JP3720890B2 - Image generation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional display means for a model to be drawn, and more particularly to a means for drawing and expressing light and glare realistically and at high speed.
[0002]
[Prior art]
In the conventional three-dimensional drawing method, a model to be drawn is registered as a triangle or other shape. When drawing, rendering is performed with reference to the registered shape model.
[0003]
Further, when there is a light source or the like, the luminance of the shape is calculated in consideration of the influence of light irradiation by the light source, and drawing is performed based on this luminance information. For this reason, when model data does not exist, drawing is not performed.
[0004]
The conventional drawing technique, because “light” generated when light irradiates fine particles in space and glare caused by light diffraction cannot be expressed by shape data itself. Then it is impossible to express.
[0005]
As a technique for expressing such a state, two techniques have been proposed in the past regarding the expression of light.
[0006]
The first method is to express a glow using a method called volume rendering. This method is described in “Computer Graphics, Principles and Practice, Addison Wesley (1990), pp1034-pp1039”, etc. Detailed in the literature.
[0007]
In other words, this technique divides the space to be drawn into a plurality of small spaces, and expresses the glow by finding the way the line of sight passes through the small spaces by integrating the luminance change in each small space. It is a technique.
[0008]
The second method is to express a glow by generating a shape. This technique is to generate a new virtual shape for expressing a glow at a position where a glow phenomenon occurs and draw the virtual shape in a semi-transparent state.
[0009]
Furthermore, regarding the glare expression, “SIGGRAPH90 Conference Proceedings Vol.24, No.4, August1990, pp395-404” Are described in detail in the literature. According to this method, glare expression is performed by performing special image processing based on the luminance data of the generated image.
[0010]
[Problems to be solved by the invention]
By the way, according to the conventional technique as described above, that is, the first conventional technique of the light expression, there is a problem that the processing time for performing the spatial integration is not taken into consideration and the processing time is significantly increased. there were. In addition, according to the second conventional technique for expressing the glow, although the processing time is not so long, since the color representing the glow is uniform, it is impossible to perform realistic expression. there were.
[0011]
Further, with regard to glare expression, the conventional technique has a problem in terms of processing speed because image processing is performed on a generated image in units of pixels.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to provide means for performing light glare expression in real and high speed, and providing means for performing glare expression in real and high speed.
[0013]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object of the present invention, there are the following means.
[0014]
That is, a boundary shape is defined with respect to a frame buffer that stores color information for each pixel, display means that performs display output with reference to the contents of the frame buffer, and a boundary shape of a partial space that occupies a certain volume. Boundary rendering means for outputting depth data from a specific position for each constituent pixel, and determining whether or not the pixels constituting the boundary shape are present at a specific position when viewed from the specific position In accordance with a predetermined rule, the corresponding depth data is encoded, and difference calculation means for performing depth data addition / subtraction processing on all pixels constituting the boundary shape, and the difference for each pixel A product-sum buffer for storing the processing result by the computing means, and for each pixel, calculates the amount of light attenuation based on the data stored in the product-sum buffer, and further corresponds Processing for determining the color information of the pixel based on the color information of the storage position of the frame buffer, the color information of the predetermined partial space, and the attenuation amount of light, and storing the color information in the corresponding position in the frame buffer And an image generating device.
[0015]
As another aspect of the present invention, there are the following means.
[0016]
That is, when it is assumed that there is a frame buffer that stores color information for each pixel, display means that performs display output with reference to the contents of the frame buffer, a light source that illuminates a three-dimensional object, and an obstacle. Light that generates a plurality of surfaces parallel to the irradiation direction, calculates the distance between the light source and an obstacle that blocks light along each surface, and sets transparency according to the distance from the light source for the surface It is an image generation device having a frame plate generation unit and a shape rendering unit that performs drawing according to transparency on each surface and stores a drawing result in the frame buffer.
[0017]
Furthermore, as another aspect of the present invention, there are the following means.
[0018]
That is, a frame buffer that stores color information for each pixel, a display unit that performs display output with reference to the contents of the frame buffer, and a glare processing unit that maps a plurality of predetermined types of glare patterns. The glare processing means is an image generating device that stores the glare pattern in the frame buffer so as to map one or more glare patterns on a straight line connecting the center position of the display screen and the light source existing position. is there.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
In order to facilitate understanding of the present invention, an example of image generation drawn by the present invention and an operation principle will be described with reference to FIGS. 2, 3, 4, and 5, and then a specific apparatus will be described. The present embodiment will be described by showing the configuration.
[0021]
FIG. 3 is a display screen example of the display unit 111 according to the present embodiment.
