Specialised Imaging Shadowgraph

The Specialised Imaging Shadowgraph (SIS) camera from Specialised Imaging enables high resolution digital imaging of ultra fast events in ambient as well as low light environments.

A shadowgraph is an optical instrument that reveals non-uniformities in transparent media like air, water, or glass. While a difference in temperature, a different gas, or a shock wave in a transparent medium cannot be directly seen, all these disturbances refract light rays, so they can cast shadows. The technique is related to, but simpler than, Schleiren methods that perform a similar function. Applications of shadowgraphy are very broad. Shadowgraphy is used in aeronautical engineering to see the flow about high-speed aircraft and missiles, as well as in combustion research, ballistics, explosions, and in the testing of glass.

New high performance image sensors have enabled the development of a camera system that will capture up to 11-million pixel images with the ability to shutter faster than 1µs. Integrating this camera with an ultrafast high intensity spark source has resulted in a sophisticated digital Shadowgraph camera that is capable of image quality only previously achievable with film cameras, but also offering the advantage of instantaneous access to data. Intuitive, yet powerful control software provides simple adjustment of imaging parameters and extensive measurement tools to accurately analyse results.

Using the SIS camera system, camera stations can be arranged in the classic configuration looking directly at a reflective screen or as orthogonal pairs to provide valuable 3D data such as the pitch and yaw of supersonic airflows. Comprehensive triggering functionality has been implemented in the SIS camera system enabling it to be interfaced with almost any triggering device. An in-built velocity trap, using optional external triggers, ensures the camera will never suffer from experimental uncertainty in measuring the velocity of an object.