JPH011082A - Object image synthesis device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an object image synthesis device that synthesizes images for displaying objects.

Technology from Ctie] As a method of synthesizing digital images for displaying objects, there is a method called the ray search method. In this method, the path of the light ray from the light source to the viewpoint is traced in the opposite direction, a process is performed to determine the intersection between the light ray and the object, and the brightness of each pixel making up the image is calculated based on the result. An example of this ray search method is published by Information Processing Society of Japan, Volume 25, No. 6, Hiroshi Deguchi, Hitoshi Nishimura, Hiroshi Yoshimura, Toru Yoda, and Isao Shirakawa.

It is described in the paper "High-speed f-based method for image generation in the computer graphics system LI NKS-1" written by Hiroshi Omura.

In order to generate images quickly using such a ray search method, the space in which the object is defined is divided into multiple regions and each region is assigned to one computer.
A method has been proposed in which each computer processes the light rays passing through its assigned area. Details of this method can be found in Computer Graphics.
Graphics, Volume 18, No. 3, Mark Dippe, John Swensen, Paper "An Adaptive Subdivision Algorithm and
Parallel architecture for realistic image synthesis (^n A+Iaptive
5ubdivision＾Igorithm andP
Arallel＾architecture for R
realistic Image Synthesis)
It is described in J. In the above method, the space is first divided into a plurality of rectangular parallelepiped regions, and each region is assigned to one computer. Next, each computer stores data on objects included in the assigned rectangular parallelepiped area. Then, each computer performs an intersection determination process between a light ray passing through one assigned area and an object. Through this intersection determination processing, when the object and the light ray intersect, reflection and transmission processing on the object surface is performed. Information about rays that do not intersect objects within that region is transferred to computers assigned to adjacent regions. When performing such processing,
There may be considerable variation in the amount of processing performed by each computer. That is, a computer assigned to an area containing many objects has a very large amount of processing to do, while a computer assigned to an area containing no objects may not be able to process much at all.

In order to reduce such variations in load between computers, a method has been proposed in which the vertices of a region divided into rectangular parallelepipeds are arbitrarily moved to change the volume and shape of the region. That is, by moving the vertices, the amount of computer processing allocated to the region whose volume has decreased is reduced. Then, the processing for that amount is shared with the computer assigned to the area whose volume has increased due to the movement of the vertex. In this way, the load is redistributed among the computers.

[Problem that the invention seeks to solve]

In such conventional load redistribution methods, the shape of the region changes in various ways because the load is redistributed by moving the vertices of the region. That is, since the deformation is due to the movement of vertices, the shape of the region is kept as a hexahedron, but the orientation and shape of each boundary surface of the region can be arbitrary. This causes the following problems.

First, when transmitting light beam information to an adjacent divided region, the region to be transferred is determined by determining the intersection of the light beam with the boundary surface of the region.

However, since the orientation and shape of each boundary surface of the region are arbitrary, the processing amount of this intersection determination process becomes extremely large. Therefore, there is a problem that the overall processing time becomes slow.

Second, when the shape of a region is changed, information about objects included in the region must also be changed. In other words, in the case of a region whose volume has decreased, there is a possibility that some objects that were included in the region before the change are no longer included in the region after the change. In the case of an increased area, there is a possibility that a new object is included in that area.When changing object information like this,
Since the shapes of the regions vary, there is a problem in that the processing amount and processing time required to determine objects included in the regions become extremely large.

As described above, the conventional method of redistributing the load by moving the vertices of the area has the problem that the redistribution requires a very large amount of processing, and the effect of the redistribution cannot be sufficiently obtained.

An object of the present invention is to simplify the process of changing the area shape for load redistribution, thereby reducing the processing involved in changing the area shape and sufficiently increasing the effect of the redistribution. The present invention provides an object image synthesis device.

[Means for solving problems]

The object image synthesis device of the present invention divides a space in which the object is defined into an initial ray generation section that generates information on a plurality of rays passing through each pixel from a viewpoint, and an object information setting section that sets object information. The brightness of the pixel is calculated by performing an intersection determination process between a light ray passing through this area and an object included in the area. Consisting of a brightness calculation unit and an image storage unit that stores the brightness calculated by the brightness calculation unit as an image, the brightness calculation unit generates data by dividing the object definition space by a plane perpendicular to the coordinate axis. area information storage means for storing the range of the area in charge of the brightness calculation section out of a plurality of areas to be processed; Mutual communication between an area storage means, a load determination means for determining a load of the brightness calculation unit, an adjacent brightness calculation unit responsible for an area adjacent to the responsible area in a direction parallel to each coordinate axis, and the brightness calculation unit. By comparing the load of the adjacent brightness calculation unit obtained through the mutual communication means and the load of the brightness calculation unit, the area in charge of the brightness calculation unit is determined by each of the adjacent brightness calculation units. expansion determining means for determining whether or not to expand in the direction of, respectively, comparing the load of the adjacent brightness calculation section with the load of the brightness calculation section, and further comparing the range of the initial area stored in the initial area storage means. Reduction determining means for comparing the range of the assigned area stored in the area information storage means and determining whether or not to reduce the assigned area in the direction of each of the adjacent brightness calculation units based on the comparison results. and area changing means for changing the range of the area in its duty stored in the area information storage means based on the decisions made by the expansion determining means and the reduction determining means.

