JPS62271076A - Synthesizing device for object image - Google Patents

Abstract

PURPOSE:To enable each computer to produce the initial light beam in parallel with each other and to synthesize a picture at a high speed, by adding an initial light beam generating means, a light beam position setting means, an initial light beam transfer means, etc. to each luminance calculating part. CONSTITUTION:The position coordinates of a visual point and the information defining the relevant partial image supplied from an information input part 6 are first sent to each luminance calculating part 3. An initial light beam generating means 40 set at each part 3 produces the information on the initial light beam started from the visual point and passing through each picture element forming the partial image. Then the coordinates of the position where each initial light beam is made incident on an object defining space via a light beam position setting means 41. The area including the first position of the initial light beam is transferred to the relevant part 3 via an initial light beam transfer means 42. Then the cross deciding process is carried out at said part 3. Thus the initial light beam is produce in parallel from each computer at a high speed in comparison with the case that a single computer is used for generation of the initial light beam. Thus an image can be synthesized at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION 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.

(Prior Art) As a method of synthesizing digital images for displaying objects, there is a method called a 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 heel skin of each pixel making up the image is calculated based on the result. An example of this ray search method is given in Reference 1: Transactions of the Information Processing Society of Japan, Volume 25, No. 6, Hiroshi Deguchi, Hitoshi Nishimura, Hiroshi Yoshimura, Toru Kawada, Isao Hakuyo, and Hiroshi Omura, paper [Computer Graphics ``Method for accelerating image generation in 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 Parallel processing methods have been proposed in which light rays passing through a region are processed. Details of this method can be found in Reference 2: Computer Graphics, Volume 1.
Volume 8, Issue 3, Mark Dipp
e), John Swensen
) author, paper [An Adaptive Subdivision Algorithm and Parallel Architecture for Realistic Image Synthesis (An Adaptive Subdivision Algorithm and Parallel Architecture)
5ubdivision Algorithm an
d Parallel Architecture for
r Realistic Image 5ynthes
is written in month.

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. An initial light beam generating means provided separately from these computers generates a plurality of light beams that pass through each pixel of the image from the viewpoint as initial light beams.

The initial ray thus generated is transferred to the computer responsible for the area where the initial ray is initially incident. Each computer performs intersection determination processing between the initial ray transferred from the initial ray generating means and an object included in the assigned area. Through this intersection determination process, when the object and the initial light ray intersect, reflection and transmission processing on the object surface is performed, and a new light ray is generated as necessary. Information about the initial rays that do not intersect objects within that region is transferred to the computer assigned to the region into which the rays will next enter. The information on the light beams thus transferred is processed in the same way in each computer.

In this way, each ray is determined to intersect only with objects included in the area through which the ray passes. Therefore, the total amount of processing is much smaller than if each ray were to be processed for intersection determination with all objects.

Furthermore, such intersection determination processing is executed in parallel on each computer. Combined with this parallel processing effect, images can be synthesized at extremely high speed.

(Problems to be Solved by the Invention) In such a conventional image compositing method, the initial light beam generating means performs the process of generating an initial light beam. The number of initial light rays generated corresponds to the number of pixels used to synthesize an image, and this number of pixels is enormous. For example, 100OX10
When composing images of 00 pixels, as many as 1 million initial rays must be generated.

Therefore, the processing amount of the initial light beam generation processing performed by the initial light beam generation means is enormous, and a large amount of processing time is required. Therefore, there is a problem in that the processing time for this initial beam generation process significantly reduces the overall image synthesis time.

In order to solve these problems, the present invention aims to provide an object image synthesis device that can generate initial light beams in parallel in each computer, thereby synthesizing images at high speed. shall be.

