by Oleg Dzhimiev
Basically, one need to direct the ip cam stream (mjpeg or rtsp) to a virtual v4l2 device which acts like a web cam and is automatically picked up by a web browser or a web cam application. This can be easily done by gstreamer or ffmpeg.
Quick setup
Install and create a virtual webcam
~$ sudo apt install v4l2loopback-dkms
~$ sudo modprobe v4l2loopback devices=1
Direct the stream
The options below are for gstreamer/ffmpeg and rtsp/mjpeg streams:
gstreamer:
# rtsp stream
~$ sudo gst-launch-1.0 rtspsrc location=rtsp://192.168.0.9:554 ! rtpjpegdepay ! jpegdec ! videoconvert ! tee ! v4l2sink device=/dev/video0 sync=false
# mjpeg stream
~$ sudo gst-launch-1.0 souphttpsrc is-live=true location=http://192.168.0.9:2323/mimg ! jpegdec ! videoconvert ! tee ! v4l2sink device=/dev/video0
ffmpeg:
# rtsp stream
~$ sudo ffmpeg -i rtsp://192.168.0.9:554 -fflags nobuffer -pix_fmt yuv420p -f v4l2 /dev/video0
# mjpeg stream
~$ sudo ffmpeg -i http://192.168.0.9:2323/mimg -fflags nobuffer -pix_fmt yuv420p -r 30 -f v4l2 /dev/video0
Finally
Start a video conference application, select the webcam from the menu (/dev/video0).
Test link: meet.jit.si
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by Oleg Dzhimiev
Fig.1 TIFF image stack
The input is a <filename>.tiff – a TIFF image stack generated by ImageJ Java plugin (using bioformats) with Elphel-specific information in ImageJ written TIFF tags.
Reading and formatting image data for the Tensorflow can be split into the following subtasks:
- convert a TIFF image stack into a NumPy array
- extract information from the TIFF header tags
- reshape/perform a few array manipulations based on the information from the tags.
To do this we have created a few Python scripts (see python3-imagej-tiff: imagej_tiff.py) that use Pillow, Numpy, Matplotlib, etc..
Usage:
~$ python3 imagej_tiff.py <filename>.tiff
It will print header info in the terminal and display the layers (and decoded values) using Matplotlib.
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by Andrey Filippov
Elphel uses embedded GNU/Linux distribution based on Yocto. For most of our development (excluding just mechanical and PCB design) we use universal Eclipse IDE: for FPGA development, Linux kernel drivers development, embedded applications and web applications, for editing LaTeX texts. And we use this popular IDE for delivering pre-configured projects to our users to make it easier for them to start efficient modification of the initial camera software and then initiate the new projects.
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by Paulina Filippova and Fyodor Filippov
Setting 3D camera on the rock at Cape Alava
Testing 3D camera
on a road trip
In August of 2017, my family and I went on a trip to the Pacific Northwest, partially for a much needed vacation, but equally as importantly, to test my dad’s new 3D camera. My dad had been designing calibrated multi-sensor cameras for as long as I can remember, and since February was working determinately on developing principally new algorithms for reconstructing a 3D model from a set of 4 simultaneously taken photographs . Now that the camera and the software were ready, there was no better time to test it.
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by Andrey Filippov
Elphel cameras offer unique capabilities – they are high performance systems out of the box and have all the firmware and FPGA code distributed under GNU General Public Licenses making it possible for users to modify any part of the code. The project does not use any “black boxes” or encrypted modules, so it is simulated with the free software tools and user has access to every net in the design. We are trying to do our best to make this ‘hackability’ not just a theoretical possibility, but a practical one.
Current camera FPGA project contains over 400 files under version control and almost 100K lines of HDL (Verilog) code, there are also constraints files, tool configurations, so we need to provide means for convenient navigation and modification of the project by the users.
We are starting a series of tutorials to facilitate acquaintance with this project, and here is the first one that shows how to install and configure the software. This tutorial is made with a fresh Kubuntu 16.04 LTS distribution installed on a virtual machine – this flavor of GNU/Linux we use ourselves and so it is easier for us to help others in the case of problems, but it should be also easy to install it on other GNU/Linux systems.
Later we plan to show how to navigate code and view/modify tool parameters with VDT plugin, run simulation and implementation tools. Next will be a “Hello world” module added to the camera code base, then some simple module that accesses the video memory.
Video resolution is 1600×900 pixels, so full screen view is recommended.
Download links for: video and captions.
Running this software does not require to have an actual camera, so it may help our potential users to evaluate software capabilities and see if it matches their requirements before purchasing an actual hardware. We will also be able to provide remote access to the cameras in our office for experimenting with them.
by Olga Filippova
We have created a short video tutorial to help our users navigate through 3D models of Elphel cameras. Cameras can be virtually taken apart and put back together which helps to understand the camera configuration and access information about every camera component. Please feel free to comment on the video quality and usefulness, as we are launching a series of tutorials about cameras, software modifications, FPGA development on 10393 camera board, etc. and we would like to receive feedback on them.
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