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What are the use cases of generating different kind of noises (e.g. white, blue and red)? I've only heard about them as background noises to fall asleep or focu

by ajot 5y ago

What are the use cases of generating different kind of noises (e.g. white, blue and red)? I've only heard about them as background noises to fall asleep or focus while working/studying. Is there something ininformation or signal theory that benefits from creating truly random (or random but with some structure to it like blue noise not having lower frequencies) noise? As a chemist, I always model real-world noise with a gaussian distribution, so I don't really get where this could br used.

dnautics 5y ago
Chemist here too but my ex was an sound consultant for an architectural firm. Iirc, different kinds of noises essentially are defined by the average amplitude (energy) vs frequency function of the rng. For architects, it can be important to model noise to ensure your structure complies with for example OSHA regulations. There can be code regulations too if you're in an urban place and say putting residential on top of street level commercial spaces, especially bars that might be open late. Finally, for gathering/events spaces you want to have a situation where a PA/presentation system doesn't have to work hard to go over conversation noise. The energy profiles for all of these scenarios is empirically determined and "well known" in the community. The ex helped model the "death star" auditorium space at the academy of motion picture arts and sciences in LA. IIRC it sounds really aquarium-ey during normal times and during events they roll out strategically placed dampeners.
mzs 5y ago
blue noise dither: http://www.imaging.org/site/PDFS/Papers/1999/RP-0-93/1786.pdf http://www.imaging.org/site/PDFS/Papers/1999/RP-0-93/1786.pd...
the__alchemist 5y ago
I'm using pink noise in an audiogram, to determine if users can hear sounds with it as background.
iamwil 5y ago
Blue noise is useful in games for generating more natural looking scenes. Here's an example of how to algorithmically place grass in the game "The Witness". https://youtu.be/Ge3aKEmZcqY?t=965 https://youtu.be/Ge3aKEmZcqY?t=965 So if you use white noise, it looks unnaturally clustered with patches. This is the part that discusses the noise. https://youtu.be/Ge3aKEmZcqY?t=1385 https://youtu.be/Ge3aKEmZcqY?t=1385
ocharles 5y ago
For one real application of blue noise in particular, see https://youtu.be/Ge3aKEmZcqY?t=1350 https://youtu.be/Ge3aKEmZcqY?t=1350 (22:30 is a good starting point). Here Casy explains a grass planting algorithm for games, where white noise wouldn't be suitable.
- iamwil 5y ago
  Haha, I guess you and I just saw the same video.
anon_123g987 5y ago
Also chemist here. Think about it the other way around, not synthesis but analysis. For example: "The term "Brown noise" does not come from the color, but after Robert Brown, who documented the erratic motion for multiple types of inanimate particles in water." (https://en.wikipedia.org/wiki/Brownian_noise https://en.wikipedia.org/wiki/Brownian_noise)
- marktangotango 5y ago
  Side note; what does a self described chemist do these days? Seems like Breaking Bad spurred a lot of interest in the field, but as someone who minored in chemistry many years ago, the actual job prospects seemed limited. And research seemed very stodgy (to me at least). If you don't mind sharing, what's your background and what types of things are you working on?
  - whatshisface 5y ago
    Chemists do the same things they always have, just for much less money than the same people would make today in software engineering. Here are some types of applied chemistry: - Deciding what ratio to mix things in for the countless liquid products that are combinations of already-discovered chemicals. Everything at the grocery store that comes in a jug or a bottle (cleaning products, hair conditioner, drain cleaner) falls in to this category. - Doing industrial research to improve existing processes. This would include discovering new catalysts, and trying out the endless permutations of solvents and conditions in which existing reactions take place, to optimize them for whatever the biggest operating costs are. - Figuring out how to recycle industrial chemicals and get the valuable stuff back out of sludge and effluent. This is a surprisingly big field with important consequences. - Working on specialty materials, like plastics and synthetic rubbers, that are not completely dissimilar from existing products but require a chemist to design them for specific, demanding applications. The fact that everything involving the physical world gets you paid way less for work that's way more difficult than programming will come back to bite us somehow, but it's hard to say when.
    - robocat 5y ago
littlestymaar 5y ago
Blue noise is useful for procedural generation, because it's what the human eye will naturally consider the “most randon” and the most pleasant. IIRC red noise appears when you have random walks or Brownian motion. > As a chemist, I always model real-world noise with a gaussian distribution Gaussian distribution is what you get when you have a lot of independent random events adding up (it's the central limit theorem), so it applies a lot in real life but it can also cause modeling issues if it's not how randomness appears in your system. (Please note that I have absolutely no knowledge on chemistry so I have no idea if it's something that could be relevant in your field)
- deleted 5y ago
  [deleted]
PragmaticPulp 5y ago
The difference is the spectral power distribution of the noise. White noise has a flat spectrum from low to high frequencies. It has the standard noise sound that most of us recognize from digital systems. Pink noise is shaped with a decreasing power as frequency increases. This results in more low frequency noise and less high frequency noise. This noise pattern occurs frequently in natural systems. Different colors of noise have different sounds to our ears, of course. The color naming scheme is loosely intended to map to light spectral distributions. For example, blue noise has a rising power with increasing frequency, similar to how blue light has more energy at higher frequencies (shorter wavelengths).
- HelloNurse 5y ago
  Different spectrums can be tailored for signal processing schemes that want to add more noise at frequencies that need it and remove the noise with a filter when it has served its purpose. For example dithering adds enough extremely high frequency noise to obliterate unwanted patterns, then applies a lowpass filter that keeps all the "good" signal and removes the noise.
jarenmf 5y ago
Sometimes certain measuring instruments can be assumed to have such profiles for noise, in this case generating noise is useful for Monte Carlo based modeling or uncertainty propagation.
dahart 5y ago
One reason to use Blue noise in graphics / games / images is anytime you need a random number per pixel for, say, some Monte Carlo process, that will have a visible effect on the image and result in visible noise in the output. Using blue noise, the output will be visibly less “noisy” looking than when using white noise, due to blue noise having no low frequencies. Blue noise is best for situations where you only have the budget for 1 or 2 samples per pixel. The very low sample counts is where it performs considerably better than white noise. If you integrate with many samples, tens or hundreds or more, then the advantage of blue noise over other “colors” diminishes. The author of this post has some examples in other articles on his blog, for example using blue noise vs white noise for ray traced soft shadows. https://blog.demofox.org/2020/05/16/using-blue-noise-for-raytraced-soft-shadows/ https://blog.demofox.org/2020/05/16/using-blue-noise-for-ray...

