| 摘要 |
PROBLEM TO BE SOLVED: To perform photographing whose color balance is satisfactory by reducing the load of maintenance. SOLUTION: The spectral distribution of a fluorescent lamp 14 is successively measured seven times at each time power is supplied. When there is fluctuation in the spectral distribution, an alarm 20 is issued, and the exchange of the fluorescent lamp 14 is urged. When there is not any fluctuation, the spectral reflectivity of a screen face 26a of a rotary screen is measured, and the difference between the measured spectral reflectivity and the initial spectral reflectivity of a new screen face is calculated. When there is not any difference, the white balance correction value of a digital camera 35 is calculated from a luminance signal to be outputted from a CCD camera 30 which has photographed the screen face 26a. When there is any difference, the number or range of low luminance pixels are checked from the luminance signal of each pixel to be outputted from the CCD camera 30, and the write balance correction value is calculated by operating interpolation processing or the like. When the processing is incapable, the screen 26 is rolled up, and the screen face is made new. When the rolling-up is incapable, the exchange of a rotary screen 15 is encouraged by the alarm 20.
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