JPS63167987A - Object image composing device - Google Patents

Abstract

PURPOSE:To sufficiently reduce the variation processing of an area shape and to improve redistribution effect by performing expansion according to the comparison result between an in-charge area and a load, and redistributing a load among respective brightness calculation parts. CONSTITUTION:The load on each brightness calculation part 3 is determined by a load determining means 43 and transferred to respective adjustment brightness calculation part 3 through a mutual communication means 31. Expansion dertermining means 44 provided to the calculation parts 3 which receive it comparesa load determined by the means 43 with loads of the respective calculation part 3 obtained through the means 31 respectively. Then the means 44 determines whether or not the areas of the calculation parts 3 are expanded in the direction of the in-charge areas of the respective calculation part 3 according to the comparison results so that the loads of the calculation parts 3 are smoothed. An area expanding means 45 varies the ranges of the in-charge areas stored in an area information storage means 33 according to the determination of the means 44 expand the in-charge areas.

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.

[Conventional technology]

A method called the ray search method is used to synthesize digital images for displaying objects.

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 described in Information Processing Society of Japan Journal, Vol.
5, No. 6, Hiroshi Deguchi, Hitoshi Nishimura, Hiroshi Yoshimura, Toru Kawada, Isao Shira, and Hiroshi Omura, in the paper ``Method for accelerating image generation in the computer graphics system LINKS-1''.

In order to perform image generation using such a ray search method at high speed, the space in which the object is defined is divided into multiple regions, each region is assigned to one computer, and each computer is Methods have been proposed for processing light rays passing through a region. Details of this method can be found in Computer Graphics (Col1pute
r Grapbics), Volume 18, No. 3, Mark Dippe, John Swensen, paper "An Adaptive Subdivision Algorithm"
and parallel architecture for realistic image synthesis (An Adaptive
e5ubdivisionAlgorithsan
d Parallel＾rcbitecture fo
r Realistic Im-age 5ynthe
sis)”.

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 a process of determining the intersection between a light beam passing through the 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 is a possibility that there will 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 ray information from a divided region to an adjacent region, the region to be transferred is determined by determining the intersection between the boundary surface of the region and the light ray.

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.

That is, 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. Furthermore, in the case of a region whose volume has increased, there is a possibility that a new object will be included in that region.

Even when such object information is changed, since the shapes of the regions vary, there is a problem in that the processing amount and processing time required for processing to determine objects included in the region become extremely large.

In this way, the conventional method of redistributing the load by moving the vertices of the area has the problem that the redistribution requires a large amount of processing, and the effect of the redistribution cannot be fully obtained. .

The present invention simplifies 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 redistribution. The purpose of the present invention is to provide an image synthesis device.

[Means for solving problems]

The object image synthesis device of the present invention includes an initial ray generation section that generates information on a plurality of rays passing through each pixel from a viewpoint, an object information setting section that sets information about the object, and a space in which the object is defined. A plurality of pixels in which the brightness of the pixel is calculated by performing intersection determination processing between a light ray passing through this region and an object included in the region in charge of one region among a plurality of regions generated by dividing the region. a brightness calculation unit, and an image storage unit that stores the brightness calculated by the brightness calculation unit as an image, and each of the brightness calculation units is generated by dividing the object definition space by a plane perpendicular to the coordinate axis. area information storage means for storing the range of one of the plurality of areas in charge; load determining means for determining the load of the brightness calculation section; A mutual communication means that performs mutual communication with an adjacent brightness calculation unit in charge of an adjacent area, and calculates the adjacent brightness by comparing the load of the adjacent brightness calculation unit obtained through the mutual communication means with its own load. expansion determining means for determining whether or not to expand the area in charge in the direction of the area in charge of the calculation unit; Area expanding means for changing the range of the area in charge is provided.

[Effect]

A method for redistributing the load of the luminance calculation unit in the present invention will be described. Each brightness calculation unit is assigned one area out 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 that brightness calculation unit. The range of this area in charge is stored in area information storage means provided in the brightness calculation section.

