| 摘要 |
A ripple detecting circuit (16) outputs a signal of a "0" level in an ON state of a light source (1) and a signal of a "1" level in an OFF state of the light source (1) when a flashing frequency of the light source (1) exceeds a prescribed frequency, while outputting a signal of a "0" level when the former is less than the latter. A holding circuit (17) outputs a ratio signal from a ratio signal generating means in response to the signal of a "0" level supplied from the ripple detecting circuit (16) while holding and outputting a ratio signal immediately ahead of change from a "0" level into a "1" level in response to the signal of a "1" level. A white balance adjusting circuit (15) performs white balance adjustment in response to an output from the holding circuit (17). When the prescribed frequency is set at a limit flashing frequency of the light source (1) substantially allowing no visual recognition, no white balance adjustment is performed on the basis of a signal in an OFF state of the light source (1) if flashing of the light source (1) cannot be visually recognized.
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