[tombos8]

Have the option under picture settings on my tv of 'noise reduction' with a choice of 'minimum, medium or maximum'. Does anyone have any idea what this setting does? Sounds like a sound thing to me!

[YellowSphere]

It's trying to reduce picture noise (film grain, compression artefacts, pixellation etc.) but basically, they're just fancy blurring algorithms that reduce detail and make motion blur more apparent.

[Alan CD]

YellowSphere is right and it's best to leave digital NR off, clearer picture with it off.

[djm1972]

I have MPEG NR "Low" on my Sony 32W40000 - I find that it noticeably cleans up some SD broadcasts - in particular the scrolling strap-lines on news channels - it removes the blocky artefacts you get around the characters as they move quickly across the screen...

[Nielo TM]

Originally Posted by YellowSphere

It's trying to reduce picture noise (film grain, compression artefacts, pixellation etc.) but basically, they're just fancy blurring algorithms that reduce detail and make motion blur more apparent.

Actually not always



Not all noise reduction algorithms are the same. Some are very good at removing noise without impacting the over-all image quality.


However, the ones found in TVs are quite average

[Alan CD]

I have yet to come across a NR system that does not reduce the quality of a picture, no matter how good it is.

There is always a heavy trade-off because NR algorithms cannot distinguish in every instance what is noise and what is part of the picture structure. Errors will always occur.

One day they might get NR to remove noise only. IMO, until that day, NR is best switched off.

[Mumid]

I can never reallly see a difference with it on or off tbh, so I leave it off for that reason.

[WillieCocker]

I agree , i've yet to see a display that NR doesn't create unecessary blur.
It is needed on certain broadcasts as they do look awful , but it certainly doesn't fall under the category of picture enhancements

[Nielo TM]

Originally Posted by Alan CD

I have yet to come across a NR system that does not reduce the quality of a picture, no matter how good it is.

There is always a heavy trade-off because NR algorithms cannot distinguish in every instance what is noise and what is part of the picture structure. Errors will always occur.

One day they might get NR to remove noise only. IMO, until that day, NR is best switched off.

I didn't say the results will be perfect and free of errors. But as long as it can fool the human eye, it really doesn't matter.

BTW, some NR methods are known to use combinations of filters to reduce the image overall image artifacts (e.g. NR+Deblock+Edge Enhancement). But like I've said before, the once found in most HDTVs are poor to average because it's hard to differentiate the errors from the image like you've said.



PS: Here's an example NR+Deblock. As you can see, the post image is somewhat softer, but over-all image is cleaner. Edge enhancement can be used compensate for the loss in definition.

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