Solid state imaging device for correcting level variations in output signals

A solid state imaging device comprising:

• a variation detecting means for detecting the period of energy variation of discharge type illumination;
• an exposure time determining means for determining an exposure time set for each frame or each field in imaging based on the period of energy variation detected by the variation detecting means;
• an imaging means for imaging, using an X-Y address type solid state imaging element for photoelectrically converting incident light to charges and accumulating the charges in an exposure time;
• a dividing means for dividing the exposure time into a plurality of exposure times;
• a separating means for separating the plurality of exposure times, divided by the dividing means, into valid exposure times and invalid exposure times;
• and
• a selective output means for selectively integrating charges accumulated in the imaging means only during the valid exposure times among charges accumulated in the imaging means during the exposure time, and for outputting a signal based on the integrated charges,
• wherein the variation detecting means (i) uses a light receiving element, placed to face an object to be captured, for detecting the period of energy variation of the discharge type illumination;
• or (ii) detects the period of energy variation of illumination based on an output signal of the imaging element in which the output signal of the imaging element contains energy variation components of the light source, the energy variation components of the light source being held for a predetermined time, and
• wherein among the charges accumulated by the imaging means, the charges accumulated during the invalid exposure times are drained scan line-by-scan line to a substrate of the imaging element.

A method for a solid state imaging device comprising:

• detecting a period of energy variation of discharge type illumination;
• determining an exposure time set for each frame or each field in imaging based on the detected period of energy variation;
• using an X-Y address type solid state imaging element for photoelectrically converting incident light to charges and accumulating the charges in an exposure time;
• dividing the exposure time into a plurality of exposure times;
• separating the plurality of exposure times into valid exposure times and invalid exposure times;
• selectively integrating charges accumulated only during the valid exposure times among charges accumulated during the exposure time;
• and
• outputting a signal based on the integrated charges,
• wherein among the accumulated charges, the charges accumulated during the invalid exposure times are drained scan line-by-scan line to a substrate of the imaging element.