Pyramidal Decomposition for Multi-Resolution Image Filtering
First Claim
1. An image processing system comprising:
- a plurality of stages (31-33, 41-43), each stage of the plurality of stages (31-33, 41-43) including;
a downsampler (110, 120, 130) that is configured to receive an input image (101, 111, 129) and to produce therefrom a first downsampled image (111, 121, 131) that is provided as the input image of a subsequent stage (32-33, 42-43),a filter (340-360, 440-460) that is configured to filter the input image (101, 111, 129) and to produce therefrom a filtered image (341-361, 441-461),an upsampler (115, 125, 135) that is configured to receive a second downsampled image (346-366, 446-466) and to provide therefrom an upsampled image (116, 126, 136), anda subtractor (140, 150, 160) that is configured to subtract the upsampled image (116, 126, 136) from the filtered image (341-361, 441-461), to provide therefrom a Laplacian image (349-369, 449-469) based on the filtered image (341-361, 441-461).
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Abstract
A modified Laplacian-pyramid method and system filters (340-360, 440-460) the Gaussian image at each level (31-33, 41-43) of the pyramid, and uses the filtered Gaussian image (341-361, 441-461) to produce the Laplacian-pyramid images (349-369, 449-469). The filtering of the Gaussian image is adaptive, and based at least in part on the characteristics of the Gaussian image at each stage. In one example embodiment, two filters (F1, F2) are used at each stage, and the Laplacian image (349-369) is based on a filtered version of the Gaussian image and an upsampled filtered version of a downsampling (346-366) of the Gaussian image. In another example, filter is used, and the Laplacian image (449-469) is based on the filtered version (441-461) of the Gaussian image and an upsampled downsampling (446-466) of the filtered version of the Gaussian image. By forming the Laplacian images (349-369, 449-469) from the filtered Gaussian images (341-361, 441-461), the aliasing conventionally produced by filtering the Laplacian images is substantially reduced.
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Citations
16 Claims
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1. An image processing system comprising:
a plurality of stages (31-33, 41-43), each stage of the plurality of stages (31-33, 41-43) including; a downsampler (110, 120, 130) that is configured to receive an input image (101, 111, 129) and to produce therefrom a first downsampled image (111, 121, 131) that is provided as the input image of a subsequent stage (32-33, 42-43), a filter (340-360, 440-460) that is configured to filter the input image (101, 111, 129) and to produce therefrom a filtered image (341-361, 441-461), an upsampler (115, 125, 135) that is configured to receive a second downsampled image (346-366, 446-466) and to provide therefrom an upsampled image (116, 126, 136), and a subtractor (140, 150, 160) that is configured to subtract the upsampled image (116, 126, 136) from the filtered image (341-361, 441-461), to provide therefrom a Laplacian image (349-369, 449-469) based on the filtered image (341-361, 441-461). - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of processing an image, comprising:
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downsampling (110) an input image (101) to produce a first downsampled image (111) at a first stage (31, 41) of a plurality of stages (31-33, 41-43) that forms an input image (111) to a second stage (32, 42) of the plurality of stages (31-33, 41-43); filtering (340, 440) the input image (101) to produce a filtered image (341, 441); upsampling (115) a second downsampled image (346, 446) to provide an upsampled image (116); and subtracting (140) the upsampled image (116) from the filtered image (341, 441) to produce a Laplacian image (349, 449) based on the filtered image (341, 441). - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification