| 摘要 |
A method of operating a photo sensor (S) in a projection display device comprises the steps of, illuminating the sensor (S) with a projected image (M). Detecting a signal (Isen) from the sensor (S) responsive to the illumination by the projected image (M). Changing a threshold value (Iref) of the detector until the signal (Isen) detection ceases. Storing a value representative of the threshold value (Iref) which terminated detection of the signal (Isen) from the sensor. <IMAGE> |
