| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a level difference measuring device and the like, capable of measuring, accurately with a simple configuration, a level difference occurring on the periphery of a manhole lid.SOLUTION: A level difference measuring device is provided, in which: an image capturing section captures an image of a road 40 and an oval outline therein is detected; a measurement point selecting section divides the oval outline into four areas comprising an upper area, a right area, a lower area and a left area and selects at least one measurement point in each area; a dark area width acquiring section acquires, for the selected measurement point, brightness of a plurality of pixels arranged in a normal direction of the outline and also in a direction from the measurement point toward the inside of the oval, and acquires a width of a dark area from a brightness profile; and a level difference calculating section compares a differential value obtained by subtracting the average dark area width of the right and left areas from the dark area width of the upper area, with a differential value obtained by subtracting the average dark area width of the right and left areas from the dark area width of the lower area, determines whether a lid 50 is rising or sinking with respect to a receiving frame, and outputs a level difference based on the differential values.</p> |
