| 摘要 |
Disclosed is a method for shortening a response time of a measurement device (100) controlling an exposure time of a CCD camera in a time of preset control cycle, wherein a camera capable of simultaneously obtaining output of two or more filters with the different transmittances is employed as the CCD camera, the transmittances are set so as to satisfy eND1 > eND2 > ... eNDi > eNDi+1 > ... > eNDi+n, the transmittances are set so as to lap a saturation value in a measurement range of camera output of a first filter having the high transmittance eNDi detecting a minimum value of the input light amount and a minimum value in a measurement range of camera output of a second filter having the low transmittance eNDi+1, a correction gain of an exposure time obtained by converting to the camera output of the first filter is obtained from the camera output of the second filter or from the ratio of the transmittance eNDi to the transmittance eNDi+1 in a case where the camera output of the first filter is saturated, the input light amount is detected in a previous control cycle, and the exposure time of the camera of the first filter is updated in a next control cycle. |
