Telescope with much larger primary can collect much more light and it is always pursued by the astronomers. Instead of
using a monolithic primary, more and more large telescopes, which are now planed or in construction, invariably adopted
segmented primary mirror. Therefore, how to sense and phase the primary mirror is the key technology. Unlike edge
sensors, which need careful calibrations, dispersed Hartmann sensor (DHS) is non-contact method using broadband point
light sources, and it can estimate piston by the two-direction spectrum formed by the transmissive grating's dispersion
and lenslet array. Thus it can realize the combination of co-focusing and co-phasing. In this paper, we introduce the
design of our dispersed Hartmann sensor together with its principle. We also manufacture a DHS sensor and do real tests
on our existing segmented mirror optics platform. Finally some conclusions are given based on the test results.
In the image-based bridge deflection measurement system, changes in weather and interference of background cause light source target hard to accurately recognize. Through analyzing the principle of
image-based deflection measurement, a conclusion was drawn that small error in light source target in image recognition cause larger error in deflection because of amplification of optical measurement
system. In order to solve the problem, analyzed gray level characteristic of target image, and proposed an image enhancing method. In addition, a new method based on horizontal projection and differential algorithm is adopted for recognition of light source target. Finally, we use gray weighted centroid algorithm to realize sub-pixel location of light source target. Moreover, experiments were done for target image with poor quality. The experimental results show that the method is adaptable to the changing weather.