Here, a brightness calculation unit in charge of an area adjacent to the area in charge of this brightness calculation unit is called an adjacent brightness calculation unit.

The load of each brightness calculation section is determined by the load determining means and transferred to each adjacent brightness calculation section via the mutual communication means. The enlargement determining means provided in the brightness calculating section that receives these compares the load determined by the load determining means with the load of each adjacent brightness calculating section obtained via the mutual communication means. Based on these comparison results, the expansion determining means determines whether or not to expand the area of this brightness calculation unit in the direction of the area in charge of each adjacent brightness calculation unit so that the load on each brightness calculation unit is smoothed. Decide each.

Finally, the area expansion means changes the range of the area in charge stored in the area information storage means according to the determination by the expansion determination means,
Execute expansion of the area of responsibility.

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

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An object image synthesis apparatus as an embodiment of the present invention will be described below with reference to the drawings. In order to simplify the explanation, the explanation will be limited to the load redistribution processing between the luminance calculation units adjacent in the direction parallel to a specific coordinate axis, but this does not impair film properties.

FIGS. 1(a) and 1(b) are block diagrams showing an object image synthesis device as an embodiment of the present invention, and FIG. 1(a) is a
Figure 1 (b) is an overall configuration diagram showing the entire object image synthesis device.
) is a configuration diagram showing the detailed configuration of the brightness calculation section 3. 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. This brightness calculation section 3
An image storage unit 4 that stores the calculated brightness as an image.
is provided. The image storage unit 4 sets all luminances to O before combining images.

These initial ray generating section 1 and object information setting section 2
A connection line 5 is provided for transmitting information between the plurality of brightness calculation units 3 and the image storage unit 4. This connection! !
An information input unit 6 is provided for inputting information via a keyboard, for example.

As shown in FIG. 1(b), the brightness calculation section 3 is provided with mutual communication means 31 that communicates with the brightness calculation sections 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 a pixel p (i, j>). As shown in the figure, a light source is used, objects 0, O', and a viewpoint E are arranged. As shown, in the ray search method, the path of the ray from the light source through the pixel p (i,
, j) is calculated. Here, pixel p(i, j
) will be called the brightness of the light ray R generated in the opposite direction from the viewpoint E through the pixel p(i, j>.
In the figures and the following description, R, R', RL, etc. indicate light rays, i, f, , 窠, etc. indicate directions, and direction indicates the direction of the light ray R, and so on.

The once ■ of this ray R is the intensity ■ of the light that passes through the pixel p(i, j> and enters the viewpoint E. The brightness factor of the ray R is
It is calculated using the following formula. (* indicates multiplication) I=ref*I' +dif* (r, r)*IL
ref: Reflection coefficient of object 0 dif: Diffusion coefficient of object O 1': Incident light intensity from direction f' IL: Incident light intensity from light source W: Unit normal vector of surface of object O r': r direction Direction vector of specular reflection ``: Direction vector of light source To find the intensities I' and IL of these two incident lights,
The direction is R, R starting from the intersection CP of the ray R and the object O.
Let's generate two rays R' and Rt that become L. In addition, the coefficients of I' and It for determining the brightness I are expressed as rays R' and R
The attenuation rate G' of L is set as GL. That is, the ray R is attenuated by colliding with the object O, and the ray R'
, Rt, are generated. These attenuation rates G',
GL is G'=G*ref GL =G*dif*(7'3"・1)G: Attenuation rate of ray R (=1). By using these attenuation rates G' and GL, The brightness I of the light ray R, that is, the brightness I of the pixel p(i, j>) is determined as follows.

I=G'*I' + GL*It In this way, when new rays R' and RL are generated, information on ray R is no longer necessary.

Furthermore, as shown in Fig. 2, when the ray R' intersects the object 0', rays R'' and RL' are generated in the same way.The attenuation rate G''+GL' of these is similarly given by Calculated by the formula.

