System for vehicular guidance with respect to harvested crop

• US 8,185,275 B2
• Filed: 01/30/2006
• Issued: 05/22/2012
• 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
• Primary Examiner(s): Keith, Jack
• Application Number:
  US11/342,760
• Publication Number:
  US 20070005208A1
• Time in Patent Office: 2,304 Days
• Field of Search: 701/23, 701/28, 701/301, 382/104
• 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

A discriminator identifies windrow pixels associated with a windrow within a collected image. A definer defines a search space with respect to a vehicle. An evaluator determines respective spatial correlations between the defined search space and the windrow pixels for different angular displacements of the search space. An alignment detector or search engine 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. An offset calculator estimates an offset of the vehicle to a 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.

Claims

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

a discriminator for identifying windrow pixels associated with a windrow within a collected color image, identifying a primary color of the windrow pixels and one or more secondary colors of background pixels, and assigning a discrimination value to each pixel in the identified windrow pixels, wherein the discrimination value indicates whether the each pixel is crop image data or background image data, and wherein each pixel in the collected color image is associated with an intensity level;

a definer for defining a search space with respect to a vehicle, the search space containing a series of scan line segments, wherein the series of scan line segments has scan line intensities based on the intensity level in the each pixel in the collected color image;

an evaluator for determining respective spatial correlations between the defined search space and the windrow pixels for different angular displacements of the search space, wherein the respective spatial correlations are based on scan line intensities associated with the scan line segments for different angular displacements;

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 color image, consistent with the desired vehicle heading.

2. The system according to claim 1 wherein the respective spatial correlations are based on an average or mean scan line intensities for corresponding scan line segments within the search space.

3. The system according to claim 1 wherein the respective spatial correlations are based on a mode scan line intensities for corresponding scan line segments within the search space.

4. The system according to claim 1 wherein the respective spatial correlations are based on aggregate scan line intensities for scan line segments within the search space.

5. The system according to claim 1 wherein the desired vehicular heading comprises a preferential angular displacement associated with a scan line intensity within the search space meeting or exceeding a threshold scan line intensity value.

6. The system according to claim 1 further comprising:

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

7. The system according to claim 1, further comprising:

a reliability estimator for estimating a reliability of the preferential angular heading based on compliance with a correlation value associated with the alignment of the search space and the windrow pixels, wherein the reliability estimator evaluates the intensity level associated with one or more windrows based on the intensity level associated with the each pixel in the collected color image.

8. The system according to claim 1, wherein the discriminator is capable of identifying the windrow pixels by:

calculating the mean of a vector for each class in a number of classes, index_mean_j, wherein the number of classes include a first class representing windrow pixels and a second class representing background pixels, wherein the vector is a data set comprising a number of values for the each pixel, and wherein the mean of the vector is used to form the discrimination value assigned to the each pixel in the identified windrow pixels;

calculating the covariance matrix for each class, cov_j;

calculating the average of the covariance matrix, cov_mean, for all classes; and

deriving the coefficients of discriminant function;

C_d=index_mean_j×

(cov_mean)<sup>−

1</sup>;

Co_j=−

0.5×

C×

index_mean_j.

9. The system according to claim 8, wherein responsive to deriving the coefficients of discriminant function, the coefficients of discriminant function are used to calculate the discriminant functions for each pixel evaluated:

DF_j=C×

X+Co_j,

wherein X is the vector of the each pixel evaluated.

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

a discriminator capable of identifying windrow image data associated with a harvested crop in a collected color image and background image data in the collected color image based on color and capable of assigning a discrimination value to each portion of image data identified in the collected color image based on whether the each portion is window image data or background image data;

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

an evaluator capable of determining respective spatial correlations between the defined search space and the windrow image data for different angular displacements of the search space, wherein the respective spatial correlations are based on scan line intensities associated with the scan line segments for different angular displacements;

an alignment detector capable of 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 image data; and

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

11. The system of claim 10, wherein the each portion of image data identified is selected from one of pixels and bit maps.