[Effect]

A load redistribution method in the present invention will be described. Each brightness calculation unit is assigned one of a plurality of areas generated by dividing the object definition space along a plane perpendicular to the coordinate axes as the area in charge of the brightness calculation unit. The range of this area in charge is stored in area information storage means provided in the brightness calculation section. Further, the range of the assigned area given as the initial value is stored in the initial area storage means as the initial area range of each brightness calculation section. Here, each coordinate axis (x, y,
The six brightness calculation units in charge of areas in the direction parallel to the z-axis are called adjacent brightness calculation units.

The load of each brightness calculation unit is determined by the load determination means and transferred to six adjacent brightness calculation units via the mutual communication means.

Next, the expansion determining means compares the load determined by the load determining means with the load of each of the six adjacent brightness calculation units obtained via the mutual communication means. If the load on this brightness calculation unit is smaller than the load on the adjacent brightness calculation unit,
When the absolute value of the difference between the two is larger than a given threshold value, it is determined that the area in charge of this brightness calculation unit is expanded in the direction of the area in charge of this adjacent brightness calculation unit. Furthermore, if the condition of the load comparison result does not hold, it is determined not to expand the area in charge of this brightness calculation unit in the direction of the area in charge of this adjacent brightness calculation unit. Such a determination is made in each direction of the area in charge of the six adjacent brightness calculation units.

At the same time, the reduction determining means compares the load determined by the load determining means with the loads of six adjacent brightness calculation units obtained via the mutual communication means.

Further, the reduction determining means compares the range of the initial area stored in the initial area storage means and the range of the area in charge stored in the area information storage means.

If the load of this brightness calculation unit is larger than the load of the adjacent brightness calculation unit, and the absolute value of the difference between the two is larger than the given threshold, then this It is decided to reduce the area in charge of the adjacent brightness calculation section. However, based on the comparison result between the assigned area and the initial area, if reducing the assigned area would result in the assigned area becoming smaller than the initial area, it is determined not to reduce the assigned area.

Also, if the conditions of the load comparison result do not hold, it is determined not to reduce the area in charge of this brightness calculation unit. Such a determination is made in each direction of the area in charge of the six adjacent brightness calculation units.

Finally, the area changing means changes the range of the area in its duty stored in the area information storage means in accordance with the decisions made by the expansion determining unit and the reduction determining unit, and executes expansion and reduction of the area in its duty.

In this way, the load is redistributed between the brightness calculation unit and its adjacent brightness calculation units by expanding or contracting the assigned area based on the load comparison results.

〔Example〕

FIGS. 1(a) and 1(b) are block diagrams showing an object image synthesizing apparatus as an embodiment of the present invention, and FIG. 1(a) is an overall block diagram showing the entire object image synthesizing apparatus. Figure 1(b)
FIG. 2 is a configuration diagram showing a detailed configuration of the brightness calculation section.

As shown in FIG. 1(a), an initial ray generating section 1 is provided which generates information on a plurality of rays passing through each pixel of an image to be synthesized from a preset viewpoint. Further, an object information setting section 2 is provided for setting information about the object to be displayed. Furthermore, taking charge of one region out of a plurality of regions generated by dividing the space in which the object is defined, and performing intersection determination processing between the light ray passing through this region and the object included in the assigned region. Accordingly, a plurality of brightness calculation units 3 are provided that calculate the brightness of each pixel. An image storage section 4 is provided to store the luminance calculated by the luminance calculation section 3 as an image. The image storage unit 4 sets all luminances to 0 before combining images. A connection line 5 is provided for transmitting information between the initial light generation section 1, the object information setting section 2, the plurality of brightness calculation sections 3, and the image storage section 4. An information input section 6 is provided via this connection line 5 for inputting information from, for example, a keyboard. As shown in FIG. 1(b), the brightness calculation unit 3 is provided with mutual communication means 31 that communicates with the brightness calculation units 3 in charge of areas adjacent in six directions. Further, a communication means 32 for communicating via the connection line 5 is provided. Furthermore, a connection line 101 is provided for transmitting information within the brightness calculation section 3.

FIG. 2 is an explanatory diagram showing a method of calculating the brightness I of the pixel p(i,j). As shown in FIG. 2, in the ray search method, from the light source to the pixel p(i).

