Digital camera
First Claim
1. A digital camera comprising:
- an imaging device including a two-dimensional array of pixels for receiving an optical image of a subject to generate an image signal;
a driver for driving a taking lens in steps each producing movement of said taking lens through a distance greater than a depth of field;
a calculator for calculating an evaluation value based on the image signal obtained from said imaging device in each position to which said taking lens is driven;
a processor for performing an interpolation process upon a plurality of evaluation values obtained in respective positions to which said taking lens is driven to determine an in-focus position of said taking lens; and
a controller for controlling said driver to drive said taking lens to said in-focus position, based on a processing result from said processor.
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Accused Products
Abstract
A taking lens is driven in steps each producing movement of the taking lens through a distance greater than a depth of field, and an evaluation value is determined based on a captured image obtained from a CCD imaging device in each position to which the lens is driven. Then, a predetermined interpolation process is performed on a plurality of evaluation values obtained in respective positions to which the lens is driven to derive an in-focus position of the taking lens for bringing an in-focus plane into coincidence with an imaging plane. The taking lens is driven to the in-focus position to achieve an in-focus condition. This allows efficient determination of the in-focus position in a digital camera.
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Citations
20 Claims
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1. A digital camera comprising:
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an imaging device including a two-dimensional array of pixels for receiving an optical image of a subject to generate an image signal;
a driver for driving a taking lens in steps each producing movement of said taking lens through a distance greater than a depth of field;
a calculator for calculating an evaluation value based on the image signal obtained from said imaging device in each position to which said taking lens is driven;
a processor for performing an interpolation process upon a plurality of evaluation values obtained in respective positions to which said taking lens is driven to determine an in-focus position of said taking lens; and
a controller for controlling said driver to drive said taking lens to said in-focus position, based on a processing result from said processor. - View Dependent Claims (2, 3, 4, 5)
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6. A digital camera comprising:
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an imaging device including a two-dimensional array of pixels for receiving an optical image of a subject to generate an image signal;
a first driver for driving a taking lens;
a second driver for driving a diaphragm having a variable aperture diameter; and
a controller for controlling said first driver to drive said taking lens, with said diaphragm adjusted to a first aperture diameter smaller than a second aperture diameter by controlling said second driver, to calculate an evaluation value based on a captured image obtained from said imaging device in each position to which said taking lens is driven, thereby determining a direction in which said taking lens is to be driven. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of controlling autofocus, comprising the steps of:
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receiving an optical image of a subject at an imaging device including a two-dimensional array of pixels to generate an image signal;
driving a taking lens in steps each producing movement of said taking lens through a distance greater than a depth of field;
calculating an evaluation value based on the image signal obtained from said imaging device in each position to which said taking lens is driven;
performing an interpolation process upon a plurality of evaluation values obtained in respective positions to which said taking lens is driven to determine an in-focus position of said taking lens; and
driving said taking lens to said determined in-focus position.
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20. A method of controlling autofocus, comprising the steps of:
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receiving an optical image of a subject at an imaging device including a two-dimensional array of pixels to generate an image signal;
calculating a change in evaluation value based on the image signal obtained from said imaging device before and after said taking lens is driven;
adjusting a diaphragm to a first aperture diameter smaller than a second aperture diameter when said change in evaluation value is less than a predetermined value; and
calculating an evaluation value based on a captured image obtained from said imaging device, with said diaphragm adjusted to said first aperture diameter, to determine a direction in which said taking lens is to be driven.
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Specification