Patent ID: 8476603

Claim:
Method for non-destructively measuring the content of at least one compound in a plant located in air, comprising: locating a device proximate said plant to establish a non-contacting, spaced apart air distance of less than 20 cm between a target zone ( 91 ) of said plant and a detection means ( 40 , 41 , 42 , 43 ) of said device; and measuring the content of the at least one compound in said plant, wherein said device ( 1 ) comprises excitation means ( 20 , 30 ) emitting excitation light in a determined wavelength band ( 61 , 62 , 63 ) for generating a fluorescence ( 49 ) in the tissues of a target zone ( 91 ), the detection means ( 40 , 41 , 42 , 43 ) being configured in a determined wavelength band ( 65 , 66 , 67 ) for detecting the fluorescence thus-generated, means for managing said excitation and detection means, and processing means arranged for dynamically correlating said excitation and detection means so as to provide a measurement of the fluorescence thus generated, wherein, the excitation means is according to a plurality of different wavelength bands and the detection means is capable of detecting a fluorescence light in a plurality of wavelength bands ( 65 , 66 , 67 ), said wavelength bands being determined so as to make it possible to carry out a plurality of fluorescence measurements; the excitation means and the detection means are arranged according to a determined geometry in order that the direction of the excitation light rays ( 29 , 39 ) illuminating said target zone ( 91 ) on the one hand and the direction of the fluorescence light rays ( 49 ) detected by the detection means on the other hand are not collinear with each other; and the excitation means include a set of emitters comprising at least two light emitters ( 21 , 24 ) situated on either side of the detection means or distributed around said detection means ( 41 , 42 , 43 ), and illuminating the target zone ( 91 ) in the same wavelength band.