| 摘要 |
An optoelectronic safety barrier wherein two columns define entry to a danger zone, an active one (10) bearing two cameras and a passive one (12) bearing two identical geometrical patterns (18, 20) aligned on the same optical axes. A control system (22) cyclically receives and processes respective images from the cameras, flips one of the images about a line orthogonal to the active column (10), compares each of the resulting images with a stored reference image (E), and issues an alarm signal whenever a difference is found between the reference image (E) and either one of said resulting images. The geometrical configuration of patterns and cameras allows for comparison with the reference image of the image from the first camera as it is, and the image of the second camera after overturn and alignment. Correct setup and alignment can also be verified by the same image comparison. |
