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Thread: Wireless Video

  1. #1
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    Default Wireless Video

    I have this Qt application that currently reads video data from a webcam plugged into my laptop and outputs it in a window. I need to make it receive data wireless-ly from a flying vehicle and display the data it receives in the window.

    I am using OpenCV to display the video currently and would like to be able to modify it to work over a wireless network. Thanks in advance for your help and patience!

  2. #2
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    Default Re: Wireless Video

    What is the question?
    ==========================signature=============== ==================
    S.O.L.I.D principles (use them!):
    https://en.wikipedia.org/wiki/SOLID_...iented_design)

    Do you write clean code? - if you are TDD'ing then maybe, if not, your not writing clean code.

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    Default Re: Wireless Video

    Hey what you used to receive camera output and show it in Qt???
    pls post some code,I also need it.

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    Default Re: Wireless Video

    To an application, a wireless network is the same as a wired one. There is no difference.

    (Assuming the wireless network is TCP/IP and not some proprietary nonsense, of course)

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    Default Re: Wireless Video

    @fatjuicymole
    Well right now I am reading the video data directly from a webcam that is plugged in to one of my usb ports on my laptop. I need to modify the code to receive video data from a vehicle flying in the air with a camera attached to it.

    @Qt Coder
    Here is the website where I downloaded some code that takes webcam video and displays it in a Qt window. It was very easy for me to integrate this into my personal project and should be the same for you. Keep in mind that OpenCV must be installed completely, along with some other things probably.
    http://qt-apps.org/content/show.php/...?content=89995

    Installation instructions for OpenCV:
    http://opencv.willowgarage.com/wiki/InstallGuide_Linux

    @high_flyer
    Basically, how do I take the attached code, and make it work with tcp/ip wireless network. I need to receive the video from a remote location, not just my own computer.

    The attached code requires OpenCV to run and it could require other things. Feel free to ask me any questions and I will help getting it running quickly. Thanks everyone for your time and patience!
    Attached Files Attached Files

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    Default Re: Wireless Video

    Quote Originally Posted by khrave View Post
    @fatjuicymole
    Well right now I am reading the video data directly from a webcam that is plugged in to one of my usb ports on my laptop. I need to modify the code to receive video data from a vehicle flying in the air with a camera attached to it.
    And? How does the flying camera transmit its data? Wifi? Bluetooth?

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    Default Re: Wireless Video

    It transmits it via wifi to a computer on the ground purposed to view video data and other stats about the flying vehicle.

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    Default Re: Wireless Video

    So what you need to do is create a server. What type of connection does it expect?

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    Default Re: Wireless Video

    We're using a camera that is mounted on the flying vehicle, which is attached via usb to a gumstix overo fire board (also mounted on the flying vehicle) which will transmit various types of information, including video data, through a tcp/ip wireless-g signal to the computer on the ground. I need to be able to get the video data from the vehicle and display it. I feel like it is an easy modification to the code I posted earlier, but I need a push in the right direction. Thanks!

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    Default Re: Wireless Video

    Wireless-G is a transport medium (well, Link Layer) for transferring data over the air-ways
    TCP over IP is a transport medium
    Before we can go further we need to know what Application Layer the camera uses. For example, HTTP, FTP, Proprietary, etc.

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    Default Re: Wireless Video

    Oh, my apologies, my terminology knowledge is relatively low. We're using UDP, sending raw data through packets between the ground computer and the vehicle.

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    Default Re: Wireless Video

    In which case, there is a nice example for UDP in the QUdpSocket documentation in Assistant.

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    Default Re: Wireless Video

    The same way I need to use IP camera in my proje.My question is

    1) How to know which application layer the camera uses?

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    Default Re: Wireless Video

    a) Wireshark (examine communication), or
    b) Experimentation, or
    c) Documentation

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    Default Re: Wireless Video

    I installd Qt 4.6.2 and OpenCV2.0 on my windows machine

    Qt is installed at C:\Qt\2010.02.1\Qt and openCV is installed at c:\OpenCV2.0

    I downloaded the QtOpenCV example which
    Opens a webcam, and displays the image in the widget.
    from http://opendesktop.org/content/show....SSID=kfmhtqozm


    I copied opencv folder where it contains cv.h,higui.h in Qt include folder also I changed .pro file as

    Qt Code:
    1. INCLUDEPATH += "C:\OpenCV2.0\src\cv"
    2. INCLUDEPATH += "C:\OpenCV2.0\src\cxcore"
    3. INCLUDEPATH += "C:\OpenCV2.0\src\cvaux"
    4. INCLUDEPATH += "C:\OpenCV2.0\src\highgui"
    5.  
    6. LIBS += -L "C:\OpenCV2.0\lib"
    7. LIBS += -lcv -lhighgui
    To copy to clipboard, switch view to plain text mode 


    when I compile example it gives me error

    Qt Code:
    1. c:/qt/2010.02.1/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lcv
    2. collect2: ld returned 1 exit status
    To copy to clipboard, switch view to plain text mode 

    why this error occures?

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    Default Re: Wireless Video

    Where is cv?

  17. #17
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    Default Re: Wireless Video

    OpenCV is installed at C:\OpenCV2.0

    Qt 4.6.2 is installed at C:\Qt\2010.02.1\qt

    also I have copied C:\OpenCV2.0\include\opencv folder to Qt include folder

    still it gives this error
    Qt Code:
    1. 1.
    2. c:/qt/2010.02.1/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lcv
    3. 2.
    4. collect2: ld returned 1 exit status
    To copy to clipboard, switch view to plain text mode 

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    Default Re: Wireless Video

    So there is a file called libcv.lib in C:\OpenCV2.0\lib ?

  19. #19
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    Default Re: Wireless Video

    C:\OpenCV2.0\lib\libcv200.dll.a

    file is there

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    Default Re: Wireless Video

    modify
    LIBS += -lcv -lhighgui

    to
    LIBS += -lcv200.dll -lhighgui

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