Method and system for vehicular guidance with respect to harvested crop

• US 20070005208A1
• Filed: 01/30/2006
• Published: 01/04/2007
• Est. Priority Date: 07/01/2005
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Han, Shufeng, Wei, Jiantao, Rovira-Mas, Francisco
• Granted Patent: US 8,185,275 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: A01B 69/001 Steering by means of optical assistance, e.g. television cameras steering devices for road marking vehicles E01C23/163
• CPC Class Codes: A01B 69/008 automatic

Abstract

The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere & Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere & Company or otherwise.

Claims

1. A method of guiding a vehicle, the method comprising:

identifying windrow pixels associated with a windrow within a collected image;

defining a search space with respect to a vehicle, the search space containing a series of scan line segments;

determining respective spatial correlations between the defined search space and the windrow pixels for different angular displacements of the search space;

determining a desired vehicular heading as a preferential angular displacement associated with a generally maximum spatial correlation between the defined search space and the windrow pixels;

estimating a central point associated with the windrow based on pixel intensity of the windrow pixels; and

estimating an offset of the vehicle to the central point of the windrow or a depth axis to achieve the desired vehicle heading and desired position of the vehicle with respect to the windrow.

2. The method according to claim 1 wherein the determining respective spatial correlations comprises determining respective scan line intensities associated with the scan line segments for different angular displacements.

3. The method according to claim 2 wherein the determining of the respective scan line intensities comprises determining an average or mean scan line intensity for scan line segments within the search space.

4. The method according to claim 2 wherein the determining of the respective scan line intensities comprises determining a mode scan line intensity for scan line segments within the search space.

5. The method according to claim 2 wherein the determining of the respective scan line intensities comprises determining an aggregate scan line intensity for scan line segments within the search space.

6. The method according to claim 2 wherein the determining a desired vehicular heading comprises determining the desired vehicular heading as a preferential angular displacement associated with a scan line intensity meeting or exceeding a threshold scan line intensity value.

7. The method according to claim 1 wherein the estimating a central point comprises estimating a central point associated with the windrow based on a weighted average of pixel intensities.

8. The method according to claim 1 wherein the search space is generally polygonal.

9. The method according to claim 1 wherein the identifying of the windrow pixels is accomplished by applying a data classification algorithm which maximizes a ratio of between-class variance to within-class variance for windrow image data as one class and background image data for another class.

10. The method according to claim 1 further comprising:

deriving a segmented image of crop rows as the crop image data from the collected color image.

11. The method according to claim 1 wherein the estimating of the offset is consistent with the following equation:

d=L*sin(θ

)−

d′

/cos(θ

) or d=L*sin(θ

)d′

/cos(θ

), where L is a scan line axis, d is the offset or transverse distance between the scan line axis and a depth axis, θ

is an angle between the depth axis and the scan line axis, and d′

is the distance between the scan line axis and a central windrow axis that intercepts the central point.

12. The method according to claim 1 comprises controlling a path of the vehicle in accordance with the desired vehicle heading and desired position.

13. A system of guiding a vehicle, the system comprising:

a discriminator for identifying windrow pixels associated with a windrow within a collected image;

a definer for defining a search space with respect to a vehicle, the search space containing a series of scan line segments;

an evaluator for determining respective spatial correlations between the define search space and the windrow pixels for different angular displacements of the search space;

an alignment detector for determining a desired vehicle heading as a preferential angular heading associated with a generally maximum spatial correlation between the defined search space and the windrow pixels; and

an offset calculator for identifying a desired offset of the vehicle that is generally aligned with respect to the windrow, associated with the collected image, consistent with the desired vehicle heading.

14. The system according to claim 13 wherein the respective spatial correlations are based on scan line intensities associated with the scan line segments for different angular displacements.

15. The system according to claim 14 wherein the respective spatial correlations are based on an average or mean scan line intensities for corresponding scan line segments within the search space.

16. The system according to claim 14 wherein the respective spatial correlations are based on a mode scan line intensities for corresponding scan line segments within the search space.

17. The system according to claim 14 wherein the respective spatial correlations are based on aggregate scan line intensities for scan line segments within the search space.

18. The system according to claim 14 wherein the desired vehicular heading comprises a preferential angular displacement associated with a scan line intensity with the search space meeting or exceeding a threshold scan line intensity value.

19. The system according to claim 13 wherein the central point is associated with the windrow based on a weighted average of pixel intensities.

20. The system according to claim 13 wherein the search space is generally polygonal.

21. The system according to claim 13 wherein the discriminator identifies the windrow pixels is accomplished by applying a data classification algorithm which maximizes a ratio of between-class variance to within-class variance for windrow image data as one class and background image data for another class.

22. The system according to claim 13 further comprising:

a segmenter for deriving a segmented image of crop rows as the crop image data from the collected color image.

23. The system according to claim 13 wherein the offset calculator applies the following equation:

d=L*sin(θ

)−

d′

/cos(θ

) or d=L*sin(θ

)d′

/cos(θ

), where L is a scan line axis, d is the offset or transverse distance between the scan line axis and a depth axis, θ

is an angle between the depth axis and the scan line axis, and d′

is the distance between the scan line axis and a central windrow axis that intercepts the central point.

24. The system according to claim 13 further comprising a vehicle guidance controller for controlling a path of the vehicle in accordance with the desired vehicle heading and desired position.