Real-time rendering of realistic rain
First Claim
Patent Images
1. A computer-implemented method comprising:
- analyzing, static image frames of video content depicting real rain to identify various sizes and shapes of real rain;
automatically modeling, in real-time, images of real rain and associated information to generate synthetic rain particles, wherein the images and associated information are automatically modeled for blending with respective ones of multiple frames of image content, and wherein automatically modeling further comprises;
for each frame of the multiple frames and for each sample raindrop represented by at least a subset of the images;
generating a rain mask for the sample raindrop, the rain mask identifying portion(s) of the frame that will be shaded by the sample raindrop, the rain mask being generated from alpha values defining opacity of the sample raindrop, the alpha values having been modeled to 3-D coordinate space of the frame;
creating a shaded rain mask from the rain mask to specify color and intensity distribution of the sample raindrop, wherein creating the shaded rain mask further comprises determining the color and intensity distribution based on pre-computed radiance transfer values and a transfer function of a sphere model of the sample raindrop, the sphere model having a refractive index of water; and
rendering, in real-time, the synthetic rain particles across respective frames of video content.
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Abstract
Real-time rendering of realistic rain is described. In one aspect, image samples of real rain and associated information are automatically modeled in real-time to generate synthetic rain particles in view of respective scene radiances of target video content frames. The synthetic rain particles are rendered in real-time using pre-computed radiance transfer with uniform random distribution across respective frames of the target video content.
22 Citations
17 Claims
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1. A computer-implemented method comprising:
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analyzing, static image frames of video content depicting real rain to identify various sizes and shapes of real rain; automatically modeling, in real-time, images of real rain and associated information to generate synthetic rain particles, wherein the images and associated information are automatically modeled for blending with respective ones of multiple frames of image content, and wherein automatically modeling further comprises; for each frame of the multiple frames and for each sample raindrop represented by at least a subset of the images; generating a rain mask for the sample raindrop, the rain mask identifying portion(s) of the frame that will be shaded by the sample raindrop, the rain mask being generated from alpha values defining opacity of the sample raindrop, the alpha values having been modeled to 3-D coordinate space of the frame; creating a shaded rain mask from the rain mask to specify color and intensity distribution of the sample raindrop, wherein creating the shaded rain mask further comprises determining the color and intensity distribution based on pre-computed radiance transfer values and a transfer function of a sphere model of the sample raindrop, the sphere model having a refractive index of water; and rendering, in real-time, the synthetic rain particles across respective frames of video content. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer-readable storage medium comprising computer-program instructions executable by a processor, the computer-program instructions, when executed by the processor for:
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creating a set of rain particles from a set of randomly selected rain stroke samples and associated information, the rain stroke samples being randomly selected from a library of extracted rain stroke samples; rendering, in real time, synthetic rain across multiple frames of video content, the synthetic rain being based on respective ones of the rain particles, the rendering comprising; for each frame of the frames, and for each particle of at least a subset of the rain particles; computing, using a graphics processing unit (GPU), velocity, 3-D position, orientation, and shape of an alpha matte associated with the particle; determining, using the GPU, a set of pixels to shade from the alpha matte; calculating a shaded rain mask, using per-pixel shader operations of the GPU in view of the pixels to shade, to specify the color and intensity distribution of pixels using pre-computed radiance transfer values and a transfer function of a sphere model associated with each rain particle, the sphere model having a refractive index of water; and
blending, using the GPU, the alpha matte and a background color associated with the frame with the shaded rain maskbased on the color and the intensity distribution of the pixels to generated a synthetic rain matted frame for presentation to a user. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A computer comprising:
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a processor; and a memory coupled to the processor, the memory comprising computer-program instructions executable by the processor for; randomly selecting static real rain stroke samples from video content; modeling, in real time using a graphics accelerator, the static real rain stroke samples as synthetic rain particles in view of respective scene radiances, wherein modeling the static real rain stroke samples as synthetic rain particles further comprises; converting rain stroke mattes into 3-D coordinate space of respective image frames of video content; calculating velocity, position, and shape attributes of alpha mattes associates with the rain stroke mattes based on previous values, physical laws, and rain stroke distribution criteria; identifying respective rain masks from the alpha masks; using pre-computed radiance transfer values and a transfer function of a sphere model associated with each rain particle, the sphere model having a refractive index of water, to identify pixel color and intensity distributions from the rain masks; and wherein rendering further comprises alpha blending the alpha masks with information associated with identified pixel color and intensity distributions and detected frame background color to create synthetic rain matted scenes for presentation to a user; and rendering the synthetic rain across scenes with uniform random distribution, controllable velocity, and color determined via pre-computed radiance transfer.
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Specification