On-the-go sugar sensor for determining sugar content during harvesting

• US 6,624,888 B2
• Filed: 01/12/2001
• Issued: 09/23/2003
• Est. Priority Date: 01/12/2000
• Status: Expired due to Term

• Current Assignee: Ndsu-Research Foundation
• Original Assignee: North Dakota State University (US Bancorp)
• Inventors: Panigrahi, Suranjan, Hofman, Vernon
• Primary Examiner(s): Lee, Diane I.
• Application Number:
  US09/758,392
• Publication Number:
  US 20010050339A1
• Time in Patent Office: 984 Days
• Field of Search: 356/32, 356/326, 356/328, 356/73.1, 356/69
• US Class Current: 356/326
• CPC Class Codes: A01D 2033/005 Yield crop determination mechanisms for root-crop harvesters
• CPC Class Codes: A01D 33/00 Accessories for digging harvesters
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01N 1/286 involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising microtomes G01N1/06; pulverising in general B02C; mixing in general B01F
• CPC Class Codes: G01N 2001/021 Correlating sampling sites with geographical information, e.g. GPS
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 33/02 Food
• CPC Class Codes: G01N 33/025 Fruits or vegetables

Abstract

An on-the-go sensor for determining the sugar content of an agricultural product, such as a sugar beet, during harvesting or at other times. The sensor is coupled to a harvester/defoliator and uses a knife to slice a cross-section from the crown of the sugar beet during harvesting. An illumination chamber radiates the exposed crown, and a sensor head receives the reflected radiation. A spectrometer converts the reflected radiation to a spectral signal. A computer digitizes and processes the spectral signal to produce data points relating to the sugar content of the sugar beet. The processing of the data points includes normalization, linearization, and other techniques. One of the techniques eliminates the conventional need to use the spectral signature of a separate physical standard as a reference.

Claims

1. A device for determining sugar content of an agricultural product while being harvested, comprising:

a sample preparation mechanism for attachment to a harvester/defoliator and for use with a received agricultural product during harvesting to create an exposed sample of the agricultural product;

an illumination chamber for radiating the exposed sample of the agricultural product;

a sensor head for receiving radiation from the exposed sample of the agricultural product;

a spectrometer, coupled to the sensor for converting the radiation into a corresponding spectral signal;

a computer, coupled to the spectrometer, for receiving the spectral signal and for processing the spectral signal to determine an indication of sugar content of the agricultural product; and

an electronic detector for detecting a location of the agricultural product.

2. The device of claim 1 wherein the sample preparation mechanism includes a cutting apparatus for cutting a cross-section of the agricultural product to create the sample.

3. The device of claim 2 wherein the sensor head receives the radiation reflected from the sample.

4. The device of claim 1 wherein the sensor head includes:

an enclosure;

a fiber optic cable coupled to the enclosure; and

one or more lenses contained within the enclosure for transmitting the radiation onto the fiber optic cable.

5. The device of claim 4 wherein the one or more lenses include:

a collimating lens attached to the fiber optic cable; and

one or more optical lenses for focusing the radiation onto the collimating lens.

6. The device of claim 4, further including a lens holder for mounting the one or more lenses within the enclosure.

7. The device of claim 1 wherein the illumination chamber includes:

an enclosure;

a light source within the enclosure; and

a light outlet hole on the enclosure for passing light from the light source for radiating the exposed sample.

8. The device of claim 7 wherein the illumination chamber further includes a ventilation mechanism to reduce heat build-up in the illumination chamber.

9. A method for determining sugar content of an agricultural product while being harvested, comprising:

preparing a sample of a received agricultural product during harvesting to create an exposed sample of the agricultural product;

radiating the exposed sample of the agricultural product;

receiving radiation from the exposed sample of the agricultural product;

converting the radiation into a corresponding spectral signal; and

receiving the spectral signal and processing the spectral signal to determine an indication of sugar content of the agricultural product,

further including detecting a location of the agricultural product using an electronic detector.

10. The method of claim 9 wherein the sample preparation step includes cutting a cross-section of the agricultural product to create the sample.

11. The method of claim 10 wherein the receiving radiation step includes receiving the radiation reflected from the sample.

12. The method of claim 9 wherein the receiving radiation step includes using one or more lenses to focus the received radiation onto a fiber optic cable.

13. A method of on-the-go sampling at intervals within a field containing a plurality of agricultural products to determine sugar content among the agricultural products, comprising:

preparing a sample of a plurality of received agricultural products at particular intervals in a field during harvesting to create an expose sample of each of the agricultural products at particular intervals;

radiating the exposed sample of the agricultural product;

receiving radiation from the exposed sample of the agricultural product;

converting the radiation into a corresponding spectral signal;

receiving the spectral signal and processing the spectral signal sugar content of the agricultural product; and

recording the determination of the sugar content for each of the plurality of agricultural products,

further including detecting a location of the agricultural product using an electronic detector.

14. The method of claim 13, further including using an output of the electronic detector for selecting the agricultural product to be sampled and synchronizing a sample preparation mechanism for preparing the sample of the plurality of received agricultural products.

15. The method of claim 13 wherein the sample preparation step includes cutting a cross-section of the agricultural product to create the sample.

16. The method of claim 15 wherein the receiving radiation step includes receiving the radiation reflected from the sample.

17. The method of claim 13 wherein the receiving radiation step includes using one or more lenses to focus the received radiation onto a fiber optic cable.

18. A portable apparatus for use in determining a constituent content of an agricultural product, comprising:

a sample holder for holding a sample of the agricultural product;

an illumination chamber for radiating the sample while in the sample holder;

a sensor head for receiving reflected radiation from the sample; and

a portable housing for containing the illumination chamber and the sensor, and for accommodating the sample holder,

wherein a surface of the sample holder has a color providing a low or minimum reflectance from surrounding areas on the surface not covered by the agricultural product sample.

19. The apparatus of claim 18 wherein the housing includes a fiber optic cable slot for accommodating a fiber optic cable for transmitting a light signal, corresponding to the received reflected radiation, from the sensor head to an external spectrometer and computer.

20. The apparatus of claim 18, further including a handle attached to an exterior of the housing.

21. The apparatus of claim 18 wherein the sample holder includes:

an arm;

a supporting plate attached to the arm; and

an anchoring mechanism attached to the supporting plate for holding the sample of the agricultural product.

22. The apparatus of claim 21 wherein a surface of the supporting plate has a color providing a low or minimum reflectance from surrounding areas on the surface not covered by the agricultural product sample.

23. A method for processing a spectral signal to predict sugar content of an agricultural product, comprising:

preparing a sample of a received agricultural product during harvesting to create an exposed sample of the agricultural product;

radiating the exposed sample of the agricultural product;

receiving radiation from the exposed sample of the agricultural product;

converting the radiation into a corresponding spectral signal;

receiving the spectral signal and processing the spectral signal to determine an indication of sugar content of the agricultural product; and

associating the indication of the sugar content with a particular location of the agricultural product,

further including detecting a location of the agricultural product using an electronic detector.

24. The method of claim 23 wherein the associating step includes associating the indication of the sugar content with a field location of the agricultural product.

25. The method of claim 23 wherein the associating step includes associating the indication of the sugar content with a harvesting batch of the agricultural product.