In mills where a Warp Tunnel cannot be used, Lucidyne's Warp Bridge measures the profile of boards as they travel on the lug chain.
Boards are relaxed as they move under the Warp Bridge on the lug chain, and this allows any bow, crook, or twist to be measured from sensors mounted above the board. This method is very accurate and easily provides measurements to meet all grade rules.
The lasers on the Warp Bridge are mounted such that they see the leading edge and top face of a board. In the left picture below, each laser's data is shown in a different color. Then the data is presented in a perspective view that represents the leading corner of the board. The surface profile of the leading edge and top face are all that are needed to determine this board's warp - it is not necessary to measure from underneath the board.
The right picture shows where the maximum bow and crook occur on the board. The legend for twist is shown at the right end of the board. Bow is Blue, Crook is Crimson (red), and Twist is green. The ends of the board are centered in the graph to simplify interpretation.
Here is an example of Idaho Forest Group's Warp Bridge in application.