Electronic still camera system compensating for image displacement

• US 5,379,063 A
• Filed: 09/13/1993
• Issued: 01/03/1995
• Est. Priority Date: 04/24/1991
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Kishi, Kenji, Nagasaki, Tatsuo
• Primary Examiner(s): Razavi, Michael T.
• Assistant Examiner(s): Ho, Tuan V.
• Application Number:
  US08/120,655
• Time in Patent Office: 477 Days
• Field of Search: 358/222, 358/209, 358/909, 358/105, 358/140, 358/163, 358/166, 358/167, 358/213.27, 358/213.15, 358/213.18
• US Class Current: 348/208.6
• 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 23/683 performed by a processor, e.g. controlling the readout of an image memory
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51

Abstract

In an electronic still camera system for forming one still frame image by synthesizing odd and even field images which are field-sequentially output from a CCD, an image compensation circuit is arranged to prevent a deterioration in quality of a still frame image due to an image shift between the two field images. The image compensation circuit includes an interpolation circuit for obtaining two pseudo frame images by performing field interpolation of the odd and even field images, a correlation arithmetic circuit for detecting an amount of image shift between the two field images on the basis of the correlation between the two pseudo frame images, and a shift compensation circuit for compensating the image shift by shifting one of the two field images in accordance with the detected amount of image shift. The correlation arithmetic circuit divides each field image into a plurality of blocks, and detects an amount of image shift in units of blocks. The shift compensation circuit shifts an image in units of blocks.

Claims

1. An electronic still camera system comprising:

an imaging element for converting an amount of light corresponding to an object image formed through an optical system to a signal corresponding to said amount of light;

imaging means for field-sequentially obtaining two field images from said signal outputted by said imaging element, one of the two field images being an odd field image constituted by odd scanning lines, and the other of the two field images being an even field image constituted by even scanning lines;

a first memory unit coupled to said imaging means and in which said odd and even field images are stored;

means for interpolating said data of each of said odd and even field images obtained by said imaging means to respectively obtain first and second pseudo frame images;

means for determining a correlation between said first and second pseudo frame images to detect an amount of image shift between the odd and even field images;

means for shifting one of the odd and even field images with respect to the other of the odd and even field images in accordance with the detected amount of image shift;

means for storing said shifted field image in a second memory unit while said other field image is retained in said first memory unit; and

means for combining the data of said stored shifted field image with the stored data of said other field image into a frame image for display as a still image.

2. A system according to claim 1, wherein said correlation determining means includes means for calculating correlation in units of block images which is obtained by dividing each field image into blocks each having a predetermined size, and said shifting means includes means for compensating for the image shift in units of blocks.

3. An apparatus according to claim 1, wherein said determining means comprises:

means for calculating correlation between a reference zone including a reference point in one of the first and second pseudo frame images and each zone including a point, in the other pseudo frame image, corresponding to the reference point;

first means for detecting a second zone in which highest correlation is established; and

second means for detecting a distance between the reference zone and the second zone as an amount of image shift; and

said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image.

4. An apparatus according to claim 3, wherein said first detecting means comprises means for detecting, as the second zone, a zone in which a correlation value φ

(t) represented by the following equation becomes minimum;

space="preserve" listing-type="equation">φ

(t)=∫

(f(x)-g(x+t)).sup.2 dx

where f(x) is pixel data at the reference point, and g(x+t) is pixel data at a point separated from a point, in the other of said first and second pseudo frame images, corresponding to the reference point, by a distance t.

5. An apparatus according to claim 3, wherein said first detecting means comprises means for detecting, as the second zone, a zone in which a variance V(s) represented by the following equation, becomes minimum:

space="preserve" listing-type="equation">V(s)=<

(f(x)-g(x+t).sup.2 >

-<

(f(x)-g(x+t)>

.sup.2

where f(x) is pixel data at the reference point, and g(x+t) is pixel data at a point separated from a point, in the other of said first and second pseudo frame images, corresponding to the reference point, by a distance t, and <

>

is an operand representing a mean value as follows;

##EQU2##

6. An apparatus according to claim 1, wherein said determining means comprises:

means for calculating correlation between reference zones each including a reference point in one of the first and second pseudo frame images and each zone including a point, in given reference regions in the other pseudo frame image, corresponding to the reference point;

means for detecting a second zone in which highest correlation is established in units of the reference regions;

means for detecting a distance between the reference zone and the second zone as an amount of image shift in units of the reference regions; and

wherein said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image in units of the reference regions.