[0022]
As shown in FIG. 3, for example, when a fine particle object irradiates light to a “partial space” 203 partially existing in the space, it is displayed so that the thickness of the partial space can be grasped. . Such a state represents, for example, a glow phenomenon caused by irradiating light to a partial space where smoke or fog exists.
[0023]
In addition, even when a translucent space such as a partial space and an opaque object 201 coexist, it is possible to generate a real image in consideration of the visible thickness of the partial space.
[0024]
Next, FIG. 2 is a drawing showing a state where the line AA ′ shown in FIG. 3 is viewed from above in a direction perpendicular to the drawing.
[0025]
Therefore, “A” and “A ′” in FIG. 2 correspond to “A” and “A ′” in FIG. 3, and “B” in FIG. 2 corresponds to the point “B” in FIG.
[0026]
In FIG. 2, three types of partial spaces 203 exist, and the background 202 is an opaque object. A point of contact with the background 202 when it is assumed that the point B is extended in the viewpoint direction is a point B ′.
[0027]
Of course, the object 201 in FIGS. 2 and 3 is common, but the shape of the object 201 is different because the position of the viewpoint is different.
[0028]
FIG. 4 shows an enlarged view focusing on the line of sight of BB ′.
[0029]
In FIG. 4, 401 is a viewpoint, 203 is a partial space, and 202 is an opaque object.
[0030]
Further, the color information Cv of each partial space 203 and the color information Cb of the opaque object 202 are determined in advance. Ce is color information expressing the color observed at the viewpoint position. As the color information, for example, data representing numerical values of (R, G, B) may be employed. Reference numerals 402, 403, 404, 405, 406, and 407 are boundary surfaces of the partial spaces 203. Note that by examining the normal vector of each boundary surface, it can be determined whether each boundary surface is on the line of sight. In the following description, the boundary surface on the viewpoint side, for example, 402 is “front side”, and the boundary surface on the opposite side, for example, 403 is “back side”.
[0031]
Here, the distance that the line of sight passes through the partial space can be obtained as follows.
[0032]
First, the opaque object 202 is drawn, and the depth distance Z0 of the opaque object 202 from the viewpoint position is determined. Thereafter, the boundary surfaces 402, 403, 404, 405, 406, and 407 of the partial space are obtained, and the distances between the boundary surfaces and the viewpoint positions, Z1, Z2, Z3, Z4, and Z5 are obtained. Further, the distance between each boundary surface and the viewpoint position is added or subtracted depending on whether or not each boundary surface exists on the viewpoint side, that is, whether it is the front side or the back side. As a result, the distance d through which the line of sight passes through the partial space can be obtained.
[0033]
In the figure, the distance from the opaque object 202 to each boundary surface is obtained as “Zn ′ = Z0−Zn (n = 0, 1, 2, 3, 4, 5, 6)”, and the front side is further determined. The distance d is obtained with the positive side and the negative side being negative. As a result, it can be seen that the distance d can be obtained by the expression “d = Z1′−Z2 ′ + Z3′−Z4 ′ + Z5′−Z6 ′”.
[0034]
Now, light passing through a partial space in which homogeneous fine particles are present attenuates logarithmically according to the passing distance. Therefore, the color Ce that reaches the viewpoint can be determined by the equation shown in FIG. That is, the attenuation amount a is determined by the equation “a = exp (−K · d)”, where K is an attenuation constant. Therefore, (1-a) indicates the transmittance.
[0035]
In FIG. 5, a distance d is taken on the horizontal axis, and a and (1−a) change as d changes.
[0036]
The color Ce is obtained by an expression “Ce = Cb · a + Cv · (1−a)”. However, Cb is the color (or background color) of the opaque object 202, and Cv is the color of the partial space.
[0037]
Next, with reference to FIG. 1, the position configuration form of the apparatus that performs the processing as described above will be described.
[0038]
This apparatus performs display output by referring to the model data storage unit 101, the image generation control unit 102, the shape rendering unit 103, the frame buffer 106 that stores color information for each pixel, and the contents of the frame buffer. The display unit 111 and the light generation unit 110 are included. The glow generation unit 110 includes a boundary rendering unit 104, a difference calculation unit 105, a product-sum buffer 108, and a synthesis unit 109.
[0039]
The display unit 111 can be realized by a CRT, a liquid crystal display, or the like, and each buffer can be realized by a memory device such as a RAM. Other components can also be realized, for example, by electronic devices such as a CPU that performs various processes, a ROM that contains a program in advance, a RAM that functions as a storage element or a work area, and a logical element that performs various logical operations. Therefore, this apparatus can be realized on one computer.
