Image pickup apparatus and method of controlling the same

• US 6,157,406 A
• Filed: 11/02/1998
• Issued: 12/05/2000
• Est. Priority Date: 04/08/1994
• Status: Expired due to Term

• Current Assignee: Hitachi Maxell Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Naoki, Imaide, Takuya, Kami, Hiroaki, Todaka, Yoshihiro, Iura, Noriyuki, Kurashige, Tomoyuki
• Primary Examiner(s): Garber, Wendy
• Assistant Examiner(s): MOE, AUNG SOE
• Application Number:
  US09/184,011
• Time in Patent Office: 764 Days
• Field of Search: 348/220, 348/221, 348/363, 348/224, 348/229, 348/230, 348/296, 348/362, 396/235
• US Class Current: 348/220.1
• CPC Class Codes: H04N 23/72 Combination of two or more compensation controls
• CPC Class Codes: H04N 23/745 Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination

Abstract

An image pickup apparatus capable of generating a motion picture and a still picture. An amount of exposure in a still imaging mode is increased as compared with the amount of exposure for mode is increased as compared with the amount of exposure for one field in the motion picture imaging mode, preferably twice as large as the latter. In the still picture mode, electric charges are swept out from a CCD by an exposure control simultaneously with closing of a diaphragm for adjusting the amount of exposure. Upon occurrence of error in the closing operation of the diaphragm, the amount of exposure in the still picture mode is set to a design value. On the basis of difference between the design value and an actually measured value of the amount of exposure, gain for video signal is corrected. In the motion picture mode, the diaphragm and the electronic shutter speed is adjusted for preventing flicker from making appearance under illumination of a fluorescent lamp in indoor photographing. The adjusted speed can be 1/100 sec.

Claims

1. An electronic camera which enables imaging a moving picture and a still picture, comprising:

a diaphragm which intercepts partially or wholly incident light, said diaphragm being closed when imaging said still picture;

an image sensor device which converts said incident light focused thereon into an electric signal;

an image sensor driving circuit which drives said image sensor device;

a signal processing circuit which processes the electric signal outputted from said image sensor device; and

a control circuit which controls said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit;

wherein said control circuit determines an amount of exposure for imaging said still picture based on an amount of exposure determined during imaging said moving picture, and controls said diaphragm to close from a last aperture of imaging said moving picture.

2. An electronic camera apparatus according to claim 1, wherein said control circuit controls said diaphragm to be opened widely when imaging said moving picture.

3. An electronic camera apparatus according to claim 2, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

4. An electronic camera apparatus according to claim 2, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and said control circuit controls said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

5. An electronic camera apparatus according to claim 2, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.

6. An electronic camera which enables imaging a moving picture and a still picture, comprising:

a diaphragm which intercepts partially or wholly incident light, said diaphragm being closed when imaging said still picture;

a diaphragm control circuit which controls said diaphragm;

an image sensor device which converts said incident light focused thereon into an electric signal;

an image sensor driving circuit which drives said imaging sensor device;

a signal processing circuit which processes the electric signal outputted from said image sensor device;

a shutter button which initiates starting of imaging said still picture; and

a control circuit which controls said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit;

wherein said control circuit determines an amount of exposure for imaging said still picture based on an amount of exposure determined during imaging said moving picture, and said control circuit maintains a last aperture of imaging said motion picture from operation of said shutter button to a next field.

7. An electronic camera apparatus according to claim 6, wherein said control circuit controls said diaphragm to be opened widely when imaging said moving picture.

8. An electronic camera apparatus according to claim 7, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

9. An electronic camera apparatus according to claim 7, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and said control circuit controls said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

10. An electronic camera apparatus according to claim 7, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.

11. An electronic camera which enables imaging a moving picture in a moving picture mode and a still picture in a still picture mode, comprising:

a diaphragm which intercepts partially incident light in the moving picture mode, said diaphragm being closed in said still picture mode;

an image sensor device which converts said incident light focused thereon into an electric signal;

an image sensor driving circuit which drives said imaging sensor device;

a signal processing circuit which processes the electric signal outputted from said image sensor device;

a shutter button which initiates starting of imaging said still picture; and

a control circuit which controls said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit in said moving picture mode;

wherein said control circuit determines an amount of exposure for imaging said still picture based on an amount of exposure measured in said moving picture mode, and controls said diaphragm to close from a last aperture of said moving picture mode when said moving picture mode is changed to said still picture mode by operation of said shutter button.

