IMAGING APPARATUS, CONTROL METHOD OF IMAGING APPARATUS, AND COMPUTER PROGRAM

• US 20070286590A1
• Filed: 06/08/2007
• Published: 12/13/2007
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Terashima, Yoshito
• Granted Patent: US 7,860,386 B2
• Time in Patent Office: Days
• US Class Current: 396/125
• CPC Class Codes: G03B 13/20 Rangefinders coupled with focusing arrangements, e.g. adjustment of rangefinder automatically focusing camera
• CPC Class Codes: G03B 3/00 Focusing arrangements of general interest for cameras, projectors or printers
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/675 comprising setting of focusing regions

Abstract

An imaging apparatus includes: a face detecting part configured to detect a face area from the input image inputted from an imaging apparatus; a subject distance computing part configured to compute a subject distance based on the size of a face detected in the face detecting part; a lens operating range computing part configured to estimate a focus position based on information about the subject distance computed in the subject distance computing part, and to set a focus lens operating range shorter than an entire operating range of a focus lens; and a focus control part configured to move the focus lens within the lens operating range set in the lens operating range computing part, and to decide a position at which the focus lens is set.

Claims

1. An imaging apparatus comprising:

a face detecting part configured to detect a face area from an input image inputted from the imaging apparatus;

a subject distance computing part configured to compute a subject distance based on the size of a face detected in the face detecting part;

a lens operating range computing part configured to estimate a focus position based on information about the subject distance computed in the subject distance computing part, and to set a focus lens operating range shorter than an entire operating range of a focus lens; and

a focus control part configured to move the focus lens within the lens operating range set in the lens operating range computing part, and to decide a position at which the focus lens is set.

2. The imaging apparatus according to claim 1, wherein the subject distance computing part is configured to perform a subject distance computing process in which at least any one of items of subject information for race, gender, age, and body conformation is inputted, and a reference value of the size of a face in accordance with a subject is applied based on the inputted subject information in the subject distance computing process based on the size of a face detected in the face detecting part.

3. The imaging apparatus according to claim 2, wherein at least any one of items of the subject information for race, gender, age, and body conformation information is information that is inputted to the subject distance computing part as an analyzed result from an image analyzing part, the result being derived from an input image inputted in the imaging apparatus.

4. The imaging apparatus according to claim 2, wherein at least any one of items of the subject information for race, gender, age, and body conformation is information that is inputted to the subject distance computing part through a user input part of the imaging apparatus.

5. The imaging apparatus according to claim 1, wherein the subject distance computing part is configured to perform a subject distance computing process to which a reference value of the size of a face in accordance with a subject is applied, and is configured to perform a process in which a reference value of the size of a face is computed as a reference value with a range of certain values, not a single value, and a reference value with the range is applied to compute a subject distance with a range.

6. The imaging apparatus according to claim 1, wherein the subject distance computing part is configured to perform a process in which a range from Dfn to Dff of a subject distance is computed in consideration of error occurring in a face template matching process.

7. The imaging apparatus according to claim 1, wherein the lens operating range computing part is configured to perform a process in which a focus lens operating range is set based on information about the subject distance computed in the subject distance computing part in consideration of error caused by a device in the imaging apparatus.

8. The imaging apparatus according to claim 1, wherein the imaging apparatus further comprises a priority analyzing part configured to set a priority of a plurality of faces detected in the face detecting part,

wherein the priority analyzing part is configured to perform a face priority decision process using the size of a face, or how a face is close to the center, or at least any one of items of subject information for race, gender, age, and body conformation, as an indicator, and

the lens operating range computing part is configured to perform a process in which a focus lens operating range is set based on face priority information decided in the priority analyzing part.

9. The imaging apparatus according to claim 8, wherein the lens operating range computing part is configured to perform a process in which a focus lens operating range is set based on information about the subject distance corresponding to a face with the highest priority decided in the priority analyzing part.

10. The imaging apparatus according to claim 8, wherein the lens operating range computing part is configured to perform a process in which a range including a plurality of focus lens operating ranges computed based on information about the subject distance corresponding to a plurality of faces in priority order decided in the priority analyzing part is set as a final focus lens operating range.

