Digital Schlieren Photography

While conventional framing cameras can be used for Schlieren photography, there is a constant struggle to reduce exposure times to a low enough value which will yield images of acceptable sharpness. Since the resolution of the final image is a function of the object motion and the exposure time, large velocities with respect to the focal plane require correspondingly short exposure times in order to resolve detail in the object. Synchroballistic photography is frequently used to overcome this problem by making the image pass over an open slit while at the same time the recording film passes below the slit at the same speed as the image. The Holloman High Speed Test Track currently uses film-based techniques to create Focusing Schlieren photos of high speed rocket sleds. Since film processing creates environmental waste, and because film manufacturing is gradually being phased out, this capability needs to be replaced with a digital solution. Salvador Imaging proposes the development of a solid-state, synchroballistic imaging camera which provides 3000x1 images with exposure times as low as 200ns per line. Salvador will make use of an existing camera under Phase I to demonstrate operation of a lower resolution array at the proposed 200ns rate.