Image capturing device, image capturing method, and storage medium having stored therein image capturing program

• US 8,310,553 B2
• Filed: 02/16/2010
• Issued: 11/13/2012
• Est. Priority Date: 02/17/2009
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Matsunaga, Kazuhisa
• Primary Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US12/706,174
• Publication Number:
  US 20100209009A1
• Time in Patent Office: 1,001 Days
• Field of Search: None
• US Class Current: 348/208.99
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6845 by combination of a plurality of images sequentially taken
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

A digital camera carries out the following steps. The digital camera acquires one image photographed with a high sensitivity for subject-blur suppression, four images of a first group consecutive in a time series photographed with an ordinary exposure time, and four images of a second group consecutive in a time series photographed with an exposure time shorter than the ordinary exposure time for multiplane addition. Then, the digital camera extracts, from among the images photographed with the ordinary exposure time, an image for which blur caused by hand movement is minimum, and if no image blur has occurred and if blur caused by hand movement is less than a predetermined value, selects the image. The digital camera selects the image for subject-blur suppression if image blur has occurred for the extracted image. Also, the digital camera generates a new image by carrying out multiplane addition of images for multiplane addition if blur caused by hand movement has occurred for the extracted image.

Claims

1. An image capturing device, comprising:

an image capturing unit which acquires a predetermined number of images, the predetermined number of images including images of a first group consecutive in time in which a subject is photographed for a first exposure time immediately in response to an instruction to photograph, and images of a second group consecutive in time in which the subject is photographed for a second exposure time that is different from the first exposure time;

a hand-blur determination unit which determines whether blur caused by hand movement has occurred during acquisition of the images of the first group by the image capturing unit;

an image-blur determination unit which determines whether image blur of the subject has occurred during acquisition of the images of the first group by the image capturing unit; and

a selection unit which selects either an image acquired from the images of the first group or an image acquired from the images of the second group, in accordance with a determination result by the hand-blur determination unit and a determination result by the image-blur determination unit.

2. An image capturing device as set forth in claim 1, wherein the selection unit selects an image acquired from the images of the second group in a case in which the image-blur determination unit determines that no image blur has occurred and the hand-blur determination unit determines that blur caused by hand movement has occurred.

3. An image capturing device as set forth in claim 1, further comprising an image processing unit which synthesizes the images of the second group to generate a new image, wherein the image acquired from the images of the second group is the new image.

4. An image capturing device as set forth in claim 1, wherein the selection unit selects an image acquired from the images of the first group in a case in which the image-blur determination unit determines that no image blur has occurred and the hand-blur determination unit determines that no blur caused by hand movement has occurred.

5. An image capturing device as set forth in claim 1, further comprising a calculation unit which obtains projective transformation matrices for images consecutive in time from among the images of the first group, and calculates a size of a motion vector for each projective transformation matrix,

wherein the image-blur determination unit determines whether image blur has occurred for the image for which the size of the motion vector calculated by the calculation unit is minimum.

6. An image capturing device as set forth in claim 5, wherein the hand-blur determination unit determines whether blur caused by hand movement has occurred for the image for which the size of the motion vector is minimum, based on whether the size of the motion vector exceeds a predetermined threshold.

7. An image capturing device as set forth in claim 1, wherein:

the image capturing unit acquires a third image in which a subject is photographed with a higher sensitivity than a sensitivity with which either images of the first group are photographed or images of the second group are photographed, and

the selection unit selects any one of the images acquired from the images of the first group, the images of the second group, and the third image, and if image blur is determined to have occurred by the image-blur determination unit, selects the third image.

8. An image capturing device as set forth in claim 1, wherein the second exposure time is shorter than the first exposure time.

9. An image capturing method, the method comprising:

an acquiring step of acquiring a predetermined number of images, the predetermined number of images including images of a first group consecutive in time in which a subject is photographed with a first exposure time immediately in response to an instruction to photograph, and images of a second group consecutive in time in which the subject is photographed with a second exposure time that is different from the first exposure time;

a hand-blur determining step of determining whether blur caused by hand movement has occurred during acquisition of the images of the first group;

an image-blur determining step of determining whether image blur has occurred during acquisition of the images of the first group; and

a selecting step of selecting either an image acquired from the images of the first group or an image acquired from the images of the second group in accordance with respective determination results of the hand-blur determining step and of the image-blur determining step.

10. A non-transitory computer readable storage medium having stored therein an image capturing program which controls a computer of an image capturing device to carry out a process comprising:

an acquiring step of acquiring a predetermined number of images, the predetermined number of images including images of a first group consecutive in time in which a subject is photographed with a first exposure time immediately in response to an instruction to photograph, and images of a second group consecutive in time in which the subject is photographed with a second exposure time that is different from the first exposure time;

a hand-blur determining step of determining whether blur caused by hand movement has occurred during acquisition of the images of the first group;

an image-blur determining step of determining whether image blur has occurred during acquisition of the images of the first group; and

a selecting step of selecting either an image acquired from the images of the first group or an image acquired from the images of the second group in accordance with respective determination results of the hand-blur determining step and of the image-blur determining step.