JP3648404B2 - Image generating apparatus and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image generation apparatus and a recording medium.
[0002]
[Prior art]
In recent years, the development of computer graphics (CG) has been remarkable, and various objects have been expressed on computers. In particular, graphics hardware can perform coordinate transformation of shape data, illumination processing, final image generation processing at high speed, and images stored in the frame buffer by mixing processing and images currently being processed. There is something that synthesizes at high speed.
Further, the demand for CG is increasing, and there is a demand for more realistic drawing such as reflection and refraction on the object surface, in addition to viewpoint information and motion information, in addition to drawing an object on a computer. .
[0003]
[Problems to be solved by the invention]
One of the realistic drawings considering such reflection and refraction is a method of using a textured mapping of a virtual sphere prepared for reflection as a reflection target. In the reflection effect realization method using this texture mapping function, when the intersection of the reflection vector and the virtual sphere at each vertex of the polygon (triangle) is referenced beyond the reference axis of the virtual sphere, the texture image is inappropriate. There was a problem of being mapped.
In this case, it is possible to reconstruct the polygon in a timely manner so that the intersection of the reflection vector at each vertex of the polygon (triangle) and the virtual sphere does not exceed the reference axis of the virtual sphere. It is unsuitable for the system to do.
[0004]
The present invention has been made in view of such problems, and an object of the present invention is to provide an image generation apparatus that generates a high-quality image in consideration of reflection effects and refraction effects at high speed.
[0005]
[Means for Solving the Problems]
In order to achieve the above-described object, a first invention is an image generation apparatus for generating a computer image, comprising: means for inputting shape information of an object; means for inputting viewpoint information; First image generation means for generating an image of the object based on the viewpoint information, and calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information And second image generation means for generating an image by combining the image created by the first image generation means and the reflection or refraction information, and the calculation means A reflection or refraction information corresponding to a vertex of a polygon of an image on a virtual sphere is calculated, and for a polygon that intersects the reference axis of the virtual sphere, the coordinates of the polygon are corrected. It is a device.
[0006]
According to a second aspect of the present invention, there is provided an image generating apparatus for generating a computer image, wherein: means for inputting object shape information; means for inputting viewpoint information; and based on the object shape information and the viewpoint information. A first image generation unit that generates an image of the object, a calculation unit that calculates and corrects reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information, and the first Second image generation means for generating an image by combining the image created by the image generation means and the reflection or refraction information, and the calculation means Among them, reflection information or refraction information corresponding to the vertex of the polygon is calculated, and for the polygon including the zenith of the virtual sphere, the polygon is divided into a plurality of polygons with the zenith as one vertex. An image generating device.
[0007]
Further, the third invention is an image generation device for generating a computer image, the means for inputting object shape information, the means for inputting motion information of the object, the shape information of the object, and the motion information. A first image generating means for generating an image of the object, a calculating means for calculating and correcting reflection or refraction information on the object surface based on the shape information and the motion information of the object; A second image generation unit configured to generate an image by combining the image created by the first image generation unit and the reflection or refraction information, and the calculation unit is a virtual sphere around the object. An image generating apparatus that calculates reflection information or refraction information corresponding to a vertex of a polygon of the image and corrects the coordinates of the polygon for a polygon that intersects the reference axis of the virtual sphere.
[0008]
According to a fourth aspect of the present invention, there is provided an image generating apparatus for generating a computer image, the means for inputting object shape information, the means for inputting motion information of the object, the shape information of the object, and the motion information. A first image generating means for generating an image of the object, a calculating means for calculating and correcting reflection or refraction information on the object surface based on the shape information and the motion information of the object; A second image generation unit configured to generate an image by combining the image created by the first image generation unit and the reflection or refraction information, and the calculation unit is a virtual sphere around the object. The reflection information or refraction information corresponding to the vertices of the polygon is calculated from the image of the above, and the polygon including the zenith of the virtual sphere is divided into a plurality of polygons with the zenith as one vertex. An image generating device according to symptoms.
[0009]
According to a fifth aspect of the present invention, there is provided an image generation apparatus for generating a computer image, wherein: means for inputting object shape information; means for inputting viewpoint information; and based on the object shape information and the viewpoint information. A first image generation unit that generates an image of the object, a calculation unit that calculates and corrects reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information, and the first Second image generation means for generating an image by combining the image created by the image generation means and the reflection or refraction information, and the calculation means Among them, the reflection information or refraction information corresponding to the vertex of the polygon is calculated, and for a polygon that intersects the reference axis of the phantom sphere, the computer functions as an image generation device that corrects the coordinates of the polygon. Which is a recording medium for recording a gram.
