Patent ID: 7639284

Claim:
A method for determining a photographic environment when an object is photographed by an imaging apparatus including an XY-address-scanning imaging device, the method comprising: a first step of setting a shutter speed of the imaging device to a first shutter speed according to a vertical sync frequency of the imaging device; a second step of integrating a video signal obtained from the imaging device at the first shutter speed within a screen area to determine an integration value, and normalizing the determined integration value by an average value of a plurality of integration values to determine a first normalized integration value, the plurality of integration values being obtained in a plurality of successive vertical sync periods; a third step of extracting a first frequency component from the first normalized integration value, and determining whether the first frequency component has a higher level than a first threshold value, the first frequency component being a first-order spectrum of the first normalized integration value; a fourth step of setting the shutter speed of the imaging device to a second shutter speed different from the first shutter speed under a condition that the level of the first frequency component is equal to or lower than the first threshold value, independent of any other condition; a fifth step of integrating a video signal obtained from the imaging device at the second shutter speed within a screen area to determine an integration value, and normalizing the determined integration value by the average value used in the second step to determine a second normalized integration value; and a sixth step of extracting a second frequency component from the second normalized integration value to determine whether the second frequency component has a higher level than a second threshold value, the second frequency component being a first-order spectrum of the second normalized integration value.