Variations
Variations on the optical schlieren method include the replacement of the knife-edge by a colored "bullseye" target, resulting in Rainbow Schlieren which can assist in visualising the flow. The adaptive optics pyramid wavefront sensor is a modified form of schlieren (having two perpendicular knife edges formed by the vertices of a refracting square pyramid).
Few complete schlieren optical systems are commercially available today, but details of theory and construction are given in Settles' 2001 book. The USSR produced a number of sophisticated schlieren systems based on the Maksutov telescope principle, many of which still survive in the former Soviet Union and China.
Read more about this topic: Schlieren Photography
Famous quotes containing the word variations:
“I may be able to spot arrowheads on the desert but a refrigerator is a jungle in which I am easily lost. My wife, however, will unerringly point out that the cheese or the leftover roast is hiding right in front of my eyes. Hundreds of such experiences convince me that men and women often inhabit quite different visual worlds. These are differences which cannot be attributed to variations in visual acuity. Man and women simply have learned to use their eyes in very different ways.”
—Edward T. Hall (b. 1914)