Schlieren photography was invented in 1864 to detect flaws in glass
'schliere' being German for 'streak'. It is familiar today as
a way of visualising shock waves in wind tunnels. The technique relies
on the change of refractive index (ability to 'bend' light) with density.
At its simplest, a parallel beam of light passes through the test area
and is focussed onto a knife edge. Any change in air density causes
part of the beam to be refracted and to fall above or below the knife
edge. This makes that part of the image to appear brighter or darker
than the background. Modern systems may use filters in place of the
knife edge to make a coloured image.
See more techniques:
Aerial Photography
Computed Tomography (CT Scans)
Endoscopy
High Speed Photography
Kirlian Photography
Light Microscopy (LM)
Magnetic Resonance Imaging (MRI)
Molecular Models
Radionuclide Scanning (Gamma Scanning)
Satellite Images
Scanning Electron Microscopy (SEM)
Scanning Tunnelling Microscopy (STM)
Schlieren Photography
Space Photography (NASA)
Thermography
Transmission Electron Microscopy (TEM)
Ultrasound Images
Ultraviolet Photography
X-Rays
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