Focal length detecting method, focusing device, image capturing method and image capturing apparatus
First Claim
1. A method of detecting a focal length, comprising:
- obtaining, while changing the focal length of an optical system, multiple image data selected from among image data including brightness data and a plurality of color data; and
calculating a focal length from the obtained multiple image data by using a peak value of contrast evaluated values of said multiple image data.
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Accused Products
Abstract
An image processing circuit enables the accurate detection of the focal length for focusing by using color data. The image processing circuit generates image data representing brightness and each of the colors of red, green and blue, image data to be used for focusing is selected either automatically or manually from the image data representing the brightness and the respective colors, and the amount of the weight for each respective image data is set. Images are photographed while the optical system is driven to change its focal length. A focal length is calculated for each selected image data. Weight is applied to each one of the calculated focal lengths so as to calculate a final focal length. This not only ensures accurate measurement of the distance for focusing but also increases the possibility of focusing on a subject which is characterized by specific color data.
84 Citations
16 Claims
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1. A method of detecting a focal length, comprising:
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obtaining, while changing the focal length of an optical system, multiple image data selected from among image data including brightness data and a plurality of color data; and
calculating a focal length from the obtained multiple image data by using a peak value of contrast evaluated values of said multiple image data. - View Dependent Claims (2, 4, 5, 6)
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3. (canceled)
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7. A focusing device, comprising:
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an image pickup device, an optical system for forming an image on said image pickup device, an optical system driver for changing the focal length of said optical system, and an image processor for processing image data output from said image pickup device and controlling said optical system driver, wherein the image processor is adapted to;
while changing the focal length of said optical system, obtain multiple image data selected from among image data of brightness data and a plurality of color data, and calculate a focal length from the obtained multiple image data by using the peak value of contrast evaluated values of said multiple image data. - View Dependent Claims (8, 9, 10, 11)
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12. An image capturing method, comprising:
using color data of a plurality of colors to detect a focal length for each respective color data and capturing an image at each focal length detected for each respective color data. - View Dependent Claims (13, 14)
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15. An image capturing apparatus, comprising:
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an image pickup device, an optical system for forming an image on said image pickup device, an optical system driver for changing the focal length of said optical system, and an image processor for processing image data output from said image pickup device and controlling said optical system driver, wherein;
the image processor is adapted to;
obtain a plurality of image data of each respective color data while changing the focal length of said optical system, and calculate a focal length for each respective color data mentioned above by using the peak value of contrast evaluated values calculated from the obtained multiple image data, and perform image capturing at each focal length calculated for each respective color data. - View Dependent Claims (16)
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Specification