Calculate the brightness of pixel p(i, j) by tracing the path of the ray in the opposite direction through j) to viewpoint E. Here, the brightness I of pixel p(i, j) is from pixel p(i, j
) is called the brightness of the light ray R generated in the opposite direction. The brightness of this light ray R is the intensity ■ of the light that passes through the pixel p(i, j) and enters the viewpoint E. The brightness I of the light ray R is calculated by the following formula.

I=ref ・I', +di f −(N−Rt,)−
ILref: Reflection coefficient of object O dif: Diffusion coefficient of object 0 1': Incident source intensity of I (Mandoryoku) IL: Incident intensity from light source N: Surface unit normal vector of object O R'': R Specular reflection direction vector RL: Direction vector of the light source To find these two incident light intensities I' and IL,
Two light rays R' and RL whose directions are R' and RL are generated starting from the intersection CP. Further, the coefficients of I' and It for determining the brightness factor are set as the attenuation rates G' and GL of the rays R' and RL.

That is, when the light ray R collides with the object O, it is attenuated and the light rays R' and RL are generated. These attenuation rates G' and GL are as follows: G'=G-ref GL =G-dif・(N-Rt,)G: Attenuation rate of light ray R (=1) These attenuation rates G' , GL, the brightness I of the ray R, that is, the pixel p (i.

The brightness I of j) is determined as follows.

I = G’・I”+GL・ENG.

In this way, when new rays R' and RL are generated,
Information about the ray R is no longer necessary.

Furthermore, as shown in FIG. 2, when the ray R° intersects the object O", rays R" and RL' are similarly generated.

These attenuation rates G'' and GL' are similarly calculated using the following equations.

G”=G’-re f’ m-1→.

GL' = G'・dif' ・ (N −RL
) ref': Reflection coefficient dif' of object ゛: Diffusion coefficient N゛ of object 0°: Unit normal vector of surface of object 0° RL': Direction vector of ray N As shown, attenuation rate G''・Gt ' is multiplied by the attenuation rate G'. However, the processing of the ray RL is different from that of the rays R and R'. When the ray RL intersects the object, the intersection point C
P becomes a shadow of the object and cannot receive the illuminating light of the ray. Therefore, the brightness IL of the light ray RL is zero.

If the light ray RL does not intersect any object, the brightness scale of the light ray RL will be the brightness of the light source. In this way, the light rays R and R' heading towards the object and the light ray RL heading towards the light source are handled differently, so it is necessary to distinguish between the types of light rays.

Therefore, a type C is set for the light ray R to distinguish the type of light ray. This type C is given a value of 1 when the ray R is directed toward an object and when it is directed toward the O1 light source.

As shown in FIG. 2, a ray of light directed toward an object generates a new ray of light directed toward the object each time it collides with an object. Therefore, in order to calculate the brightness I of one pixel p, many light rays may have to be processed. However, each time the light ray collides with an object, it is attenuated, so as the number of collisions increases, the effect of the light ray on the luminance (■) becomes almost negligible. Therefore, in order to limit the number of collisions of the ray R, a number T is set for the ray R. This number of times T
indicates the possible number of collisions of the ray R.

When a ray R with a number of times T collides with an object and a ray R° directed towards the object is generated, the number T' of the ray R' is (T-
1). If a ray R whose number of times T is 0 collides with an object, a ray R'' toward the object is not generated, but only a ray Rt toward the light source is generated.
In FIG. 2, there is only one light source LI, but if a plurality of light sources Ll (i=1.2, . . . ) exist, light rays directed toward all the light sources LI must be generated.

By the way, in the case of the light ray RL heading toward the light source, no new light ray is generated even if it intersects with an object, as described above, so
The number of times T as information about the light source RL has no meaning. Therefore, when a plurality of light sources Ll exist, the number i of the light source to which the light ray RL is directed is set as the number T of the light ray RL.

By setting the number of times T of the light rays RL in this manner, even if there are a plurality of light sources L+, the number i of the light source L1 to which each light ray RL is directed can be determined, so that processing can be performed correctly. Also, here, for simplicity, only reflection on the surface of the object was considered. If transmission through the object is also taken into consideration, it is sufficient to generate a ray in the transmission direction at the intersection of the object and the ray R. However, this type of light ray is a ray directed toward an object, and if it is processed in the same manner as the above-mentioned ray R°, the transmission of the object can be accurately expressed.

FIG. 3 is an explanatory diagram showing information on the light ray R that should be set when the light ray R is generated. When the ray R is generated as shown in FIG. 3, the information about the ray R is the starting point position coordinates (S,) of the half-line indicating the ray R.

S, , S2) and direction (dX, dy, d2) are set. Furthermore, the pixel p(i, j
) position (i, j) is also set as information on the ray R. Furthermore, the attenuation rate G of the light ray R, the number of times T of the light ray R, and the type C of the light ray R are also set as information about the light ray R.

FIG. 4 is an explanatory diagram for explaining the operation of the initial light beam generating section 1. As shown in FIG. 4, in the initial ray generating section 1, the starting point is the viewpoint E.

