Method for classifying seeds
The present invention relates to a method for classification and/or sorting of seeds with the help of terahertz time-domain spectroscopy, use of terahertz time-domain spectroscopy for classification and/or sorting of seeds and seeds classified and/or sorted with terahertz time-domain spectroscopy.
1. A method for classifying seeds by using radiation in the terahertz range, comprises:
(a) applying an input terahertz pulse to the seed;
(b) measuring a signal generated by the input terahertz pulse after transmission and/or reflection by the seed;
(c) comparing the measured signal with the input terahertz pulse to determine a difference;
(d) determining one or more of the parameters based on the difference between the measured signal and the input terahertz pulse, the parameters being selected from the group consisting of a change in amplitude, a time delay in passing through the seed, additional echo pulses as a result of reflections within the seed, and field oscillations following the input terahertz pulse;
(e) assigning the seed to a predetermined seed class based on the one or more parameters obtained in step (d) as compared to a corresponding reference value.
2. The method according to claim 1 , wherein the method has a sorting accuracy of at least 75%.
3. The method according to claim 1 , wherein the method is automated.
4. The method according to claim 1 , wherein the terahertz pulse has a duration in the range of 3 picoseconds (ps) to 25 ps.
5. The method according to claim 1 , wherein the terahertz pulse has a delay of 0-104 ps with an interval of 0.05 ps.
6. The method according to claim 1 , wherein the seed is assigned to the predetermined class based on a determination of an embryo status of the seed, and wherein the embryo status of the seed is determined based on the one or more parameters determined in step (d).
7. The method according to claim 6 , wherein the embryo status of the seed is determined based on the change in amplitude, the time delay in passing through the seed, the additional echo pulses as a result of reflections within the seed, and the field oscillations following the input terahertz pulse.
8. The method according to claim 1 , wherein the terahertz radiation of the terahertz pulse has a frequency of 0.1 THz-10 THz.
9. The method according to claim 8 , wherein the terahertz radiation of the terahertz pulse has a frequency of 0.1-2 THz.
10. The method according to claim 1 , wherein the method involves the use of a terahertz time-domain spectrometer.
11. The method according to claim 10 , wherein the seed is sorted according to its predetermined seed class after taking it out of the measurement range of the terahertz time-domain spectrometer.
12. The method according to claim 10 , wherein the seed is calibrated prior to classification.
13. The method according to claim 10 , wherein the method comprises a step of introducing the seed into the measurement range of the spectrometer prior to step (a) and/or a step of taking the seed out of the measurement range of the spectrometer after step (d) and/or after step (e).
14. The method according to claim 1 , wherein the seed is selected from the group consisting of vegetable seeds, cereal seeds, grains of pitted fruit, grains of berries, nuts, and grains of Amaranthaceae family.
15. The method according to claim 14 , wherein the seed is the seed of the genus selected from the group consisting of Beta, Allium, Helianthus , and Capsicum.
16. The method according to claim 15 , wherein the seed is from the species selected from the group consisting of Beta vulgaris, Allium cepa , and Helianthus annuus.