| 摘要 |
<p>PURPOSE:To measure a distance at high accuracy in a wide measuring scope by changing a threshold in accordance with the measured distance. CONSTITUTION:Where data calculated by a distance arithmetic circuit 4 in a time (i) and its previous time (i-1) are assumed to be X1 and Xi-1, respectively, the data Xi and Xi-1 are stored in the 1st memory circuit 5 and the 2nd memory circuit 6, respectively. A subtractor 7 outputs the value of (Xi-Xi-1), and an absolute value arithmetic circuit 8 outputs ¦Xi-Xi-1¦. In a threshold arithmetic circuit 10 threshold Rth=Xi-1 is set, and in a comparator 9 B= Rth-¦Xi-Xi-1¦ is calculated. Where B>0, a transfer command is outputted to make the data in the 2nd memory circuit 6 into Xi, which is outputted outside. Simultaneously the threshold arithmetic circuit 10 modifies the threshold Rth based on the new data Xi.</p> |
