[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 :)

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

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