In the case of the examples above, the car crash testers want to see how safety systems and their components perform, and also see the movements of the crash dummy or dummies. For a machine, it can be important to see how material being processed behaves when machined or shaped.
A practical method of providing this information is to use high-speed photography. Filming the event with a high-speed camera means that it can subsequently be seen in slow motion and analysed step by step.
SP has two high-speed digital video cameras for recording rapid events. The cameras, made by Kodak, can take up to 1 000 frames/second with an exposure time of 0,1-1 ms. At 1 000 frames/s, it is possible to capture a sequence lasting 2,7 seconds, while 250 frames/s can capture a sequence of about 10 seconds. The system also includes an analysis programme that can measure the movement of parts of the object from dimension markers on the object. The processed information can be transferred to CDs or DVDs. With good lighting, the picture quality is very high.
The cameras are used mainly for documentation of crash tests of systems and components, but can of course be used for other purposes, such as industrial processes etc: only imagination sets limits to their applications. The equipment is portable, so can also be used for filming outside the laboratory.
High-speed video