Iris control method and apparatus for television camera for controlling iris of lens according to video signal, and television camera using the same

A television camera comprising:

• a lens unit having an iris;
• a solid state image pickup device, to which light beams from an object are applied through said lens, for outputting on a time division basis a long-time exposure video signal obtained from said light beams exposing said object for a long time and a short-time exposure video signal obtained from said light beams exposing said object for a short time;
• a division unit for dividing an image screen displayed by said long-time exposure video signal into a plurality of predetermined areas;
• a detection unit for detecting a first and a second area, each of which has a different luminance level of said long-time exposure video signal;
• a weighting unit for applying different weighting to said long-time exposure video signals of said first and second areas, respectively;
• a synthesis unit for synthesizing said long-time exposure video signal and said short-time exposure video signal;
• and
• a control unit for controlling said iris of said lens in response to said weighted long-time exposure video signal.

An iris control method of a television camera comprising the steps of:

• outputting on a time division basis a long-time exposure video signal obtained from light beams exposing an object for a long time and a short-time exposure video signal obtained from light beams exposing said object for a short time;
• b) dividing an image screen displayed by said long-time exposure video signal into a plurality of predetermined areas;
• c) detecting a first and a second area each of which has a different luminance level of said long-time exposure video signal;
• d) applying different weighting to said long-time exposure video signals of said first and second areas, respectively;
• and
• e) controlling an iris of a lens, through which said light beams are applied to said solid state image pickup device, in response to said weighted long-time exposure video signal.