| 摘要 |
In a method and a device for non-contact detection of plants (31), reflected light (6) is collected from a surface (5) by means of an optical system (7). The reflected light (6) is devided by means of a beam splitter (13) into two light beams (14, 15) each of which is filtered by an interference filter (16, 17) to a respective predetermined wavelength. Two photodiodes (18, 19) convert a respective wavelength (14, 15) into an electric signal (20, 21), each of these signals being amplified in a respective operational amplifier (22, 23). A divider (26) receives the two signals (20, 21) and divide them for emitting a ratio signal (27). This ratio signal (27) is compared in a comparator (28) with a preselected reference signal (29) for emitting an output signal (30) which indicates the presence/non presence of a plant (31) on the surface. |
