Abstract: The apparatus and method of the present invention utilize a pair of fixed-position laser triangulation sensors, with one sensor located above the board and one directly below. Each sensor produces a measurement signal proportional to the distance between itself and the corrugated board's surface. In one embodiment, the output signal from each sensor is simultaneously processed along two different parallel paths to measure different corrugated board characteristics. A second pair of sensors may be located on the opposite edge of the board. When both board edges are measured, the left and right-edge measurements are averaged to produce a mean value for the board's full width, as well as subtracted from one another to determine the coss-machine gradient.