Dynamic auto-focus window selection that compensates for hand jitter
First Claim
1. A method for auto-focusing an image, wherein the image is captured through a lens, comprising:
- obtaining a first image frame having a first focus window;
moving the lens from a first position to a second position;
obtaining a second image frame having a second focus window;
obtaining a first motion vector between the first and second image frames;
obtaining a third image frame having a third focus window adjusted by the first motion vector to cover substantially the same target image portion as the first focus window; and
comparing the target image in the third focus window with the target image in the first focus window to auto-focus the lens.
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Accused Products
Abstract
The invention relates to methods and devices for mitigating and/or minimizing effects of hand jitter or shaking during an auto-focusing process of an image-capturing device. In order to more accurately focus a lens for capturing a digital image, the lens is moved between a minimum and maximum position (along an axis) while capturing sample image frames using a focus window at various lens positions. Improved auto-focusing is achieved by dynamically adjusting the relative position of the focus window for each image frame to cover substantially the same image portion of the target image. By adjusting the focus window for each image frame to cover substantially the same image portion of the target image, variations from shaking may be minimized, thereby improving auto-focusing.
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Citations
30 Claims
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1. A method for auto-focusing an image, wherein the image is captured through a lens, comprising:
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obtaining a first image frame having a first focus window; moving the lens from a first position to a second position; obtaining a second image frame having a second focus window; obtaining a first motion vector between the first and second image frames; obtaining a third image frame having a third focus window adjusted by the first motion vector to cover substantially the same target image portion as the first focus window; and comparing the target image in the third focus window with the target image in the first focus window to auto-focus the lens. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An image-capturing device, comprising:
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means for obtaining a first image frame having a first focus window; means for moving the lens from a first position to a second position; means for obtaining a second image frame having a second focus window; means for obtaining a first motion vector between the first and second image frames; means for obtaining a third image frame having a third focus window adjusted by the first motion vector to cover substantially the same image portion as the first focus window; and means for comparing the target image in the third focus window with the target image in the first focus window to auto-focus the lens. - View Dependent Claims (12, 13, 14, 15)
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16. An image-capturing device, comprising:
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an image sensor for capturing image frames; and an auto-focus module coupled to the image sensor, the auto-focus module configured to obtain a first image frame having a first focus window; move the lens from a first position to a second position; obtain a second image frame having a second focus window; obtain a first motion vector between the first and second image frames; obtain a third image frame having a third focus window adjusted by the first motion vector to cover substantially the same target image portion as the first focus window; and compare the target image in the third focus window with the target image in the first focus window to auto-focus the lens. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A computer-readable medium having one or more instructions operational on an image-capturing device to mitigate the effects of shaking during auto-focusing, which when executed by a processor causes the processor to:
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obtain a first image frame having a first focus window; move the lens from a first position to a second position; obtain a second image frame having a second focus window; obtain a first motion vector between the first and second image frames; obtain a third image frame having a third focus window adjusted by the first motion vector to cover substantially the same image portion as the first focus window; and compare the target image in the third focus window with the target image in the first focus window to auto-focus the lens. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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Specification