(Means for Solving the Problems) The object image synthesis device of the present invention performs intersection determination processing between an object and a light beam by tracing the path of the light source from the light source to the viewpoint in the opposite direction, and creates an image displaying the object. In order to synthesize the above images using a ray search method that calculates the brightness of each pixel constituting the image, an object information setting section that sets information about the object, and an image generated by dividing the space in which the object is defined. a plurality of brightness calculation units that calculate the brightness of the pixel by performing an intersection determination process between a light beam passing through the area and an object included in the area in charge of one of the plurality of areas; an image storage section that stores the luminance calculated by the luminance calculation section as the image; initial ray generating means for generating information on the rays as a plurality of initial rays that are in charge of the image and passing through each pixel of the partial image from the viewpoint; and the rays as the initial rays generated by the initial ray generating means. a ray position setting means for newly setting the position of said ray as one element constituting the information of said ray to a position where said initial ray first enters said object definition space; and said brightness calculation unit in said object definition space. Area information storage means for storing the range of the area in charge; mutual communication means for mutual communication between the brightness calculation unit and a plurality of adjacent brightness calculation units responsible for areas adjacent to the area in charge; and the initial light beam generation unit. ray information storage means for storing information on the rays generated by the rays and information on the rays transferred from the adjacent brightness calculation unit by the mutual communication means; and information on the rays stored in the ray information storage means. The position of the light beam as one element is compared with the information of the range stored in the area information storage means, and if the position of the light beam is outside the range, the An initial beam transfer means for performing a process of transferring information about the light beam is provided.

(Operation) A method for generating an initial light beam in the object image synthesis device of the present invention will be described. Each brightness calculation unit is in charge of a partial image of a plurality of partial images generated by dividing an image to be synthesized, and generates information on an initial ray passing through each pixel constituting the partial image.

To do this, first, the position coordinates of the viewpoint and information defining the corresponding partial image are input from the information input section and transferred to each brightness calculation section. The initial ray generating means provided in each brightness calculation unit generates information about an initial ray starting from the viewpoint and passing through each pixel constituting this partial image. At this time, the position of the initial ray as one element of the initial ray information is set to the viewpoint position.

In response to the information on the initial rays generated in this way, the ray position determination means determines the coordinates of the position where each initial ray enters the object definition space. The coordinates of the position obtained in this way are converted into integers and newly set as the position as one element of the information of this initial ray. Information on the set initial light beam is then stored in a light beam information storage means provided in each brightness calculation section.

The initial light ray generated in this way must first be subjected to intersection determination processing in a brightness calculation unit that is in charge of the area that includes this initial position, that is, the area where this light ray first enters. Therefore, information on the generated initial light ray is transferred between the brightness calculation units, and is then transferred to the brightness calculation unit that is in charge of the area including the initial position of this initial light ray. In this brightness calculation unit, initial ray intersection determination processing is started.

Next, a method of transferring initial light beam information to the brightness calculation section will be described.

A plurality of cubes generated by dividing the object definition space into a plurality of equally spaced planes perpendicular to the coordinate axes are divided into lit cubes. The first position of the initial leading line determined by the beam position setting means indicates this unit cube. Further, the object definition space is divided by some or all of these planes to generate a plurality of regions. The area thus generated is a rectangular parallelepiped made of one or more unit cubes, and each boundary surface of this rectangular parallelepiped is perpendicular to each coordinate axis. One area among these multiple areas is assigned as the area in charge of one brightness calculation unit. The range of this area in charge is stored in area information storage means provided in the brightness calculation section.

The initial light beam transfer means of each brightness calculation section reads light beam information from the light beam information storage means provided in each brightness calculation section.

This light ray information storage means stores both information on a light ray to be subjected to intersection determination processing in this brightness calculation section and information on a light initial ray to be subjected to intersection determination processing in another brightness calculation section. Therefore, the position of each light beam is compared with the range of the assigned area stored in the area information storage means.

If the position is within the assigned area, this light ray is a light ray that should undergo intersection determination processing in this brightness calculation unit. However, if the position of the light ray is outside the assigned area, this light ray is an initial light ray, and moreover, this initial light ray has not yet reached the brightness calculation unit where the intersection determination processing is to be performed first. Therefore, without performing the intersection determination process of this initial ray, the direction of information transfer of this initial ray is determined, and the initial ray is sent to a brightness calculation unit in charge of an area adjacent to the transfer direction via mutual communication means. transfer information.

Note that this mutual communication means is provided in each brightness calculation section in order to perform mutual communication with a plurality of adjacent brightness calculation sections that are in charge of areas adjacent to the area in charge.

In this way, the initial ray information is transferred between the respective brightness calculation units, and the information on the initial ray is transferred to the brightness calculation unit that is in charge of the area including the initial position of this initial ray.

(Example) FIGS. 1(a) and 1(b) are block diagrams showing an object image synthesis device as an example 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. As shown in FIG. 1(a), an object information setting section 2 is provided for setting information about the object to be displayed.

