An imaging system having reduced susceptibility to thermally-induced stress birefringence comprising relay optics and projection optics. The plates are formed integrally from a plastic material and the segments are linked in a circumferential direction and in a pipe-length direction to install a segmental rehabilitation pipe inside an existing pipe. Features in the first region have a first lateral dimension, and features in the second region have a second lateral dimension, wherein the second lateral dimension is greater than the first lateral dimension.