Row detection system, agricultural machine having a row detection system, and method of row detection

An agricultural machine comprising:

• a wheel;
• an automatic steering controller;
• and
• a row detection system including:
• a camera mounted to an agricultural machine to image a ground surface that is traveled by the agricultural machine to acquire time-series images including at least a portion of the ground surface;
• and
• a processor configured or programmed to perform image processing for the time-series images;
• wherein
• the processor is configured or programmed to:
• from a plurality of images among the time-series images that have been acquired at different points in time, determine a first amount of movement of each of a plurality of feature points in an image plane through feature point matching;
• through perspective projection of each of the plurality of feature points from the image plane onto a reference plane corresponding to the ground surface, determine a second amount of movement of each of a plurality of projection points in the reference plane based on the first amount of movement;
• based on the second amount of movement, estimate heights of the plurality of feature points from the reference plane to detect a ridge on the ground surface;
• determine mean values of the heights of the feature points along a plurality of scanning lines extending in a predetermined direction on the reference plane and generate a histogram of the heights based on the mean values of the heights;
• detect the ridge on the ground surface based on the histogram;
• refer to a mean value of the heights in the histogram, and determine positions of edge lines of the ridge from predetermined positions on opposite sides of a peak of the mean values of the heights;
• acquire time-series color images from the imaging device;
• generate from the time-series color images a plan view image of the ground surface in which a color of a crop row extending along the ridge is enhanced;
• classify the plan view image into first pixels of which an index value for the color is equal to or greater than a threshold and second pixels of which the index value is below the threshold;
• and
• determine positions of edge lines of the crop row based on the index values of the first pixels;
• and
• the automatic steering controller is configured or programmed to control a steering angle of the wheel based on at least one of the positions of the edge lines of the ridge as determined by the processor and the positions of the edge lines of the crop row.