Surface Shape Measuring Method for Space Structures Based on Images in Ultra-Violet Range

抄録

We have worked to develop new optical surface shape measuring methods enable to grasp surface shape of large space structures with high precision and high speed on orbit for future space antenna and telescope. These methods are applicable to testing such structures on ground. In these methods, we analyze phase values of projected or painted grating patterns on the structures and perform calibration using a reference plane. It is hard to project such patterns on large structural surface on orbit, however, we must paint some grating patterns on the structures. In that case, high contrast images of grating patterns, for example white and black grating painting, are needed for precise measurement. Nevertheless, high contrast white and black patterns on surface make thermo-optical features of the structure more complex, then there is a possibility of interfering with thermal design of spacecraft. Therefore, to widen the application range of our method, we propose surface shape measuring method based on grating patterns using ultra-violet range. We use two different kinds of painting materials and cameras having sensitivity to light of ultra-violet range. Both painting materials are photographed as white in the visible range, however, one is white and one is black in the ultra-violet range. In this method, we can get high contrast grating images on the surface only in the ultra-violet range. In this study, we provide some feasibility study using commercially available ultra-violet cameras and painting materials such as titanium oxide.