| 摘要 |
PURPOSE:To increase the efficiency of a harvesting machine by a method wherein an object to be detected is irradiated with near-infrared rays, transmitted light is detected by a photodetector and whether the object to be detected is root vegitables or soil and stone is detected. CONSTITUTION:Light is emitted from a pulse-laser element 3 by a pulse-laser drive circuit 1 and a pulse-laser head 2. The cross section of a laser beam is oval-shaped, it is changed to parallel light by a collimator lens 4, the short- axis side of the oval cross section is corrected by a prism 5, and it is changed to parallel light whose cross section is circular. An object 10 to be detected is irradiated with the parallel light, transmitted light is condensed with a condenser lens 6, and the light is made incident on a photodetector 7. An avalanche photodiode is used for the detector 7, its output is amplified by a signal amplification circuit 8, and the output is observed by an oscilloscope 9. In this case, when the object 10 to be detected is soil and stone, the output of the detector 7 cannot be observed. When the object is edible roots, an output which can be observed is generated. The output is used as a sorting signal, and the object 10 to be detected can be automatically sorted easily. |
