Image pickup device, automatic focusing method, automatic exposure method calculating an exposure based on a detected face

• US 7,973,853 B2
• Filed: 05/08/2007
• Issued: 07/05/2011
• Est. Priority Date: 09/18/2001
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ojima, Noriaki, Sanno, Masato
• Primary Examiner(s): VU, NGOC YEN T
• Application Number:
  US11/745,753
• Publication Number:
  US 20070263934A1
• Time in Patent Office: 1,519 Days
• Field of Search: 348/364
• US Class Current: 348/364
• CPC Class Codes: H04N 2101/00 Still video cameras
• 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 23/632 for displaying or modifying preview images prior to image capturing, e.g. variety of image resolutions or capturing parameters
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/675 comprising setting of focusing regions
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

An image pickup device provided with an automatic exposure function includes an image pickup unit configured to input image data corresponding to a subject, a face detection unit configured to detect a human face from the image data input from the image pickup unit, a photometric unit configured to measure optical intensity, designating the human face detected by the face detection unit as a photometric area, and an exposure control unit configured to calculate the exposure based on the photometric result of the human face by the photometric unit, and to perform exposure control based on the calculated exposure.

Claims

1. An image pickup device provided with an automatic exposure function, comprising:

an image pickup unit configured to input image data corresponding to a subject;

a face detection unit configured to detect a human face from the image data input from the image pickup unit;

a photometric unit configured to measure optical intensity, the photometric unit configured to measure a photometric result of the optical intensity, the photometric result including the optical intensity of all areas including the human face detected by the face detection unit and not including optical intensity from areas not including the human face detected by the face detection unit, and the photometric unit configured to measure a second photometric result of the optical intensity by designating a whole screen as the photometric area; and

an exposure control unit configured to calculate the exposure based on the photometric result or the second photometric result of the human face by the photometric unit, and to perform exposure control based on the calculated exposure, the exposure control unit configured to calculate the exposure by giving more weight to the photometric result of the human face compared with the second photometric result of the whole screen, based on the photometric result of the human face and the second photometric result of the whole screen by the photometric unit, the exposure control unit configured to set the exposure based on the photometric result when a ratio of the face occupying the whole screen is large, and the exposure control unit configured to set the exposure based on the second photometric result in all other cases.

2. The image pickup device according to claim 1, further comprising:

a photometric method selection unit, by which a user can select either of a first photometric method in which the exposure is calculated based on the photometric result of the human face, and a second photometric method in which the exposure is calculated by giving more weight to the photometric result of the human face compared with the second photometric result of the whole screen, based on the photometric result of the human face and the second photometric result of the whole screen.

3. The image pickup device according to claim 1, further comprising:

a weighting setup unit, by which a user sets weighting to the photometric result of the human face with respect to the second photometric result of the whole screen.

4. The image pickup device according to claim 1, wherein the exposure control unit is configured to set weighting to the photometric result of the human face with respect to the second photometric result of the whole screen, based on the ratio of the face occupying in the screen or the position of the face or both.

5. The image pickup device according to claim 1, further comprising:

a face detection operation setup unit, by which a user sets permission/inhibition of the face detection operation of the face detection unit, wherein when permission of the face detection operation of the face detection unit is set, the exposure control unit allows the face detection unit to execute the face detection operation, to thereby perform the exposure control based on the photometric result of the detected human face, and when inhibition of the face detection operation of the face detection unit is set, the exposure control unit performs the exposure control, without allowing the face detection unit to execute the face detection operation.

6. The image pickup device according to claim 1, further comprising:

a mode setup unit configured to set a first photographing mode in which exposure control is performed by executing the face detection operation of the face detection unit, or a second photographing mode in which exposure control is performed without executing the face detection operation of the face detection unit, wherein when the first photographing mode is set, the exposure control unit allows the face detection unit to execute the face detection operation, to thereby perform exposure control based on the photometric result of the detected human face, and when the second photographing mode is set, the exposure control unit performs exposure control without allowing the face detection unit to execute the face detection operation.

7. The image pickup device according to claim 1, further comprising:

a notification unit configured to notify a user of the detection result of the human face by the face detection unit.

8. The image pickup device according to claim 7, wherein the notification unit is a monitor screen for displaying the image data.

9. The image pickup device according to claim 7, wherein the notification unit is a sub-LCD for displaying the operation condition or the like of the image pickup device.

10. The image pickup device according to claim 7, wherein the notification unit is an LED.

11. The image pickup device according to claim 1, wherein when a human face cannot be detected by the face detection unit, the exposure control unit performs exposure control based on the photometric result of another photometric method.

12. The image pickup device according to claim 1, further comprising:

an input device configured to receive a selection by a user of the photometric result or the second photometric result,

wherein the exposure control unit is configured to set the exposure based on the selection received by the input device.

13. An automatic exposure method comprising:

inputting image data corresponding to a subject;

detecting a human face from the image data input at the image input step;

measuring a photometric result of optical intensity, the photometric result including the optical intensity of all areas including the human face detected at the face detection step and not including optical intensity from areas not including the human face detected at the face detection step, and measuring a second photometric result of the optical intensity by designating a whole screen as the photometric area; and

calculating, using a processor, the exposure based on the photometric result or the second photometric result of the human face at the photometric step, the calculating including giving more weight to the photometric result of the human face compared with the second photometric result of the whole screen, based on the photometric result of the human face and the second photometric result of the whole screen at the photometric step, and setting the exposure based on the photometric result when a ratio of the face occupying the whole screen is large, and setting the exposure based on the second photometric result in all other cases, and performing exposure control based on the calculated exposure.

14. A non-transitory computer readable medium including computer executable instructions, wherein the instructions, when executed by a processor, cause the processor to perform a method comprising:

inputting image data corresponding to a subject;

detecting a human face from the image data input at the image input step;

measuring a photometric result of optical intensity, the photometric result including the optical intensity of all areas including the human face detected at the face detection step and not including optical intensity from areas not including the human face detected at the face detection step, and measuring a second photometric result of the optical intensity by designating a whole screen as the photometric area; and

calculating the exposure based on the photometric result or the second photometric result of the human face at the photometric step, the calculating including giving more weight to the photometric result of the human face compared with the second photometric result of the whole screen, based on the photometric result of the human face and the second photometric result of the whole screen at the photometric step, and setting the exposure based on the photometric result when a ratio of the face occupying the whole screen is large, and setting the exposure based on the second photometric result in all other cases, and performing exposure control based on the calculated exposure.