Recherche avancée

Sur d’autres sites (11928)

• Using ImageMagick to efficiently stitch together a line scan image

  2 octobre 2018, par rkantos

  I’m looking for alternatives for line scan cameras to be used in sports timing, or rather in the part where placing needs to be figured out. I found that common industrial cameras can readily match the speed of commercial camera solutions at >1000 frames per second. For my needs, usually the timing accuracy is not important, but the relative placing of athletes. I figured I could use one of the cheapest Basler, IDS or any other area scan industrial cameras for this purpose. Of course there are line scan cameras that can do a lot more than a few thousand fps (or hz), but it is possible to get area scan cameras that can do the required 1000-3000fps for less than 500€.

  My holy grail would of course be the near-real time image composition capabilities of FinishLynx (or any other line scan system), basically this part : https://youtu.be/7CWZvFcwSEk?t=23s

  The whole process I was thinking for my alternative is :

  • Use Basler Pylon Viewer (or other software) to record 2px wide images at the camera’s fastest read speed. For the camera I am
    currently using it means it has to be turned on it’s side and the
    height needs to be reduced, since it is the only way it will read
    1920x2px frames @ >250fps
  • Make a program or batch script that then stitches these 1920x2px frames together to, for example one second of recording 1000*1920x2px
    frames, meaning a resulting image with a resolution of 1920x2000px
    (Horizontal x Vertical).
  • Finally using the same program or another way, just rotate the image so it reflects how the camera is positioned, thus achieving an image
    with a resolution of 2000x1920px (again Horizontal x Vertical)
  • Open the image in an analyzing program (currently ImageJ) to quickly analyze results

  I am no programmer, but this is what I was able to put together just using batch scripts, with the help of stackoverflow of course.

  • Currently recording a whole 10 seconds for example to disk as a raw/mjpeg(avi/mkv) stream can be done in real time.
  • Recording individual frames as TIFF or BMP, or using FFMPEG to save them as PNG or JPG takes 20-60 seconds The appending and rotation
    then takes a further 45-60 seconds
    This all needs to be achieved in less than 60 seconds for 10 seconds of footage(1000-3000fps @ 10s = 10000-30000 frames) , thus why I need something faster.

  I was able to figure out how to be pretty efficient with ImageMagick :

  magick convert -limit file 16384 -limit memory 8GiB -interlace Plane -quality 85 -append +rotate 270 “%folder%\Basler*.Tiff” “%out%”
  
  
  
  #%out% has a .jpg -filename that is dynamically made from folder name and number of frames.

  This command works and gets me 10000 frames encoded in about 30 seconds on a i5-2520m (most of the processing seems to be using only one thread though, since it is working at 25% cpu usage). This is the resulting image : https://i.imgur.com/OD4RqL7.jpg (19686x1928px)

  However since recording to TIFF frames using Basler’s Pylon Viewer takes just that much longer than recording an MJPEG video stream, I would like to use the MJPEG (avi/mkv) file as a source for the appending. I noticed FFMPEG has “image2pipe” -command, which should be able to directly give images to ImageMagick. I was not able to get this working though :

     $ ffmpeg.exe -threads 4 -y -i "Basler acA1920-155uc (21644989)_20180930_043754312.avi" -f image2pipe - | convert - -interlace Plane -quality 85 -append +rotate 270 "%out%" >> log.txt
  
      ffmpeg version 3.4 Copyright (c) 2000-2017 the FFmpeg developers
  
        built with gcc 7.2.0 (GCC)
  
        configuration: –enable-gpl –enable-version3 –enable-sdl2 –enable-bzlib –enable-fontconfig –enable-gnutls –enable-iconv –enable-libass –enable-libbluray –enable-libfreetype –enable-libmp3lame –enable-libopenjpeg –enable-libopus –enable-libshine –enable-libsnappy –enable-libsoxr –enable-libtheora –enable-libtwolame –enable-libvpx –enable-libwavpack –enable-libwebp –enable-libx264 –enable-libx265 –enable-libxml2 –enable-libzimg –enable-lzma –enable-zlib –enable-gmp –enable-libvidstab –enable-libvorbis –enable-cuda –enable-cuvid –enable-d3d11va –enable-nvenc –enable-dxva2 –enable-avisynth –enable-libmfx
  
