Focus detection apparatus, image pickup apparatus, image pickup system, focus detection method, and non-transitory computer-readable storage medium

• US 9,380,202 B2
• Filed: 03/03/2015
• Issued: 06/28/2016
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kunieda, Shutaro, Ogawa, Takeshi
• Primary Examiner(s): OSINSKI, MICHAEL S
• Application Number:
  US14/636,344
• Publication Number:
  US 20150172533A1
• Time in Patent Office: 483 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04N 23/672 based on the phase difference signals
• CPC Class Codes: H04N 25/62 Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
• CPC Class Codes: H04N 25/704 Pixels specially adapted for focusing, e.g. phase difference pixel sets

Abstract

A focus detection apparatus performs focus detection by a phase difference method using an image pickup element including first and second pixels, the focus detection apparatus includes a correlation data calculator which calculates correlation data between pixel data obtained from the first pixels and the second pixels in ranges of image data, a detector which detects a saturated pixel having a level of at least a predetermined value in each of the ranges, an adding processor which performs an addition processing of the correlation data calculated in each of the ranges based on a detection result, and a defocus amount calculator which calculates a defocus amount based on a result of the addition processing, and the adding processor performs the addition processing using correlation data obtained from a first range in which the number of the saturated pixels is less than a predetermined number.

Claims

1. A focus detection apparatus which performs focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection apparatus comprising:

a processor which;

calculates comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels in a plurality of ranges of image data obtained from the image pickup element;

detects a saturated pixel having a level of at least a predetermined value in each of the plurality of ranges; and

performs addition processing of the comparison data calculated in each of the plurality of ranges, based on a result of detecting the saturated pixel; and

a lens drive controller which performs drive control of a lens apparatus based on the addition processed comparison data output from the processor,

wherein the processor performs the addition processing using comparison data obtained from the plurality of ranges in which a number of the saturated pixels is less than a predetermined number.

2. The focus detection apparatus according to claim 1, wherein the lens drive controller performs the focus detection by a phase difference method, and

wherein the lens drive controller further calculates a defocus amount based on a result of the addition processing and performs the drive control based on the defocus amount.

3. The focus detection apparatus according to claim 1, wherein the range of image data corresponds to a line of image data obtained from the image pickup element.

23. The focus detection apparatus according to claim 1, wherein the predetermined number is one.

4. A focus detection method of performing focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection method comprising:

calculating comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels in a plurality of ranges of image data obtained from the image pickup element;

detecting a saturated pixel having a level of at least a predetermined value in each of the plurality of ranges;

performing addition processing of the comparison data calculated in each of the plurality of ranges, based on a detection result of the saturated pixel; and

performing a drive control of a lens apparatus based on the added comparison data,

wherein the addition processing is performed using comparison data obtained from a range in which a number of the saturated pixels is less than a predetermined number.

5. The focus detection method according to claim 4, wherein the focus detection is performed by a phase difference method, and

wherein, in the step of performing the drive control of the lens apparatus, a defocus amount is calculated based on a result of the addition processing and the drive control is performed based on the defocus amount.

6. The focus detection method according to claim 4, wherein the range of image data corresponds to a line of image data obtained from the image pickup element.

7. A focus detection apparatus which performs focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection apparatus comprising:

processor which;

calculates comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels in a plurality of lines of image data obtained from the image pickup element;

detects a saturated pixel having a level of at least a predetermined value in each of the plurality of lines; and

performs addition processing of the comparison data calculated in each of the plurality of lines, based on a detection result of the saturated pixel; and

a lens drive controller which performs drive control of a lens apparatus based on the addition processed comparison data output from the processor,

wherein the processor performs the addition processing using comparison data obtained from the plurality of lines in which a number of the saturated pixels is less than a predetermined number.

8. The focus detection apparatus according to claim 7, wherein the lens drive controller performs the focus detection by a phase difference method, and

wherein the lens drive controller further calculates a defocus amount based on a result of the addition processing and performs the drive control based on the defocus amount.

