| 摘要 |
PURPOSE:To accurately discriminate the presence or the absence of an image by using correction data preliminarily stored in a memory to correct the slice level in accordance with movement of a line sensor and discriminating the presence or the absence of an image on the basis of the number of times of corrected slice level crossing of the output signal. CONSTITUTION:Correction data for the variance of illuminance of each lens is preliminarily stored, and a CPU 52 corrects a contrast C and an output signal d' or slice levels Sn and Sp for a turning position theta of a line sensor 40. A projection lens 20 is moved once so that the focus point is traversed and the focus point is obtained from the half-width of the change characteristic curve of luminance at this time, or the projection lens 20 is moved in all of the range once to obtain the position where a luminance I is maximum. A control means 50 drives the line sensor 40 out of a screen in this manner. If the print mode is set after an expanded projection image appearing on the screen 28 is seen, a reflection mirror 24 is turned to the dotted-line position in the first figure and the image is transferred to a transfer paper 38 to obtain a hard copy. |
