Patent ID: 8422782

Claim:
A computer-implemented method of classifying an image as being of a left-facing item or a right-facing item, comprising: under control of one or more computer systems configured with executable instructions, creating an edge image of the image of an item of interest, the edge image being defined by pixels organized in rows and columns and having a left side, a right side, a top side, and a bottom side; creating a contour image that represents an outline of the edge image, the contour image including a left contour of the left side of the edge image, a right contour of the right side of the edge image, a top contour of the top side of the edge image, and a bottom contour of the bottom side of the edge image, the contour image being created by: creating the left and right contours by: traversing a first window having a height along each of a subset of the rows, the first window traverses from a left position toward the left side of the edge image and from a right position toward the right side of the edge image; stopping the traversing of the first window at a location on the row where the first window covers a threshold amount of pixels; and activating at least one pixel at the location of the row; creating the top and bottom contours by: traversing a second window having a width along each of a subset of the columns, the second window traverses from a top position toward the top side of the edge image and from a bottom position toward the bottom side of the edge image; stopping the traversing of the second window at a location of the column where the second window covers the threshold amount of pixels; and activating at least one pixel at the location of the column; positioning a center of the radial grid having a plurality of radial-polar bins at a center of a bounding box of the contour image, the bounding box being defined by a left-most pixel, a right-most pixel, a bottom-most pixel, and a top-most pixel of the contour image; determining the number of pixels of the contour image that are located in the radial-polar bins of the radial-polar grid; creating a histogram for the image, the histogram having a plurality of bins that correspond to the radial-polar bins of the radial-polar grid, the contents of the bins represent the number of pixels in the corresponding radial-polar bins; and classifying the image of the item of interest as being of a left-facing item or a right-facing item based at least in part on the histogram of the image.