        libavutil      55. 78.100 / 55. 78.100
  
        libavcodec     57.107.100 / 57.107.100
  
        libavformat    57. 83.100 / 57. 83.100
  
        libavdevice    57. 10.100 / 57. 10.100
  
        libavfilter     6.107.100 /  6.107.100
  
        libswscale      4.  8.100 /  4.  8.100
  
        libswresample   2.  9.100 /  2.  9.100
  
        libpostproc    54.  7.100 / 54.  7.100
  
      Invalid Parameter - -interlace
  
      [mjpeg @ 000000000046b0a0] EOI missing, emulating
  
      Input #0, avi, from 'Basler acA1920-155uc (21644989)_20180930_043754312.avi’:
  
        Duration: 00:00:50.02, start: 0.000000, bitrate: 1356 kb/s
  
          Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj422p(pc, bt470bg/unknown/unknown), 1920x2, 1318 kb/s, 200 fps, 200 tbr, 200 tbn, 200 tbc
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (mjpeg (native) -> mjpeg (native))
  
      Press [q] to stop, [?] for help
  
      Output #0, image2pipe, to ‘pipe:’:
  
        Metadata:
  
          encoder         : Lavf57.83.100
  
          Stream #0:0: Video: mjpeg, yuvj422p(pc), 1920x2, q=2-31, 200 kb/s, 200 fps, 200 tbn, 200 tbc
  
          Metadata:
  
            encoder         : Lavc57.107.100 mjpeg
  
          Side data:
  
            cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
  
      av_interleaved_write_frame(): Invalid argument
  
      Error writing trailer of pipe:: Invalid argument
  
      frame=    1 fps=0.0 q=1.6 Lsize=       0kB time=00:00:00.01 bitrate= 358.4kbits/s speed=0.625x
  
      video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%
  
      Conversion failed!

  If I go a bit higher for the height, I no longer get the “[mjpeg @ 000000000046b0a0] EOI missing, emulating” -error. However the whole thing will only work with <2px high/wide footage.

  edit : Oh yes, I can also use ffmpeg -i file.mpg -r 1/1 $filename%03d.bmp or ffmpeg -i file.mpg $filename%03d.bmp to extract all the frames from the MJPEG/RAW stream. However this is an extra step I do not want to take. (just deleting a folder of 30000 jpgs takes 2 minutes alone…)

  Can someone think of a working solution for the piping method or a totally different alternative way of handling this ?

• Help us Reset The Net today on June 5th

  5 juin 2014, par Piwik Core Team — Community, Meta

  This blog post explains why the Piwik project is joining ResetTheNet online protest and how you can help make a difference against mass surveillance. It also includes an infographic and links to useful resources which may be of interest to you.

  Snowden revelations, a year ago today

  On June 5, 2013 the Guardian newspaper published the first of Edward Snowden’s astounding revelations. It was the first of a continuous stream of stories that pointed out what we’ve suspected for a long time : that the world’s digital communications are being continuously spied upon by nation states with precious little oversight.

  Unfortunately, mass surveillance is affecting the internet heavily. The Internet is a powerful force that can promote democracy, innovation, and creativity, but it’s being subverted as a tool for government spying. That is why Piwik has decided to join Reset The Net.

  June 5, 2014 marks a new year : a year that will not just be about listening to the inside story of mass surveillance, but a new year of fighting back !

  How do I protect myself and others ?

  Reset the Net is asking everyone to help by installing free software tools that are designed to protect your privacy on a computer or a mobile device.

  Reset the Net is also calling on websites and developers to add surveillance resistant features such as HTTPS and forward secrecy.

  Participate in ResetTheNet online protest

  Have you got your own website, blog or tumblr ? Maybe you can show the Internet Defense League’s “Cat Signal !” on your website.Get the code now to run the Reset the Net splash screen or banner to help make privacy viral on June 5th.

