The addition of noise to push low level signals above the noise floor is a known technique for making these signals perceivable. It essentially boost some information just below the floor above it, and given the brain is adept at handling noise, it improves the overall dynamic range of the system.
Scintillating vision at night with dark adapted eyes is another example of this phenomenon. Adding in a little familiarity with the environment makes it easy make to the bathroom at night without any lights. But the cost of this improvement is clearly a degraded image with missing edges and false objects hits as well as an undulating video lacking smooth continuity. I find it interesting to learn how this process is implemented at a synaptic level, fascinating. I see it as a refinement, something that could be added based on the application. Such as cleaning up weak noisy radio transmissions, audio or video to bring previously unattainable information out. (never fails to trip me up that one of those words ends in dio and the other deo even tho they sound the same) This blog explains how adding (good) noise before something is encoded improves dynamic range. This might be an argument for playing with this idea at the encoder level. http://blog.discmakers.com/2013/01/dithering-adding-good-noise-to-improve-your-home-recordings/ Taking this a little further, I use image stacking to reduce the noise and improve the dynamic range of my astrophotos. Its a common technique used by astrophotographers, taking many frames of the same object taken at different times and using photoshop or special image stacking software to align them and average each pixel. This has the effect of canceling the noise to some degree and adding to the signal. Contrast is greatly improved. Using this technique at the encoder level would also be a nice way to remove some unwanted noise (possible after it was added in for reasons described above). I'm wondering if these techniques in tandem would be worth investigating. Thanks TIm! Patrick On Sep 8, 2013, at 12:22 AM, Tim Boudreau wrote: > Thought this might be of interest on this list: > > "Release of neurotransmitter is an inherently random process, which could > degrade the reliability of postsynaptic spiking, even at relatively large > synapses. This is particularly important at auditory synapses, where the rate > and precise timing of spikes carry information about sounds." > http://www.ncbi.nlm.nih.gov/pubmed/24005293 > > It suggests that the phenomenon that introducing dither noise into an audio > signal can improve intelligibility of low amplitude signals (pushing enough > samples above the noise floor that the brain will fill in the blanks) is also > inherently present in the brain. > > -Tim > > -- > http://timboudreau.com > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org _______________________________________________ nupic mailing list [email protected] http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org