[0040]
The model data storage unit 101 stores model data and viewpoint information.
[0041]
Model data includes shape data representing the shape of an object existing in the three-dimensional space to be displayed, arrangement data representing arrangement and size, attribute data representing color and texture, illumination setting conditions and irradiation direction. There is lighting data. The viewpoint information includes data indicating the position, direction, angle of view, and the like of the viewpoint 401.
[0042]
The depth buffer 107 stores depth data from a specific position, for example, a viewpoint position to model data, in order to perform hidden surface removal.
[0043]
The image generation control unit 102 refers to the contents stored in the model data storage unit 101, and accesses various buffers to convert and generate the three-dimensional data of the object viewed from the viewpoint 401 into two-dimensional image data. The operation is performed and the operation of the shape rendering unit 103 is controlled.
[0044]
The shape rendering unit 103 performs two-dimensional image drawing generation processing with reference to model data and the like.
[0045]
When generating an image, the image generation control unit 102 first initializes a frame buffer 106 for storing image information, a work buffer used for generating an image, and a depth buffer 1071 in the example shown in FIG. To do.
[0046]
The initialization of the frame buffer 106 may be performed by storing the background color of the image to be generated, for example, black data in the buffer. To initialize the depth buffer 107, a value of infinity may be set in the buffer.
[0047]
The image generation control unit 102 draws the shape after the initialization process.
[0048]
That is, the image generation control unit 102 gives viewpoint data and illumination data to the shape rendering unit 103, and then sequentially gives the shape data to the shape rendering unit 103, thereby causing the shape rendering unit to generate an image.
[0049]
The shape rendering unit 103 performs projection conversion on the shape data with reference to the viewpoint data, and obtains the storage position of the shape data in the frame buffer 106 and the depth distance from the viewpoint position in units of pixels.
[0050]
Next, the shape rendering unit 103 determines the color information of each pixel according to the illumination data. At this time, in order to perform hidden surface removal, the following processing is further performed.
[0051]
That is, the depth data of the corresponding pixel position in the depth buffer 107 is read, and when the value representing the position before the depth data with respect to the shape data is already written in the depth buffer 107, the frame buffer 106 The color information is not written in. On the other hand, when the value of the depth buffer 107 is not a value representing the previous position, the color information is written to the corresponding pixel in the frame buffer 106. Further, a process of writing the value of the shape depth data into the depth buffer 107 is performed. By performing such processing, information for drawing the three-dimensional model viewed from the viewpoint position is stored in the frame buffer 106.
[0052]
Note that the rendering process performed by the shape rendering unit 103 described above is a known technique called “Z-Buffer method”, and thus detailed description thereof is omitted.
[0053]
The image information stored in the frame buffer 106 is displayed on the screen by the display unit 111.
[0054]
Next, a process for generating a partial space in which fine particles partially exist in the three-dimensional space as an image will be described. As a model in which fine particles partially exist, for example, there is a light spot phenomenon that occurs when light irradiated on the fine particles diffuses and the fine particles in the part where the light reaches becomes visible, or a CT scanner is provided. A model having a distribution in the density of data obtained by three-dimensional tomography can be considered.
[0055]
Specific examples of the former include a state in which an automobile headlight irradiates the fog, a case of shining light on cigarette smoke, and the like. In addition, a state in which light enters from the window into the room is also conceivable.
[0056]
Examples of the latter include data indicated by a tomographic photograph of a human head.
[0057]
Next, a process performed by the light generation unit 110, which is a main part of the present invention, will be described.
[0058]
First, the image generation control unit 102 creates the boundary of the partial space as shape data. As a creation method, as shown in FIG. 2, a plurality of partial spaces occupying a certain volume are generally arranged.
[0059]
As another creation method, with respect to the glow, the boundary shape of the partial space is obtained by sweeping the outline of the light shielding object (opaque object) in the direction opposite to the position where the light source exists. Here, sweeping means generating shape data on the assumption that the shape is extended in a predetermined direction, and is a general technique for graphic processing.
[0060]
In the example of the three-dimensional tomographic data, a boundary line of a region where the data distribution density is greater than or equal to a certain value (or smaller than a certain value) is generated as a boundary shape.
[0061]
When generating the boundary shape, the direction of the normal to the boundary shape is set to face either the inside or the outside of the partial space. As a result, when the boundary shape is viewed from the viewpoint, it is possible to determine whether the boundary is the boundary on the viewpoint side of the partial space or the boundary on the opposite side, that is, the front / back.