by ajot 5y ago

dnautics 5y ago

Chemist here too but my ex was an sound consultant for an architectural firm. Iirc, different kinds of noises essentially are defined by the average amplitude (energy) vs frequency function of the rng. For architects, it can be important to model noise to ensure your structure complies with for example OSHA regulations. There can be code regulations too if you're in an urban place and say putting residential on top of street level commercial spaces, especially bars that might be open late. Finally, for gathering/events spaces you want to have a situation where a PA/presentation system doesn't have to work hard to go over conversation noise. The energy profiles for all of these scenarios is empirically determined and "well known" in the community. The ex helped model the "death star" auditorium space at the academy of motion picture arts and sciences in LA. IIRC it sounds really aquarium-ey during normal times and during events they roll out strategically placed dampeners.

mzs 5y ago

blue noise dither: http://www.imaging.org/site/PDFS/Papers/1999/RP-0-93/1786.pdf http://www.imaging.org/site/PDFS/Papers/1999/RP-0-93/1786.pd...

the__alchemist 5y ago

I'm using pink noise in an audiogram, to determine if users can hear sounds with it as background.

iamwil 5y ago

Blue noise is useful in games for generating more natural looking scenes. Here's an example of how to algorithmically place grass in the game "The Witness". https://youtu.be/Ge3aKEmZcqY?t=965 https://youtu.be/Ge3aKEmZcqY?t=965 So if you use white noise, it looks unnaturally clustered with patches. This is the part that discusses the noise. https://youtu.be/Ge3aKEmZcqY?t=1385 https://youtu.be/Ge3aKEmZcqY?t=1385

ocharles 5y ago

For one real application of blue noise in particular, see https://youtu.be/Ge3aKEmZcqY?t=1350 https://youtu.be/Ge3aKEmZcqY?t=1350 (22:30 is a good starting point). Here Casy explains a grass planting algorithm for games, where white noise wouldn't be suitable.