G" = G'*ref'GL' = G' *dt f' * (N, R
t) ref': Reflection coefficient of object O'dir': Diffusion coefficient of object O'W': Unit normal vector of surface of object O' r°: Direction vector of light source Thus, attenuation rate G'', GL' has a damping rate G'
is accumulated.

However, the processing of the light ray RL is different from that of the light rays R and R'.

When the light ray RL intersects an object, the intersection point CP becomes a shadow of the object and cannot receive the illumination light from the light source. Therefore, the brightness It of the light ray RL is zero. If the ray R
If L does not intersect any object, the brightness IL 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 an O5 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 luminance (2) of one pixel p, it may be necessary to process many light rays. However, since the light ray is attenuated each time it collides with an object, as the number of collisions increases, the influence of the light ray on the brightness I 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 T indicates the number of possible collisions of the ray R. When a ray R with a number of times T collides with an object and a ray R' directed toward the object is generated, the number T' of the ray R' is set to (T-1>).If the number T is O When the light ray R collides with an object, a light ray R' directed toward the object is not generated, but only a light ray RL directed toward the light source is generated.

In addition, in Figure 2, there is only one light source LL, but if there are multiple light sources L+ (i = 1.2...), it is necessary to generate light rays directed to all light sources LL. No. 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, if there are multiple light sources Ll,
As the number of times T of the light ray R5, the number i of the light source to which the light ray RL is directed is set. ).

By setting the number i of the light source L+ instead of the number of times T for the light ray RL in this way, even if there are multiple light sources LL, the number i of the light source L+ to which each light ray RL is directed can be known, so the process can be performed correctly. It can be performed.

Also, here, for simplicity, only reflection on the surface of the object was considered. If transmission through an object is also taken into consideration, a ray in the transmission direction may be generated at the intersection of the object and the ray R.However, this type of ray is a ray directed toward the object, and the above-mentioned ray R ′, the transparency of the object can be expressed correctly.

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,,S,> and the direction (d,,y,d,) are set. Furthermore, the pixel p (i
, j> (i, j> is also set as information of the ray R. Furthermore, the attenuation rate G of the ray R and the number of times T of the ray R
and the type C of the ray R are also set as information on the 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, the initial light ray generation unit 1 generates a ray R on an extension of a half-straight line starting from the viewpoint E and passing through each pixel p(i, j>) constituting the image P.

For this purpose, the initial ray generating unit 1 in FIG.
, ) are input. In addition, as information defining the image P to be synthesized, parameters indicating the plane and range of the image P are
The information is input from the information input section 6. In the initial light beam generation section 1,
Information on the light ray R is generated based on these parameters. An example of a method for finding a half-line indicating this ray R is written by T. Whitted, Communication of NCM.
23, No. 6, pp. 343-349, the article "Improved IIIu+
1ina-tion Model for 5hade
d Display).

Next, among the intersections of this half-line and the object definition space, the position coordinates (S,,S,) of the intersection closest to the viewpoint.

Find S,). The corner position coordinates (S,, S,, S,) become the starting point position coordinates (S,, S y, S z) of the ray R. That is, the position where the ray R first enters the object definition space becomes the starting point of the ray R. Also, the direction from the viewpoint E toward the pixel p is the direction of the light ray R (d ,,d ,.

d2). Furthermore, the position (i,
j> is set as the pixel position of the ray R (i, j>).

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 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 the object Oi to be set is the object number nl for distinguishing the object o1 + the center coordinates of the sphere as the object (X l+3' l,
z +), radius r1.1 Diffusion coefficient d i indicating the material of the object
f, , the reflection coefficient ref. Furthermore, the object OL
The range of the smallest rectangular parallelepiped that includes the object is set as information indicating the circumscribed area of .

FIG. 6 is an explanatory diagram showing a circumscribed region of a sphere as an object. As shown in FIG. 6, the circumscribed area of object 01 is the range in the X direction (x + -, x ++), the range in the 3' direction (y
I-+ 3' ++), Z-direction range (zI-+ Z
It is a rectangular parallelepiped indicated by l and ). These values are obtained using the following equations.