A ray R is generated on the extension of a half straight line passing through each pixel p (i, j) constituting the image (%P).
), the information input unit 6 inputs the position coordinates (E, , Ey) of the viewpoint E to the initial ray generating unit 1 .

E,) is input. Further, as information defining the image P to be synthesized, parameters indicating the plane and range of the image P are input from the information input unit 6. The initial light beam generating section 1 generates information about the light beam R based on these parameters. An example of a method for dyeing a half-line indicating this ray R is written by T. Whittea.
Communication of NCM
nicatiton of ACM), Vol. 23, No. 6, pp. 343-349, the article "An improved illumination model for shaping displays"
minatio[1Model forShaded
Display) J. Next, among the intersections between this half-line and the object definition space, the position coordinates (S, , Sy, S2) of the intersection closest to the viewpoint are determined. These position coordinates (S,,Sy,S2) become the starting point position coordinates (S,,S,,Sz) of the ray R. In other words, the position where the ray R first enters the object definition space is the position of the ray R. It becomes the starting point. Further, the direction from the starting point E toward the pixel p is the direction of the light ray R (d,, d,, d,). Furthermore, pixel p(i,
The position (i, j) of j) is the pixel position (i, j) of the ray R
is set as In the initial light beam generating section 1, the attenuation rate G of the generated light beam R is set to 1, that is, the light beam R is not attenuated at all. Further, as the number of times T, a constant value set in advance is given to the initial light beam generation section 1 from the information input section 6. Further, as type C, a value of O indicating a ray of light directed toward an object is given. In the initial light beam generation section 1, a light beam R having such information is generated corresponding to all the pixels p(i, j) of the image P, and is transferred to the brightness calculation section 3.

FIG. 5 is an explanatory diagram showing object information set in the object information setting section 2. As shown in FIG. To simplify the explanation, the displayed object will be limited to a sphere, but the same method can be used when displaying objects such as polyhedrons and free-form surfaces. As shown in FIG. 5, object information is input from the information input section 6 and set in the object information setting section 2. As shown in FIG. The information on object i that is set includes object number n1.n1 for distinguishing object i. The center coordinates of the sphere as an object (X,.

'/+ + Z+), radius 'l+diffusion coefficient dif+ indicating the material of the object, and reflection coefficient ref. Further, as information indicating the circumscribed area of the object i, the range of the smallest rectangular parallelepiped including the object is set.

FIG. 6 is an explanatory diagram showing a circumscribed area of a sphere as an object. As shown in FIG. 6, the circumscribed area of object i is the range in the X direction (X+-,
++) r It is a rectangular parallelepiped indicated by the range (Zl-, Z1+) in the z direction. These values are obtained using the following equations.

xl-: xl-rI X I+= X 1 + r I'/I-='/t r t3'
++=3'++r+ zl-=z, -r.

Z14=21+r+ FIG. 7 is an explanatory diagram showing light source information set in the object information setting section 2. To simplify the explanation, the explanation will be limited to point light sources, but the same procedure can be applied to various types of illumination light such as parallel rays and spotlights. As shown in FIG. 7, information on a light source for illuminating an object is input from the information input section 6 and set in the object information setting section 2. The information on the light source that is set is the position coordinates (Xl, '/+, Zl) of the point light source i and the brightness ILI of the light source. This brightness ILI is a real value between 0 and 1. The value of the brightness ILI indicates the brightness of the light source, and when it is 1, it is the brightest, and when it is 0, it is a completely dark light source. The object information and light source information thus set are transmitted from the object information setting section 2 to the brightness calculation section 3 via the connection line 5.

FIG. 8 is an explanatory diagram showing a method of combining a plurality of brightness calculation units 3 into a three-dimensional array. As shown in FIG. 8, the brightness calculation units 3 are connected in a three-dimensional array via mutual communication means 31 provided within the brightness calculation units 3. That is, each brightness calculation unit 3 is connected to the brightness calculation units 3 on both sides in the x, y, and z directions, and these brightness calculation units 3
information can be mutually transmitted. Here, x, y
, the a, b, and c-th brightness calculation units 3 in the z direction are (a, b,
c) If we call it the brightness calculation unit 3, (a, b, c)
The brightness calculation unit 3 calculates (a-1°b, c), (a+
1. b, c), (a, b-1゜c),
(a, b+1. c), <a, b, c-
1>(a, b, c+l) Connected to the brightness calculation unit 3. Further, the brightness calculation units 3 are arranged in A, B, and C pieces in the x, y, and z directions in the figure, respectively, and the total number of brightness calculation units 3 is as follows: D=A-B-C.

FIG. 9 is an explanatory diagram showing a method of dividing a space defining an object into areas S assigned to each brightness calculation unit 3. As shown in FIG.

The object definition space is divided into a plurality of rectangular parallelepiped-shaped regions by planes perpendicular to one of the y and z coordinate axes.

