Talk:Image noise

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[edit] This article needs work

Much of what this page says is wrong or unclear. And it needs sources. I'm going to start by putting sources and cleanup tags, and removing the image unless someone can explain it including a source that justifies it. Dicklyon 07:19, 18 January 2007 (UTC)

OK, I took out what I considered to be the worst of the hot air. It would be good to put something back about noise types or sources, but if we have names like "salt and pepper noise" they need to be backed up with credible sources. Dicklyon 07:37, 18 January 2007 (UTC)

The part I took out started with "salt-and-pepper noise (also known as random noise or independent noise), pixels in the image are vastly different in color from their surrounding pixels." I'm pretty familiar with image noise statistics, but I don't see how "random", "independent" and "salt-and-pepper" can mean the same thing, and certainly none of them imply "vast" differences. Hence, the need for something verifiable instead. Dicklyon 07:45, 18 January 2007 (UTC)

I've corrected some confusing terminology: "sensitivity" in place of "film speed" (it was clearly misplaced with reference to digital cameras) "definition" in place of the very ambiguous "resolution" ; "detail" in place of "pixels", and so on. The whole page is still crying out for a major overhaul, maybe even a merge. Most of the noise reduction section is verbatim from the noise reduction page ~ mikaul^talk 18:50, 1 May 2007 (UTC)

"Film speed" refers to ISO on both digital and film cameras. Even though film is not used in digital cameras, it still refers to sensor sensitivity, as film speed on film cameras refers to film sensitivity. Furthermore, "sensitivity" is not quite as precise, since it can refer to things other than sensor sensitivity. Finally, image noise occurs with both digital and film cameras. "Film speed" is appropriate wording. Althepal 17:17, 9 May 2007 (UTC)

I realise that's the way the "beginners guide" photography books introduce it, but there's really no proper correlation between ISO (film speed) and ISO (electronic device sensitivity) - if you don't believe me, see the ISO website. I'm not sure which other thing "sensitivity" could be confused with vis a vis digital capture, and "noise" is a term common to electronics; "grain" is the equivalent for analogue capture. If you have an appropriate citation to support all of this, by all means go ahead and post up the changes. You might want to do so at Film speed as well, as there's nothing to support what you're saying ther either, as far as I can see. mikaul^talk 20:07, 9 May 2007 (UTC)

I simply pointed out that ISO is popularly referred to as film speed for both digital and film cameras. If you don't believe me, you can check out photography forums and articles, and you will see that ISO is described as or referred to as "film speed" without regard for camera type. (Even in the previous version of this article it was referred to as such.) Film speed always means film/sensor sensitivity, while sensitivity refers to how sensitive anything in the world is. I'm not making changes, just pointing out facts. Althepal 21:44, 9 May 2007 (UTC)

That's ok, I'm with you. It's definitiely in regular colloquial use, I see it used it all the time in this context. mikaul^talk

IIRC, the ISO speeds are specific scientific standards based on optimum exposure for silver halide-based images. A digital camera has what are considered ISO-equivalent "speeds", but it must also be remembered that in fact the sensor only has one true sensitivity - the rest is essentially the software, and would be considered the same as lifting in the print or perhaps force processing - past a limited point, all of these reach a threshold at which the signal to noise ratio drops greatly. Girolamo Savonarola 00:44, 10 May 2007 (UTC)

You do not recall correctly. The film speed is based on the minimum amount of light needed to get a certain quality threshold. Similar standards exist for digital, though they define 3 different methods of computing different ISO speed ratings for digital cameras. These are not generally applicable to the sensor in isolation, though logically they should be. The ISO setting or exposure index is something else again, as you say. Dicklyon 04:46, 10 May 2007 (UTC)

[edit] WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:54, 10 November 2007 (UTC)