Imaging apparatus with dual white balance adjusting systems for different color temperatures

• US 6,184,940 B1
• Filed: 03/13/1998
• Issued: 02/06/2001
• Est. Priority Date: 03/14/1997
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sano, Toshiyuki
• Primary Examiner(s): Miller, John W.
• Application Number:
  US09/041,751
• Time in Patent Office: 1,061 Days
• Field of Search: 348/221, 348/222, 348/223, 348/224, 348/225, 348/228, 348/229, 348/230, 348/655, 348/656, 348/362, 348/363, 348/364, 348/365, 348/366, 348/367
• US Class Current: 348/655
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

In an imaging apparatus, a signal obtained through a long exposed signal and a shortly exposed signal are synthesized into a luminance signals, a color difference (CD) signal R−G and a CD signal B−G to yield a video signal. The shortly exposed signal has been modulated by one of four colors. The magnitude of each pixel value in the shortly exposed signal is multiplied by one of four gains (prepared for the four colors) associated with the modulation color. The magnitudes of colors, e.g., R and B are multiplied by first and second gains, respectively. The microcontroller provides, for each field, a long/short mode signal. In each field of the short mode, the controller finds the four gains such that at least one of averages of the first and second CD signals converges on a predetermined target value (e.g., 0). In each field of the long mode, the controller finds the first and second gains such that said at least one of said averages converges on the value.

Claims

1. An imaging apparatus for separately adjusting white balance for a long exposed image and a shortly exposed image comprising:

an imaging device alternately generating in one field period of time a long exposed signal and a shortly exposed;

a time scale converter which outputs said long exposed signal and shortly exposed signal in a same time axis;

a synthesizer synthesizing said long exposed signal and said shortly exposed signal, said synthesizer outputting a synthesized image signal;

a first white balance adjusting device adjusting a white balance of said shortly exposed signal; and

a second white balance adjusting device adjusting a white balance of said long exposed signal,

wherein said first white balance adjusting device adjusts the white balance of said shortly exposed signal before being synthesized with said long exposed signal by said synthesizer; and

said second white balance adjusting device adjusts the white balance of said long exposed signal after being synthesized with said shortly exposed signal by said synthesizer.

2. An imaging apparatus for separately adjusting white balance for a long exposed image and a shortly exposed image comprising:

an imaging device alternately generating in one field period of time a long exposed signal and a shortly exposed signal;

a time scale converter which outputs said long exposed signal and shortly exposed signal in a same time axis;

a synthesizer synthesizing said long exposed signal and said shortly exposed signal, said synthesizer outputting a synthesized image signal;

a first white balance adjusting device adjusting a white balance of said shortly exposed signal; and

a second white balance adjusting device adjusting a white balance of said long exposed signal,

wherein said first white balance adjusting device adjusts the white balance of said shortly exposed signal after being synthesized with said long exposed signal by said synthesizer; and

said second white balance adjusting device adjusts the white balance of said long exposed signal before being synthesized with said shortly exposed signal by said synthesizer.

3. An imaging apparatus for separately adjusting white balance for a long exposed image and a shortly exposed image comprising:

an imaging device alternately generating in one field period of time a long exposed signal and a shortly exposed signal;

a time scale converter which outputs said long exposed signal and shortly exposed signal in a same time axis;

a synthesizer synthesizing said long exposed signal and said shortly exposed signal, said synthesizer outputting a synthesized image signal;

a first white balance adjusting device adjusting a white balance of said shortly exposed signal; and

a second white balance adjusting device adjusting a white balance of said long exposed signal;

the imaging apparatus further comprising;

a color difference signal generating device generating a color difference signal of said long exposed signal; and

an average signal generating device generating an average signal of said color difference signal;

wherein said first white balance adjusting device and said second white balance adjusting device adjust the respective signals thereof according to said average signal.

4. An imaging apparatus for separately adjusting white balance for a long exposed image and a shortly exposed image comprising:

an imaging device alternately generating in one field period of time a long exposed signal and a shortly exposed signal;

a time scale converter which outputs said long exposed signal and shortly exposed signal in a same time axis;

a synthesizer synthesizing said long exposed signal and said shortly exposed signal, said synthesizer outputting a synthesized image signal;

a first white balance adjusting device adjusting a white balance of said shortly exposed signal; and

a second white balance adjusting device adjusting a white balance of said long exposed signal;

the imaging apparatus further comprising;

a pulse generating device, said pulse indicating a bright area and a dark area of said long exposed signal,

a color difference signal generating device generating a color difference signal of the bright area and the dark area of said long exposed signal referring to said pulse;

an average signal generating device generating an average signal of said color difference signal of a bright area and a dark area respectively;

wherein said first white balance adjusting device adjusts the white balance of said shortly exposed signal according to said average signal of said bright area; and

said second white balance adjusting device adjusts the white balance of said long exposed signal according to said average signal of said dark area.

