeding to 112, one of the polytopes in the hierarchy for which the existence of the SO plane is to be confirmed is sequentially and selectively selected, and one of the constituent edges thereof is selectively and sequentially selected, and the direction of this edge is set to the normal line. Is generated, and the same processing as described above is performed. At 1114, the polytope is 2 with respect to the SO plane whose normal is the direction of an edge.
If it is confirmed that they are separated, the position and the normal n are obtained at 1115, and (d, n) is defined as the plane. n is a vector. If it is determined in step 1114 that two minutes are not possible, the process returns to step 112 via step 111, and an edge (hereinafter, referred to as a first edge) having a certain polytope (referred to as a first polytope) from the history of the previous processing is determined. Since it is used, a normal is generated using the second edge, and processing is performed in the same manner as described above.
If it is determined that the processing is not possible for two minutes in this processing, the process returns to 112, and since the first and second edges are used from the history of the previous processing, a normal is generated using the third edge. The same processing is performed. In this way, it is determined whether or not the polytope is divided into two minutes.
If it is not possible to divide the first polytope by using all the edges, the processing is performed by using the edges of the second polytope sequentially. If the polytope cannot be divided into two even if the edge of the polytope of the hierarchy for which the existence of the SO plane is to be confirmed is used, the process proceeds from 1114 to 111, via 111 and 112. At step 113, one of the polytopes of the hierarchy for which the existence of the SO plane is to be confirmed is sequentially and selectively selected, and one of the constituent planes is selectively and sequentially selected, and the normal of this plane is set as the normal. An SO plane (which is parallel to the plane) is generated and processed as described above. If it is confirmed at 1114 that the polytope is bisected on the SO plane parallel to a plane constituting the polytope, at 1115 its position and normal are obtained. If it is determined in step 1114 that it is not possible to perform two minutes, the process returns to 112 via 111, and a surface (hereinafter referred to as a first surface) having a certain polytope (referred to as a first polytope) from the history of the previous processing is used. Second
A normal is generated by using the surface of (1), and the same processing is performed as described above. If it is determined that it is not possible to perform two minutes in this process, the process returns to 113, and since the first and second surfaces are used based on the history of the previous process, a normal is generated using the third surface. The same processing is performed. In this way, it is determined whether the polytope is divided into two. If it is not possible to return to two, the process returns to step 113. The treatment is performed using the surfaces of the polytope No. 2 sequentially. If the polytope cannot be divided into two by using the surface of the polytope of the hierarchy for which the existence of the SO plane is to be confirmed, the data is passed from 1114 to 111 and 112 to 113 at 11.
The process proceeds to “Error_Exit” of No. 16 and ends as automatic selection disabled.

As described above, by layering in advance as shown in FIG. 5, the calculation of the separation plane becomes practically practical. The lower limit of the separation plane calculation time after hierarchization is as follows.

As described in the prior art, when the number of points is p, the amount of calculation is O (p ² ). Therefore, one cluster (a cluster is a group separated in advance, and ) And terrain (terrain).) The amount of calculation in) is O (n ² ). Where n
Is the average number of vertices in each hierarchy. If N is the number of all vertices constituting a model to be calculated (including a polytope of a primitive model and a polytope enclosing a plurality of polytopes), the number of clusters is N / n.
Then, the amount of calculation in all clusters is (N / n) O (n ² )
If the cluster is regarded as a vertex,
((N / n) ² )

[0039]

O (N ² / n ² ) + (N / n) O (n ² ) (1)

## EQU4 ## The lower limit O (N ² ) of the conventional separation surface calculation time without hierarchization, and the calculation lower limit O (N ² / n ² ) + (N / n) O (n ² ) when hierarchization is performed as in the present invention. Is shown in FIG. As shown in FIG. 13, as N increases, that is, as the number of models increases, the superiority of the two becomes remarkable, and the calculation amount of the present invention decreases.

[0041]

According to the present invention, since a model is hierarchized to generate a separation plane, a complicated problem can be handled as a hierarchized "part" problem, so that simplification and high-speed processing can be realized.

Thus, the database of the separation plane and the model can be created in a time that can be practically used.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a method for creating a simulated visual field database according to the present invention.

FIG. 2 is a diagram illustrating an example of a model configured using a separation surface.

FIG. 3 is a diagram illustrating tree structure source data and a binary tree structure;

FIG. 4 is a functional block diagram illustrating a simulated visual field database creation device according to the present invention.

FIG. 5 is a diagram illustrating the syntax of source data.

FIG. 6 is a flowchart illustrating generation of a polytope tree.

FIG. 7 is a diagram illustrating a polytope and a rectangular parallelepiped.

FIG. 8 is a flowchart illustrating generation of a polytope.

FIG. 9 is a diagram illustrating the generation (merging) of a new polytope including polytopes.

FIG. 10 is a flowchart illustrating generation of a separation plane (SO plane).

