Determining a weed percentage and agricultural control device

1. A method for determining a weed percentage in an observation section of a field, the method comprising:

acquiring actual spectral information using an optical observation section sensor aimed at the observation section;

acquiring reference spectral information using an optical reference sensor aimed at a reference section of the same ground area;

determining a difference between the actual spectral information and the reference spectral information; and

mapping the difference to the weed percentage using predefined mapping.

2. The method as claimed in claim 1 , wherein the reference section and the observation section comprise regions of the same field and are arranged close together or at least partially overlapping.

3. The method as claimed in claim 1 , further comprising the reference sensor fastened on an area of the field over which the observation section or the optical observation section sensor is guided.

4. The method as claimed in claim 1 , wherein the actual spectral information and the reference spectral information characterize a spectrum interval, and the actual spectral information and the reference spectral information include a respective value or sequence of values relating to different wavelengths of light.

5. The method as claimed in claim 1 , further comprising acquiring the actual spectral information or the reference spectral information using color sensors or electronic cameras; and

determining color values over the entire image or over an image section from the cameras with a color detection unit connected downstream of the cameras.

6. The method as claimed in claim 1 , further comprising determining shading of the observation section and of the reference section; and

in the event of different shading, adapting either (a) the actual spectral information, or (b) the reference spectral information, or (c) the difference between the actual and reference spectral information by means of arithmetic combination with a predefined lighting correlation variable.

7. The method as claimed in claim 1 , further comprising aligning the reference sensor with a reference area which does not have a weed percentage or has a tolerable weed percentage.

8. An agricultural control device ( 100 ) having

an optical observation section sensor;

a reference sensor receiving interface;

an optional optical reference sensor;

the observation section sensor and the reference sensor receiving interface fastened to a vehicle;

a comparator connected downstream of the sensors to compare actual spectral information from the observation section sensor with reference spectral information from the optical reference sensor; and

a mapping unit connected downstream of the comparator to map the comparison result from the comparator to a weed percentage and to provide the mapped result to an output of the agricultural control device.

9. The agricultural control device as claimed in claim 8 , further comprising the reference sensor receiving interface connected to the optical reference sensor via a wireless data connection.

10. The agricultural control device as claimed in claim 8 , further comprising:

a color detection unit connected downstream of the optical observation section sensor or the reference sensor receiving interface; and

the reference sensor or the optical observation section sensor recording an electronic image and the receiving interface receiving the electronic image.