Image sensing apparatus, image sensing method, program, and storage medium

• US 20040032490A1
• Filed: 05/16/2003
• Published: 02/19/2004
• Est. Priority Date: 05/29/2001
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Uchida, Mineo
• Application Number:
  US10/439,766
• Publication Number:
  US 20040032490A1
• Time in Patent Office: Days
• US Class Current: 348/96
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/677 for reducing the column or line fixed pattern noise
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence
• CPC Class Codes: H04N 9/7921 for more than one processing mode
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

If photographing conditions such as the ISO speed or shutter speed or environmental conditions such as the ambient temperature require no dark image data during photography, an AF operation and AE operation are performed when a shutter switch SW1 is pressed, and photography is performed when a shutter switch SW2 is pressed after that, without performing any dark loading, in both single shot photography and continuous photography. In development, horizontal dark shading correction is performed using one-dimensional correction data. This one-dimensional correction data of one horizontal line for use in the horizontal dark shading correction is formed by performing a projective arithmetic operation for an image which is obtained by dark photography and stored in a nonvolatile memory 56 in a production process.

Claims

1. An image sensing apparatus for recording a photographed image on a recording medium comprising:

image sensing means capable of image sensing in a first image sensing mode in which first image data is obtained by performing image sensing in a non-exposed state, and a second image sensing mode in which second image data is obtained by performing image sensing in an exposed state;

correction data storage means for storing correction data for correcting the second image data obtained in the second image sensing mode, which is obtained by an arithmetic operation on the basis of the first image data;

selecting means for selecting one of the first image data obtained in the first image sensing mode and the stored correction data; and

correcting means for correcting the second image data obtained in the second image sensing mode by using the selected first image data or correction data.

2. The apparatus according to claim 1 wherein the correction data is stored in said correction data storage means in a production process.

3. The apparatus according to claim 1, wherein,

said image sensing means is an image sensor,

the first image data obtained in the first image sensing mode is dark current noise data of said image sensor,

the second image data obtained in the second image sensing mode is photographed image data sensed by said image sensor, and

the correction data is fixed-pattern noise equivalent to circuit system noise of said image sensor.

4. The apparatus according to claim 1, wherein said selecting means performs selection on the basis of photographing conditions and environmental conditions.

5. The apparatus according to claim 4, wherein the photographing conditions include a shutter speed and ISO speed.

6. The apparatus according to claim 4, wherein the environmental conditions include an ambient temperature.

7. The apparatus according to claim 3, wherein the correction data is one-dimensional correction data obtained from the first image data.

8. The apparatus according to claim 7, wherein the one-dimensional correction data is horizontal data obtained by performing a projective arithmetic operation in a vertical direction for image data obtained in the first image sensing mode.

9. An image sensing method of recording a photographed image on a recording medium comprising:

a first image sensing step of obtaining first image data by performing image sensing in a non-exposed state;

a second image sensing step of obtaining second image data by performing image sensing in an exposed state;

a correction data storage step of storing correction data for correcting the second image data, which is obtained by an arithmetic operation on the basis of the first image data;

a selection step of selecting one of the obtained first image data and the stored correction data; and

a correction step of correcting the obtained second image data by using the selected first image data or correction data.

10. The method according to claim 9, wherein the correction data storage step is performed in a production process of an image sensing apparatus.

11. The method according to claim 9, wherein,

the first image data is dark current noise data of an image sensor,

the second image data is photographed image data sensed by the image sensor, and

the correction data is fixed-pattern noise equivalent to circuit system noise of the image sensor.

12. The method according to claim 9, wherein the selection step comprises performing selection on the basis of photographing conditions and environmental conditions.

13. The method according to claim 12, wherein the photographing conditions include a shutter speed and ISO speed.

14. The method according to claim 12, wherein the environmental conditions include an ambient temperature.

15. The method according to claim 11, wherein the correction data is the first image data obtained in the first image sensing mode or data obtained by an arithmetic operation on the basis of the first image data.

16. The method according to claim 15, wherein the correction data is one-dimensional correction data obtained from the first image data.

17. The method according to claim 16, wherein the one-dimensional correction data is horizontal data obtained by performing a projective arithmetic operation in a vertical direction for image data obtained in the first image sensing mode.

18. A storage medium holding a computer-readable program code for implementing the image sensing method cited in any one of claims 9.

19. A program having a computer-readable program code for implementing the image sensing method cited in any one of claims 9.

20. An image sensing apparatus for recording a photographed image on a recording medium comprising:

image sensing means capable of image sensing in a first image sensing mode in which first image data is obtained by performing image sensing in a non-exposed state, and a second image sensing mode in which second image data is obtained by performing image sensing in an exposed state;

correction data storage means for storing correction data for correcting the second image data obtained in the second image sensing mode;

selecting means for selecting one of the first image data obtained in the first image sensing mode and the stored correction data before the image sensing by said image sensing means; and

correcting means for correcting the second image data obtained in the second image sensing mode by using the selected first image data or correction data.