Development of 3‐D shape measurement system using fiber grating

There is an increasing demand in industry and medicine for the noncontact measurement of the shape of a 3‐D object. Various studies are being made to develop highly accurate and simple means of such measurements. When a laser light is incident to the fiber grating in the vertical direction, a square spot array is produced. When the array is projected on a 3‐D object with a general shape, the array is distorted. By using the distortion as the data for the processing, the 3‐D shape can be measured strictly. This paper reports on the 3‐D shape measurement using an optical fiber grating. No particular application is considered in the design of the system. The projector of the spot array can be constructed with a lightweight and small size, and it is suitable as a built‐in device for the endoscopy, or a visual device to be installed directly on the industrial robot arm.