| 摘要 |
PROBLEM TO BE SOLVED: To provide a projector which accurately specifies a focal position even in the case of using a contrast value with noise components. SOLUTION: While changing a focal distance by shifting a projection lens optical system 8 from an initial position for a fixed time, the contrast value of an image outputted from a calculation part 22 is compared with a threshold by a control circuit 5. The shift time from the initial position when a contrast value exceeding the threshold is obtained is recorded. When the projection lens optical system 8 completely finished shifting, the average of a plurality of obtained shift times is obtained, then, taken as the shift time for the focal point. By extracting only the shift time when the contrast value exceeding the threshold is measured and obtaining the average of the shift times, the focal point is specified even in the case of the contrast value with the noise components. COPYRIGHT: (C)2005,JPO&NCIPI |