In this case, the area is divided into five so that the number of areas in the X direction is A, the number of areas in the X direction is B, and the number of areas in the Z direction is C. And (a.

b, c) In the brightness calculation unit 3, the 8th in the X direction, the 5th in the X direction
Allocate the 0th area in the 2nd direction. All the areas thus divided are each divided into one brightness calculation unit 3.
can be assigned to Moreover, by performing such allocation, the brightness calculation units 3 connected via the mutual communication means 31 are respectively in charge of adjacent areas.

10 and 11 are explanatory diagrams showing the contents of area information indicating the area S in charge of the brightness calculation unit 3.

As shown in FIG. 10, the area information storage means 33 provided in the brightness calculation unit 3 stores the area S of the brightness calculation unit 3.
Area information indicating the area is stored. This area information includes:
The values of (a, b, c) indicating the number in the x, y, and z directions, and the range of the assigned area S in the x, y, and z directions (x-1X, >, < y-, y-ya), (z-, z-ya)
is memorized. In addition, the initial values of these area information are
This is stored in the initial area storage means 40 as the range of the initial area So of each brightness calculation unit 3. Further, in the brightness calculation units 3 existing on the outer periphery of the three-dimensional array, the brightness calculation units 3 may not be connected by the mutual communication means 31. Therefore, in each direction connected by the mutual communication means 31,
Whether the brightness calculation section 3 is actually connected or not is stored in the area information storage means 33 as presence/absence information. These area information are input from the information input means 6 and transmitted to each brightness calculation section 3.

FIG. 12 is an explanatory diagram showing the process of transferring information on the light ray R from the initial light generation section 1 to the brightness calculation section 3. As shown in FIG.
will be transferred all at once.

Information on the light ray R transferred from the initial light generation section 1 is inputted to the light ray information determination means 37 provided in each brightness calculation section 3 via the communication means 32. At the same time, the information on the assigned area S stored in the area information storage section 33 is read out by the light beam information determining means 37. The starting point position coordinates (SX, S, , S,) of the input light ray R are set to the position where the light ray R first enters the object definition space. Therefore, if this starting point position coordinate (SX).

If S,,S,> is included in the assigned area S, then the ray I(
will pass through the assigned area S first. Therefore, the light ray information determining means 37 determines the starting point position coordinates (SX
, Sy, Sz) and the range of the responsible area S (x-, X+),
(y-,3'+>.

(z-, z,) are compared.

If all of the three conditional expressions X-≦S Contains
The light ray R will first pass through the assigned area S. In this case, the information on the ray R is transferred from the ray information determining means 37 to the ray information storage means 34 and stored therein. Also, if any of these conditional expressions does not hold, the ray R
This means that the light is first incident on another assigned area S'.

Therefore, information on the light ray R is not stored in this brightness calculation section 3.

Through the above processing, information on the light ray R generated by the initial light generation section 1 is stored in the light ray information storage means 34 of the brightness calculation section 3 which is in charge of the first incident area.

FIG. 13 is an explanatory diagram showing a process of storing object information and light source information from the object information setting section 2 in the object information storage means 35 and light source information storage means 36 provided in the brightness calculation section 3. As shown in FIG. 13, all the object information and light source information stored in the object information setting section 2 are transferred to all the brightness calculation sections 3 via the connection line 5. The light source information storage means 36 provided in the brightness calculation section 3 stores all the light source information transferred via the communication means 32. The object information storage means 38 provided in the brightness calculation section 3 stores all the object information transferred via the communication means 32.

FIG. 14 is an explanatory diagram showing the process of changing the area S in its duty by the brightness calculation unit 3. This enlargement process of the assigned area S is performed by moving the boundary surface of the assigned area S in parallel. As shown in FIG. 14, the load determination means 43 provided in the brightness calculation section 3 determines the number of light rays R stored in the light beam information storage means 37 as the load F of the brightness calculation section 3. In addition,
Although such a load determination method is used here for the sake of simplicity of explanation, various other load determination methods are also possible. Even if a method other than this is used, the processing can be performed in the same way as in the case of the above method. The load on each brightness calculation unit 3 may be determined based on these values. The load F determined by the load determining means 43 in this way is
1, x- of the brightness calculation unit 3.

X·, y−, y·, z−, z+ Brightness calculation unit 3 (x−), (x+), (y−) connected in the force direction.

(y+), (z-), and (z+), respectively. Then, the enlargement determining means 44 determines the brightness calculation unit 3 (x
-), (x+), (y-), (y+).

Loads F (x-), F (x+) transmitted from (z-), (z+) via the mutual communication means 31.

F (y-), F (y+), F (z-),
F (z,) and the load F of the brightness calculation unit 3 are compared. Based on these comparison results, X-, X+.

y:, y, 2-. In each direction, the 2+ direction, whether or not to expand the assigned area S is determined as follows. However, K is an integer from 1 to 6, and from 1 to X-, X+, and y-, respectively.

