| 摘要 |
A component (1,2,4,5) is provided for parallel movement of a laser lobe in a measurement plane in accordance with a specific movement pattern, pref. with constant speed, in repetitive sweeps between two outer positions (Xa,Xb). The detector, dependent upon the laser light sensed, transmits a first signal to a computer (7), where such signal relates to a primary sweep of the laser lobe. During a second laser lobe sweep, the detector transmits a second signal to the computer. From the two received signals, the computer calculates the length (X2 - X1) of an investigate object. It is also preferable to obtain third and fourth signals from the detector, the third being the equivalent of the second signal from which the first signal value, multiplied by a factor less than 1, has been deducted. A fourth signal can be used by comparison of the third with a reference level, and comprises higher and lower signal levels from which a measurement value can be calculated with precision. This value is compared with the laser source calibration value to provided the true dimension of the investigation object. (Provisional basic advised week 87/01) |