iamwil 5y ago
Haha, I guess you and I just saw the same video.

anon_123g987 5y ago

Also chemist here. Think about it the other way around, not synthesis but analysis. For example: "The term "Brown noise" does not come from the color, but after Robert Brown, who documented the erratic motion for multiple types of inanimate particles in water." (https://en.wikipedia.org/wiki/Brownian_noise https://en.wikipedia.org/wiki/Brownian_noise)

marktangotango 5y ago
Side note; what does a self described chemist do these days? Seems like Breaking Bad spurred a lot of interest in the field, but as someone who minored in chemistry many years ago, the actual job prospects seemed limited. And research seemed very stodgy (to me at least). If you don't mind sharing, what's your background and what types of things are you working on?
- whatshisface 5y ago
  Chemists do the same things they always have, just for much less money than the same people would make today in software engineering. Here are some types of applied chemistry: - Deciding what ratio to mix things in for the countless liquid products that are combinations of already-discovered chemicals. Everything at the grocery store that comes in a jug or a bottle (cleaning products, hair conditioner, drain cleaner) falls in to this category. - Doing industrial research to improve existing processes. This would include discovering new catalysts, and trying out the endless permutations of solvents and conditions in which existing reactions take place, to optimize them for whatever the biggest operating costs are. - Figuring out how to recycle industrial chemicals and get the valuable stuff back out of sludge and effluent. This is a surprisingly big field with important consequences. - Working on specialty materials, like plastics and synthetic rubbers, that are not completely dissimilar from existing products but require a chemist to design them for specific, demanding applications. The fact that everything involving the physical world gets you paid way less for work that's way more difficult than programming will come back to bite us somehow, but it's hard to say when.
  - robocat 5y ago

littlestymaar 5y ago

Blue noise is useful for procedural generation, because it's what the human eye will naturally consider the “most randon” and the most pleasant. IIRC red noise appears when you have random walks or Brownian motion. > As a chemist, I always model real-world noise with a gaussian distribution Gaussian distribution is what you get when you have a lot of independent random events adding up (it's the central limit theorem), so it applies a lot in real life but it can also cause modeling issues if it's not how randomness appears in your system. (Please note that I have absolutely no knowledge on chemistry so I have no idea if it's something that could be relevant in your field)

deleted 5y ago
[deleted]

PragmaticPulp 5y ago

The difference is the spectral power distribution of the noise. White noise has a flat spectrum from low to high frequencies. It has the standard noise sound that most of us recognize from digital systems. Pink noise is shaped with a decreasing power as frequency increases. This results in more low frequency noise and less high frequency noise. This noise pattern occurs frequently in natural systems. Different colors of noise have different sounds to our ears, of course. The color naming scheme is loosely intended to map to light spectral distributions. For example, blue noise has a rising power with increasing frequency, similar to how blue light has more energy at higher frequencies (shorter wavelengths).

HelloNurse 5y ago
Different spectrums can be tailored for signal processing schemes that want to add more noise at frequencies that need it and remove the noise with a filter when it has served its purpose. For example dithering adds enough extremely high frequency noise to obliterate unwanted patterns, then applies a lowpass filter that keeps all the "good" signal and removes the noise.

jarenmf 5y ago

Sometimes certain measuring instruments can be assumed to have such profiles for noise, in this case generating noise is useful for Monte Carlo based modeling or uncertainty propagation.

dahart 5y ago

One reason to use Blue noise in graphics / games / images is anytime you need a random number per pixel for, say, some Monte Carlo process, that will have a visible effect on the image and result in visible noise in the output. Using blue noise, the output will be visibly less “noisy” looking than when using white noise, due to blue noise having no low frequencies. Blue noise is best for situations where you only have the budget for 1 or 2 samples per pixel. The very low sample counts is where it performs considerably better than white noise. If you integrate with many samples, tens or hundreds or more, then the advantage of blue noise over other “colors” diminishes. The author of this post has some examples in other articles on his blog, for example using blue noise vs white noise for ray traced soft shadows. https://blog.demofox.org/2020/05/16/using-blue-noise-for-raytraced-soft-shadows/ https://blog.demofox.org/2020/05/16/using-blue-noise-for-ray...