How It Works
In a typical image transmission setup, all stationary images are transmitted at full resolution. Moving pictures possess a lower resolution visually, based on complexity of interframe image content.
When one uses Nyquist subsampling as a standards conversion technique, the horizontal and vertical resolution of the material are reduced – this is an excellent method for converting HDTV to standard definition television, but it works very poorly in reverse.
- As the horizontal and vertical content change from frame to frame, moving images will be blurred (in a manner similar to using 16 mm movie film for HDTV projection).
- In fact, whole-camera pans would result in a loss of 50% of the horizontal resolution.
The Nyquist subsampling method of systems conversion only works for HDTV to Standard Definition Television, so as a standards conversion technology it has a very limited use. Phase Correlation is usually preferred for HDTV to standard definition conversion.
Read more about this topic: Television Standards Conversion, Standards Conversion Methods in Common Use, Nyquist Subsampling
Famous quotes containing the word works:
“When life has been well spent, age is a loss of what it can well spare,—muscular strength, organic instincts, gross bulk, and works that belong to these. But the central wisdom, which was old in infancy, is young in fourscore years, and dropping off obstructions, leaves in happy subjects the mind purified and wise.”
—Ralph Waldo Emerson (1803–1882)