[0062]
The image generation control unit 102 gives viewpoint data and illumination data to the boundary rendering unit 104, and then gives information about the obtained boundary shape. The boundary rendering unit 104 performs front / back determination of the specified boundary shape. This can be obtained by comparing the normal direction of the boundary shape with the direction of the line of sight. This determination result is given to the difference calculation unit 105.
[0063]
Next, the boundary rendering unit 104 performs boundary shape rendering. The rendering process is performed by a process similar to that of the shape rendering unit 103. At this time, the luminance calculation is not performed, and only the depth data for the boundary surface of the partial space is obtained with reference to the depth buffer 107.
[0064]
If the boundary shape is visible from the viewpoint position, the depth data is given to the difference calculation unit 105. The calculation of depth information for each pixel in rendering is performed by adopting a general method called “3DDDA” that is also used in the shape rendering unit 1031. By providing dedicated hardware, the processing speed can be increased.
[0065]
Here, an outline of processing of the difference calculation unit 105 will be described with reference to FIG.
[0066]
FIG. 6A shows the boundary rendering unit 104, the depth buffer 107, the product-sum buffer 108, and the difference calculation unit 105.
[0067]
The product-sum buffer 108 is initialized with “0” before the image generation processing of the subspace. After that, the depth data of the pixels (“pixel” in the figure and one pixel shown in the figure) determined to be visible from the viewpoint position by the boundary rendering unit 104 is given to the subtraction unit included in the difference calculation unit 105.
[0068]
Next, the difference between 601 and 602 is obtained by referring to the depth data 602 of the corresponding pixel in the depth buffer 107. This difference value is “Zn ′” shown in FIG.
[0069]
The addition / subtraction unit included in the difference calculation unit 105 performs front / back determination from the normal direction obtained by the boundary rendering 104, adds a sign of “+” to “Zn ′” if the front side, and “Zn ′” if the back side. The sign of “−” is added to the value, the value of the data 603 corresponding to the pixel of the product-sum buffer 108 and the obtained difference value are calculated, and the calculation result is again displayed in the area for the pixel 603 of the product-sum buffer 108. Store.
[0070]
Thereby, the distance that the line of sight passes through the partial space, that is, d shown in FIG. 4 can be obtained.
[0071]
In this way, distance information in units of pixels is stored in the product-sum buffer 108.
[0072]
Note that, in the case of a model that includes only partial space data and does not have an opaque object, such as three-dimensional tomography data, the configuration of the difference calculation unit 105 can be simplified. This is shown in FIG. As shown in the figure, difference processing with the depth buffer 107 is eliminated, and only arithmetic processing with the product-sum buffer 108 is performed. The calculation process is a subtraction process when the boundary shape is on the viewpoint side, and an addition process when the boundary shape is on the opposite side. The adder / subtractor obtains the distance d through which the line of sight passes through the partial space by such processing, and stores it in the product-sum buffer 108.
[0073]
Next, the image generation control unit 102 instructs the synthesis unit 109 to synthesize a partial space rendering image. The synthesizer 109 performs the following calculation for each pixel using the distance data d stored in the product-sum buffer 108.
[0074]
a = exp (−K · d) (Formula 1)
(Where K is a constant indicating the attenuation rate when light passes through the subspace)
The attenuation amount of light is obtained by the following formula. And
Ce = Cb · a + Cv · (1.0−a) (Formula 2)
In this equation, color information from the viewpoint position is determined for each pixel.
[0075]
Cb is color information stored in the frame buffer 106, and Cv indicates color information of the partial space. A is obtained by the following equation.
[0076]
The combining unit 109 performs the above calculation and stores the value of Ce in the frame buffer 106.
[0077]
Thereby, the display unit 111 can display and output an image in consideration of light irradiation to the partial space.
[0078]
As described above, according to the present embodiment, it is possible to generate a fine particle model that exists uniformly in a partial space in a real and high speed so that the thickness thereof can be understood. As a result, it is possible to realize an image generation apparatus that can express light, three-dimensional tomographic data, and the like in real time and at high speed.
[0079]
Next, a second embodiment for expressing the glow will be described with reference to FIGS.
[0080]
FIG. 7 shows a configuration example in the second embodiment.
[0081]
The apparatus includes a model data storage unit 101, a shape rendering unit 103, a frame buffer 106, a depth buffer 107, a display unit 111, a glow plate generation unit 702, and an image generation that controls the operation of each component. And a control unit 701.
[0082]
The model data storage unit 101, the shape rendering unit 103, the frame buffer 106, the depth buffer 107, and the display unit 111 are the same as those given the same reference numerals in FIG.