7. An apparatus according to claim 1, wherein said determining means comprises:

means for calculating correlation between reference zones each including a reference point in one of the first and second pseudo frame images and each zone including a point, in the other pseudo frame image, corresponding to the reference point, in units of block regions which is obtained by dividing a frame image into blocks each having a predetermined size;

means for detecting a second zone in which highest correlation is established in units of block regions;

means for detecting a distance between the reference zone and the second zone as an amount of image shift in units of the block regions; and

wherein said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image in units of the block regions.

8. An electronic still camera apparatus comprising:

imaging means for imaging an object, and for sequentially outputting odd and even field images respectively constituted by odd line and even line scanning lines;

field memory means, connected to said imaging means, for storing the odd and even field images;

means for forming first and second pseudo frame images from the odd and even field images by interpolating the even and odd scanning lines by using the odd and even scanning lines of the odd and even field images output from said field memory means, respectively;

detecting means for calculating a correlation between the first and second pseudo frame images in order to detect an image shift of one of said odd and even field images with respect to the other of said odd and even field images;

means for compensating for an image shift of one of the odd and even field images with respect to the other of the odd and even field images in accordance with the image shift detected by said detecting means, and for storing said compensated field image in a memory while the other field image is retained in the field memory means; and

means for forming a frame image on the basis of said one of the odd and even field images, the image shift of which is compensated for by said compensating means, and the other of the odd and even field images output from said imaging means by combining said compensated field image and one of the odd and even field images to form a still image.

9. An apparatus according to claim 8, further comprising frame memory means for storing the frame image output from said imaging means.

10. An apparatus according to claim 8, wherein said field memory means is one of a memory card and a floppy disk which can be detached from a main body of the apparatus.

11. An apparatus according to claim 8, wherein said detecting means comprises:

means for calculating a correlation between a reference zone including a reference point in one of the first and second pseudo frame images and each zone including a point, in the other pseudo frame image, corresponding to the reference point;

means for detecting a second zone in which highest correlation is established; and

means for detecting a distance between the reference zone and the second zone as an amount of image shift; and

said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image.

12. An apparatus according to claim 8, wherein said detecting means comprises means for detecting, as the second zone, a zone in which a correlation value φ

(t) represented by the following equation becomes minimum;

space="preserve" listing-type="equation">φ

(t)=∫

(f(x)-g(x+t)).sup.2 dx

where f(x) is pixel data at the reference point, and g(x+t) is pixel data at a point separated from a point, in the other of said first and second pseudo frame images, corresponding to the reference point, by a distance t.

13. An apparatus according to claim 8, wherein said detecting means comprises means for detecting, as the second zone, a zone in which a variance V(s) represented by the following equation, becomes minimum:

space="preserve" listing-type="equation">V(s)=<

(f(x)-g(x+t).sup.2 >

-<

(f(x)-g(x+t)>

.sup.2

where f(x) is pixel data at the reference point, and g(x+t) is pixel data at a point separated from a point, in the other of said first and second pseudo frame images, corresponding to the reference point, by a distance t, and <

>

is an operand representing a mean value as follows;

##EQU3##

14. An apparatus according to claim 8, wherein said detecting means comprises:

means for calculating a correlation between reference zones each including a reference point in one of the first and second pseudo frame images and each zone including a point, in given reference regions in the other pseudo frame image, corresponding to the reference point;

means for detecting a second zone in which highest correlation is established in units of the reference regions; and

means for detecting a distance between the reference zone and the second zone as an amount of image shift in units of the reference regions; and

said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image in units of the reference regions.

15. An apparatus according to claim 8, wherein said detecting means comprises:

means for calculating a correlation between reference zones each including a reference point in one of the first and second pseudo frame images and each zone including a point, in the other pseudo frame image, corresponding to the reference point, in units of block regions which is obtained by dividing a frame image into blocks each having a predetermined size;

means for detecting a second zone in which highest correlation is established in units of block regions; and

means for detecting a distance between the reference zone and the second zone as an amount of image shift in units of the block regions; and

said shifting means comprises means for shifting a position of one of the odd and even field images associated with the other pseudo frame image in units of the block regions.

16. An apparatus according to claim 8, wherein said imaging means comprises a solid-state imaging device.