IPB

Welcome Guest ( Log In | Register )

Ditherómy explanation of how it keeps details below quantization level, Was: "Dither" (TOS #6)
KMD
post Mar 7 2012, 13:22
Post #1





Group: Members
Posts: 123
Joined: 21-January 09
From: UK
Member No.: 65825



To help with the understanding of dither, I am posting an explanation, of how signal details smaller than the quantization level are retained, after quantization, when Dither Noise is added to the source material.
A small signal detail with height less than the quantization level, and centred half way between two quantization steps, is too small to cross a quantization step. It is lost when the waveform is quantized. With a Dither Noise waveform added, the height of the two waveforms summed is occasionally greater than the quantization level. At these occasional points the waveform crosses a quantization step. So now when this waveform is quantized, although the result is noisy, the shape of the original signal detail is retained.
Discussion invited.
Go to the top of the page
+Quote Post
 
Start new topic
Replies
NullC
post Mar 8 2012, 17:39
Post #2





Group: Developer
Posts: 200
Joined: 8-July 03
Member No.: 7653




I highly recommend the first few sections of this thesis for a careful technical explanation of how dither works and why it's important. It starts with the sampling theorem, shows how quantization breaks it, then shows how dither (of the right kind) fixes the breakage. It's well worth the read, even though the latter parts are dealing with image processing rather than audio.

Go to the top of the page
+Quote Post
icstm
post Mar 9 2012, 16:14
Post #3





Group: Members
Posts: 121
Joined: 25-January 12
Member No.: 96698



QUOTE (NullC @ Mar 8 2012, 16:39) *
I highly recommend the first few sections of this thesis for a careful technical explanation of how dither works and why it's important. It starts with the sampling theorem, shows how quantization breaks it, then shows how dither (of the right kind) fixes the breakage. It's well worth the read, even though the latter parts are dealing with image processing rather than audio.
read sections 1 and 2. Good find.
I just wish it was written by an engineer rather than a mathematician
Go to the top of the page
+Quote Post

Posts in this topic
- KMD   Ditherómy explanation of how it keeps details below quantization level   Mar 7 2012, 13:22
- - icstm   QUOTE (KMD @ Mar 7 2012, 12:22) To help w...   Mar 7 2012, 13:29
- - pdq   You might add that even when that small signal DOE...   Mar 7 2012, 15:07
|- - Paulhoff   QUOTE (pdq @ Mar 7 2012, 10:07) You might...   Mar 8 2012, 19:03
- - KMD   icstm - Thanks pdq - true, that is another funct...   Mar 7 2012, 16:10
- - icstm   Spatial dither: In a video feed spatial dither can...   Mar 7 2012, 17:43
- - mjb2006   Please do what you can to improve our wiki article...   Mar 7 2012, 21:43
|- - Notat   QUOTE (mjb2006 @ Mar 7 2012, 14:43) Pleas...   Mar 22 2012, 15:38
- - NullC   I highly recommend the first few sections of this ...   Mar 8 2012, 17:39
|- - icstm   QUOTE (NullC @ Mar 8 2012, 16:39) I highl...   Mar 9 2012, 16:14
- - KMD   Paulhoff - You were probably getting the benefi...   Mar 8 2012, 19:12
- - KMD   NullC - If you put fig 2.4, 2.5 ,2.11, 4.6 in...   Mar 8 2012, 19:15
- - KMD   Reference for this subject. Paper titled, ...   Mar 8 2012, 20:05
- - KMD   mjb2006 - Will do   Mar 9 2012, 15:24
- - greynol   In light of the recent conversation over the quant...   Mar 21 2012, 21:14
|- - mjb2006   QUOTE (greynol @ Mar 21 2012, 14:14) Afte...   Mar 22 2012, 01:57
|- - saratoga   Obviously someone who doesn't understand sampl...   Mar 22 2012, 02:05
- - benski   I remember the first lab in University Physics cla...   Mar 21 2012, 21:42
- - 2Bdecided   Important points: Dither removes the potentially ...   Mar 22 2012, 11:38
- - alanofoz   Warning: very shallow & not very scientific: ...   Mar 22 2012, 12:05


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 25th October 2014 - 11:28