Also, to be in charge of one area out of a plurality of areas generated by dividing the space in which the object is defined, and to perform intersection determination processing between a ray passing through this area and an object included in the assigned area. 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. This image storage unit 4 sets all luminances to 0 before combining images.

A connection line 5 is provided for transmitting information between 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. Also,
Communication means 32 are provided for communicating via the connection line 5. Furthermore, a connection line 101 is provided for transmitting information within the brightness calculation section 3.

FIG. 2 shows a method of calculating the brightness I of pixel p(ij),
It is an explanatory diagram. As shown in Figure 2, in the ray search method, the brightness of the pixel p(ij) is calculated by tracing the path of the ray from the light source through the pixel p(ij) to the viewpoint E in the opposite direction. . Here, the brightness I of the pixel p(ij) will be referred to as the brightness of the light ray R generated in the opposite direction from the viewpoint E through the pixel p(i, j). The brightness I of this light ray R is the intensity I of the light that passes through the pixel p(ij) and enters the viewpoint E. The brightness I of the light ray R is calculated by the following formula.

I = ref*I'+dif"*(N-RL)*
II.

ref: Reflection coefficient dir' of object 0, Diffusion coefficient I' of object O: Incident light intensity from the R' direction IL: Incident light intensity from the light source N: Unit normal vector of the surface of object O -HR, Yodo Specular reflection direction vector RL: Direction vector of light source In order to obtain these two incident light intensities I' and II, two light rays RT whose starting point is the intersection CP and whose directions are R' and RL.

Generate RL. Also, the process for determining the brightness I.

Let the coefficients of II, be the attenuation rates G', GL of the rays R', RI,
Set as . That is, when the light ray R collides with the object 0, it is attenuated and the light rays R' and RI are generated. These attenuation factors G' and OL are as follows: G'=G-ref GL=G*dif*(N-RI,) G: Attenuation rate of light ray R (=1). By using these attenuation rates G' and GL, the brightness I of the light ray R, that is, the brightness factor of the pixel p(ij) is
It is calculated as follows.

I=G''*I' + GL umbrella IL 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 similarly generated.

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

G"= G'*ref', -2→ GL'=G'*dtf*(N'・RI,")ref':
Reflection coefficient dif' of object 0'': Diffusion coefficient dif' of object O': Normal vector of the surface of object 0'' -→ RI, ': Direction vector of light source Thus, attenuation rate G'', GL ' is multiplied by the attenuation rate G'.

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

When the light ray RL crosses an object, the intersection point CP becomes a shadow of the object and cannot receive the illumination light from the light source.

Therefore, the luminance ■L of the light ray RL becomes O. If the ray RL
does not intersect any object, then the brightness I of the ray RL
L is 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 0 when the ray R is directed toward an object, and 1 when the ray R is directed toward a 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, 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 having 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 set to (T-1). If the light ray R whose number of times T is 0 collides with an object, the light ray R' directed toward the object is not generated, but only the light ray RL directed toward the light source is generated.

In addition, although there is only one light source Li in Figure 2, if there are multiple light sources Li (i = 1.2...), it is necessary to generate light rays directed to all the light sources Li. Must be. By the way, in the case of the light ray RL heading towards the light source,
As described above, even if the light ray intersects with an object, no new light ray is generated, so the number of times T as information about the light ray RL has no meaning. Therefore, when there are multiple light sources Li,
The light source RL is set as the number of times T, and the number i of the light source to which the light beam RL is directed is set.

By setting the number of times T of light sources RL in this way, even if there are a plurality of light sources Li, the number i of the light source Li to which each light ray RL is directed can be known, so that processing can be performed correctly.

Also, here, for practical purposes, only reflection on the surface of an object was considered. If transmission through the object is also taken into consideration, a light beam may be generated in the transmission direction at the intersection of the object and the light beam 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 a ray R is generated as shown in FIG.
, dy, dz) are set. Furthermore, the position (ij) of the pixel p(ij) that is affected by the brightness of the ray R is also
It is set as the information. 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 showing information set on the ray R in order to generate a row of unit cubes through which the ray R passes as a three-dimensional digital straight line. Here, a plurality of cubes generated by dividing the object definition space by a plurality of equally spaced planes perpendicular to the x, y, and z coordinate axes is called a unit cube. Fourth
As shown in the figure, the position (Tx, Ty, Tz) of the last unit cube generated among the unit cubes sequentially generated as a three-dimensional digital straight line is set as information on the ray R. That is, this position (Tx, Ty, Tz) indicates the current position of the ray R, and is updated as the ray R passes through the object definition space. In addition, the error information ER for sequentially generating three-dimensional digital straight lines is
This is set as the information of the ray hole. By adding this error information ER and making a determination, a three-dimensional digital straight line can be generated at high speed.

