[asvs] Re: When Would Synthetic Vision be Useful?

  • From: "Will Pearson" <will-pearson@xxxxxxxxxxxxx>
  • To: <asvs@xxxxxxxxxxxxx>
  • Date: Fri, 1 Oct 2004 18:56:46 +0100


I agree that cancellation may be problematic, and from the two electives I
did as an undergrad on communications technology, I know that if the
signal's amplitude frequency and phase are equal, you'd get complete
cancellation of both signals due to the attenuation created.  I think
there's a couple of possible solutions, although my physics ain't great, so
I might be wrong.

Firstly, allow the display to be shifted about in space.  This will break
the symetry between the two points.  This is also a useful thing to do to
overcome the issue of low auditory definition.  We can only detect sounds
that are at least one degree apart.  So, in order to pick up on the finer
detail, you will need to zoom in and shift the display about any way.  It's
a bit like low vision users needing magnification to overcome the poor
visual definition created by low vision.

Secondly, alter the frequency very slightly.  Psycho-acoustically, we can
only distinguish differences in frequency of between 10 and 15Hz.  So,
adjust the freq. by a hertz or two would still give the appearance of the
frequencies being identical, although they're not.  I don't know how much
you would need to shift the freq. by to avoid cancellation, but I think this
should work.  I'll check on monday, as one of the lecturers who took me for
comms. tech. is one of the people I'm having a meeting with on Monday about
a research project, and his PhD superviser was Prof. H H H, who did the
theory on optical storage, that later became the CD.

----- Original Message ----- 
From: "Zorro" <blindfold@xxxxxxxxxx>
To: <asvs@xxxxxxxxxxxxx>
Sent: Friday, October 01, 2004 4:37 PM
Subject: [asvs] Re: When Would Synthetic Vision be Useful?

> Hi David and all,
>  > The model we are working on would provide a simultanious three d view
> Of course we all want that, but the key problem is to prevent that,
> say, the sounds of two identical visual objects at the same elevation,
> symmetrically placed on your left and on your right side, cancel out
> their relative phases such that sound appears to come from one point
> straight ahead rather than from those two positions on your left and
> right. I think only a sequential protocol, some form of scanning, can
> break this inherent ambiguity in using sound coming from many sources
> in space.
> Best wishes,
> Peter
> Seeing with Sound - The vOICe
> http://www.seeingwithsound.com
> http://www.visualprosthesis.com

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