[0083]
The image generation control unit 701 renders model data other than the light bleed by activating the shape rendering unit 103, and expresses the light bleed by activating the light plate generation unit 702.
[0084]
Now, with reference to FIG. 8, an outline of the process of expressing the glow performed by the glow plate generating unit 702 will be described.
[0085]
Here, as shown in FIG. 8A, it is assumed that a light source 801 for illumination and a viewpoint 401 exist. The light source 801 exists on the Z-axis of the X, Y, Z coordinate system with the point 803 on the object 802 to be irradiated as the origin, and the region 804 is an illumination area. The coordinates of the viewpoint 401 are (Ex, Ey, Ez), and the gaze point 805 that is the coordinates (Ax, Ay, Az) is being watched. The line of sight is represented by 806.
[0086]
The glow plate 811 for expressing the glow is generated as shown in FIGS. 8B and 8C.
[0087]
First, a straight line 807 obtained by projecting the line of sight 806 on the XY plane is obtained by calculation. Next, a straight line 808 parallel to the straight line 807 and passing through the coordinate system origin 803 is determined. Next, a straight line 809 that is orthogonal to the straight line 808 on the XY plane is generated at predetermined intervals so as to cover the illumination area 804. Next, a straight line 810 parallel to the straight line 809 and passing through the light source position 801 is obtained.
[0088]
The glow plate 811 is generated as a plane including the straight line 810 and each straight line 809.
[0089]
A translucent attribute pattern is generated as shown in FIGS. 8D and 8E for the light-emitting plate 811 generated as described above. FIG. 8D is an image viewed from the viewpoint 401. As shown in FIG. 8D, the light from the light source position 801 is irradiated to the irradiation objects 802 and 812.
[0090]
Reference numeral 814 denotes a light beam blocked by an irradiation object 802, 812 or the like.
[0091]
FIG. 8E shows the contents of the depth buffer 107 when the irradiation objects 802 and 812 are projected in the light irradiation direction from the light source position 801 in FIG. 8D. As shown in FIG. 8E, the depth buffer 107 stores distances Z0 and Z1 from the light source position 801 to the irradiation objects 802 and 812 as shown in the figure. In FIG. 8E, reference numerals 816 and 815 denote the x-axis and y-axis for the depth buffer 107, respectively. The shape rendering unit 103 creates data to be stored in the depth buffer 107. That is, the image generation control unit 701 gives the illumination position and the illumination direction as viewpoint information to the shape rendering unit 103, and further gives the shape data of the irradiation area irradiated with light to the shape rendering unit 103. Data to be stored in the depth buffer 107 is generated. Then, based on the generated depth data, a translucent attribute pattern of the glow plate is determined for each plate.
[0092]
As shown in FIG. 8E, the glow plate is observed as a straight line 817 when viewed from the light source position. By tracing this straight line 817 and obtaining depth data, the distance that the illumination reaches on the glowing plate 811 can be obtained.
[0093]
Also, the semitransparent attribute is set up to the distance indicated by the value stored in the depth buffer 107, starting from the light source position 813 on the glow plate 811.
[0094]
In addition, a transparent attribute may be set for a portion longer than the distance indicated by the value stored in the depth buffer 107 or a portion that does not become an illumination area. The lower part of FIG. 8 (e) shows each light-emitting plate 811. The white part is the part for setting the translucent attribute.
[0095]
By such processing, a cross section of the light beam can be generated on the light beam plate 811. A translucent attribute pattern can be generally expressed as a surface attribute of a shape by a technique called texture mapping.
[0096]
By instructing the shape rendering unit 103 to draw the light plate 811 generated by the above processing, it is possible to express the light beam blocked by the irradiation objects 802, 812 and the like. At this time, the drawing of the glowing plate 811 may be performed in order from the farthest from the viewpoint position.
[0097]
In addition, when setting the attributes of the glow plate, as shown in FIG. 9, a plurality of types of attribute patterns 901 having a lower transparency at the center and higher transparency toward the periphery are prepared in advance. Therefore, it is also possible to set an attribute pattern by cutting out only a necessary part (see FIG. 9, 902). In addition, by changing the transparency linearly with respect to the distance from the center or inversely proportional to the square of the distance from the center, the attenuation state of the illumination light according to the distance can be expressed realistically. It becomes possible.
[0098]
When creating data stored in the depth buffer 107 when viewed from the light source position, depth information is generated so that the viewpoint direction is equal to the X-axis 816 direction or Y-axis 815 direction of the buffer. If this is done, the attribute setting process of the glowing plate 811 is facilitated, which is preferable.