24. The focus detection apparatus according to claim 7, wherein the predetermined number is one.

9. A focus detection apparatus which performs focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection apparatus comprising:

a processor which;

calculates comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels; and

detects a saturated pixel having a level of at least a predetermined value in each of a plurality of ranges in the image pickup element; and

a lens drive controller which performs drive control of a lens apparatus based on statistics of the comparison data,

wherein the statistics of the comparison data are calculated based on comparison data obtained from pixel data other than the detected saturated pixel.

10. The focus detection apparatus according to claim 9, wherein the lens drive controller performs the focus detection by a phase difference method, and

wherein the lens drive controller further calculates a defocus amount based on the statistics of the comparison data and performs the drive control based on the defocus amount.

11. The focus detection apparatus according to claim 9, wherein the range corresponds to a line in the image pickup element.

12. A focus detection apparatus which performs focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection apparatus comprising:

a processor which;

calculates comparison data between pixel data obtained from the plurality of first pixels and pixel data in a plurality of ranges of image data obtained from the plurality of second pixels; and

detects a saturated pixel having a level of at least a predetermined value in each of the plurality of ranges; and

a lens drive controller which performs drive control of a lens apparatus based on statistics of the comparison data,

wherein the statistics of the comparison data are calculated based on comparison data, of the plurality of ranges, multiplied by a weight depending on a number of the saturated pixels in each of the plurality of ranges.

13. The focus detection apparatus according to claim 12, wherein the lens drive controller performs the focus detection by a phase difference method, and

wherein the lens drive controller calculates a defocus amount based on the statistics of the comparison data and performs the drive control based on the defocus amount.

14. The focus detection apparatus according to claim 12, wherein the range of image data corresponds to a line of image data obtained from the plurality of second pixels.

25. The focus detection apparatus according to claim 12, wherein the weight is zero in a case where all of the pixels in a range are saturated pixels.

15. A focus detection method of performing focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection method comprising:

calculating comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels in a plurality of lines of image data obtained from the image pickup element;

detecting a saturated pixel having a level of at least a predetermined value in each of the plurality of lines;

performing addition processing of the comparison data calculated in each of the plurality of lines, based on a result of detecting the saturated pixel; and

performing a drive control of a lens apparatus based on the added comparison data,

wherein the addition processing is performed using comparison data obtained from the plurality of lines in which a number of the saturated pixels is less than a predetermined number.

16. The focus detection method according to claim 15, wherein the focus detection is performed by a phase difference method, and

wherein, in the step of performing the drive control of the lens apparatus, a defocus amount is calculated based on a result of the addition processing and the drive control is performed based on the defocus amount.

17. A focus detection method of performing focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection method comprising:

calculating comparison data between pixel data obtained from the plurality of first pixels and pixel data obtained from the plurality of second pixels;

detecting a saturated pixel having a level of at least a predetermined value in each of a plurality of ranges in the image pickup element; and

performing a drive control of a lens apparatus based on statistics of the comparison data,

wherein the statistics of the comparison data are calculated based on comparison data obtained from pixel data other than the detected saturated pixel.

18. The focus detection method according to claim 17, wherein the focus detection is performed by a phase difference method, and

wherein, in the step of performing the drive control of the lens apparatus, a defocus amount is calculated based on the statistics of the comparison data and the drive control is performed based on the defocus amount.

19. The focus detection method according to claim 17, wherein the range corresponds to a line in the image pickup element.

20. A focus detection method of performing focus detection using an image pickup element including a plurality of first pixels and a plurality of second pixels, each pair of the first and second pixels sharing one microlens, the focus detection method comprising:

calculating comparison data between pixel data obtained from the plurality of first pixels and pixel data in a plurality of ranges of image data obtained from the plurality of second pixels;

detecting a saturated pixel having a level of at least a predetermined value in each of the plurality of ranges; and

performing a drive control of a lens apparatus based on statistics of the comparison data,

wherein the statistics of the comparison data are calculated based on comparison data, of the plurality of ranges, multiplied by a weight depending on a number of the saturated pixels in each of the plurality of ranges.

21. The focus detection method according to claim 20, wherein the focus detection is performed by a phase difference method, and

wherein, in the step of performing the drive control of the lens apparatus, a defocus amount is calculated based on the statistics of the comparison data and the drive control is performed based on the defocus amount.

22. The focus detection method according to claim 20, wherein the range of image data corresponds to a line of image data obtained from the plurality of second pixels.