The directions of force are shown as y, z-, and z+.

When F (K)-F>TH, dF, (K)=1 Otherwise, dF, (K)=O TH: The positive threshold value dFl(K), which is set in advance through the information input section 6, is , indicates whether or not to expand the responsible area S in the direction shown by K. If the value dF1 (K) is 1, it will be expanded, and if the value apt (K) is 0, it will not be expanded. There is. The enlargement determining means 44 outputs these values dF and (K) to the area changing means 46. In response to the thus determined value dF, (K), if this value is 1, the area changing means 46 expands the range of the area S in charge.

The area changing means 46 first reads the range a(K) of the area S in its duty in the direction indicated by the value from the area information storage means 33 and stores it. For example, if the value K is 1, then
, and in the case of 2, read X+. Next, a new range a' (K) is determined as shown below.

When K=1.3.5, a' (K)=a (K)-dS When K=2.4.6, a' (K)=a (K) 10dS dS: Preliminarily input through the information input section 6 The set positive change amount The range a' (K) thus determined is written into the area information storage means 33 to expand the range of the area S in charge. Similarly, the reduction determination means 45 uses the brightness calculation unit 3 (x-)
, (x+), (y-).

(y+), (z-), (z+) to mutual communication means 3
The load F (K) (K=1゜2,・
. . , 6) and the load F of the brightness calculation unit 3 are compared. Then, the reduction determining means 45 determines the range a(K) of the area S in charge of the brightness calculation unit 3 in each direction indicated by the value.
is read out from the area information storage means 33. At the same time, the range a of the initial area So of the brightness calculation unit 3 in the direction indicated by the value.

(K) is read from the initial area storage means 40.

Then, these ranges a(K) and range aO(K) are compared. Here, the reason for comparing the range a(K) and the range a, )(K) is to prevent the assigned area S from being smaller than the initial area So in the direction indicated by the value. That is, a (K) ”ao (K
), the assigned area S is equal to the initial area So in the direction indicated by the value, so no reduction is performed. Also, when a(K)≠ao(K), the assigned area S is expanded in the direction indicated by the value, so even if it is reduced in the direction indicated by the value, it will be smaller than the initial area So. In this way, range a(K) and range ao(K)
Based on the comparison with , it is possible to prevent the assigned area S from being smaller than the initial area So in the direction indicated by the value.

Based on these comparison results, it is determined as follows whether or not to reduce the assigned area S in each direction indicated by the values.

FF (K)>TH and a (K)≠ao (K)
When dF2=1 Otherwise, dF2=O TH: Positive threshold value dF set in advance through the information input unit 6, (K) is whether to reduce the assigned area S in the direction indicated by the value. When the value dF2(K) is 1, it is reduced, and when the value dF2(K) is 0, it is not reduced. The reduction determining means 45 outputs these values dF2 (K) to the area changing means 46. In response to the value dFz(K) determined in this manner, if this value is 1, the area changing means 46 reduces the range of the area S in its duty.

The area changing means 46 first reads the range a(K) of the area S° in its duty in the direction indicated by the value from the area information storage means 33 and stores it. For example, if the value K is 1, then
- is read out, and in the case of 2, X+ is read out. Next, a new range a' (K) is determined as shown below.

When K=1.3.5, a'(K)''a (K) + dS When K=2.4.6, a' (K) = a (K) - dS dS: Set in advance through the information input section 6 The range a' (K) calculated in this way is written in the area information storage means 33, and the range of the area S in charge is reduced. , the number of objects included in each assigned area S and the number of light rays passing through can be increased or decreased, and the calculation amount of each brightness calculation unit 3 can be increased or decreased.At the same time, the adjacent areas in the expansion direction can be increased or decreased. It is possible to reduce the load on the adjacent brightness calculation section 3 which is responsible for this, and it is possible to increase the load on the adjacent brightness calculation section 3 which is responsible for areas adjacent to each other in the reduction direction. Appropriate load redistribution can be achieved.

FIGS. 15(a) and 15(b) are explanatory diagrams showing a method of transferring information on the light ray R between the brightness calculation units 3.

As shown in FIG. 15(a), changing the assigned area S causes the boundary surfaces of the areas to overlap. Also, Fig. 15 (b
), the connection between the luminance calculation units 3 via the mutual communication means is fixed.

Therefore, in the cases shown in FIGS. 15(a) and 15(b), information on the light ray R incident on the responsible area S is directly transmitted from the brightness calculation unit 3a via the mutual communication means 31. cannot be transferred to the brightness calculation unit 3b. Therefore,
Such information on the light ray R is first sent to the brightness calculation section 3. from,
It is transferred to the brightness calculation unit 3° via the mutual communication means 31.

The information on the transferred light ray R is once transferred to the brightness calculation unit 3.
The information is stored in the ray information storage means 34 at .

