| 摘要 |
Apparatus for determining the dimension and position of an elongate object (1) travelling freely in space, for example, a cable being coated in an on-line extrusion process. Two separate out-of-focus images of the object (1) are formed on respective charge coupled devices (5) and (6) positioned on either side of the image plane of the optical system (2, 4) employed. By monitoring variations in the comparative characteristics of the two images caused by object movement and size variation, using conditioning circuits (7) and (8) and an indicator/controller unit (9), the spatial position of the object (1) and its dimensions are determined on a continuous basis whereby it is possible to compensate for inaccuracies in dimensional measurement caused by object movement in space, and to control thereby the extrusion process.
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