Digital camera and method of controlling operation of same

• US 20020093577A1
• Filed: 12/27/2001
• Published: 07/18/2002
• Est. Priority Date: 01/12/2001
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Ichikawa, Chiaki, Kitawaki, Reiko
• Granted Patent: US 6,940,550 B2
• Time in Patent Office: Days
• US Class Current: 348/241
• CPC Class Codes: H04N 1/4097 Removing errors due external factors, e.g. dust, scratches
• CPC Class Codes: H04N 23/663 for controlling interchangeable camera parts based on electronic image sensor signals
• CPC Class Codes: H04N 23/811 by dust removal, e.g. from surfaces of the image sensor or processing of the image signal output by the electronic image sensor
• CPC Class Codes: H04N 25/673 by using reference sources
• CPC Class Codes: H04N 25/68 applied to defects

Abstract

An all-white reference subject is imaged by a CCD and image data representing the reference subject is obtained. The position of any dust on the reference subject represented by the reference-subject image data is detected by a dust position detector. Address data representing the position of the dust is stored in a memory that stores dust address data. When the user images a subject, image data obtained by such imaging is input to a dust correction circuit. The dust address data is read from the memory and the image at the position represented by this dust address data is eliminated from the image of the subject by reason of the fact that the image at this position is that of dust.

Claims

1. A digital camera having an imaging device for sensing the image of a subject using a solid-state image sensor and outputting image data representing the image of the subject, and an imaging lens for forming the image of the subject on a photoreceptive surface of the solid-state image sensor, comprising:

a dust position detector operative in a dust detection mode for detecting the position of dust on an image, which is represented by image data output from the imaging device, on the basis of image data output from the imaging device;

a storage device for storing the dust position detected by said dust position detector; and

a correction unit operative in an image sensing mode for correcting for the image of the dust, at the position stored in said storage device, in the image of the subject represented by the image data output from the imaging device.

2. The digital camera according to claim 1, wherein the imaging lens is detachable from said digital camera;

said storage device stores the dust position, which has been detected by said dust position detector, in association with magnification of the imaging lens; and

in the image sensing mode, said correction unit corrects for the image of dust at the position conforming to the magnification of the imaging lens that has been mounted.

3. The digital camera according to claim 2, wherein a diaphragm has been provided in front the solid-state image sensor;

said storage device stores the dust position, which has been detected by said dust position detector, in association with a combination of an f-stop number of the diaphragm and the magnification of the imaging lens; and

in the image sensing mode, said correction unit corrects for the image of dust at the position conforming to the combination of the f-stop number and magnification of the imaging lens.

4. A method of controlling operation of a digital camera having an imaging device for sensing the image of a subject using a solid-state image sensor and outputting image data representing the image of the subject, and an imaging lens for forming the image of the subject on a photoreceptive surface of the solid-state image sensor, the method comprising the steps of:

detecting, in a dust detection mode, the position of dust on an image, which is represented by image data output from the imaging device, on the basis of image data output from the imaging device;

storing the detected dust position; and

correcting, in an image sensing mode, the image of the dust at the stored position in the image of the subject represented by the image data output from the imaging device.