QED Technologies and Subaperture Stitching Interferometry (SSI) have released the SSI-A, which is a metrology tool for aspheres.
This new product includes full aperture measurement of aspheres with more than 200 waves (120µm) of departure from best fit sphere, without the use of null lenses. The SSI-A incorporates an enhanced stitching engine that provides improved measurement accuracy over a broad range of aspheres. The new metrology system is also capable of taking full aperture measurements of spheres and flat surfaces.