Topic: excellent overview of pixel noise in digital images

[Clive]

also offers up some plugins to help make your photos look better and print cleaner. I'd noticed the effects and noise in much of my digital photos, but had no idea how to remove it -- until now.


http://rondayview.com/000002.php

[DJ]

Thanks Clive. As part of my degree we're currently doing a module on image processing and manipulation - so that'll come in handy.

DJ

[Clive]

Gosh... have I actually helped somebody?  That's one for the record books.      

[daveeb]

Thanks Clive. As part of my degree we're currently doing a module on image processing and manipulation - so that'll come in handy.

DJ

dj do you know anything about digital artefacts produced by digital still cameras, particularly the lower megapixel range.  if so i'd like to pick your brain.    

[DJ]

Not at the moment - the module may cover it at a later date. But do post your questions and I'll ask some mates and maybe even email my lecturer! (He's a World Leader in Image Processing, Vision and graphics).

I'll see what I can do

DJ

[Adept]

dj do you know anything about digital artefacts produced by digital still cameras, particularly the lower megapixel range.  if so i'd like to pick your brain.    

I don't know if this is what you want Dave, but Paint Shop Pro (version 7 onwards) has a rather nifty filter that can remove jpg artifacts without losing very much detail.

[daveeb]

Actually what i'm looking for info on is the inherent artefacts that occur with digital photography.  To be more specific ghost photography and things called orbs which are supposed to be the first stage of an apparition.  They have only really appeared since the advent of digital ccd photography and are particularly prevalent in the 2-3 megapixel range of camera.  These orbs generally appear as small whiteish vaguely circular objects in photos, sometimes they appear to have surface markings.

What i'm looking for is any info on known conditions that may cause this to happen, maybe a
characteristic flaw in the way ccd's work

Any info much appreciated, and i'll throw in a freebie bottle of ectoplasm.    

[Dack]

I take it you didn't watch the recent channel 5 program about how to fake a lot of psychic effects then

Orbs were in episode 4 I believe.

[Dack]

Summary:

It's because cameras have got smaller. Now the flash unit is nearer the lens and as a result any small dust particles, dandruff, condensation etc. near the lens are shown up by the flash.

To make your very own orb picture:
1. go into a darkened room
2. shake a paper tissue / duster above the camera
3. take shot

You can keep the ectoplasm

[Simon]

DACK!!!  >  You do realise we're all going to have to try that now!  

[daveeb]

Summary:

It's because cameras have got smaller. Now the flash unit is nearer the lens and as a result any small dust particles, dandruff, condensation etc. near the lens are shown up by the flash.

i know its quite easy to fake them but often there have been many  situations e.g. when no "orbs" have been picked up in a room for ages, suddenly a cold spot appears or a presence is felt and is verified by a laser thermometer a picture is taken and there's an orb there.  If dust was responsible you would expect to get more of these events than actually occurs.
I was looking more for an explanation in which the CCD produces artefacts in certain conditions.  If you can eliminate that you might have a spook.