| 摘要 |
An imaging optical system (16) produces an image of an observed field of view on an image sensor (18). The image sensor generates two image patterns from the image elements corresp. to the image of the field of view at two time points separated by a short time interval. The image patterns are passed to image processing devices which form the differences of the intensity values in corresp. image elements. The difference signals provide images of the rotor blades of a helicopter detected by the image sensor. <IMAGE> |
