Method and system for generating intrinsic images using a smooth illumination constraint
AssigneeTandent Vision Science, Inc.
InventorsAndrew Neil Stein, Casey Arthur Smith
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Abstract
In a first exemplary embodiment of the present invention, an automated, computerized method is provided for processing an image. According to a feature of the present invention, the method comprises the steps of providing an image file depicting an image, in a computer memory, organizing information relevant to the image according to a smooth-illumination constraint enforcing a Laplacian filter response such that ∇2ƒ(x, y)=0 and utilizing the smooth-illumination constraint to generate an intrinsic image from the image.
Claims11
An automated, computerized method for processing an image, comprising the steps of:
- providing an image file depicting an image, in a computer memory;
- organizing information relevant to the image according to a smooth-illumination constraint enforcing a Laplacian filter response such that ∇2ƒ(x, y)=0;
- and
- utilizing the smooth-illumination constraint to generate an intrinsic image from the image,
- wherein the organizing includes applying the Laplacian filter response, ∇2ƒ(x, y)=0, to a log-illumination image,
- wherein the organizing includes approximating second derivatives in the x and y directions to represent ∇2ƒ(x, y) with discrete centered differences to provide a Laplacian filtering kernel, wherein the organizing includes convolving the Laplacian filtering kernel with ƒ(x, y) to develop a linear system of constraints,
- wherein the linear system of constraints is developed by applying the Laplacian filtering kernel to log-image data to generate a right-hand side of the linear system of constraints and building a left-hand matrix enforcing the same linear filtering relationship on unknown values.
A computer system which comprises:
- a CPU;
- and
- a memory storing an image file containing an image;
- the CPU arranged and configured to execute a routine to organize information relevant to the image according to a smooth-illumination constraint enforcing a Laplacian filter response such that ∇2ƒ(x, y)=0 and utilize the smooth-illumination constraint to generate an intrinsic image from the image,
- wherein the organizing includes applying the Laplacian filter response, ∇2ƒ(x, y)=0, to a log-illumination image,
- wherein the organizing includes approximating second derivatives in the x and y directions to represent ∇2ƒ(x, y) with discrete centered differences to provide a Laplacian filtering kernel, wherein the organizing includes convolving the Laplacian filtering kernel with ƒ(x, y) to develop a linear system of constraints,
- wherein the linear system of constraints is developed by applying the Laplacian filtering kernel to log-image data to generate a right-hand side of the linear system of constraints and building a left-hand matrix enforcing the same linear filtering relationship on unknown values.
A computer program product, disposed on a non-transitory computer readable media, the product including computer executable process steps operable to control a computer to:
- provide an image file depicting an image, in a computer memory, organize information relevant to the image according to a smooth-illumination constraint enforcing a Laplacian filter response such that ∇2ƒ(x, y)=0 and utilize the smooth-illumination constraint to generate an intrinsic image from the image,
- wherein the organizing includes applying the Laplacian filter response, ∇2ƒ(x, y)=0, to a log-illumination image,
- wherein the organizing includes approximating second derivatives in the x and y directions to represent ∇2ƒ(x, y) with discrete centered differences to provide a Laplacian filtering kernel,
- wherein the organizing includes convolving the Laplacian filtering kernel with ƒ(x, y) to develop a linear system of constraints,
- wherein the linear system of constraints is developed by applying the Laplacian filtering kernel to log-image data to generate a right-hand side of the linear system of constraints and building a left-hand matrix enforcing the same linear filtering relationship on unknown values.
Dependencies are inferred from the claim text.