I´m trying to use a Genius VideoCam Express (or some other one) in an industial application (fruit selection), that´s why I was wondering if anyone can help me.

Is there anyway to access the data that camera provides? I mean, to access the different levels of gray of each pixel?

I hope you understand my english.

Thanks in advance.

 

I have used quite a few cameras in industrial applications. I don't really understand your question. The data coming from the camera _is_ the various levels of gray with a monochrome camera and three sets of such data for most color cameras. This is, of course after capture
with a frame grabber card which does the A/D conversion. Perhaps that's the missing link?

Regards

cww

 

The camera mentioned is a USB webcam. It does not interface with a framegrabber board, but rather hooks directly to the USB port. It normally is used by packaged internet applications. But it would be nice if it could also be used by custom industrial application programs, because it is such a cheap solution. I don't know how to do that either, but I sure would like to hear from anyone who does know how to do that.

Robert Scott
Real-Time Specialties

 

I haven't done what you're trying to do, but if you're using Linux, I can point you in the right direction.

The Linux webcam HOWTO can be found here:

http://hshanemd.net/docs/HOWTOS/Webcam/devices.html

and the Linux USB driver for Omnivision-based webcams (of which the Genius is one) is here:

http://alpha.dyndns.org/ov511/

Best of luck,

Greg Goodman

 

That is unfortunate. Not because they don't work, but because there is very likely no standardization in the protocol they use and they are proprietary. Without cooperation from the manufacturer, it would be pretty difficult to use it with anything but the original software. It's not beyond hope that some enterprising soul has written an open source interface that could be made to do your bidding. It's worth a google search for "Linux (name of camera)" Still, perhaps the closed software can be persuaded to output jpgs or some other known format to a known location and then proceed as normal. Creating a named pipe with the default filename will get the data into your program. Since these are webcams, they probably send complete frames rather than mpeg streams or the like. It doesn't really matter how you get an image as long as you can freeze it and work on it. Bitmaps are easy to work with and jpgs can be converted to PGM or PNM formats with readily available free tools that run as filters. I've used them on Linux and they had makefiles for other systems. Google "netpbm" for lots of conversion tools for various formats. Once in a simple RGB or monochrome format the software to do manipulation is fairly straightforward. The biggest problem is that compressed formats are a pita to work with and conversions take time. It's quite practical to pipe this stuff together once you find a way to feed the pipe.

Still, with a high res NTSC or PAL monochrome camera at $150 and a frame grabber at $40 and the free Video4Linux stuff, I don't know how much effort it would be worth to use the proprietary stuff. But if you want to bad enough, there's almost always a way. I actually enjoy coding the machine vision stuff. Too bad I don't have any paying customers at the moment.

Regards

cww

 

Cool!

This is great because many of these webcams sell for very little. And they're useful for quite a few applications where precise measurements aren't needed. (the lenses tend to be of the "fisheye" variety) And think of the "secrets" you can learn by looking at the code. Should be a USB primer as well as a video example. I may have to find a couple surplus eyeballs for my toybox

Ya know, I used to be able to keep up with most of the Linux development in the areas I'm most concerned with, but those days are long gone. And that's a good "problem" to have. It's absolutely amazing how much ground is covered now compared to just a year or two ago. And the pace is accellerating. In this case, I'm very happy to stand corrected when I thought there wasn't an easy Linux solution.

Regards

cww

 

One of the nice things about Open Source: not too many secrets.

The Linux USB sub-system
http://www.linux-usb.org/USB-guide/book1.html

Programming Guide for Linux USB Device Drivers
http://wwwbode.cs.tum.edu/Par/arch/usb/usbdoc/

 

I just found 'VideoOCX' for a similar situation. Just search, it is all over the web. Good luck.