XI−=XI rI
21 r'1z,, = Zl
+rl FIG. 7 is an explanatory diagram showing the 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. 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 as shown in FIG. The information on the light source to be set is the position coordinates of the point light source LI (XI + 3'+ +
Zl>+luminance Ill of the light source. This brightness ILI
is a real number between 0 and 1. The value of this brightness ILI is
This indicates the brightness of the light source; when it is 1, it is the brightest, and when it is 0, it is pitch black.

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.

The a, b, and c-th brightness calculation units 3 in the y and z directions are (a, b
, c) If we call it the brightness calculation unit 3, then (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+1>connected to the brightness calculation unit 3.

Further, A, B, and C brightness calculation units 3 are arranged in the x, y, and z directions in the figure, respectively, and the total number of brightness calculation units 3 is 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 regions by planes perpendicular to one of the y and z coordinate axes. In this case, the number of regions in the X direction is A, and the number of regions in the X direction is B.
The division is performed so that the number of regions in the Z direction is zero. And (a, b.

C) Allocate the 8th area in the X direction, the 5th area in the X direction, and the 0th area in the Z direction to the brightness calculation unit 3. Thereby, all the divided areas can be assigned to one brightness calculation unit 3, respectively.

Moreover, by performing such allocation, the brightness calculation units 3 connected via the mutual communication means 31 are respectively in charge of adjacent areas.

FIG. 10.11 is an explanatory diagram 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 section 3 stores area information indicating the area S in charge of the brightness calculation section 3. This area information includes the values (a, b, c) indicating the number in the x, y, and Z directions, and the range (x, y, and Z directions) of the assigned area S as shown in FIG. −, X+,
).

(y-, 3/+) and (z-, Z+) are stored.

Furthermore, this is a case in which the brightness calculation units 3 located on the outer periphery of the three-dimensional array are not connected to each other by the mutual communication means 31. Therefore, whether or not the brightness calculation section 3 is actually connected in each direction connected by the mutual communication means 31 is stored in the area information storage means 33 as presence/absence information.

These area information are input from the information input means 6,
It is transmitted to each brightness calculation unit 3.

FIG. 12 is an explanatory diagram illustrating the process of transferring information about the light ray R from the initial light generation section l to the brightness calculation section 3. Information on all the rays R generated by the initial ray generator 1 is transmitted through the connecting line 5.
The brightness calculation unit 3 is simultaneously transferred to all the brightness calculation units 3 via. Then, as shown in FIG. 12, the 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. Ru. 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 (S, ,
S,,S,) is set at the position where the ray R first enters the object definition space. Therefore, if the starting point position coordinates (S8°S, , S, , ) are included in the assigned area S, the light ray R will pass through the assigned area S first.

Therefore, the ray information determining means 37 uses the starting point position coordinates (SX, S, , S,) of the ray R and the range (x-,
X+ >, (y-, 3/+), (z-.

2) are compared.

If all of the three conditional expressions X-≦SX< Therefore, the light ray R will first pass through the assigned area S. In this case, the information on the light ray R is transferred from the light ray information determination means 37 to the light ray information storage means 34 and stored therein.

Furthermore, if any of these conditional expressions does not hold, it means that the light ray R 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 the light beam information storage means 36 provided in the brightness calculation section 3. 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. As shown in FIG. 13, 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.

Further, object information determination means 38 provided in the brightness calculation section 3
First, it receives the object information transferred via the communication means 32. Next, it reads out the range of the area S in charge of the brightness calculation section 3 from the area information storage means 33. The range (x-, XI) of this responsible area S.

(y-, 3'+ >, (z-, Z+) and the range of the circumscribed area of object information (XI-T Xl+) + (3' l
−+ y++) +(z 1−, z ++) are compared.

FIGS. 14(a) and 14(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. 14(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+ It is determined whether or not the area has a common part. As a result, if there is a common part, it is determined that the object 01 is included in the assigned area S, and all information about the object 01 is stored in the object information storage means 35. If they do not have a common part, they are not stored.

