A method is provided for evaluating a possible pallet structure. The method comprises: providing a gray scale image comprising one or more possible lines; providing respective pixel locations in the gray scale image for an estimated upper left corner and an estimated upper right corner; calculating, using a computer, a value h based on the estimated upper left corner location and the estimated upper right corner location; estimating, using the computer, a first hole with a first rectangle having a height h; estimating, using the computer, a second hole with a second rectangle having the height h; and estimating, using the computer, the possible center stringer with a third rectangle having the height h.