| 摘要 |
PURPOSE:To prevent erroneous measurement due to pseudo-correspondence and thereby to improve precision by a method wherein a focusing state is detected on the basis of differential signals of distribution of measured illuminance and thereafter a distance to a part wherein the focusing state is detected is calculated on the basis of the disposition of an optical system or the like. CONSTITUTION:CCD arrays 3 and 4 are driven for reading simultaneously by a driving circuit 31, while a pulse motor 22 is driven by a driving circuit 32. Image signals from the arrays 3 and 4 are differentiated by differentiating circuits 33 and 34 and a difference signal of the two differential signals is obtained in a differential circuit 35. The differential signal is inputted to a comparator circuit 40 through an A/D converter 36, a delay circuit 37 and a differential circuit 38 and compared with a first threshold value therein. In a comparator circuit 39, on the other hand, a signal from the converter 36 is compared with a second threshold value, and an output thereof is inputted to an AND circuit 41 together with an output of the circuit 40. From the circuit 32 a motor rotation angle (position in the directions of the optical axes of the arrays 3 and 4) is inputted to a distance calculation circuit 43, and an output thereof is inputted to CPU 42 together with an output from the circuit 41 and stored in a memory 44. |
