摘要 |
A boom (3) on the rig is positioned close to the drilled hole (11) with the aid of a positioning system on the rig, enabling a camera (5) mounted on the boom to generate a digital image, which is stored in a computer (2) and converted into an image comprising only black and white components. A device (6) is used to measure the distance between the boom and drilled hole, the image is scanned to find a black region with a size within a range corresponding to the size of the hole and the position of the hole entrance is determined on the basis of the black region position and the measured distance. |