[0099]
The more the amount of light plate generated, the more realistic the expression of the light plate, but it is also conceivable to change the amount of light plate generated according to the viewpoint position 401 and the position of the light beam. That is, when the viewpoint position 401 is close to the position of the light beam, a large amount of light plate is generated, and when it is far, the generation amount of the light plate is decreased. Such perspective may be determined by providing a threshold value. It is also conceivable to change the illumination according to the number of objects that shield the illumination.
[0100]
As described above, according to the second embodiment, it is possible to perform realistic and high-speed expression of a light beam blocked by a shielding object. In addition, the state where light is attenuated can be expressed realistically.
[0101]
Next, an embodiment of a so-called glare expression method that occurs due to the diffraction phenomenon of light when looking at high brightness will be described with reference to FIGS.
[0102]
FIG. 10 shows an apparatus configuration example according to the third embodiment.
[0103]
This apparatus performs image generation by controlling operations of the model data storage unit 101, the shape rendering unit 103, the frame buffer 106, the depth buffer 107, the display unit 111, the glare plate generation unit 1002, and the respective units. And an image generation control unit 1001 to be configured. The model data storage unit 101, the shape rendering unit 103, the frame buffer 106, the depth buffer 107, and the display unit 111 are the same as those shown in FIG.
[0104]
The image generation control unit 1001 causes the shape rendering unit 103 to render model data other than glare, and causes the glare plate generation unit 1002 to generate the glare expression.
[0105]
The glare plate generation unit 1002 prepares and prepares image data for expressing glare as shown in FIG. 11A, that is, glare patterns 1101 and 1102 in advance. It goes without saying that the illustrated glare pattern is an example.
[0106]
For these glare patterns, attributes that change the transparency are set. That is, a portion that is not related to the glare expression is transparent, and a semi-transparent attribute is set only for the portion of the glare pattern.
[0107]
Next, from the illumination information for the model data, the position of the point 1104 where the illumination is to be projected on the screen 1103 of the display unit 111 is calculated.
[0108]
FIG. 11B shows a point 1104 on the display screen 1103 of the display unit 111.
[0109]
Next, the glare plate generation unit 1002 calculates how much illumination is incident on the viewpoint from the illumination information. This calculation is performed by the following equation.
[0110]
I = Io · F (θ) / r ² (Formula 3)
Here, Io represents the luminance of illumination, and r represents the distance to the light source position. Further, F (θ) is a value that takes into consideration the directivity of illumination. When the light source has directivity like a spotlight, F (θ) takes a value that takes into consideration directivity characteristics. On the other hand, for a light source having no directivity, It becomes a constant value. Note that θ is an angle formed by the illumination direction 1202 at the illumination position 1201 and the viewpoint position 401, as shown in FIG. Note that reference numeral 1203 indicates the outermost light beam at which the illumination light is visible at a certain viewpoint position.
[0111]
The glare plate generation unit 1002 appropriately changes the size and transparency of the glare pattern 1101 and superimposes and synthesizes it on the projection position 1104 of the illumination based on the obtained luminance of the illumination at the viewpoint.
[0112]
As a method of superimposing and combining, glare patterns can be mapped to a plane as texture data, and the glare can be expressed at high speed by using the semi-transparent mapping function of texture mapping. At this time, the plane on which the texture mapping is performed is directly opposed to the line of sight, and the position is set at the illumination position. Also, Z-Buffer comparison processing is not performed at the time of plane rendering.
[0113]
Further, a lens flare generated when a high-intensity illumination is taken with a photograph or the like is appropriately set on a line connecting the center position of the screen (light points of lines a and b in FIG. 11C) and the projection position 1104 of the illumination. It can be expressed by arranging. This is shown in FIG.
[0114]
It is also conceivable to extract a high-brightness portion on the screen from the result of the illuminance calculation processing by the shape rendering unit 103 and express it in glare. That is, the result of rendering the shape by the shape rendering unit 103 is stored in the frame buffer 106. The data stored in the frame buffer 106 is sequentially examined, and an area in which the brightness higher than the expressible brightness is stored is obtained from the characteristics of the camera. Thereafter, the size and transparency of the glare pattern 1101 are changed according to the brightness value of the obtained position of high brightness, and superposition and synthesis are performed. Also by such a method, glare can be expressed for a high luminance part.
[0115]
As described above, according to the present embodiment, real and high-speed glare can be expressed.
[0116]
Next, an apparatus configuration including the glow generation unit 110 and the glare generation unit will be described with reference to FIG.