11. The imaging apparatus according to claim 1, wherein the imaging apparatus further comprises a display control part configured to put an in-focus mark on a face area in a monitor output image, the in-focus mark showing that focusing is successful, and the monitor output image being determined that focusing is successful based on the decision for a position at which the focus lens is set in the focus control part.

12. A control method of an imaging apparatus which performs auto focusing control in the imaging apparatus, the method comprising the steps of:

detecting a face area in a face detecting part from an input image inputted from the imaging apparatus;

computing a subject distance in a subject distance computing part based on the size of a face detected in the face detecting part;

estimating a focus position in a lens operating range computing part based on information about the subject distance computed in the subject distance computing part, and setting a focus lens operating range shorter than an entire operating range of a focus lens; and

moving a focus lens in a focus control part within the lens operating range set in the lens operating range computing part, and deciding a position at which the focus lens is set.

13. The control method of an imaging apparatus according to claim 12, wherein the step of computing a subject distance is the step of performing a subject distance computing process in which at least any one of items of subject information for race, gender, age, and body conformation is inputted, and a reference value of the size of a face in accordance with a subject is applied based on the inputted subject information in the subject distance computing process based on the size of a face detected in the face detecting part.

14. The control method of an imaging apparatus according to claim 13, wherein at least any one of items of the subject information for race, gender, age, and body conformation is information that is inputted to the subject distance computing part as an analyzed result from an image analyzing part, the result being derived from an input image inputted in the imaging apparatus.

15. The control method of an imaging apparatus according to claim 13, wherein at least any one of items of the subject information for race, gender, age, and body conformation is information that is inputted to the subject distance computing part through a user input part of the imaging apparatus.

16. The control method of an imaging apparatus according to claim 12, wherein the step of computing a subject distance is the step of performing a subject distance computing process to which a reference value of the size of a face in accordance with a subject is applied, and is the step of performing a process in which a reference value of the size of a face is computed as a reference value with a range of certain values, not a single value, and a reference value with the range is applied to compute a subject distance with a range.

17. The control method of an imaging apparatus according to claim 12, wherein the step of computing a subject distance is the step of performing a process in which a range from Dfn to Dff of a subject distance is computed in consideration of error occurring in a face template matching process.

18. The control method of an imaging apparatus according to claim 12, wherein the step of computing a lens operating range is the step of performing a process in which a focus lens operating range is set based on information about the subject distance computed in the subject distance computing part in consideration of error caused by a device in the imaging apparatus.

19. The control method of an imaging apparatus according to claim 12, wherein the control method of an imaging apparatus further includes the step of analyzing priority in a priority analyzing part configured to set a priority of a plurality of faces detected in the face detecting part,

wherein the step of analyzing priority is the step of performing a face priority decision process using the size of a face, or how a face is close to the center, or at least any one of items of subject information for race, gender, age, and body conformation, as an indicator, and

the step of computing a lens operating range is the step of performing a process in which a focus lens operating range is set based on face priority information decided in the priority analyzing part.

20. The control method of an imaging apparatus according to claim 19, wherein the step of computing a lens operating range is the step of performing a process in which a focus lens operating range is set based on information about the subject distance corresponding to a face with the highest priority decided in the priority analyzing part.

21. The control method of an imaging apparatus according to claim 19, wherein the step of computing a lens operating range is the step of performing a process in which a range including a plurality of focus lens operating ranges computed based on information about the subject distance corresponding to a plurality of faces in priority order decided in the priority analyzing part is set as a final focus lens operating range.

22. The control method of an imaging apparatus according to claim 12, wherein the control method of an imaging apparatus further comprises the step of display control in display control part, in which an in-focus mark is put on a face area in a monitor output image, the in-focus mark showing that focusing is successful, and the monitor output image being determined that focusing is successful based on the decision for a position at which the focus lens is set in the focus control part.

23. A computer program which performs auto focusing control in an imaging apparatus, the program comprising the steps of:

detecting a face area in a face detecting part from an input image inputted from the imaging apparatus;

computing a subject distance in a subject distance computing part based on the size of a face detected in the face detecting part;

estimating a focus position in a lens operating range computing part based on information about the subject distance computed in the subject distance computing part, and setting a focus lens operating range shorter than an entire operating range of a focus lens; and

moving a focus lens in focus control part within the lens operating range set in the lens operating range computing part, and deciding a position at which the focus lens is set.