Shadowgraph Measuring
Robert Lucas
A shadowgraph is an optical method that reveals non-uniformities in transparent media. A shadowgraph is a type of flow visualisation.
Generally, a difference in temperature, gas, or a shock wave in the transparent air cannot be seen by the human eye or cameras. However, all these disturbances refract light rays, allowing them to cast shadows. Thus, the shadowgraph technology is able measure our products using the shadow casts on at least a 10x greater scale, significantly reducing the degree of inaccuracy.
The image below shows the shadowgraph in use, measuring complex and small shapes.