USB web cam communication

[LSoft]

Hello!
Is there a possibility to get a picture from USB web cam (e.g. Logitech, Genius, etc.) by using LabVIEW? Or even video sequence?
Thanks, Libor.

[Pavel_K]

Hallo Libor,
there are several entries on NI Discussion Forum about using Web cameras and LabVIEW already.
USB cameras do not have a standard format, so NI has not come out with a USB driver for acquiring the image data. If you can find a driver from the web cam manufacturer that allows you to get access to the 2-D array of pixels, you can convert this to a LV image type and use Vision processing on it.
Another possibility is use of ActiveX Control. Go to http://www.INVENTeering.com there is a free evaluation activex control that interfaces to most webcams. It has LabVIEW examples and IMAQ example also.
Pavel

[rolfk]

Well, there is no standard USB protocol for webcams or lets say each major webcam manufacturer invented its own standard (and they like to change that between model releases too). So forget about talking to a webcam through a manufacturer independant driver. That said each webcam comes with a driver which plugs into Video for Windows (VfW) and mostly also some form of Direct X. For our uses VfW is best suited as it is actually a standard and its API is fairly simple to use although you don't get around C programming. Luckily there have been some smart people who did that work already for you 😉

Check out:
http://www.hytekautomation.com/Products/IVision.html

or

http://www.cs.unc.edu/~parente/labview/index.shtml

The first is a rather impressive Video
Manipulation library with a nice video capture interface to VfW too, and the second is a simple video capture library to access any VfW compliant device.

Rolf K