12. An electronic camera apparatus according to claim 11, wherein said control circuit controls said diaphragm to be opened widely when imaging said moving picture.

13. An electronic camera apparatus according to claim 12, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

14. An electronic camera apparatus according to claim 12, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and said control circuit controls said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

15. An electronic camera apparatus according to claim 12, wherein said image sensor driving circuit drives said image sensor device to sweep out the charges at a given timing and drives said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.

16. A method of controlling an electronic camera which enables imaging a moving picture and a still picture, wherein the electronic camera includes a diaphragm which intercepts partially or wholly incident light, said diaphragm being closed when imaging said still picture, an image sensor device which converts said incident light focused thereon into an electric signal, an image sensor driving circuit which drives said image sensor device, a signal processing circuit which processes the electric signal outputted from said image sensor device, and a control circuit, the method comprising the steps of:

controlling said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit;

determining an amount of exposure for imaging said still picture based on an amount of exposure determined during imaging said moving picture; and

controlling said diaphragm to close from a last aperture of imaging said moving picture.

17. A method according to claim 16, further comprising the step of widely opening said diaphragm when imaging said moving picture.

18. A method according to claim 17, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

19. A method according to claim 17, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and controlling said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

20. A method according to claim 17, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.

21. A method of controlling an electronic camera which enables imaging a moving picture and a still picture, wherein the electronic camera includes a diaphragm which intercepts partially or wholly incident light, said diaphragm being closed when imaging said still picture, a diaphragm control circuit which controls said diaphragm, an image sensor device which converts said incident light focused thereon into an electric signal, an image sensor driving circuit which drives said imaging sensor device, a signal processing circuit which processes the electric signal outputted from said image sensor device, a shutter button which initiates starting of imaging said still picture, and a control circuit, the method comprising the steps of:

controlling said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit;

determining an amount of exposure for imaging said still picture based on an amount of exposure determined during imaging said moving picture; and

maintaining a last aperture of imaging said motion picture from operation of said shutter button to a next field.

22. A method according to claim 21, further comprising the step of widely opening said diaphragm when imaging said moving picture.

23. A method according to claim 22, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

24. A method according to claim 22, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and controlling said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

25. A method according to claim 22, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.

26. A method of controlling an electronic camera which enables imaging a moving picture in a moving picture mode and a still picture in a still picture mode, wherein the electronic camera includes a diaphragm which intercepts partially incident light in the moving picture mode, said diaphragm being closed in said still picture mode, an image sensor device which converts said incident light focused thereon into an electric signal, an image sensor driving circuit which drives said imaging sensor device, a signal processing circuit which processes the electric signal outputted from said image sensor device, a shutter button which initiates starting of imaging said still picture, and a control circuit, the method comprising the steps of:

controlling said diaphragm and said image sensor driving circuit according to an amount of exposure determined based on a luminance signal outputted from said signal processing circuit in said moving picture mode;

determining an amount of exposure for imaging said still picture based on an amount of exposure measured in said moving picture mode; and

controlling said diaphragm to close from a last aperture of said moving picture mode when said moving picture mode is changed to said still picture mode by operation of said shutter button.

27. A method according to claim 26, further comprising the step of widely opening diaphragm when imaging said moving picture.

28. A method according to claim 27, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges at starting of a closing operation of said diaphragm.

29. A method according to claim 27, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and controlling said diaphragm to maintain the aperture during a field after sweeping out of the electronic charges from said image sensor device.

30. A method according to claim 27, further comprising the steps of driving said image sensor device to sweep out the charges at a given timing and driving said image sensor device to sweep out the electronic charges during a closing operation of said diaphragm.