Image pickup apparatus and image pickup method

• US 20050270410A1
• Filed: 06/03/2005
• Published: 12/08/2005
• Est. Priority Date: 06/03/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takayama, Masahiro
• Granted Patent: US 7,733,412 B2
• Time in Patent Office: Days
• US Class Current: 348/345
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/959 by adjusting depth of field during image capture, e.g. maximising or setting range based on scene characteristics

Abstract

An image pickup apparatus which can reduce the time required for automatic focus scanning. The size of the face is determined based on information on a subject'"'"'s face, which is detected from image data acquired by shooting by an image pickup device. The subject distance is estimated based on the determined size of the face. The depth of field is calculated. A range over which the focus lens is driven varies according to the estimated subject distance and the calculated depth of field.

Claims

1. An image pickup apparatus comprising:

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field,

wherein a range over which the focus lens is driven varies according to the estimated subject distance and the calculated depth of field.

2. An image pickup apparatus according to claim 1, wherein the range over which the focus lens is driven includes a position of said focus lens at which said focus lens is focused at the estimated subject distance, and is wider as the depth of field is larger and is narrower as the depth of field is smaller.

3. An image pickup apparatus according to claim 1, wherein said controller controls a range of movement of said focus lens according to the depth of field.

4. An image pickup apparatus according to claim 1, wherein said controller provides control such that at and in a vicinity of a position of said focus lens at which said focus lens is focused at the estimated subject distance, a range over which said focus lens moves is made smaller.

5. An image pickup apparatus according to claim 1, wherein said controller inhibits execution of the automatic focusing when the estimated subject distance is within a focusing range under shooting conditions in acquiring the image data from which the information on the face has been detected.

6. An image pickup apparatus comprising:

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field,

wherein said controller provides control such that a range of movement of said focus lens varies according to the estimated subject distance and the calculated depth of field.

7. An image pickup apparatus according to claim 6, wherein said controller provides control such that at and in a vicinity of a position of said focus lens at which said focus lens is focused at the estimated subject distance, a range over which said focus lens moves is made smaller.

8. An image pickup apparatus according to claim 6, wherein said controller inhibits execution of the automatic focusing when the estimated subject distance is within a focusing range under shooting conditions in acquiring the image data from which the information on the face has been detected.

9. An image pickup apparatus comprising:

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field based on the estimated subject distance,

wherein said controller provides control such that a range of movement of said focus lens varies according to a result of the calculation carried out by said depth-of-field calculating device.

10. An image pickup apparatus comprising:

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field based on a focal point distance at which the image data from which the information on the face has been detected was acquired,

wherein a range of movement of said focus lens varies according to a result of the calculation carried out by said depth-of-field calculating device.

11. An image pickup apparatus comprising:

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field based on the estimated subject distance,

wherein said controller inhibits execution of the automatic focusing when a focal point distance at which the image data from which the information on the face has been detected was acquired is within the calculated depth of field.

12. An image pickup apparatus comprising;

an image pickup device that shoots a subject to acquire image data on the subject;

a controller that drivingly controls a focus lens to cause said image pickup device to perform automatic focusing;

a face information detecting device that detects information on a face of the subject from the acquired image data;

a distance estimating device that estimates a subject distance from said image pickup device to the subject based on the detected information on the face; and

a depth-of-field calculating device that calculates a depth of field based on a focal point distance at which the image data from which the information on the face has been detected was acquired,

wherein said controller inhibits execution of the automatic focusing when the estimated subject distance is within the calculated depth of field.

13. An image pickup method comprising:

an automatic focusing executing step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing by driving a focus lens;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field,

wherein a range over which the focus lens is driven varies according to the estimated subject distance and the calculated depth of field.

14. An image pickup method comprising:

a control step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing by driving a focus lens;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field,

wherein said control step comprises providing control such that a range of movement of the focus lens varies according to the estimated subject distance and the calculated depth of field.

15. An image pickup method comprising:

a control step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing by driving a focus lens;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field based on the estimated subject distance,

wherein a range of movement of the focus lens varies according to a result of computation carried out in said calculating step.

16. An image pickup method comprising:

a control step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing by driving a focus lens;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field based on a focal point distance at which the image data from which the information on the face has been detected was acquired,

wherein a range of movement of said focus lens varies according to a result of the calculation carried out in said calculating step.

17. An image pickup method comprising:

a control step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field based on the estimated subject distance,

wherein execution of the automatic focusing is inhibited when a focal point distance at which the image data from which the information on the face has been detected was acquired is within the calculated depth of field.

18. An image pickup method comprising:

a control step of causing an image pickup device that shoots a subject to acquire image data on the subject to perform automatic focusing;

a face information detecting step of detecting information on a face of the subject from the acquired image data;

a distance estimating step of estimating a subject distance from the image pickup device to the subject based on the detected information on the face; and

a calculating step of calculating a depth of field based on a focal point distance at which the image data from which the information on the face has been detected was acquired,

wherein execution of the automatic focusing is inhibited when the estimated subject distance is within the calculated depth of field.