Reduction
Speckle is considered to be a problem in laser based display systems like the Laser TV. Speckle is usually quantified by the speckle contrast. Speckle contrast reduction is essentially the creation of many independent speckle patterns, so that they average out on the retina/detector. This can be achieved by,
- Angle diversity: Illumination from different angles.
- Polarization diversity: Use of different polarization states.
- Wavelength diversity: Use of laser sources which differ in wavelength by a small amount.
Rotating diffusers—which destroys the spatial coherence of the laser light—can also be used to reduce the speckle. Moving/vibrating screens may also be solutions. The Mitsubishi Laser TV appears to use such a screen which requires special care according to their product manual. A more detailed discussion on laser speckle reduction can be found in
Synthetic array heterodyne detection was developed to reduce speckle noise in coherent optical imaging and coherent DIAL LIDAR.
In scientific applications, a spatial filter can be used to reduce speckle.
Read more about this topic: Speckle Pattern
Famous quotes containing the word reduction:
“The reduction of nuclear arsenals and the removal of the threat of worldwide nuclear destruction is a measure, in my judgment, of the power and strength of a great nation.”
—Jimmy Carter (James Earl Carter, Jr.)