For an example of how to generate a three-dimensional digital straight line, and the meaning and calculation method of this error information ER, see Reference 3: Pixel (PIxEL), No. 37, Akira Akimoto, "Ray...
Techniques for speeding up tracing are described in previous techniques and ARTS technique J.

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.

Information about object i to be set includes object number ni for distinguishing object i, center coordinates of the sphere as an object (xbybZi
), radius ri, diffusion coefficient di indicating the material of the object, and reflection coefficient refi. 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 region of a sphere as an object. As shown in FIG. 6, the circumscribed area of object i is the range in the X direction (xi-, xl + ), the range in the X direction (yi
−.

yi+) and a range in two directions (zi-, zi+), which is a rectangular parallelepiped made up of a plurality of unit cubes. These values are integer values and are determined by the following formula.

xi−==floor(xi−ri)xi+=c
eil(xi+ri)yi-= floor(yH-
ri) yi+ == ceil(yH+ rH)zi-= f
loor(zl −ri)zi+ =: ceil(z
H+ ri) floor(a): Maximum integer value not larger than a ceil(a): Minimum integer value not smaller than a FIG. 7 shows the light source information set in the object information setting section 2. It is a diagram. To simplify the explanation,
Although the explanation will be limited to point light sources, the same method can be used when dealing with various types of illumination light such as parallel light rays and spotlights. As shown in FIG. 7, information on a light source as illumination of 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 coordinate (xb)'bzi) 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, the brightness calculation section 3 is connected to the brightness calculation sections 3 on both sides in the x, y, and Z directions, and can mutually transmit information with these brightness calculation sections 3. Here, X+3'
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+ 1)
It is connected to the brightness calculation section 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=AxBxC.

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. 9, the object definition space is divided into a plurality of rectangular parallelepiped-shaped regions by some or all of the plurality of planes serving as the boundary surfaces of the unit cube. By performing such division, each region can be composed of a plurality of unit cubes or one unit cube.

In this case, division is performed so that the number of regions in the X direction is A, the number of regions in the X direction is B, and the number of regions in the two directions is C. Then, the third area in the X direction, the fifth area in the X direction, and the 0th area in the second direction are assigned to the (a, b, c) 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, area information storage means 33 provided in the brightness calculation section 3
Area information indicating the area S in charge of the brightness calculation unit 3 is stored in . This area information is X.

The values of (a, b, c) indicating the number in the y and z directions, and the ranges (X-2X+), (y-2y+) in the X, y, and z directions of the assigned area S as shown in FIG. ), (z-, Z+) are stored. Since each region is composed of a plurality of unit cubes or one unit cube, the values indicating these ranges are integer values.

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, whether or not the luminance 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 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. 12, the object information setting section 2
All object information and light source information stored in the connection line 5
The brightness calculation unit 3 is simultaneously transferred to all the brightness calculation units 3 via. 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, the initial information determination means 38 provided in the brightness calculation section 3
First, the object information transferred via the communication means 32 is received. Next, the range of the area S in charge of the brightness calculation section 3 is read out from the area information storage means 33.

Range of this responsible area S (X, x+), (y +y+)
+ (z-, z+) and the range of the circumscribed area of the object information (Xi
+Xi + ), (yi +yi ten (zi-2zi+
) are compared.

FIGS. 13(a) and 13(b) are explanatory diagrams showing a comparison process between the responsible ridge area S of the brightness calculation unit 3 and the circumscribed area of the object information. As shown in FIGS. 13(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-≧Xi+ It is required to find out whether they have a common part. As a result, if there is a common part, it is determined that the object i is included in the assigned area S, and all information about the object i 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. 14 is an explanatory diagram showing a method of dividing image P into partial images Pn in order to generate initial light rays in parallel in each brightness calculation unit 3. As shown in FIG. 14, the image P is divided into partial images Pn, the number of which is equal to the number of brightness calculation units. Here, the image P is equally divided into A pieces vertically and (BXC) pieces horizontally. The initial light ray generating means 40 provided in each of the brightness calculation units 3 generates a light ray R as a half straight line starting from the viewpoint E and passing through each pixel p(ij) constituting the corresponding partial image Pn.