[0010]
According to a sixth aspect of the present invention, there is provided an image generation apparatus for generating a computer image, wherein: means for inputting object shape information; means for inputting viewpoint information; and based on the object shape information and the viewpoint information. A first image generation unit that generates an image of the object, a calculation unit that calculates and corrects reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information, and the first Second image generation means for generating an image by combining the image created by the image generation means and the reflection or refraction information, and the calculation means Among them, the reflection information or the refraction information corresponding to the vertex of the polygon is calculated, and for the polygon including the zenith of the virtual sphere, the polygon is divided into a plurality of polygons with the zenith as one vertex. A recording medium for recording a program that causes a computer to function.
[0011]
Further, a seventh invention is an image generation apparatus for generating a computer image, wherein means for inputting object shape information, means for inputting motion information of the object, shape information of the object, and motion information A first image generating means for generating an image of the object, a calculating means for calculating and correcting reflection or refraction information on the object surface based on the shape information and the motion information of the object; A second image generation unit configured to generate an image by combining the image created by the first image generation unit and the reflection or refraction information, and the calculation unit is a virtual sphere around the object. A computer is used as an image generating device for calculating the reflection information or refraction information corresponding to the vertex of the polygon in the image and correcting the coordinates of the polygon for the polygon intersecting the reference axis of the virtual sphere. A recording medium for recording a program for.
[0012]
Further, an eighth invention is an image generation device for generating a computer image, wherein means for inputting shape information of an object, means for inputting motion information of the object, shape information of the object, and motion information A first image generating means for generating an image of the object, a calculating means for calculating and correcting reflection or refraction information on the object surface based on the shape information and the motion information of the object; A second image generation unit configured to generate an image by combining the image created by the first image generation unit and the reflection or refraction information, and the calculation unit is a virtual sphere around the object. The reflection information or refraction information corresponding to the vertices of the polygon is calculated from the image of the image, and the polygon including the zenith of the virtual sphere is divided into a plurality of polygons with the zenith as one vertex. A program that causes a computer to function as a device which is a recording medium for recording.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an image generation apparatus 1 according to the present embodiment.
[0014]
In FIG. 1, the image generation device 1 creates CG image data based on the three-dimensional CG data read from the external storage device 2 and the viewpoint information input from the external input device 3, and outputs the CG image data to the external display device 4. .
[0015]
The external storage device 2 connected to the image generation device 1 stores object information including object shape, texture, texture image information, etc., and light source information including type, position, attribute, etc. -ROM or the like. As the external storage device 2, another external storage device connected to a network may be used.
[0016]
The external input device 3 is a device such as a mouse, a keyboard, and a joystick, and inputs viewpoint information such as a position where an object shape is observed.
The external display device 4 is a device that displays an image, and is a CRT display or the like.
[0017]
As shown in FIG. 1, the image generation apparatus 1 includes a CG data reading unit 5, a CG data storage unit 6, a viewpoint information calculation unit 7, a viewpoint information storage unit 8, a first rendering processing unit 9, a reflection information calculation unit 10, 2 rendering processing unit 11. The image generation device 1 is composed of, for example, a single computer.
[0018]
In FIG. 1, a CG data reading unit 5 reads CG data of an object from the external storage device 2, and a CG data storage unit 6 stores it. Further, the viewpoint information calculation unit 7 calculates viewpoint position coordinates and the like from the viewpoint information input by the external input device 3 and stores them in the viewpoint information storage unit 8.
[0019]
The first rendering processing unit 9 generates an object image, and the reflection information calculation unit 10 calculates reflection information on the object surface. The generated object image and reflection information are combined by the second rendering processing unit 11.
[0020]
Processing in each unit of the image generation device 1 will be described below. FIG. 2 is a flowchart showing image generation processing by the image generation apparatus 1.
In FIG. 1, the CG data reading unit 5 reads the three-dimensional CG data of the object from the external storage device 2 and stores it in the CG data storage unit 6 (step 201).
[0021]
Next, viewpoint position coordinates and the like are calculated by the viewpoint information calculation unit 7 from the viewpoint information input by the external input device 3 and stored in the viewpoint information storage unit 8 (step 202). FIG. 3 is a diagram showing the viewpoint 35 and the reflection angle ν. The viewpoint information calculation unit 7 calculates the position coordinates and the like of the viewpoint 35 specified by the mouse or the like and stores it in the viewpoint information storage unit 8.