  Message from Edward Snowden

  Evan from FFTF sent us this message from Edward Snowden and we thought we would share it with you :

  One year ago, we learned that the internet is under surveillance, and our activities are being monitored to create permanent records of our private lives — no matter how innocent or ordinary those lives might be.

  Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same. That’s why I’m asking you to join me on June 5th for Reset the Net, when people and companies all over the world will come together to implement the technological solutions that can put an end to the mass surveillance programs of any government. This is the beginning of a moment where we the people begin to protect our universal human rights with the laws of nature rather than the laws of nations.

  We have the technology, and adopting encryption is the first effective step that everyone can take to end mass surveillance. That’s why I am excited for Reset the Net — it will mark the moment when we turn political expression into practical action, and protect ourselves on a large scale.

  Join us on June 5th, and don’t ask for your privacy. Take it back.

  – Message by Edward Snowden

  ResetTheNet privacy pack infographic

  

  Additional Resources

  Configure Piwik for Security and Privacy

  • Turn on automatic SSL redirection in your Piwik.
  • Configure Piwik for advanced Privacy.
  • Best security practises for Piwik.

  More info

  • Learn why this matters (EFF)
  • Data Privacy Day – Why is privacy important ? (Piwik)
  • Web Analytics Privacy (Piwik)

• Help us Reset The Net today on June 5th

  5 juin 2014, par Piwik Core Team — Community, Meta

  This blog post explains why the Piwik project is joining ResetTheNet online protest and how you can help make a difference against mass surveillance. It also includes an infographic and links to useful resources which may be of interest to you.

  Snowden revelations, a year ago today

  On June 5, 2013 the Guardian newspaper published the first of Edward Snowden’s astounding revelations. It was the first of a continuous stream of stories that pointed out what we’ve suspected for a long time : that the world’s digital communications are being continuously spied upon by nation states with precious little oversight.

  Unfortunately, mass surveillance is affecting the internet heavily. The Internet is a powerful force that can promote democracy, innovation, and creativity, but it’s being subverted as a tool for government spying. That is why Piwik has decided to join Reset The Net.

  June 5, 2014 marks a new year : a year that will not just be about listening to the inside story of mass surveillance, but a new year of fighting back !

  How do I protect myself and others ?

  Reset the Net is asking everyone to help by installing free software tools that are designed to protect your privacy on a computer or a mobile device.

  Reset the Net is also calling on websites and developers to add surveillance resistant features such as HTTPS and forward secrecy.

  Participate in ResetTheNet online protest

  Have you got your own website, blog or tumblr ? Maybe you can show the Internet Defense League’s “Cat Signal !” on your website.Get the code now to run the Reset the Net splash screen or banner to help make privacy viral on June 5th.

  Message from Edward Snowden

  Evan from FFTF sent us this message from Edward Snowden and we thought we would share it with you :

  One year ago, we learned that the internet is under surveillance, and our activities are being monitored to create permanent records of our private lives — no matter how innocent or ordinary those lives might be.

  Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same. That’s why I’m asking you to join me on June 5th for Reset the Net, when people and companies all over the world will come together to implement the technological solutions that can put an end to the mass surveillance programs of any government. This is the beginning of a moment where we the people begin to protect our universal human rights with the laws of nature rather than the laws of nations.

  We have the technology, and adopting encryption is the first effective step that everyone can take to end mass surveillance. That’s why I am excited for Reset the Net — it will mark the moment when we turn political expression into practical action, and protect ourselves on a large scale.

  Join us on June 5th, and don’t ask for your privacy. Take it back.

  – Message by Edward Snowden

  ResetTheNet privacy pack infographic

  

  Additional Resources

  Configure Piwik for Security and Privacy

  • Turn on automatic SSL redirection in your Piwik.
  • Configure Piwik for advanced Privacy.
  • Best security practises for Piwik.

  More info

  • Learn why this matters (EFF)
  • Data Privacy Day – Why is privacy important ? (Piwik)
  • Web Analytics Privacy (Piwik)