For this purpose, the position and size of the partial image Pn in charge of the position coordinates (E, E, , E2) of the viewpoint E are input from the information input unit 6 to the initial ray generating means 40 via the communication means 32. . The initial light beam generating means 40 generates information on the light ray R as the initial light beam based on these values. An example of a method for finding a half-line indicating the ray R as the initial ray is given in Reference 4: Tee, Whittet)' (T,
Whitted), Communication of ACM
, Vol. 23, No. 6, pp. 343-349, article "An Improved Illuminated Model 7 Display"
illumination Model forShade
d Display) J.

FIG. 15 is an explanatory diagram for explaining the operations of the initial beam generating means 40 and the beam position setting means 41. 15th
As shown in the figure, the position coordinates (Ex, Ey, Ez) of viewpoint E, which is the starting point of the half-line, are set as the starting point position coordinates (Sx, Sy, Sz) of ray R as the initial ray, and
The direction from pixel p to the direction of ray R (dx, dy
, dz). Further, the position (ij) of the pixel p(ij) is set as the pixel position (ij) of the light ray R.

In the initial beam generating means 40, the attenuation rate G of the generated beam R is set to 1, that is, the beam R is not attenuated at all. Further, as the number of times T, a preset constant value is given to the initial beam generating means 40 from the information input section 6. Further, as type C, a value of 0 is given, which indicates a ray of light directed toward an object.

In the initial light beam generation section 40, a light beam R having such information is generated.
is generated corresponding to all pixels p(i,j) of the partial image Pn in charge of the pixel p(i,j).

In response to the information on the ray R generated in this way, the ray position setting means 41 selects one of the intersection points of the ray R and the object definition space.
Position coordinates of the intersection closest to viewpoint E (tx, t,, tz)
seek. However, if the viewpoint E exists inside the object definition space, the position coordinates (tX, t3F, tZ) are set to the position coordinates (Ex, Ey, Ez) of the viewpoint E.

The position coordinates (tx, ty, Ez) are converted into integers to find a unit cube that includes this intersection, and this is used as the position (Tx) of the ray R as information.

T, , T, L). This position (Tx, Ty
, Tz) indicates the unit cube at the position where the ray R first enters the object definition space. Then, using this unit cube as the first unit cube, a row of unit cubes through which the light ray R passes in the object definition space is generated as a three-dimensional digital straight line in each brightness calculation section 3.

In subsequent processing, when the ray R passes through the area S and enters the area S', the information on the ray R is transferred to the brightness calculation unit 3.
transferred between. At that time, the current position (Tx, Ty, Tz) of the three-dimensional digital straight line as information of the ray R is
The position of the unit cube including the intersection of the new region S' and the ray R is updated.

Further, in the beam position setting means 41, an initial value of error information ER for sequentially generating three-dimensional digital straight lines is calculated and set as the error information ER of the beam R. The method for calculating this initial value is detailed in Document 3, as mentioned above.

Information on the light ray R set in this way is stored in the light ray information storage means 34 provided in the brightness calculation section 3.

FIG. 16 shows the position (Tx, Ty, Tz) of the ray R as the initial ray from the tumor degree calculation unit 3 where the ray R was generated.
FIG. 3 is an explanatory diagram showing a process of transferring information about a light ray R to a brightness calculation unit 3 in charge of an area including the area. As shown in FIG. 16, the information on the light beam R read out from the light beam information storage means 34 is manually input to the initial light beam transfer means 42. As shown in FIG. At the same time, the information on the assigned area S stored in the area information storage section 33 is read out by this initial beam transfer means 42.

If this ray R is an initial ray, its position (Tx
, Ty, Tz) are set at the position where the initial ray first enters the object definition space. Therefore, this position (
Tx, Ty, Tz) are included in the assigned area S, the light ray R will pass through the assigned area S first.

Therefore, the intersection determination process for this light ray R can be performed.

At the same time, even if this ray R is not the initial ray, its position (Tx, Ty, Tz) is set to the position where the intersection determination process of this ray should be performed. Therefore, if the position of the ray R (T, Ty, T2) is included in the assigned area S, the intersection determination process for this ray R is performed regardless of whether this ray R is the initial ray or not. can be done.

