Refined row guidance parameterization with Hough transform

1. A machine-readable medium that is not a transitory propagating signal, the machine-readable medium including instructions that, when executed by a machine, cause the machine to perform operations comprising:

receiving an electronic representation of a field (ERF);

performing a steering variable calculation based on the ERF;

selecting an intermediate value used in the steering variable calculation;

identifying a refined intermediate value from the intermediate value by:

measuring a difference between the intermediate value and an anchor value; and

rejecting the intermediate value when the difference is beyond a threshold and keeping the intermediate value otherwise; and

adjusting the steering variable calculation using the refined intermediate value including abandoning the steering variable calculation in response to a rejection of the intermediate value.

2. The machine-readable medium of claim 1 , wherein the combination of one or more previously calculated intermediate values is an average of the one or more previously calculated intermediate values.

3. The machine-readable medium of claim 1 , wherein the intermediate value is a current vanishing point, wherein the anchor value is a combination of previous vanishing points, and wherein the difference between the intermediate value and the anchor value is a distance between the current vanishing point and the combination of previous vanishing points.

4. The machine-readable medium of claim 3 , wherein the distance is determined by at least one of sum of squares, root sum of squares, or sum of absolute values.

5. The machine-readable medium of claim 3 , wherein the threshold is calibrated to a mechanism used to determine the distance.

6. The machine-readable medium of claim 1 , wherein the intermediate value is a mousetail magnitude from a plurality of mousetail magnitudes computed for the steering variable calculation, each of the plurality of mousetail magnitudes being a magnitude of a sum of vectors, the vectors each having an angle representing a distance of a corresponding line intercept from a camera intercept represented in a first parameter space of cascaded Hough transform used to perform the steering variable calculation;

wherein the anchor value is a greatest mousetail magnitude of the plurality of mousetail magnitudes within the steering variable calculation; and

wherein identifying the refined intermediate value includes modifying a component that contributes to a vector of the vectors to produce the refined intermediate value, the refined intermediate value being a mousetail magnitude not less than the anchor and greater than the intermediate value.

7. The machine-readable medium of claim 6 , wherein the component is a second threshold used to classify pixels in the ERF.

8. The machine-readable medium of claim 7 , wherein the second threshold is a color threshold used to distinguish between crop pixels and furrow pixels.

9. A machine-implemented method comprising:

receiving an electronic representation of a field (ERF);

performing a steering variable calculation;

selecting an intermediate value used in calculating the steering variable;

identifying a refined intermediate value from the intermediate value by:

measuring a difference between the intermediate value and an anchor value; and

rejecting the intermediate value when the difference is beyond a threshold and keeping the intermediate value otherwise; and

adjusting the steering variable calculation using the refined intermediate value including abandoning the steering variable calculation in response to a rejection of the intermediate value.

10. The method of claim 9 , wherein the combination of one or more previously calculated intermediate values is an average of the one or more previously calculated intermediate values.

11. The method of claim 9 , wherein the intermediate value is a current vanishing point, wherein the anchor value is a combination of previous vanishing points, and wherein the difference between the intermediate value and the anchor value is a distance between the current vanishing point and the combination of previous vanishing points.

12. The method of claim 11 , wherein the distance is determined by at least one of sum of squares, root sum of squares, or sum of absolute values.

13. The method of claim 11 , wherein the threshold is calibrated to a mechanism used to determine the distance.

14. The method of claim 9 , wherein the intermediate value is a mousetail magnitude from a plurality of mousetail magnitudes computed for the steering variable calculation, each of the plurality of mousetail magnitudes being a magnitude of a sum of vectors, the vectors each having an angle representing a distance of a corresponding line intercept from a camera intercept represented in a first parameter space of a cascaded Hough transform used to perform the steering variable calculation;

wherein the anchor value is a greatest mousetail magnitude of the plurality of mousetail magnitudes within the steering variable calculation; and

wherein identifying the refined intermediate value includes modifying a component that contributes to a vector of the vectors to produce the refined intermediate value, the refined intermediate value being a mousetail magnitude not less than the anchor and greater than the intermediate value.

15. The method of claim 14 , wherein the component is a second threshold used to classify pixels in the ERF.

16. The method of claim 15 , wherein the second threshold is a color threshold used to distinguish between crop pixels and furrow pixels.

17. A system comprising:

a scene module arranged to receive an electronic representation of a field (ERF);

and

a steering parameter calculation module arranged to:

perform a steering variable calculation based on the ERF;

select an intermediate value used in calculating the steering variable;

identify a refined intermediate value from the intermediate value including the steering parameter calculation module to:

measure a difference between the intermediate value and an anchor value; and

reject the intermediate values when the difference is beyond a threshold and keep the intermediate value otherwise; and

adjust the steering variable calculation using the refined intermediate value including the steering parameter calculation module to abandon the steering variable calculation in response to a rejection of the intermediate value.

18. The system of claim 17 , wherein the combination of one or more previously calculated intermediate values is an average of the one or more previously calculated intermediate values.

19. The system of claim 17 , wherein the intermediate value is a current vanishing point, wherein the anchor value is a combination of previous vanishing points, and wherein the difference between the intermediate value and the anchor value is a distance between the current vanishing point and the combination of previous vanishing points.

20. The system of claim 19 , wherein the distance is determined by at least one of sum of squares, root sum of squares, or sum of absolute values.

21. The system of claim 19 , wherein the threshold is calibrated to a mechanism used to determine the distance.

22. The system of claim 17 , wherein the intermediate value is a mousetail magnitude from a plurality of mousetail magnitudes computed for the steering variable calculation, each of the plurality of mousetail magnitudes being a magnitude of a sum of vectors, the vectors each having an angle representing a distance of a corresponding line intercept from a camera intercept represented in a first parameter space of a cascaded Hough transform used to perform the steering variable calculation;

wherein the anchor value is a greatest mousetail magnitude of the plurality of mousetail magnitudes within the steering variable calculation; and

wherein to identify the refined intermediate value includes the steering parameter calculation module arranged to modify a component that contributes to a vector of the vectors to produce the refined intermediate value, the refined intermediate value being a mousetail magnitude not less than the anchor and greater than the intermediate value.

23. The system of claim 22 , wherein the component is a second threshold used to classify pixels in the ERF.

24. The system of claim 23 , wherein the second threshold is a color threshold used to distinguish between crop pixels and furrow pixels.