[0022]
Next, the first rendering processing unit 9 performs an object rendering process from the CG data of the object and the viewpoint information in consideration of an illumination effect or the like (step 203). This rendering process is performed by computer graphics hardware.
[0023]
FIG. 4 is a diagram illustrating a car 41 that is a drawing target object, and FIG. 5 is a diagram illustrating rendering data in the pixel 49. CG data such as the coordinates of the car 41 is read from the external storage device 2 to the CG data reading unit 5 and stored in the CG data storage unit 6. The first rendering processing unit 9 performs the rendering process of the car 41 in consideration of the illumination effect from the CG data of the car 41, the viewpoint position, the light source position, and the like.
[0024]
As shown in FIG. 5, the rendering data of the pixel 49 at the end of the first rendering by the first rendering processing unit 9 has pixel colors R (red), G (green), and B (blue) components (r1, g1, b1) and the alpha value (weighting coefficient) is α1. In order to realize the reflection effect, α1 is normally “1.0”, but any value can be set.
[0025]
Next, the reflection information calculation unit 10 calculates texture coordinates and reflectance for mapping the reflection texture image at each vertex of the object shape (step 204), and the second rendering processing unit 11 is processed in step 203. The reflection effect calculated using the texture coordinates and the reflectance calculated in step 204 is combined and rendered on the image (step 205). The combined and rendered image is displayed on the external display device 4 (step 206).
[0026]
The reflection information calculation unit 10 shown in FIG. 1 calculates texture coordinates and reflectance for mapping a reflection texture image by a method described later. The second rendering processing unit 11 sets the texture coordinates of each vertex of the object shape to the texture coordinates calculated by the reflection information calculation unit 10, sets the alpha value to the reflectance calculated by the reflection information calculation unit 10, An image used for texture mapping is set as a reflection texture, and the image generated by the first rendering processing unit is combined and rendered.
[0027]
That is, for example, in the pixel 49 shown in FIG. 5, when the pixel color being processed by the second rendering processing unit 11 is (r2, g2, b2) and the alpha value is α2, the pixel 49 at the end of the second rendering process The final value is (α1 × r1 + α2 × r2, α1 × g1 + α2 × g2, α1 × b1 + α2 × b2). In this case, the corresponding reflectance value of each polygon is set in α2.
[0028]
Since such a composite rendering process is performed by computer graphics hardware, it is processed at a very high speed.
The final image created in this way is displayed by the external output device 4 shown in FIG.
[0029]
In FIG. 5, rendering is performed for each pixel. Actually, however, for example, the surface of the car 41 shown in FIG. 4 is divided into triangular polygons, and the vertex pixels of each polygon are used. The process shown in FIG. 5 is performed. A rendering value corresponding to a pixel inside the polygon is obtained by interpolating the obtained rendering value of each vertex.
[0030]
Hereinafter, a method for calculating the texture coordinates and the reflectance for mapping the reflection texture image at each vertex of the object shape as the reflection information will be described in detail. FIG. 6 shows the definition of the texture coordinates 50. The texture coordinates 50 are defined with the horizontal direction of the image being U and the vertical direction being V, and a range of 0.0 to 1.0 is assigned respectively.
[0031]
When mapping a texture image to a polygon, a range is designated using the texture coordinates. FIG. 7 shows an example of a texture image. In FIG. 7, the texture image 53 has a texture U coordinate of 0.3 to 0.7, a texture V coordinate of 0.0 to 1.0, and is mapped to a polygon.
[0032]
In addition, a value of 1.0 or more can be specified for U and V. In this case, several folding methods such as lap and mirror are selected. FIG. 8 shows an example of the wrap 55 and the mirror 57.
[0033]
FIG. 9 shows the definition of the phantom sphere 43. As shown in FIG. 9, with the origin of the phantom sphere 43 as the center, the upward direction is the Y axis and the depth direction is the Z axis, which are defined in the left-handed coordinate system. The texture U coordinates are set around the Z axis, the texture V coordinates are set in the vertical direction, and the U and V coordinates are associated with each other in the range of 0.0 to 1.0.
That is, if the virtual sphere 43 is compared to the earth, U corresponds to longitude and V corresponds to latitude with the South Pole being “0”.
