| 摘要 |
PROBLEM TO BE SOLVED: To control the voltage of a light source lamp and contrast in an image signal, according to brightness in a room, projection distance, screen size, and brightness in an input image signal, and to achieve optimum brightness in an image on a screen. SOLUTION: In a discrimination section 15, LUT that is read from a storage section 14 is used to discriminate a lamp voltage, corresponding to data from a section 8 for measuring the brightness in the room, based on the output of a photosensor 7, data from a section 10 for calculating the projection distance based on the angle of rotation of a focus motor, and data from a section 12 for calculating the screen size based on the angle of rotation of a zoom motor 11 and the projection distance. The voltage of the light source lamp 6 is controlled at a lamp voltage control section 5, the brightness in the image signal from an A/D conversion section 2 is calculated at a section 13 for calculating the brightness in the image, the contrast corresponding to calculation data is discriminated at the discrimination section, according to the LUT, and the contrast in the image signal is controlled at a contrast control section 3, is inputted to a liquid crystal panel at a display section 4, and is projected by a projection lens.
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