5. An imaging apparatus for separately adjusting white balance for a long exposed image and a shortly exposed image comprising:

an imaging device alternately generating in one field period of time a long exposed signal and a shortly exposed signal;

a time scale converter which outputs said long exposed signal and shortly exposed signal in a same time axis;

a synthesizer synthesizing said long exposed signal and said shortly exposed signal, said synthesizer outputting a synthesized image signal;

a first white balance adjusting device adjusting a white balance of said shortly exposed signal; and

a second white balance adjusting device adjusting a white balance of said long exposed signal;

the imaging apparatus further comprising;

an operation completion detection means for detecting completion of operation of said first white balance adjusting device and of said second white balance adjusting device;

wherein said first white balance adjusting device adjusts the white balance of said shortly exposed signal when said second white balance adjusting device completes the adjustment of the white balance of said long exposed signal according to said operation completion detection means.

6. An imaging method comprising the steps of:

alternately providing a long exposed signal and a shortly exposed signal in one field period of time;

converting said long exposed signal and said shortly exposed signal in a same time axis;

synthesizing said long exposed signal and said shortly exposed signal in a synthesized image signal;

adjusting a white balance of said shortly exposed signal; and

adjusting a white balance of said long exposed signal, wherein;

said step of adjusting a white balance of said shortly exposed signal is performed before synthesizing said shortly exposed signal and said long exposed signal;

and said step of adjusting a white balance of said long exposed signal is performed after synthesizing said shortly exposed signal and said long exposed signal.

7. An imaging method comprising the steps of:

alternately providing a long exposed signal and a shortly exposed signal in one field period of time;

converting said long exposed signal and said shortly exposed signal in a same time axis;

synthesizing said long exposed signal and said shortly exposed signal in a synthesized image signal;

adjusting a white balance of said shortly exposed signal; and

adjusting a white balance of said long exposed signal, wherein;

said step of adjusting a white balance of said long exposed signal is performed before synthesizing said shortly exposed signal and said long exposed signal;

and said step of adjusting a white balance of said shortly exposed signal is performed after synthesizing said shortly exposed signal and said long exposed signal.

8. An imaging method comprising the steps of:

alternately providing a long exposed signal and a shortly exposed signal in one field period of time;

converting said long exposed signal and said shortly exposed signal in a same time axis;

synthesizing said long exposed signal and said shortly exposed signal in a synthesized image signal;

adjusting a white balance of said shortly exposed signal; and

adjusting a white balance of said long exposed signal;

the imaging method further comprising the steps of;

generating a color difference signal of said long exposed signal;

generating an average signal of said color difference signal;

said step of adjusting a white balance of said shortly exposed signal is performed according to said average signal before synthesizing said shortly exposed signal with said long exposed signal; and

said step of adjusting a white balance of said long exposed signal is performed according to said average signal after synthesizing said shortly exposed signal and said long exposed signal.

9. An imaging method comprising the steps of:

alternately providing a long exposed signal and a shortly exposed signal in one field period of time;

converting said long exposed signal and said shortly exposed signal in a same time axis;

synthesizing said long exposed signal and said shortly exposed signal in a synthesized image signal;

adjusting a white balance of said shortly exposed signal; and

adjusting a white balance of said long exposed signal;

the imaging further comprising the steps of;

generating a pulse, said pulse indicating a bright area and a dark area of said long exposed signal,

generating a color difference signal of a bright area and a dark area of said long exposed signal in accordance with said pulse;

generating an average signal of said color difference signal of each of said bright area and said dark area, respectively;

said step of adjusting the white balance of said shortly exposed signal is performed according to said average signal of said bright area; and

said step of adjusting the white balance of said long exposed signal is performed according to said average signal of said dark area.

10. An imaging method comprising the steps of:

alternately providing a long exposed signal and a shortly exposed signal in one field period of time;

converting said long exposed signal and said shortly exposed signal in a same time axis;

synthesizing said long exposed signal and said shortly exposed signal in a synthesized image signal;

adjusting a white balance of said shortly exposed signal; and

adjusting a white balance of said long exposed signal, wherein

said step of adjusting a white balance of said shortly exposed signal is started upon completion of said step of adjusting a white balance of said long exposed signal.