Through the above processing, among the object information stored in the object information setting section 2, only the object information included within the assigned area S is stored in the object information storage means 35 provided in the brightness calculation section 3.

FIG. 15 is an explanatory diagram showing the process of enlarging 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 perpendicular to a specific coordinate axis in a direction parallel to this specific coordinate axis. This specific coordinate axis is determined by information input from the information input section 6. Here, a case will be explained in which two coordinate axes are specified as specific coordinate axes, but this does not impair film properties.

As shown in FIG. 15, 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. Note that although this method of determining the load is used here for the sake of simplicity, various other methods of determining the load are possible. Even if a method other than this is used, processing can be performed in the same manner as above.For example, load determining means 4
3, the time during which each brightness calculation unit 3 actually performs processing and the time during which it has information on the ray R may be measured, and the load on each brightness calculation unit 3 may be determined from these values. .

The load F thus determined by the load determining means 43 is transmitted to the brightness calculating section 3 (hereinafter referred to as the brightness calculating section 3 (z,
) and a brightness calculation unit 3 (hereinafter referred to as brightness calculation unit 3 (Z-)) connected in one direction. The enlargement determining means 44 then calculates the brightness calculation unit 3 (z
-), (z,), the load F (z-) transmitted via the mutual communication means 31.

F (Z,) (The load on the brightness calculation unit 3 (z-) is F <
The enlargement determining means 44 compares the load F determined by the load determining means 43 with the load F determined by the load determining means 43. Based on the comparison, it is determined whether or not to expand the assigned area S as follows, and the results dF- and dF+ are output.

F (z-) - When F > T H dF-=
When IF −F (z−)>TH dF−=−1
Otherwise dF--O F (Z+) When F > TH dF, =
When IF-F(Z,)>TH dF+=-1 Otherwise dF+= O TH: Positive threshold value set in advance through the information input unit 6 As a result, when dF- is 1, the assigned area S 2 Expand in one direction. Also, as a result, when dF- is -1,
Although the area S in charge is not enlarged, the area in charge of the brightness calculation unit 3 connected in one direction of Z is shown to be expanded.

Similarly, when dF+ is 1, the assigned area S is expanded in the Z+ force direction. Further, when the result dF+ is -1, the area S in charge is not expanded, but the area in charge of the brightness calculation unit 3 connected in the 2+ direction is expanded.

Expansion direction dF-, dF of the area S in charge determined in this way
+, and if these values are 1, the area enlarging means 4
5, the range of the area S in charge is expanded. This area expanding means 45 first reads the area S in its charge from the area information storage means 33.
The range in two directions (z-, Z+) is read and stored.

Next, create a new range (z’ −, z’) as shown below.

).

When dF, -=1, z' -=z--dSdF,
When =1, z' + =z++cisdS = positive enlargement amount set in advance through the information input section 6. The range thus obtained (z' -, z', etc.) is written in the area information storage means 33, Expand the scope of the responsible area S.

By performing such expansion processing of the assigned area S,
The number of objects included in the assigned area S and the number of light rays passing through can be increased, and the amount of calculation by the brightness calculation unit 3 can be increased. At the same time, the adjacent brightness calculation unit 3
(z+), 3 (z-) loads can be reduced. Therefore, it is possible to average the total amount of calculations and redistribute the load appropriately.

When the assigned area S is expanded in this way, information on objects included in the expanded area must be received from the adjacent brightness calculation section 3 and added to the object information recording means 35.

For this reason, when dF- is -1, the region enlarging means 45 outputs the value of dF- as control information to the object information storage means 35. Upon receiving this, the object information storage means 35 stores the information of each object 01 via the mutual communication 31 in the brightness calculation section 3 (
Transfer to z-).