Note that the definition of the axis of the phantom sphere 43 may be changed to the right-handed coordinate system. Further, the correspondence between the texture coordinates U and V and each axis of the virtual sphere 43 may be changed to another combination.
[0034]
FIG. 10 is a flowchart of reflection information calculation. That is, the process of step 204 in FIG. 2 is shown in detail. The incident vector 36 at the vertex P is calculated from the position coordinates of the viewpoint 35 and the normal vector 39, etc. (step 301).
[0035]
Next, a reflection vector 37 with respect to the incident vector 36 is calculated (step 302).
[0036]
Next, the intersection of the reflection vector 37 and the phantom sphere 43 is calculated, and the texture coordinates U and V and the reflectance are calculated (step 303). The X flag and Z flag indicating whether each intersection exists in the positive or negative area of X or Z are also stored. In the present embodiment, as shown in FIG. 4, the target object whose intersection is to be obtained is provided with a virtual sphere 43 around the vehicle 41 to be drawn, and an image pasted on the virtual sphere 43 is used as a texture image 45. .
[0037]
The reflectance is calculated from a reflectance function W (γ) prepared in advance according to the material. Here, γ is an angle formed by the reflection vector 37 and the normal vector 39, that is, the reflection angle as shown in FIG. FIG. 11 is a diagram illustrating an example of the reflectance W (γ) with respect to the reflection angle γ.
[0038]
After the processing from step 301 to step 303 is performed on each vertex of the object shape, the texture coordinates are corrected for each polygon (step 304).
[0039]
For the three vertices constituting the polygon, (1) there is at least one vertex whose X flag is positive. (2) The Z flag of all vertices is not positive. (3) There is at least one vertex having a positive Z flag. Polygons that satisfy all of these conditions exist beyond the reference axis of the phantom sphere 43. If texture mapping is performed as it is, an inappropriate image area is mapped. Therefore, the polygon satisfying the conditions (1) to (3) described above has the U coordinate of the vertex whose Z flag exceeding the reference axis is positive. = U + 1.0
[0040]
FIG. 12 shows the correction of the texture coordinates when the polygon exists beyond the reference axis. As shown in FIG. 12A, polygons a1a2a3 satisfying the above conditions (1) to (3) exist beyond the reference axis (U = 0.0) of the phantom sphere. If texture mapping is performed as it is, vertices a1, a2, and a3 are set to texture coordinates a′1, a′2, and a′3, respectively, as shown in FIG. 12B, and inappropriate image areas are mapped. The Accordingly, the U coordinate of the vertex a′1 whose Z flag is positive is corrected to U = U + 1, and appropriate texture mapping is executed.
[0041]
In addition, when the polygon surrounds the zenith of the virtual sphere, a problem occurs even if the texture coordinates are corrected as described above. In this case, the polygon is reconstructed and texture mapping is performed.
[0042]
FIG. 13 shows the reconstruction of a polygon when the polygon surrounds the zenith of the virtual sphere. As shown in FIG. 13A, when the polygon b1b2b3 surrounds the zenith of the phantom sphere, it is necessary to perform an appropriate texture mapping 65 as shown in FIG. 13B. As shown in (c), the vertices b1, b2, and b3 are set to texture coordinates b′1, b′2, and b′3, respectively, and become inappropriate image mapping 67. In this case, the polygon b1b2b3 is divided. In this way, appropriate texture mapping 69 is performed as shown in FIG.
[0043]
The second rendering processing unit 11 performs a composite rendering process of the texture coordinates and reflectance thus obtained and the object image obtained by the first rendering processing unit 9, and a final image is displayed on the external display device 4.
[0044]
Reflection calculation processing and composite rendering processing can also be performed by a program, but high-speed drawing cannot be performed because much calculation time is required. However, if graphics hardware is used as in this embodiment, realistic drawing can be performed at high speed.
[0045]
As described above, according to the present embodiment, it is possible to quickly generate and display a sophisticated image in consideration of the reflection effect depending on the viewpoint using the texture mapping function of the graphic hardware of the computer. Is possible. As a result, a high-quality image can be generated even on a personal computer that does not have a graphic engine.
[0046]
In the present embodiment, the position of the viewpoint 35 is input from the external input device 3. However, it is also possible to fix the viewpoint position and input the amount of movement of the car 41 from the external input device 3. In this case, the reflection effect can be calculated more efficiently by selecting the shape of the virtual object that captures the image in accordance with the amount of movement and the direction of movement of the car 41.