However, if this position (TX, Ty, Tz) is not included in the area S in charge, the information on this ray R must be transferred to the brightness calculation unit 3 in charge of the area including that position. .

Therefore, the initial beam transfer means 42 determines the position of the beam R (Tx
, Ty, Tz) and the range of the responsible area S (XrX10) + (y
+'/+)+(z-, z+).

X-≦Tx<x+ (1)
y-≦T, <y+ (2)
2-≦T2<z+ (3)
If all three conditional expressions are satisfied, the position (Tx
, Ty, Tz) are included in the area S in charge. Therefore,
Information on the light ray R is transferred from the initial light beam transfer means 42 to the intersection determination means 39, and a light beam hole intersection determination process is performed.

Furthermore, if any of these conditional expressions does not hold, the light ray R is the initial light ray that first enters the other assigned area S'. Therefore, the information on the light ray R must not be processed by the brightness calculation unit 3. Therefore, in such a case, information on the light ray R is transferred via the mutual communication means 31 to the brightness calculation unit 3 in charge of the adjacent area.

For example, if condition (1) does not hold and Tz < x −, information on the light ray R is transferred to the brightness calculation unit 3 connected in the X direction via the mutual communication means 31.

Further, in the case of Tx≧X+, information on the light ray R is transferred to the brightness calculation unit 3 connected in the X direction.

If condition (1) is true but condition (2) is not true, the same transfer process is performed for y.

Then, if both conditions (1) and (2) hold, but only condition (3) does not hold, the same transfer process is performed for 2.

By performing such transfer processing, the ray R
Information on this light ray R can be transferred to the brightness calculation unit 3 in charge of the area including (Tx, Ty, Tz).

FIG. 17 is an explanatory diagram showing a processing method for determining the intersection of light rays R in the brightness calculation unit 3. As shown in FIG. 17, the intersection determination means 39 receives information about the light ray R transferred from the initial ray transfer means 42 as described above, and determines the intersection between the light ray R and the object stored in the object information storage means 35. Perform judgment processing.

As a result of this intersection determination process, if the ray R intersects the object, new rays R' and RL are generated from the ray R, and information on these rays R' and RL is stored in the ray information storage means. 34. However, if the number of times T as information about the light ray R is 0, no new light ray R' is generated as described above.

Such intersection determination processing is shown in each of the above-mentioned documents and FIG. 2.

Furthermore, as a result of the intersection determination process in the intersection determination means 39,
Information about the ray R that does not intersect the object is transferred to the adjacent brightness calculation unit 3.

FIGS. 18(a) and 18(b) are explanatory diagrams showing the process of transferring information on the light ray R between the brightness calculation units 3. Figure 18 (
a).

As shown in (b), first, the straight line generation means 43 receives information about the ray R that does not intersect with the object from the intersection determination means 39, and
Remember this information. Then, one unit cube through which the ray R passes is generated by the addition determination process of the error information ER, which is information about the ray R.

In order to generate such a unit cube, the straight line generation means 43 first performs an addition determination process on the error information ER, and then performs an update process on the error information ER based on the result. Next, the straight line generating means 43 selects and determines a coordinate axis for generating a unit cube from among the X, y, and z coordinate axes based on the result of this addition determination process, and determines selection information SEL.

The value of this selection information SEL is any one of 0°1.2, and these values are x and y, respectively.

Two coordinate axes are shown. At the same time, the straight line generating means 43 also determines the direction DIR of the generated unit cube. This direction D
The value of IR is 1 or -1. The method for determining these values is shown in Bunyu 3 as mentioned above.

For example, as shown in FIG. 18(a), a unit cube (Ti
c.

Ty, T2), if the selection information SEL is determined to be 1 in the O1 direction DIR by the addition judgment process of the error information ER of the ray R in the straight line generation means 43, the straight line generation The means 43 is a unit cube (
TX+1. Ty, Tz). Further, when the selection information SEL is determined to be 0 and the direction DIR is determined to be -1, the straight line generation means 43 generates a unit cube (Tz 1.Ty
, Tz).

Then, the straight line generating means 43 changes the position (Tx+TytTz) of the stored information of the light ray R to the newly generated unit cube (Tx', Ty', Tz'). By doing this, the position (Tx, Ty, Tz) of the ray R is updated so that this position (Tx, Ty, Tz) indicates the last unit cube in the row of unit cubes as a three-dimensional digital straight line. become.

