Re: Is it possible to transfer data by using light
Re: Is it possible to transfer data by using light
- Subject: Re: Is it possible to transfer data by using light
- From: Michael David Crawford <email@hidden>
- Date: Thu, 17 Sep 2015 10:43:15 -0700
Flashing the entire screen as I describe should not be done in product
(App Store) code, rather one might use it as a very, very rough
prototype.
I expect production-quality software could modulate the screen is
far-more subtle ways that both would transmit data far faster as well
as avoid stimulating seizures.
For the most part it is sharp, sudden flashes as from the Xeon strobes
in emergency responder vehicle lights (ie. Squad Car Lights) that,
without a doubt, trigger my own seizures. While I also suspect
computer animations, I am as yet uncertain.
Analog transmission by displaying shades of grey could transmit more
data while avoiding the stimulation of seizures.
Michael David Crawford P.E., Consulting Process Architect
email@hidden
http://mike.soggywizard.com/
One Must Not Trifle With Wizards For It Makes Us Soggy And Hard To Light.
On Thu, Sep 17, 2015 at 9:46 AM, Pascal J. Bourguignon
<email@hidden> wrote:
>
>
> On 17/09/15 17:32, Michael David Crawford wrote:
>>
>> And what the man said: I myself experience seizures in which I lose
>> consciousness for as long as three weeks. Before they were diagnosed
>> I would experience seizures while driving my car then suddenly find
>> myself in unfamiliar places without any clue how I got there.
>>
>> I don't know for sure but strongly suspect that modern computer user
>> interfaces caused my seizure disorder as well as that of my cousin.
>> Seizures are not otherwise found among any of our blood relatives.
>
>
> But then if you don't use the whole screen, but only the area that
> should be in front of the camera of the superposed phone, then users
> shouldn't be subjected to much stroboscopic light.
>
> Having the objective so close from the light source does not allow
> the camera to distinguish pixels; for example, a black to white
> transition takes about 1/10 of the height of the camera view.
> But this means that you might still able to transmit about ten pixels at
> once,
> and you can multiply that by a number of color that you can detect reliably
> being that out of focus. Basically, I would expect 8 colors to be clearly
> distinguishable. Actually, probably more colors should be distinguishable,
> if you can filter out the interferences due to the grid of the camera vs.
> the grid of the screen. So assume 4 bits for the color, and 9 areas,
> that's 36 bit/moment, and you should be able to do 30 moment/second,
> for a total of 1080 bit/second. A little less for ECC, about 1 KB/s
> is not too bad. It's good enough to transmit a good private key, and then
> transfer the data thru wifi.
>
>
> Of course, if you move the camera out to focus on the screen, then
> you can transmit at a higher speed things like QR codes, but they
> could also be seen over the shoulder by high resolution cameras.
>
> --
> __Pascal J. Bourguignon__
> http://www.informatimago.com/
>
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