Further, when dF- is 1, the area enlarging means 45
A value of - is output to the object information determining means 38. Upon receiving this, the object information determining means 38 reads out the expanded range of the area S in its duty from the area information storage means 33. Further, via the mutual communication means 31, the information on the object OJ transferred from the brightness calculation section 3(z-) is read out. Then, a process is performed to determine whether or not the circumscribed region of this object Oj and the assigned region S have a common part. The determination process at this time is performed in the same manner as already shown in FIG. As a result of this judgment process,
If the circumscribed area of the object Oj and the assigned area S have a common part, it is determined that the object Oj is included in the assigned area S,
Information about this object O4 is stored in the object information storage means 35.

However, information about the same object as this object Oj may already be stored in the object information storage means 35. Therefore,
In order to avoid storing the information of object OJ redundantly, this object 0. The object number n of the object 01 is compared with the object number nl of the object 01 stored in the object information storage means 35. Based on this comparison result, if the same object ol as the object OJ is not stored, information on the object OJ is stored in the object information storage means 35.

Furthermore, similar processing is performed for dF+ to change object information.

When the assigned area S is expanded through the above processing, the object information stored in the object information storage means 35 is added.

FIGS. 16(a) and 16(b) are explanatory diagrams showing a method of transferring information on the light ray R between the brightness calculation units 3. The area in charge of each of the brightness calculation units 3a to 3d shown in FIG. 15(b) is the 15th area.
The responsible areas Sa to Sd shown in Figure (a) are the responsible areas S.
a is enlarged. As shown in FIG. 16(a), changing the assigned area S causes the boundary surfaces of the areas to overlap. Further, as shown in FIG. 16(b), the connection between the luminance calculation units 3 via the mutual communication means is fixed. Therefore, in the case shown in FIGS. 16(a) and 16(b), the information on the light ray R incident from the assigned area Sa to the assigned area sb is directly transmitted from the luminance calculation unit 3a via the mutual communication means 31. It cannot be transferred to the calculation section 3b.

Therefore, such information on the light ray R is first sent to the brightness calculation unit 3.
a, it is transferred to the brightness calculation unit 3C via the mutual communication means 31. The information on the transferred light ray R is temporarily stored in the light ray information storage means 34 of the brightness calculation section 3C.

The information on the ray R stored in the ray information storage means 34 in this way is first read out by the ray information determination means 37. The light ray information determining means 37 compares the Z coordinate value SZ of the starting point position coordinate of the light ray R with the two-direction range (z-, Z+) of the assigned area S read from the area information storage means 33.

If SZ≧2+, information on the light ray R is transferred to the brightness calculation unit 3d connected in the 2+ direction via the mutual communication means 31. Further, in the case of Sz (z-), information on the light ray R is transferred to the luminance calculation unit 3b connected in one direction to the other via the mutual communication means 31.

That is, the range in two directions of the area in charge (z-).

Since only z+) is changed, if the information on the light ray R is transferred to the brightness calculation section 3 connected in two directions, the information on the light ray R can be processed by the correct brightness calculation section 3.

FIG. 17 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. 17, the information on the ray R stored in the ray information storage means 34 is first read out to the ray information determination means 37. As a result of the determination process in the light ray information determination means 37, information on the light ray R that has not been transferred to the brightness calculation section 3 (z, , ) or the brightness calculation section 3 (z,) is sent to the intersection determination means 39. This intersection determination means 39 performs intersection determination processing between the light ray R and the object stored in the object information storage means 35.

Furthermore, for the ray R that does not intersect with the object, the intersection of the ray R and the boundary surface of the assigned area S is first determined. From this point of intersection, the adjacent 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. The information of the light ray R is transferred via the intercommunication means, 31 to the brightness calculation unit 3 in the determined direction.

At this time, the starting point position coordinates of the light ray R 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 of the light ray R transferred in this way is transmitted to the mutual communication means 31
, and stored in the light beam information storage means 34.

Furthermore, when the light ray R intersects an object and a new light ray R' or light ray RL is generated from the light ray R, information on these light rays R' and ray RL is stored in the light ray information storage means 34. be done.

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.

Note that the description has been made here assuming that the load redistribution process is performed only between the brightness calculation units 3 adjacent in two directions. If, X
When load redistribution processing is also performed between brightness calculation units 3 adjacent in the +y direction, the load redistribution can be performed using the same process.

