Volume measurement for powder chamber based on ring structured light

The volume of the powder chamber is a crucial parameter affecting the interior and exterior ballistic performance. Conventional methods have the disadvantages of inefficiency and inaccuracy. An innovative system that mainly consists of a ring structured light projector and a CCD camera is designed to deal with the volumetric issue. The projector emits a conical light surface, which intersects with the inner surface of the chamber, and the camera is used to capture the image of the intersection representing the chamber section contour. With a series of such contours obtained from consecutive and sufficiently dense axial positions, it is able to get the complete 3D discrete data of the chamber. In regard to the change of the end of the powder chamber caused by the friction with the shot and combustion of the powder, a novel virtual gauge method is promoted to decide the end point by calculating the similarity of an ideal model with the measured data. The feasibility and accuracy of the technology is testified by experiment with real gun.