In order to perform such a transfer process, the information on the light ray R stored in the light ray information storage means 34 of each brightness calculation section 3 is first read out to the light ray information determination means 37. This light ray information determining means 37 determines the starting point position coordinates (S, , Sy, S
2), the range of the assigned area S read from the area information storage means 33 (x-, X+), (y-, y+)
, (z−・z+) and performs the following processing.

(2) When S x < x-, the information on the light ray R is transferred to the brightness calculation section 3 connected in one direction of X via the mutual communication means 31, and the process proceeds to (2).

(2) When SX≧X+, information on the light ray R is transferred to the brightness calculation unit 3 connected in the X+ force direction via the mutual communication means 31, and the process proceeds to (2).

(2) When S y < y-, the information on the light ray R is transferred to the brightness calculation section 3 connected in one direction (y) via the mutual communication means 31, and the process proceeds to (2).

(2) When Sy≧y+, the information on the light ray R is transferred to the brightness calculation unit 3 connected in the y+ force direction via the mutual communication means 31, and the process proceeds to (2).

(2) When S 2 < z-, the information on the light ray R is transferred to the brightness calculation unit 3 connected in one direction to the two through the mutual communication means 31, and the process proceeds to (2).

(2) When S2≧2+, information on the light ray R is transferred to the brightness calculation unit 3 connected in the 2+ direction via the mutual communication means 31, and the process proceeds to (2).

(2) End By transferring the information on the light ray R between the brightness calculation units 3 in this way, the information on the light ray R can be processed by the correct brightness calculation unit 3.

FIG. 16 is an explanatory diagram showing a method of calculating the brightness of each pixel by the process of determining the intersection between a light ray and an object in the brightness calculation unit 3. As shown in FIG. 16, the information on the light ray R stored in the G light ray information storage means 34 is first read out to the light ray information determination means 37. As a result of the judgment process in the light ray information judgment means 37, information on the light rays R that has not been transferred to the adjacent brightness calculation section 3 is sent to the intersection judgment means 39. This intersection determination means 39 detects the object included in the area S and the light ray R.
Performs intersection determination processing with For this purpose, the object information determining means 38 stores the area information storage means 33 in the range (
x-, X+), (y-.

y+ ), (z-, z+) and the range of the circumscribed area of each object i (xl-, xl+) + (3/+-+ 37
++) + (Zl-+71+) to determine whether each object i is included in the assigned area S.

FIGS. 17(a) and 17(b) show the area S in charge of the brightness calculation unit 3.
FIG. 4 is an explanatory diagram showing a comparison process between the object information and the circumscribed area of the object information. As shown in FIGS. 17(a) and (b), the responsible area S
When and the circumscribed area have no common part, at least one of the following conditional expressions holds true.

X-≧Xl+ 9 As a result, if they have a common part, it is determined that the object i is included in the assigned area S, and the three intersection determination means Information is transferred. If they do not have common parts, they will not be transferred.

Through the above processing, of the object information stored in the object detail storage means 35, only the object information included within the assigned area S is transferred from the object information determination means 38 to the intersection determination means 39. Then, the intersection determination means 39 performs an intersection determination process between the object i transferred from the object information determination means 38 and the ray R. As a result, for the ray R that does not intersect with the object, first the boundary surface of the area S in charge and the ray R The intersection of R is found. From this point of intersection, the region S' into which the light ray R will next enter is determined, and the direction in which the information of the light ray R should be transferred is determined. Information on the light ray R is transferred via the mutual communication means 31 to the brightness calculation unit 3 in the determined direction. At this time, the starting point position coordinates of the light rays are changed to the position coordinates of the obtained intersection point. As a result, the starting point position coordinates of the light ray R will be included in the area to which the light ray R should enter next. The information on the light beam R thus transferred is read out from the mutual communication means 31 and stored in the light beam information storage means 34. Also, if the ray R intersects the object, a new ray R′ or a new ray RL is generated from the ray R.
When the light beam R° and the light beam RL are generated, information on the light beam R° and the light beam RL is stored in the light beam information storage means 34. Such intersection determination processing is shown in each of the aforementioned papers and FIG. 2. When the brightness I of the light ray R is determined by this process, the brightness I is added to the pixel p (i, j) of the image storage unit 4 indicated by the information about the light ray R via the communication means 32. Ru.

The synthesis of the image P is completed when all the information on the light rays R stored in the light ray information storage means 34 of each brightness calculation section 3 has been processed by the above-described intersection determination process.

