Reducing Noise by Downsampling? at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


Reply
 
Thread Tools Search this Thread
Old October 10th, 2004, 07:07 PM   #1
New Boot
 
Join Date: Nov 2003
Location: Maryland
Posts: 7
Reducing Noise by Downsampling?

My theory: If I have a 100x100 pixel movie - and it has lots of noise - I can resize it to 25x25, and remove noise at the same time. This is because 16 source pixels = 1 pixel on the final cut, and this 1 pixel is an average of the 16 noisy ones. Therefore a much better signal.

Am I correct? I have DV footage (shot in frame mode) that looks noisy, and I don't mind reducing the size of the movie to enhance it.

Yet simply changing the output resolution in premiere doesn't seem to cut it.
Brian Klug is offline   Reply With Quote
Old October 11th, 2004, 03:30 AM   #2
RED Code Chef
 
Join Date: Oct 2001
Location: Holland
Posts: 12,514
Your theory is sound in theory. However it largely depends on
how the downsample is done. See if you can change the way
Premiere does the downsample. It might just drop columns and
lines instead of averaging them out.
__________________

Rob Lohman, visuar@iname.com
DV Info Wrangler & RED Code Chef

Join the DV Challenge | Lady X

Search DVinfo.net for quick answers | Buy from the best: DVinfo.net sponsors
Rob Lohman is offline   Reply With Quote
Old October 11th, 2004, 04:44 AM   #3
Major Player
 
Join Date: Sep 2002
Location: Belgium
Posts: 804
If straight downsampling is performed, not only there will be no noise reduction, but also extra aliasing effects will be introduced if the original (yr 100x100) was sampled at near Nyquist limit. Most decimators used for downsampling use FIR or IIR lowpass filtering before downsampling. Whether noise will be significantly reduced if further dependend on the original noise "spectrum"
Andre De Clercq is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 04:44 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network