[0047]
Further, although the reflection effect has been described in the present embodiment, refraction calculation is performed using the reflection vector as a refraction vector, and if a refractive index corresponding to the material is prepared, refraction information is calculated and composite rendering processing is similarly performed. Is possible.
[0048]
Further, the program for performing the processing shown in FIG. 2 may be distributed by being held in a recording medium such as a CD-ROM, or the program can be transmitted / received via a communication line.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, a high-quality image in consideration of the reflection effect and the refraction effect can be generated at high speed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an image generation apparatus 1 according to an embodiment of the present invention. FIG. 2 is a flowchart showing image generation processing by the image generation apparatus 1. FIG. 3 is a diagram showing a viewpoint 35 and a reflection angle ν. 4 is a diagram showing a car 41. FIG. 5 is a diagram showing image data of a pixel 49. FIG. 6 is a diagram showing a definition of texture coordinates 50. FIG. 7 is a diagram showing a texture image 53. FIG. 8 is a wrap 55 and a mirror 57. FIG. 9 is a diagram showing a definition of a virtual sphere. FIG. 10 is a flowchart of reflection information calculation. FIG. 11 is a diagram showing a reflectance W (γ) with respect to a reflection angle γ. Fig. 13 is a diagram showing the correction of texture coordinates when it exists beyond the boundary. Fig. 13 is a diagram showing reconstruction of the polygon when the polygon surrounds the zenith of the virtual sphere.
DESCRIPTION OF SYMBOLS 1 ......... Image generation apparatus 2 ......... External storage device 3 ......... External input device 4 ......... External display device 5 ......... CG data reading unit 6 ... CG data storage unit 7 ......... Viewpoint information Calculation unit 8... View information storage unit 9... First rendering processing unit 10... Reflection information calculation unit 11.

Claims (9)

An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting viewpoint information;
First image generation means for generating an image of the object based on the shape information of the object and the viewpoint information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
An image generating apparatus characterized by correcting coordinates of a polygon that intersects a reference axis of the virtual sphere. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting viewpoint information;
First image generation means for generating an image of the object based on the shape information of the object and the viewpoint information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
An image generating apparatus for dividing a polygon including a zenith of the virtual sphere into a plurality of polygons with the zenith as one vertex. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting movement information of the object;
First image generating means for generating an image of the object based on the shape information of the object and the motion information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the motion information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
An image generating apparatus characterized by correcting coordinates of a polygon that intersects a reference axis of the virtual sphere. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting movement information of the object;
First image generating means for generating an image of the object based on the shape information of the object and the motion information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the motion information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
An image generating apparatus for dividing a polygon including a zenith of the virtual sphere into a plurality of polygons with the zenith as one vertex. In the image generation device according to any one of claims 1 to 4,
The second image generation means includes
A first image created by first image generation means and representing the object information in pixel color and alpha value;
A second image representing the reflection or refraction information in terms of pixel color and alpha value;
An image generation apparatus characterized by combining the above. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting viewpoint information;
First image generation means for generating an image of the object based on the shape information of the object and the viewpoint information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
A recording medium that records a program that causes a computer to function as an image generation device that corrects the coordinates of a polygon for a polygon that intersects the reference axis of the virtual sphere. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting viewpoint information;
First image generation means for generating an image of the object based on the shape information of the object and the viewpoint information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the viewpoint information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
A recording medium in which a program that causes a computer to function as an image generation apparatus that divides a polygon including the zenith of the virtual sphere into a plurality of polygons with the zenith as one vertex is recorded. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting movement information of the object;
First image generating means for generating an image of the object based on the shape information of the object and the motion information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the motion information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
A recording medium that records a program that causes a computer to function as an image generation device that corrects the coordinates of a polygon for a polygon that intersects the reference axis of the virtual sphere. An image generation device for generating a computer image,
Means for inputting object shape information;
Means for inputting movement information of the object;
First image generating means for generating an image of the object based on the shape information of the object and the motion information;
Calculation means for calculating and correcting reflection or refraction information on the object surface based on the shape information of the object and the motion information;
Second image generating means for generating an image by combining the image created by the first image generating means and the reflection or refraction information;
Comprising
The calculation means calculates reflection information or refraction information corresponding to a vertex of a polygon in an image on a virtual sphere around the object,
A recording medium in which a program that causes a computer to function as an image generation apparatus that divides a polygon including the zenith of the virtual sphere into a plurality of polygons with the zenith as one vertex is recorded.

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