Further, the direction determining means 44 uses the selection information SEL determined by the straight line generating means 43, the direction DIR, and the position (Tx, Ty, T
z), a process of determining the passing direction of the light ray R is performed.

As shown in FIG. 18(a), when the generated unit cube is within the area S in charge, the passing direction of the light ray R cannot be determined, so the direction determining means 44 uses the straight line generating means 43
sends control information to generate the next unit cube.

Further, as shown in FIG. 18(b), when the generated unit cube is outside the range of the assigned area S, the direction in which the unit cube is generated becomes the passing direction of the light ray R.

To perform this process, the direction determining means 44 first reads the range value of the area S in its duty indicated by the selection information SEL and the direction DIR from the area information storage means 33. and,
Selection information S among this value and position (Tx, Ty, Tz)
By comparison with the value indicated by EL, it is determined whether the generated unit cube is within the range of the assigned area S or not.

For example, as shown in FIG. 18(a), when the selection information SEL is 0 and the direction DIR is 1, the value of X+ in the range is read out. This value X+ is compared with the value Tx indicated by the selection information SEL of the position, and the following determination is made.

When Tz>x+: Outside the range When Tx≦X+: Within the range Also, when the selection information SEL is 0 and the direction DIR is -1, the value of X- in the range is read out. This value X- is compared with the value T indicated by the selection information SEL among the positions, and the following determination is made.

When T x X- Outside the range When Tx≧X- Within the range Thus, the direction determining means 44 determines the position ('r:, Ty, T
If it is determined that z) is within the range, as described above, the passing direction of the ray R cannot be determined, so control information is sent to the straight line generating means 43 to generate the next unit cube.

Further, when the direction determination means 44 determines that the position (TX, Ty, T2) is outside the range, the brightness calculation section 3 is connected in the direction indicated by the selection information SEL and the direction DIR from the area information storage means 33. Reads information on whether it is being used or not.

If the brightness calculation section 3 is connected in this direction, values from 1 to 6 are output to the light beam information transfer means 45 as information indicating this direction. These values from 1 to 6 are
The X-2x+, y-5y10, and z-2z10 directions are shown, respectively.

Furthermore, if the brightness calculation section 3 is not connected in this direction, zero is output to the light beam information transfer means 45 as information indicating that it is not connected.

The light beam information transfer means 45 receives the values output from the direction determining means 44, reads out the information on the light beam R stored in the straight line generation means 43, and transfers the information on the light beam R.

If the direction determination means 44 outputs zero, that is, if the brightness calculation unit 3 is not connected in the direction in which information about the ray R should be transferred, the ray R will go outside the object definition space. Become. Therefore, it can be seen that this ray R does not intersect with the object.

Therefore, the light beam information transfer means 45 outputs information about this light beam R to the brightness determination means 37. The brightness determining means 37 determines, based on the value of the type C of the light ray R, whether the light ray R is directed toward an object or a light source. If the ray R
If the light beam R is directed toward a light source, the light source information is read from the light source information storage means 36, and the brightness (■) of the light beam R is determined.

However, if there are multiple light sources Li, the light source R
The brightness I is determined by referring to the light source number i indicated by the rotation T of , reading the information of the light source Li having that number.

Also, if the ray R is directed towards an object, then
There is no need to perform any processing.

This determination process is as shown in each of the above-mentioned documents and FIG. 2.

Then, via the communication means 32, the luminance ■ is added to the pixel p(ij) of the image storage unit 4 indicated by the information on the light ray R.

Further, when a value from 1 to 6 is output from the direction determining means 44, the beam information transfer means 45 sends the mutual communication means 3 to the brightness calculation section 3 connected in the direction indicated by the value.
The information of the ray R is transferred via 1.

For example, when the selection information SEL is 0 and the direction DIR is 1, the direction determination means 44 outputs 2, and the light beam information transfer means 45 that receives this value is connected to the brightness calculation unit connected in the X direction. The information of the ray R is transferred to 3. Similarly, when the selection information SEL is O and the direction DIR is -1, the direction determination means 44 outputs 1, and the light beam information transfer means 45 that receives this value outputs the luminance value connected in the X direction. Information on the ray R is transferred to the calculation unit 3.

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.

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 through the above-described intersection determination process, the composition of the image P is completed.