FIG. 11 is a flowchart illustrating details of generation of a separation plane (SO plane).

FIG. 12 is a diagram illustrating generation of a projected span, merging, and derivation of a midpoint.

FIG. 13 is a diagram for comparing and explaining the amount of calculation.

[Explanation of symbols]

41: convex polyhedron generation unit, 42: span calculation unit, 43: merge unit, 44: separation plane position calculation unit, 45: control unit, 46
... storage unit.

Claims (4)

(57) [Claims] 1. A first procedure for giving a model as a tree structure classified into at least two groups according to a space in which each model in a simulated view exists, and from a terminal node of the tree structure to an uppermost node sequentially Generation of convex polyhedron of each model for terminal nodes,
A second procedure for sequentially generating, for each node other than the terminal node, a convex polyhedron enclosing the models at the node or generating a convex polyhedron enclosing the convex polyhedra at the node; From the upper node to the terminal node,
For each of the convex polyhedrons at each node generated by the second procedure, the X, Y, and Z axes are assumed to be the normals of the separation plane, and the edges of the convex polyhedron are projected onto the assumed normals. When the line segment can be divided into two, a separation plane having a distance between the midpoints of the end points close to each other is obtained. When the separation plane cannot be obtained, the direction of the edge of the convex polyhedron is determined by the normal to the separation plane. Assuming that the edge of the convex polyhedron is projected onto the assumed normal, and when the projected line segment can be divided into two, a separation plane having a distance between the midpoints of the end points close to each other is obtained. When the surface cannot be obtained, the normal of the surface constituting the convex polyhedron is assumed to be the normal of the separation surface, and the edge of the convex polyhedron is projected on the assumed normal. When possible, a separation plane whose distance is the midpoint of the end points that are close to each other Because, third procedure database creating a simulated view, characterized in that it consists of a binary tree structure separating surface and the respective model obtained from the uppermost node to the end node. 2. The method according to claim 1, wherein the convex polyhedron is a convex polyhedron or a minimum rectangular parallelepiped wrapping the convex polyhedron with edges parallel to the X, Y, and Z axes. 3. Data of a tree structure in which models are classified into at least two groups according to a space where each model in the simulated field of view is present, and from the terminal node of the tree structure to the highest node in order, Convexes that sequentially generate a convex polyhedron of each model for a node, generate a convex polyhedron that wraps the models at the node for each node other than the terminal node, or generate a convex polyhedron that wraps the convex polyhedrons at the node. A polyhedron generator, from the top node of the tree structure to the terminal node sequentially
For each of the convex polyhedrons at each node generated by the convex polyhedron generating unit, the length of a line segment where each edge of the convex polyhedron is projected on the X, Y, and Z axes, or each edge of the convex polyhedron is the convex A span calculating unit that calculates the length of a line segment projected on an edge of the polyhedron, or the length of a line segment projected on the normal of a surface that constitutes the convex polyhedron at each edge of the convex polyhedron; A merging unit for merging each line segment calculated by the calculating unit to calculate the position of an end point of a continuous line segment; and an end point which is close to each other when the number of continuous line segments obtained from the merging unit is two. A separation plane position calculation unit that calculates a point, the tree structure is sequentially traced from the top to the last node, and for each node, the span calculation unit, the merge unit, and the separation plane position calculation unit are controlled, and for each node, X, Y or When the midpoint is obtained by calculating the length of the line segment projected on the Z axis, calculating the end point position of the line segment by the merging unit, and calculating the midpoint by the separation plane position calculating unit, the convex polyhedron passes through the midpoint. If a plane perpendicular to the axis on which the edge of is projected is defined as a separation plane, and the separation plane cannot be obtained through the calculation of the length of the line segment projected on the X, Y or Z axis by the span calculation unit, The calculation of the length of the line segment projected on the edge of the convex polyhedron by the span calculation unit, the calculation of the end point of the line segment by the merge unit, and the calculation of the midpoint by the separation plane position calculation unit. A plane perpendicular to the edge where the edge of the convex polyhedron passes through the midpoint is defined as a separation plane, and the separation plane cannot be obtained through the calculation of the length of the line segment projected on the edge of the convex polyhedron by the span calculator. In the case, a convex polyhedron is configured by the span calculation unit. When the midpoint is obtained by calculating the length of the line segment projected on the normal of the surface, calculating the end point position of the line segment by the merging unit, and calculating the midpoint by the separation plane position calculating unit, A plane perpendicular to the normal on which the edge of the convex polyhedron is projected is defined as a separation plane, and a separation plane obtained from the highest node to the terminal node and a control unit for forming each model into a binary tree structure. An apparatus for creating a simulated view database. 4. The simulated field of view database creating apparatus according to claim 3, wherein the convex polyhedron is a convex polyhedron or a minimum rectangular parallelepiped wrapping the convex polyhedron with edges parallel to the X, Y, and Z axes.