| 摘要 |
PURPOSE:To recognize the generation of the abnormality of a CCD image pickup element before image pickup is made impossible, by providing an abnormality decision means which decides the abnormality of the CCD image pickup element when the value of a dark current held by a dark current holding means exceeds a prescribed value. CONSTITUTION:A buffer memory 23 as the dark current holding means which holds a digital signalized dark current signal from a camera 20, and a computing element 24 which corrects a picture signal from the camera 20 setting the dark current signal held by the buffer memory 23 as a reference value are provided. A CPU compares the value of the dark current held by the buffer memory 23 with a value set in advance, and generates alarm when the value of the dark current exceeds the set value. Therefore, even when a CCD line sensor can be still used, the CPU of a host device issues the alarm when the dark current exceeds the prescribed value, and informs the abnormality of the CCD line sensor. And an operator exchanges the CCD line sensor, or can investigates the cause of the generation of the abnormality.
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