Alternatively, information on all objects may be stored in the object information storage means 35 of each brightness calculation unit 3, and only objects included in the assigned area may be selected to perform the intersection determination process. By doing so, there is no need to transfer object information between the brightness calculation units 3 during load redistribution processing.

〔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 a boundary surface perpendicular to a specific coordinate axis in a direction parallel to that 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.

Furthermore, when the shape of the assigned area is changed, information on objects included in this assigned area must be changed.

Even in this case, since the area in charge is kept in the form of a rectangular parallelepiped, object information can be easily changed.

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 the drawing]

1(a) and 1(b) are block diagrams showing the overall configuration of an object image synthesis device according to an embodiment of the present invention, and block diagrams showing the detailed configuration of the brightness calculation section; FIG. (Explanatory diagram showing the method of calculating the brightness I for i, j>, 3rd
The figure shows the information on the ray R that should be set when the ray R is generated, FIG. 4 is an explanatory diagram for explaining the operation of the initial ray generating section 1, and FIG. FIG. 6 is an explanatory diagram showing the circumscribed area of a sphere as an object, FIG. 7 is a diagram showing information on the light source set in the object information setting section 2, and FIG. 8 is an explanatory diagram showing the circumscribed area of a sphere as an object. FIG. 9 is an explanatory diagram showing a method of combining the brightness calculation units 3 in a three-dimensional array; FIG. 11 and 11 are respectively a diagram of area information showing the area S in charge of the brightness calculation section 3 and an explanatory diagram showing it three-dimensionally, and FIG. FIG. 13, a block diagram showing the transfer process, shows the process of storing object information and light source information from the object information setting unit 2 into the object information storage means 35 and light source information storage means 36 provided in the brightness calculation unit 3. The block diagram and FIGS. 14(a) and 14(b) are explanatory diagrams showing the comparison process between the assigned area S of the brightness calculation unit 3 and the circumscribed area of the object information, and the assigned area S and the circumscribed area each have a common part. FIG. 15 is a block diagram showing the process of changing the area S in charge of the brightness calculation unit 3, and FIG. 16 (a> and (b) shows information on the ray R between the brightness calculation units 3. FIG. 17 is a block diagram showing a method of calculating the brightness of each pixel by the intersection determination process between a light ray and an object in the brightness calculation unit 3. 1. Initial light ray generation unit, 2. ...Object information setting section, 3
゜3a, 3b, 3c, 3d... Brightness calculation section, 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 beam information judgment means, 38... Object information judgment means, 39... Intersection judgment means, 43... Load determination Means, 44... Enlarged 10th figure χ-2rsu No 10th figure (a) (b) Supply 74th figure ￥17 figure

Claims (1)

[Scope of Claims] A light ray that reversely traces the path of the light ray from the light source to the viewpoint, performs an intersection determination process between the object and the light ray, and calculates the brightness of each pixel constituting an image in which the object is to be displayed. An object image synthesis device based on a tracking method, comprising: an initial ray generation section that generates information about a plurality of rays passing through each pixel from the viewpoint; an object information setting section that sets information about the object; and an object information setting section that sets information about the object. Performing an intersection determination process between a light ray passing through a designated area, which is one of a plurality of regions generated by dividing a defined space by a plane perpendicular to a coordinate axis, and the object included in the designated area. a plurality of brightness calculation units that calculate the brightness of the pixel according to an area information storage means for storing, a load determining means for determining respective loads, and an adjacent brightness calculation unit which is the brightness calculation unit responsible for the area adjacent to the area in its duty in a direction parallel to each of the coordinate axes. A mutual communication means that performs mutual communication compares the load of the adjacent brightness calculation section obtained through this mutual communication means with its own load, and calculates the area in the direction of the area that the adjacent brightness calculation section is in charge of. expansion determining means for determining whether or not to expand the area; and area expanding means for expanding the range of the area in its duty stored in the area information storage means in order to expand the area in its duty based on the determination by the expansion determining means. An object image synthesis device comprising: