Portable image pick-up apparatus and method of controlling operation thereof

• US 6,714,246 B1
• Filed: 05/19/2000
• Issued: 03/30/2004
• Est. Priority Date: 05/21/1999
• Status: Expired due to Term

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Sawachi, Youichi
• Primary Examiner(s): Le, Vu
• Assistant Examiner(s): Hernandez, Nelson D.
• Application Number:
  US09/573,343
• Time in Patent Office: 1,411 Days
• Field of Search: 348/345, 348/229.1, 348/333.12, 348/349, 348/255, 348/227.1, 396/137, 396/99, 396/108
• US Class Current: 348/345
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 23/76 by influencing the image signals
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence

Abstract

If a digital still camera is set for a manual focus adjustment and the luminance of a subject has a value less than a predetermined threshold value, the amplification factor of an amplifier circuit is set to a display amplification factor higher than that of the ordinary amplification factor. A video signal that has been amplified at this high amplification factor is applied to a liquid crystal display unit of the camera. A bright image of the subject is thus displayed on the display unit. Since the image of the subject is made easier to see owing to the increased brightness thereof, manual focusing is easy even when photography is performed at dark location.

Claims

1. A portable image pick-up apparatus comprising:

an image sensing device for sensing the image of a subject and outputting a video signal representing the image of the subject;

a focusing setting unit for setting autofocus and manual focus selectively;

a signal amplifier circuit for amplifying the video signal output from said image sensing device;

an amplification-factor changeover unit, responsive to setting of manual focus by said focusing setting unit, for changing over an amplification factor of said signal amplifier circuit from a predetermined initial amplification factor to a first display amplification factor that is greater than the initial amplification factor;

a display unit for displaying the image of the subject represented by the video signal amplified by said signal amplifier circuit;

a trigger signal generating circuit for generating a trigger signal in response to a record command applied thereto; and

a recording control unit, responsive to the trigger signal generated by said trigger signal generating circuit, for recording the video signal, which is output from said image sensing device, on a recording medium.

2. The apparatus according to claim 1, wherein said amplification-factor changeover unit returns the amplification factor in said signal amplifier circuit from the first display amplification factor to the initial amplification factor in response to the record command.

3. The apparatus according to claim 1, further comprising:

a photometer unit for metering luminance of a subject; and

a subject-luminance discrimination unit for determining whether a luminance value of the subject metered by said photometer unit is less than a predetermined threshold value;

wherein said amplification-factor changeover unit changes over the amplification factor of said signal amplifier circuit from the initial amplification factor to the first display amplification factor in response to a determination by said subject-luminance discrimination unit that the luminance value of the subject is less than the predetermined threshold value and, moreover, to setting of manual focus by said focusing setting unit.

4. The apparatus according to claim 1, further comprising:

a setting unit for setting amount of brightness adjustment; and

a brightness adjustment unit for performing a brightness adjustment in such a manner that the brightness of the image of the subject displayed on said display unit is made greater than initial brightness.

5. The apparatus according to claim 4, wherein said amplification-factor changeover unit changes over the amplification factor of said signal amplifier circuit from the initial amplification factor to a second display amplification factor larger than the initial amplification factor in response to setting of autofocus by said focusing setting unit.

6. The apparatus according to claim 4, wherein said brightness adjustment unit performs adjustment in such a manner that the brightness of the image of the subject displayed on said display unit becomes greater than the initial brightness in response to setting of manual focus by said focusing setting unit.

7. A method of controlling operation of a portable image pick-up apparatus having an image sensing device for sensing the image of a subject and outputting a video signal representing the image of the subject, and a signal amplifier circuit for amplifying the video signal output from the image sensing device, said method comprising the steps of:

providing a focusing setting unit for setting autofocus and manual focus selectively;

changing over an amplification factor of the signal amplifier circuit from a predetermined initial amplification factor to a first display amplification factor that is greater than the initial amplification factor in response to setting of manual focus by the focusing setting unit;

displaying the image of the subject represented by the video signal amplified by the signal amplifier circuit; and

recording the video signal, which is output from the image sensing device, on a recording medium in response to a trigger signal generated by application of a record command.