From: boyd@apt0.sao.arizona.edu   
      
   Phil Hobbs wrote:   
   > On 11/08/2013 03:57 PM, laloum.eric@gmail.com wrote:   
   >   
   >> Dear All,   
   >>   
   >> Is it possible that an image is correctly sampled according to Nyquist   
   >> (2 to 3 pixel per resolution element) but nevertheless show some   
   >> pixelization effect when sufficiently zoomed ?   
   >> I guess both issues (Digital sampling and pixellisation) are highly   
   >> related...and it's quite easy to conceive that correct Nyquist   
   >> sampling is a necessary condition for avoiding pixelization, but is it   
   >> also a sufficient condition ?   
   >>   
   >>   I would say no but can't explain why ;-(   
   >>   
   >> Thanks,   
   >>   
   >>   Eric   
   >>   
   >   
   > Visible pixellation is caused by crude zoom algorithms that just   
   > replicate pixels.   
      
   Sampling isn't what causes pixelization.  It's the attempt to redisplay   
   an image on a scale where a single sample is displayed on multiple   
   pixels of the the display device that causes pixelization.  That image   
   could  be smoothed with various algorithms to remove the "sharp edges"   
   but then you just have a blurry image.  You can't restore what isn't   
   there unless  there is some foreknowledge of what the original image   
   contains.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)