Instrumental design for capturing three‐dimensional moiré images

Describes the setting up of a moiré topographic system to measure three‐dimensional convex and concave surfaces of moulded brassière cups. The essential features of the system consisted of a photographic instrument which precisely controlled the position of the light source, the camera, the grid and the cup sample. As the uniformity of the grid was most crucial to produce a high contrast moiré picture, a photochemical‐machined grid plate was developed, and a pneumatic grid translation device was incorporated into the system to produce a clear image. The tolerance of the instrumental error was derived by the law of error propagation and the confidence with the moiré set‐up was assured.