Method for denoising time-of-flight range images
AssigneeMitsubishi Electric Research Laboratories, Inc.
InventorsMing-Yu Liu, Yuichi Taguchi, Kilho Son
Life of this patent
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Abstract
A method for denoising a range image acquired by a time-of-flight (ToF) camera by first determining locations of edges, and a confidence value of each pixel, and based on the locations of the edges, determining geodesic distances of neighboring pixels. Based on the confidence values, reliabilities of the neighboring pixels are determined and scene dependent noise is reduced using a filter.
Claims17
A method for denoising an image, wherein the image is a time-of-flight (ToF) range image, wherein the image includes a 2D grid of pixels, comprising steps of:
- determining locations of edges, and a confidence value of each pixel;
- determining, geodesic distances of neighboring pixels, wherein the geodesic distances are determined using a binary edge map, wherein a geodesic distance between two neighboring pixels is set to a constant when the two neighboring pixels are not on different sides of an edge of the binary edge map, otherwise, the geodesic distance is set to ∞ infinity;
- determining, based on the confidence values, reliabilities of the neighboring pixels;
- and
- reducing scene dependent noise using a filter, wherein the filter uses the geodesic distances and the reliabilities of the neighboring pixels, wherein the ToF range image is acquired by a ToF range camera, and the steps are performed in a processor.
A method for denoising an image, the image is a time-of-flight (ToF) range image of pixels, such that the ToF range image is acquired by an input interface connected to a processor, wherein the processor stores the ToF range image in a non-transitory computer readable memory, and embodied in the non-transitory computer readable memory is a program executable by the processor for performing the method, comprising:
- determining locations of edges, and a confidence value of each pixel;
- determining, based on the locations of the edges, geodesic distances of neighboring pixels, wherein the geodesic distances are determined using a binary edge map, such that the binary edge map is generated based on the locations of the edges, wherein a geodesic distance between two neighboring pixels is set to a constant when the two neighboring pixels are not on different sides of an edge of the binary edge map, otherwise, the geodesic distance is set to ∞ infinity;
- determining, based on the confidence values, reliabilities of the neighboring pixels;
- reducing scene dependent noise using a filter, such that the filter uses the geodesic distances and the reliabilities of the neighboring pixels, and transforms the image to produce a filtered image;
- and
- outputting the filtered image via an output interface in communication with the processor, wherein noise in the filtered image is less than noise in the image.
A system for denoising an image, wherein the image is a time-of-flight (ToF) range image of pixels, comprising:
- a non-transitory computer readable memory that includes the image stored therein;
- a ToF range camera;
- an output interface;
- and
- a processor connected to the non-transitory computer readable memory, wherein the non-transitory computer readable memory includes embodied thereon a program executable by the processor to:
- acquire, by the processor, the stored ToF range image, wherein the ToF range image is generated by the ToF range camera;
- determine locations of edges, and a confidence value of each pixel;
- determine, geodesic distances of neighboring pixels, wherein the geodesic distances are determined using a binary edge map, such that the binary edge map is generated based on the locations of the edges, such that a geodesic distance between two neighboring pixels is set to a constant when the two neighboring pixels are not on different sides of an edge of the binary edge map, otherwise, the geodesic distance is set to ∞ infinity;
- determine, based on the confidence values, reliabilities of the neighboring pixels;
- reduce scene dependent noise using a filter, such that the filter uses the geodesic distances and the reliabilities of the neighboring pixels, and transforms the image to produce a filtered image;
- and
- output the filtered image via the output interface in communication with the processor, wherein noise in the filtered image is less than noise in the image.
A method for denoising an image, wherein the image is a time-of-flight (ToF) range image of pixels, comprising steps of:
- determining locations of edges, and a confidence value of each pixel;
- determining, based on the locations of the edges, geodesic distances of neighboring pixels;
- determining, based on the confidence values, reliabilities of the neighboring pixels;
- and
- reducing scene dependent noise using a filter, wherein the filter uses the geodesic distances and the reliabilities of the neighboring pixels, such that the filter is
- R
- ^
-
- (
- p
- )
- =
- ∑
- q
- ∈
- N
-
- (
- p
- )
-
- w
-
- (
- p
- ,
- q
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-
- R
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- ∑
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- N
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- (
- p
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- where R(q) is a range at pixel q in the input range image, {circumflex over (R)}(p) is the range value at p N(p) is the neighboring pixels of p, and w(p, q) is a weighting function measuring a relation between the pixels p and q, and that the weighting function is asymmetric and has two exponential (exp) components
- w
-
- (
- p
- ,
- q
- )
- =
- exp
-
- (
- γ
-
-
- C
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-
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-
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- (
- -
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- σ
- 2
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- ,
- where a first factor measures the confidence C of pixel q and a second factor measures a similarity of p and q, γ and σ represent a shape of the filter, G represnts the geodesic distance, wherein the ToF range image is acquired by a ToF range camera, and the steps are performed in a processor.
Dependencies are inferred from the claim text.