[aprssig] Packet Compressed Sensing Imaging (PCSI)
MJ Inabnit
ke6sls at arrl.net
Tue Jul 7 00:50:53 EDT 2020
If we're dreaming, then lets add one more idea. FLamp (from the FLdigi
software) has the ability to copy part of a message, then request fills
of only what it didn't get. So perhaps this new mode can add that
element so if a user QSY's and only gets 75% of image, it would only ask
for fills of the 25% it didn't get.
Dreaming :)
73
Jaye ke6sls
On 7/1/20 7:42 AM, Robert Bruninga wrote:
> This is fantastic. Its what I have always thought would be useful
> adjunct to APRS> See http://aprs.org/aprn.html
> Although that (Auto Picture Relay Network) was based on SSTV, this new
> digital method should work fine.
>
> But NOT on the APRS channel.
> What we need is an OBJECT that gets posted on the APRS local channel
> that announces a PCSI image and that points to the FREQUENCY to download.
> Two methods I guess? The image runs continuously for a set period, or
> someone who wants the image QSY's and requests it.
> THat way it starts when they are ready.
>
> If the FREQ object format is followed, then the Kennwoods and Yaesu's
> can auto QSY with the press of the TUNE or QSY button.
> THough they will QSY the other band, and not the data band
>
> bob, WB4APR
>
>
> On Tue, Jun 30, 2020 at 2:58 PM Mobilinkd LLC <mobilinkd at gmail.com
> <mailto:mobilinkd at gmail.com>> wrote:
>
> Would love to see iOS and Android versions of this -- send/receive
> photos directly from a smart device. If there's anything I can do
> to help make this happen please let me know.
>
> I've linked to your work
> here: https://www.reddit.com/r/hamdevs/comments/hisp7h/packet_compressed_sensing_imaging_pcsi/
>
>
> Kind Regards,
>
> Rob Riggs WX9O
> Mobilinkd LLC
>
>
> On Sun, Jun 28, 2020 at 6:20 PM Scott Howard <showard at nd.edu
> <mailto:showard at nd.edu>> wrote:
>
> Dear APRS SIG,
>
> I'm happy to share a new image transfer method called PCSI
> that a team of students and I have been developing during
> quarantine. PCSI is digital (packet based), unconnected
> multicast (UI frames), compatible with APRS (basically
> turbo-charged APRS
> Vision https://www.tapr.org/pdf/DCC1997-APRSvision-WB4APR.pdf),
> resilient to packet loss (every receiving station can receive a
> different random set of packets and still reconstruct the entire
> image), and computationally trivial for the transmitter (8-bit
> microcontroller can easily construct packets). The goal is to be
> used with low-power microcontrollers and weak signals (even HF
> modes) transmitting images when packets will likely be lost. In
> SSTV and other unconnected digital image modes like SSDV, if the
> signal is weak or packets are lost, entire sections of the image
> are distorted or missing. In PCSI, if packets are lost, you
> still receive the entire image. Every additional packet received
> (in any order) simply increases image quality. Images take
> between 1-4 minutes to come in using 1200 baud, which is on par
> with SSTV. It's all controlled with an easy GUI where you just
> set your call sign, load your file, then click send.
>
> I've used it to transmit images locally between a hamshield KISS
> system and a kenwood TH-D72a, and between two direwolf systems
> acoustically through speakers and microphones. Now it's ready
> for testing in the wild.
> *Details and usage videos are here:*
> https://maqifrnswa.github.io/PCSI/
> *Windows and Linux binaries* (for TCP or serial port KISS
> devices) are available here:
> https://github.com/maqifrnswa/PCSI/releases/tag/v0.0.0 (It
> should work on Macs too, I just don't have one to build
> binaries. If you're comfortable with python on Mac, you can also
> just use the source code.)
> *Python Source code (_everything is open source_)*:
> https://github.com/maqifrnswa/PCSI
>
> The method isn't necessarily tied to APRS and can be used over
> any band or mode, but if you'd like to explore its use for
> tactical and timely image transmission over APRS (basically the
> goal of APRS Vision), you can set it to use base91 encoding, use
> the "{{V" info prefix, and use an appropriate altnet. For now,
> I've been using the destination address PCSI to indicate that
> these are PCSI packets.
>
> Since this is a specialized group of experts, I'd appreciate any
> testing and feedback you can give. It's kind of a fun mode - you
> start watching the entire image come in over time, and as
> packets arrive, the image comes in to focus. To transmit and
> receive, you just need any KISS TNC/soundmodem/direwolf/etc. It
> might be a cool way to send low-res images over lossy and weak
> HF channels when you don't want to spend bits on FEC (although
> you could also put FEC on top of this method). Any feature
> requests, advice, or tips are welcome as well.
>
> Backstory: When CoVid-19 shut down universities, students
> weren't able to continue lab based work. I came up with this
> project so that undergraduate lab assistants could work remotely
> while supporting a new educational initiative that my university
> is pursuing around students developing technology for high
> altitude balloons. The results are like magic - even receiving
> 20%-30% of the total bytes of the original image (i.e., 70-80%
> packet loss) gives high quality images. And it's a good
> introduction for students to the math behind compressed sensing
> imaging. There are also other tricks under the hood, like the
> optional use of chroma compression to increase speed.
>
> Cheers and thanks!
> Scott
>
> --
> *
> *
> *
> *
> *Scott Howard, PhD*
> /Associate Professor/
> Department of Electrical Engineering
> University of Notre Dame
> http://ee.nd.edu
>
> 574-631-2570 (direct)
> 574-631-4393 (fax)
>
> h <http://www.nd.edu/~showard>ttps://howardphotonics.nd.edu
> <http://howardphotonics.nd.edu>
> Follow me on Twitter @HowardPhotonics
> <https://twitter.com/HowardPhotonics>
>
> 262 Fitzpatrick Hall
> Notre Dame, IN 46556
>
>
wishing you well
Jaye, ke6sls--via the toshiba w/thunderchicken
More information about the aprssig
mailing list