[0117]
This apparatus includes a model data storage unit 101, a shape rendering unit 103, a frame buffer 106, a depth buffer 107, a display unit 111, a glare plate generation unit 1002, a glare generation unit 110, and the operation of each unit. And an image generation control unit 1301 that controls to generate an image.
[0118]
Here, the model data storage unit 101, the shape rendering unit 103, the frame buffer 106, the depth buffer 107, and the display unit 111 are the same as those shown in FIG.
[0119]
The glare plate generation unit 1002 is the same as that shown in FIG.
In contrast, the light generation unit 110 may employ either the light generation unit 110 shown in FIG. 1 or the light generation unit shown in FIG.
[0120]
Further, the image generation control unit 1301 is a unit that combines the functions of the image generation control unit 102 shown in FIG. 1 or the image generation control unit 701 shown in FIG. 7 and the function of the image generation control unit 1001 shown in FIG. It is.
[0121]
Since the detailed operation is the same as described above, it is possible to express the light and glare realistically and at high speed with this apparatus, although avoiding redundant explanation.
[0122]
By the processing performed by the present apparatus, for example, as shown in FIG. 14, it is possible to express the glare of the headlight and the glare of the headlight as shown in FIG. Such a drawing process can be applied to a system such as a drive simulator or a flight simulator to construct a system for displaying a high-quality image.
[0123]
【The invention's effect】
As described above, according to the present invention, by performing rendering in consideration of a partial space in which fine particles, three-dimensional tomographic data, and the like are present, it is possible to express a glow in real and high speed. According to the present invention, glare can be expressed realistically and at high speed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 3 is an explanatory diagram of an example of image generation according to the present invention.
4 is an enlarged view taken along line BB ′ of FIG.
FIG. 5 is an explanatory diagram of attenuation.
FIG. 6 is an explanatory diagram of processing performed by a difference calculation unit.
FIG. 7 is a configuration diagram of a second embodiment of the present invention.
FIG. 8 is an explanatory diagram of processing according to the second embodiment.
FIG. 9 is an explanatory diagram of an attribute pattern expressing transparency.
FIG. 10 is a configuration diagram of a third embodiment of the present invention.
FIG. 11 is an explanatory diagram of processing according to the third embodiment.
FIG. 12 is an explanatory diagram of a relationship between an illumination irradiation direction and a line of sight.
FIG. 13 is a configuration diagram of another embodiment of the present invention.
FIG. 14 is an explanatory diagram of a processing result according to another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 ... Model data storage part 102 ... Image generation control part 103 ... Shape rendering part 104 ... Boundary rendering part 105 ... Difference calculation part 106 ... Frame buffer 107 ... Depth buffer 108 ... Product-sum buffer 109 ... Combining unit, 110 ... Glow generating unit, 111 ... Display unit

Claims (9)

A frame buffer for storing color information for each pixel;
Display means for performing display output with reference to the contents of the frame buffer;
Boundary rendering means for outputting depth data from a specific position for each pixel constituting the boundary shape with respect to the boundary shape of the subspace that occupies a certain volume;
Determining whether or not the pixels constituting the boundary shape are present at a specific position when viewed from the specific position, and encoding the corresponding depth data according to a predetermined rule, Difference calculating means for performing the addition / subtraction processing on all the pixels constituting the boundary shape;
Using the processing result of the difference calculation means for each pixel, the light attenuation amount of each pixel is calculated, and further, color information of the storage position of the corresponding frame buffer, color information of a predetermined partial space and, based on the attenuation of the light, it sets the color information of the pixel, synthesizing means for performing a process of storing in the corresponding location in the frame buffer,
An image generation apparatus having Model data storage means for storing the shape of the object to be displayed, model data including arrangement information, and position information of the viewpoint for observing the object;
Image generation control means for controlling processing for generating a two-dimensional image obtained by observing an object from the viewpoint position with reference to the model data and the position information of the viewpoint;
Shape rendering means for performing drawing generation processing of a two-dimensional image according to the control operation of the image generation control means with reference to the model data;
A frame buffer for storing the processing result of the shape rendering means for each pixel as image data;
A depth buffer for storing depth data from a viewpoint position to model data for performing hidden surface removal processing;
Display means for performing display output with reference to the contents of the frame buffer, and
Boundary rendering means for outputting depth data from a specific position for each pixel constituting the boundary shape with respect to the boundary shape of the subspace that occupies a certain volume;
Determining whether or not the pixels constituting the boundary shape are present at a specific position when viewed from the specific position, and encoding the corresponding depth data according to a predetermined rule, Difference calculating means for performing the addition / subtraction processing on all the pixels constituting the boundary shape;
Using the processing result of the difference calculation means for each pixel, the light attenuation amount of each pixel is calculated, and further, color information of the storage position of the corresponding frame buffer, color information of a predetermined partial space and, based on the attenuation of the light, it sets the color information of the pixel, synthesizing means for performing a process of storing in the corresponding location in the frame buffer,
