Compensating for undesirable camera shakes during video capture
First Claim
1. A method of obtaining stable video images of a scene using a video camera, said method comprising:
- receiving a first source frame and a second source frame, wherein said first source frame and said second source frame respectively represent a first image and a second image of a scene captured at different time instances;
generating a first subsampled frame from a first set of pixels in said first source frame and a second subsampled frame from a second set of pixels in said second source frame;
computing a displacement of said second image relative to said first image;
refining said displacement by searching a plurality of pixel locations within said first and second sets of pixels in said first and second source frames for a correspondence to said first and second subsampled frames;
determining if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and
shifting said second source frame by an opposite of said displacement when said sequence of displacements does not follow a uniform pattern.
1 Assignment
0 Petitions
Accused Products
Abstract
An image processor in an image capture device compensates for the effects of undesirable camera shakes occurring during video capture The image processor receives a pair of source frames representing images of a scene, generates a pair of subsampled frames from the source frames, and computes a coarse displacement of the captured image due to camera shakes by comparing the two subsampled frames. The image processor may then refine the determined coarse displacement by comparing the two source frames and a bound determined by an extent of subsampling, and compensate for the displacement accordingly. Display aberrations such as blank spaces caused due to shifting are also avoided by displaying only a portion of the captured image and shifting the displayed portion to compensate for camera shake. The image processor also recognizes displacements due to intentional camera movement, and does not correct for such displacements.
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Citations
21 Claims
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1. A method of obtaining stable video images of a scene using a video camera, said method comprising:
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receiving a first source frame and a second source frame, wherein said first source frame and said second source frame respectively represent a first image and a second image of a scene captured at different time instances; generating a first subsampled frame from a first set of pixels in said first source frame and a second subsampled frame from a second set of pixels in said second source frame; computing a displacement of said second image relative to said first image; refining said displacement by searching a plurality of pixel locations within said first and second sets of pixels in said first and second source frames for a correspondence to said first and second subsampled frames; determining if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and shifting said second source frame by an opposite of said displacement when said sequence of displacements does not follow a uniform pattern. - View Dependent Claims (2, 3)
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4. A method of obtaining stable video images of a scene using a video camera, said method comprising:
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receiving a first set of pixel values representing a first image; displaying a first area which covers only a first portion of said first image; receiving a second set of pixel values representing a second image; determining a displacement of said second image relative to said first image; refining said displacement by searching a plurality of pixel locations comprised in said first area for a correspondence to said first portion; determining if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and displaying a second area which covers only a second portion of said second image, wherein said second area is shifted by opposite of said displacement in relation to said first area and said correspondence. - View Dependent Claims (5, 6, 7)
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8. A machine readable non-transitory medium carrying one or more sequences of instructions for obtaining stable video images of a scene using a video camera, wherein execution of said one or more sequences of instructions by one or more processors contained in said video camera causes said video camera to perform the actions of:
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receiving a first source frame and a second source frame, wherein said first source frame and said second source frame respectively represent a first image and a second image of a scene captured at different time instances; generating a first subsampled frame from a first set of pixels in said first source frame and a second subsampled frame from a second set of pixels in said second source frame; computing a displacement of said second image relative to said first image; refining said displacement by searching a plurality of pixel locations within said first and second sets of pixels in said first and second source frames for a correspondence to said first and second subsampled frames; determining if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and shifting said second source frame by an opposite of said displacement when said sequence of displacements does not follow a uniform pattern. - View Dependent Claims (9, 10)
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11. A machine readable non-transitory medium carrying one or more sequences of instructions for obtaining stable video images of a scene using a video camera, wherein execution of said one or more sequences of instructions by one or more processors contained in said video camera causes said video camera to perform the actions of:
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receiving a first set of pixel values representing a first image; displaying a first area which covers only a first portion of said first image; receiving a second set of pixel values representing a second image; determining a displacement of said second image relative to said first image, said displacement being comprised in a sequence of displacements corresponding to a plurality of images including said first and second images; refining said displacement by searching a plurality of pixel locations within said first and set of pixel values in said first image for a correspondence to said first area; determining if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and displaying a second area which covers only a second portion of said second image, wherein said second area is shifted by opposite of said displacement in relation to said first area and said correspondence. - View Dependent Claims (12, 13, 14)
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15. A video camera designed to provide stable video images of a scene, said video camera comprising:
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an image sensor designed to receive light representing an image of said scene, and generating a plurality of frames including a first source frame and a second source frame, wherein said first source frame and said second source frame respectively represent a first image and a second image of a scene captured at different time instances; and an image processor operable to; receive said first source frame and said second source frame; generate a first subsampled frame from a first set of pixels in said first source frame and a second subsampled frame from a second set of pixels in said second source frame; compute a displacement of said second image relative to said first image by examining said first subsampled frame and said second subsampled frame; refine said displacement by searching a plurality of pixel locations within said first and second sets of pixels in said first and second source frames for a correspondence to said first and second subsampled frames; determine if said displacement is an intentional displacement by determining whether said displacement is comprised in a sequence of displacements following a uniform pattern; and shift said second source frame by an opposite of said displacement when said sequence of displacements is determined to follow a uniform pattern. - View Dependent Claims (16, 21)
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17. A video camera designed to provide stable video images of a scene, said video camera comprising:
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an image sensor designed to receive light representing an image of said scene, and generating a plurality of frames including a first source frame and a second source frame, wherein said first source frame and said second source frame respectively represent a first image and a second image of a scene captured at different time instances; and an image processor operable to; receive a first set of pixel values representing a first image; display a first area which covers only a first portion of said first image; receive a second set of pixel values representing a second image; determine a displacement of said second set of pixel values relative to said first set of pixel values, said displacement being comprised in a sequence of displacements corresponding to a plurality of images including said first and second images; refine said displacement by searching a plurality of pixel locations comprised in said first image for a correspondence in said first portion; determine if said displacement is an intentional displacement by checking whether said sequence of displacements follows a uniform pattern; and display a second area which covers only a second portion of said second image, wherein said second area is shifted by opposite of said displacement in relation to said first area. - View Dependent Claims (18, 19, 20)
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Specification