| 摘要 |
A conveyor defines a plane in which elongated workpieces, substantially parallel to one another, are transported transversely to their lengths through a measuring zone at which each workpiece is illuminated from above and lengthwise scanned by an array camera. A pit at the measuring zone has its bottom below said plane and in shadow, to provide a strongly contrasting background for the workpiece being scanned. To accommodate skewed workpieces, the array camera makes repeated scans of each workpiece as it passes the measuring zone, and data from such scanning is stored in a computer memory. Detectors cooperate with the array camera and the computer, signaling entry of each workpiece into the measuring zone and its departure therefrom. Thickness of each workpiece is measured near the measuring zone; and in calculating length of a workpiece from the stored scanning data for it, compensation is made for scanning parallax due to thickness. |