An image generation apparatus comprising: The image generation control means according to claim 2,
First, the frame buffer, the depth buffer is initialized,
Secondly, the model data is read from the model data storage means, the shape rendering means is activated to generate an image viewed from the viewpoint, and the image generated data is stored in the frame buffer,
Third, generate a boundary shape of the partial space, activate the boundary rendering means and difference calculation means ,
Fourth, images generator you characterized by activating the synthesis means. In claim 2, assuming that there are light sources and obstacles,
The partial space is a space indicating a predetermined amount of volume to which the irradiation light from the light source reaches, and the image generation control means applies the light to the boundary shape of the obstacle that will make a shadow by the irradiation light. the direction generated by extending in opposite directions, the resulting boundary shape, images generator you characterized by providing said boundary rendering means. In claim 2, assuming data distributed in a three-dimensional space,
The partial space indicates a space where the distribution density of the data is a predetermined value or more or a predetermined value or less,
The image generation control means, the distribution density of the data, the generated boundary shape against a predetermined value or more or a predetermined value or less subspace, images generator you characterized by providing said boundary rendering means. A frame buffer for storing color information for each pixel;
Display means for performing display output with reference to the contents of the frame buffer;
When it is assumed that a light source that illuminates a three-dimensional object and an obstacle exist, a plurality of surfaces parallel to the irradiation direction are generated, and the distance between the light source and the obstacle that blocks light is obtained along each surface. against said surface, and hand stage to set the transparency in accordance with the distance from the light source,
An image generation apparatus comprising: a shape rendering unit that performs rendering according to transparency on each surface and stores a rendering result in the frame buffer. Model data storage means for storing the shape of the object to be displayed, model data including arrangement information, and position information of the viewpoint for observing the object;
Image generation control means for controlling processing for generating a two-dimensional image obtained by observing an object from the viewpoint position with reference to the model data and the position information of the viewpoint;
Shape rendering means for performing drawing generation processing of a two-dimensional image according to the control operation of the image generation control means with reference to the model data;
The processing results of the shape rendering unit, and a frame buffer for storing each pixel as image data,
A depth buffer for storing depth data from a viewpoint position to model data for performing hidden surface removal processing;
Display means for performing display output with reference to the contents of the frame buffer, and
When it is assumed that a light source that illuminates a three-dimensional object and an obstacle exist, a plurality of surfaces parallel to the irradiation direction are generated, and the distance between the light source and the obstacle that blocks the light is obtained along each surface. against said surface, and a hand stage to set the transparency in accordance with the distance from the light source,
Further, the shape rendering unit has a function of performing drawing according to transparency on each surface and storing a drawing result in the frame buffer.   An image generation method performed by a computer having a frame buffer for storing color information for each pixel and display means for performing display output with reference to the contents of the frame buffer,
  A step of calculating depth data from a specific position for each pixel constituting the boundary shape with respect to the boundary shape of a partial space that occupies a certain volume;
  Determining whether or not the pixels constituting the boundary shape are present at a specific position when viewed from the specific position, and encoding the corresponding depth data according to a predetermined rule. A difference calculation step for performing the addition / subtraction process on all the pixels constituting the boundary shape;
  Using the processing result for each pixel in the difference calculation step, the light attenuation amount of each pixel is calculated, and color information of the storage position of the corresponding frame buffer is determined in advance. Determining the color information of the pixel using the color information of the partial space and the amount of light attenuation, and storing the color information in the corresponding position in the frame buffer.
An image generation method characterized by the above.   A frame buffer for storing color information for each pixel;
  Display means for performing display output with reference to the contents of the frame buffer;
  Boundary rendering means for obtaining depth data from a specific position for each pixel constituting the boundary shape with respect to the boundary shape of a partial space that occupies a certain volume;
  Using the obtained depth data, difference calculating means for calculating distance information indicating the sum of the depths of the partial spaces for each pixel;
  Using the distance information for each pixel calculated by the difference calculation means, the light attenuation amount for each pixel is calculated, and further, the color information of the storage position of the corresponding frame buffer, the color of the predetermined partial space Combining means for determining the color information of the pixel using the information and the attenuation amount of the light, and storing the information at a corresponding position in the frame buffer;
An image generation apparatus having

Images