〔Effect of the invention〕

In the object image synthesis device of the present invention, the shape of the area in charge of each brightness calculation section is a rectangular parallelepiped, and each surface of the rectangular parallelepiped is perpendicular to the coordinate axis. Therefore, it is very easy to determine the intersection between the boundary surface of the assigned area and the light beam. Therefore, when a light beam passes through the assigned area, it is possible to determine the area to which the information of this light beam should be transferred with a much smaller amount of processing than in the past. Further, the shape of the assigned area is changed by moving the boundary surface perpendicular to each coordinate axis in a direction parallel to the coordinate axis. Therefore, even if the shape of the area in charge is changed, the area in charge is kept in the shape of a rectangular parallelepiped, so the above-mentioned effects are not impaired. In this way, since the amount of processing required when changing the shape of the assigned area is small, it is possible to sufficiently obtain the effect of redistributing the load of each brightness calculation unit by changing the shape of the assigned area.

[Brief explanation of drawings]

FIG. 1(a) is an overall configuration diagram showing the entire object image synthesis device, FIG. 1(b) is a configuration diagram showing the detailed configuration of its brightness calculation section, and FIG. An explanatory diagram showing how to calculate the luminance ■ of ray R.
An explanatory diagram showing information on the light ray R that should be set when .
Fig. 4 is an explanatory diagram for explaining the operation of the initial ray generating section 1, Fig. 5 is an explanatory diagram showing object information set in the object information setting section 2, and Fig. 6 is an explanatory diagram showing the circumference of a sphere as an object. FIG. 7 is an explanatory diagram showing information on the light source set in the object information setting section 2, and FIG. 8 is an explanatory diagram showing the area. FIG.
FIG. 9 is an explanatory diagram showing a method of combining in a dimensional array, FIG.
12 is an explanatory diagram showing the contents of area information indicating the area S in charge of the brightness calculation section 3. FIG. 13
The figure is an explanatory diagram showing a process of storing object information and light source information from the object information setting section 2 in the object information storage means 35 and light source information storage means 36 provided in the brightness calculation section 3, and FIG. 14 is a diagram of the brightness calculation section An explanatory diagram showing the change process of the responsible area S of No. 3,
FIGS. 15(a) and (b) are explanatory diagrams showing the method of transferring information on the ray R between the brightness calculation units 3, and FIG. 17(a) and 17(b) are explanatory diagrams showing the brightness calculation method, and are explanatory diagrams showing the comparison process between the area S in charge of the brightness calculation unit 3 and the circumscribed area of the object information.In the figure, 1.・Initial ray generation section, 2...Object information setting section, 3
．． 3a, 3b, 3C23d... Brightness calculation unit, 4...
Image storage section, 5... Connection line, 6... Information input section, 3
1... Mutual communication means, 32... Communication means, 33...
-Area information storage means, 34...Light information storage means, 3
5... Object information storage means, 36... Light source information storage means, 37... Light ray information determination means, 38... Object information determination means, 39... Intersection determination means, 40... Initial area Storage means, 43... Load determining means, 44... Enlargement determining means, 45... Reduction determining means, 46... Area changing means. Kaya 1 time ((1) 1st 1M (I=) $8 Figure Kaya 11th time /2 Figure Cα) (b) Kaya Is Figure Cha lA Figure

Claims (1)

[Claims] The above image is created using the ray tracing method, which traces the path of the light ray from the light source to the viewpoint in the opposite direction, performs a process to determine the intersection between the object and the light ray, and calculates the brightness of each pixel that makes up the image that should display the object. an initial ray generation unit that generates information on a plurality of rays passing through each pixel from the viewpoint in order to perform synthesis; an object information setting unit that sets information on the object;
By taking charge of one region out of a plurality of regions generated by dividing the space in which the object is defined, and performing intersection determination processing between a ray passing through this region and an object included in the said region. In an object image synthesis device comprising a plurality of brightness calculation units that calculate the brightness of the pixels, and an image storage unit that stores the brightness calculated by the brightness calculation units as the image, the brightness calculation unit includes the Area information storage means for storing the range of the area in charge of the brightness calculation section among a plurality of areas generated by dividing the object definition space by a plane perpendicular to the coordinate axis, and the range of the area in charge given as an initial value. initial area storage means for storing the range of the initial area of the brightness calculation unit; load determining means for determining the load of the brightness calculation unit; Comparing the load of the adjacent brightness calculation unit obtained through the mutual communication means and the load of the brightness calculation unit obtained through the mutual communication means between the adjacent brightness calculation unit and the brightness calculation unit, respectively, and the load of the brightness calculation unit, Expansion determining means for determining whether to expand the area in charge of the brightness calculation unit in the direction of the area in charge of each of the adjacent brightness calculation units, and comparing the load of the adjacent brightness calculation unit and the load of the brightness calculation unit. Furthermore, the range of the initial area stored in the initial area storage means is compared with the range of the area in charge stored in the area information storage means, and based on the results of these comparisons, the area in charge is adjusted to each adjacent brightness level. Reduction determining means for determining whether or not to reduce in the direction of the area in charge of the calculating section, and a range of the area in charge stored in the area information storage means based on the decisions of the expansion determining means and the reduction determining means. 1. An object image synthesis device comprising: a region changing means for changing an object image.