JeVois  1.3
JeVois Smart Embedded Machine Vision Toolkit
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Getting started with Windows host computer

The JeVois smart camera is used like a regular USB camera. To get started with a Windows host:

  • Download a disk image from http://jevois.org and flash it to a MicroSD card.

  • Insert MicroSD card into JeVois smart camera, with the MicroSD contacts pointing up as shown below.

    sd-insert.png
    microsd-fully-inserted.jpg

  • Connect camera to a host computer. The smart camera requires up to 3.5 Watts of power, which is above the limit of what a single USB 2.0 port is designed to supply, but is within the limits of a single USB 3.0 port. It is important to use a high-quality USB-to-miniUSB cable that can carry that full power without loss. Look for a cable with 24awg power wires. It is recommended that you use a USB 3.0 port on your host computer, as those provide more power. If that is not available, you can use a USB Y-cable to connect to two USB 2.0 ports on your host computer, or to one USB 2.0 port and one external USB power supply (e.g., phone charger). Make sure that you do not use a USB hub, unless that hub has a strong external power supply (transformer, wall adapter).

  • Observe the LED on the smart camera next to the USB connector:

    • Green: Power is on and is strong enough.
    • After about 3 seconds: Flash orange: The camera sensor chip has been detected and initialized.
    • After about 5 seconds: Solid orange: The smart camera is ready for use.
    • Wait a few more seconds for your host computer to detect the camera and prepare itself for video capture.

  • Start a video capture software. You may want to try VLC, skype, etc. Here we will use AMCap.

    • Download and install the AMCap software. You can get it for free at http://noeld.com/updates.asp
    • Start the AMCap software. Under "Devices" make sure you select your JeVois smart camera (if you have several cameras, for example also a built-in webcam in your laptop computer). Here for example we run the ArUco demo on JeVois and view the results on a host PC using AMCap:
    amcap-aruco.png
    • Selection of different machine vision algorithms is achieved by selecting different video resolutions in your video capture software. To change video resolutions, select "Options", "Video Device", "Capture Format" as shown below:
    amcap-menu.png
    • Once you see the Properties dialog, select one of the available "Color Space / Compression" (most machine vision modules output YUY2 video), and one "Output Size" resolutions as shown below to launch the corresponding machine vision algorithm on your JeVois camera:
    amcap-setres.png
    • To Access the camera's controls such as brightness, contrast, etc can be done by selecting "Options", "Video Device", "Properties", as shown below:
    amcap-properties.png
    amcap-props.png

    Note that on Windows and for some video software like VLC, the latency (delay or lag between capture and display) is horrible with many video capture apps. This is not a limitation of JeVois. When used with a Linux host, there is no lag.

  • Make sure you quit your camera viewing software before you unplug your JeVois smart camera. Otherwise your host computer may become awfully confused trying to use a camera that does not exist anymore.

  • No shutdown procedure is needed before powering off your JeVois camera. Just close your video capture software and unplug the camera.

Enabling greyscale capture

In addition to being able to output color streaming video, JeVois can, when some machine vision algorithms are enabled, also stream greyscale video. This is particularly useful when running machine vision algorithms that produce intended for further processing on the host computer. For example, see the Edge Detection Module or the Optical Flow Module. Under windows, AMCap requires an additional filter to be installed in order to be able to capture greyscale video (in USB video specifications, greyscale is called Y800 mode).

The instructions below were contributed by JeVois user pelrun. Many thanks, pelrun!

  • Download http://www.gdcl.co.uk/YUVxfm.zip. A mirror copy is here.
  • Extract it to c:\windows\system32
  • Open a command prompt window with administrator privileges
  • Enter regsvr32 c:\windows\system32\YUVxfm.dll in the command window.

This will install a directshow filter which supports the Y800 mode and will allow you to use the JeVois machine vision modules that output greyscale video.

Troubleshooting

Nothing here for now.