(Effects of the Invention) In the object image synthesis device of the present invention, initial light beams are generated in parallel by each computer. Therefore, the initial beam can be generated much faster than when the initial beam is generated by a single computer. This effect has a large effect on the overall processing time, and can significantly speed up the overall image synthesis.

In particular, since the number of initial light rays is proportional to the number of pixels, the greatest effect can be achieved when synthesizing high-quality images with a large number of pixels.

[Brief explanation of the drawing]

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. ), FIG. 3 is an explanatory diagram showing the information about the ray R that should be set when the ray R is generated, and FIG.
5 is an explanatory diagram showing the information set in the ray R in order to generate the row of unit cubes through which it passes as a three-dimensional digital straight line. FIG. 5 shows the object information set in the object information setting section 2. An explanatory diagram, FIG. 6 is an explanatory diagram showing a circumscribed area of a sphere as an object, FIG. 7 is an explanatory diagram showing information on a light source set in the object information setting section 2, and FIG. 8 is an explanatory diagram showing a plurality of luminances. Explanatory diagram showing a method of combining calculation units 3 into a three-dimensional array, No. 9
FIG.
0.11 is an explanatory diagram showing the contents of area information indicating the area S in charge of the brightness calculation section 3, and FIG. 12 is an explanatory diagram showing the contents of the area information indicating the area S in charge of the brightness calculation section 3.
An explanatory diagram showing the process of storing object information and light source information from the object information setting unit 2, FIGS. FIG. 14 is an explanatory diagram showing a method of dividing image P into partial images Pn in order to generate initial rays in parallel in each brightness calculation unit 3, and FIG. 15 is an explanatory diagram showing a comparison process with FIG. 16 is an explanatory diagram for explaining the operations of the initial light beam generation means 40 and the light beam position setting means 41. FIG. 16 shows the position (Tx , Ty, Tz); FIG. 17 is an explanatory diagram showing the process of transmitting the information of the ray R to the brightness calculation unit 3 which is in charge of the area including the areas including the brightness calculation unit 3; FIGS. 18(a) and 18(b) are explanatory diagrams showing the process of transferring information on the light ray R between the brightness calculation units 3. In the figure, 2...object information setting section, 3...luminance calculation section, 4...
・Image storage section, 5... Connection line, 6... Information input section,
31... Mutual communication means, 32... Communication means, 33.
... Area information storage means, 34... Ray information storage means,
35... Object information storage means, 36... Light source information storage means, 37... Heel skin determining means, 38... Initial information determining means, 39... Intersection determining means, 40... Initial light ray Generation means, 41... Light beam position setting means, 42... Initial beam transfer means, 43... Straight line generation means, 44...
Direction determining means, 45... Light O 1 Figure O I Figure (b) O 4 Figure O 6 Mouth OXl-xt+ a) (b) Figure -714 Partial image Pn Figure 16 Figure 17 Figure 18 (a)

Claims (1)

[Claims] An object information setting unit that sets information about the object, and a light ray that is responsible for one area out of a plurality of areas generated by dividing the space in which the object is defined and passes through this area. a plurality of brightness calculation units that calculate the brightness of the pixel by performing an intersection determination process between the pixel and the object included in the responsible area;
In an object image synthesis device comprising an image storage unit that stores the brightness calculated by the brightness calculation unit as the image, the brightness calculation unit includes: (a) a plurality of images generated by dividing the image; (b) initial ray generating means for generating information on the rays as a plurality of initial rays that are in charge of one of the partial images and pass through each pixel of the partial image from the viewpoint; (b) the initial ray generating means; a ray position setting means for newly setting the position of the ray as one element constituting the information of the ray as the initial ray generated at the position where the initial ray first enters the object definition space; c) area information storage means for storing the range of the area in charge of the brightness calculation unit in the object definition space; and (d) a plurality of adjacent brightness calculation units responsible for areas adjacent to the area in charge and the brightness calculation unit. (e) a light beam for storing information on the light beam generated by the initial light beam generation means and information on the light beam transferred from the adjacent brightness calculation unit by the mutual communication means; (f) reading the information of the light beam stored in the light beam information storage means and comparing the position of the light beam as one element with the information of the range stored in the area information storage means; initial beam transfer means for performing a process of transferring information of the light beam via the mutual communication means when the position of the light beam is outside the range; .