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Need to access an image from my webcam (WDM compliant)

Posted on 2003-10-28
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Background:
I'm building a robot for my senior design that carries a laptop and a webcam.  It will be doing some basic line following with the webcam input.  That means I will need a good frame rate.  I tried using some shareware utility that captures jpeg images from my webcam.  The problem is the utility only captures about 2 frames per second and on top of that I have to convert the jpegs to a format I can easily put into a matrix.

So naturally I want to write a program that will access my webcam directly.  I'm not sure what the heck to use though.  I know I want to use C#.  But as for what API to use I'm clueless.  I tried reading on the MSDN site about Direct Show and Windows Image Acquisition (WIA), but I am not a windows programmer.  I don’t know the first think about the windows SDK.  So I’m finding it hard to find a place to start especially with my time constraint of about another month.  Don’t get me wrong, I’m a very good programmer (both in Java and C++), but being a student I haven’t had the opportunity to do anything with windows libraries.

My robotics class professors (EE guys) are idiots, they say that windows programming is garbage and I should use linux.  Sure linux is probably easier to use then a windows API, but the support for webcams under linux is pathetic.  I want to use my Logitech 3000 pro and prove them wrong ;p

The Question:
What is an easy, but efficient way to get a raw image from my webcam, which is WDM compliant?

Thanks in advance,
Juzzam
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Question by:Juzzam
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Xikilm earned 1020 total points
ID: 9635836
Greetings Juzzam:

You'll want to research DirectX video capture with C#.  Basically, you want to poll the device at a set interval and capture the current video.  Here are some samples that may provide a good start:

http://www.codeproject.com/csharp/webcamservice.asp
http://www.codeproject.com/cs/media/directxcapture.asp


HTH,
Xikilm
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Author Comment

by:Juzzam
ID: 9644667
This first tutorial was excellent.  I was able to compile the source and modify it.

Even when I change the sleep time between captures to 1ms, I can't get a reading from the webcam any faster than 1 snapshot per second.  Is this a limitation of DirectShow for capturing an image?

My robot can't possibly figure out which way to go with only 1fps.  I guess I will need video, but in order to process an image I am putting it into a matrix.  So I guess I need a way to capture video from my webcam and then a way to grab a frame and map it to a matrix?

Again, I don't know where to start :(
Juzzam
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