Acquiring images with usb camera

[n00bzor]

Hey, i'm obviously trying to acquire images with a usb camera. Using LV8.5. Vision 8.5 and the usb drivers installed. My program is supposed to take pictures continously with the camera and dump testX.jpg in a folder, where X is the number of the picture taken.

Problem is it only works for 1 in 100 or 200 or 300 pictures (i can't seem to get a pattern, it's a random thing).  I only get one valid image, the rest are black. I think it has to do with synchronising the camera with the vi. Any ideas? Thanks in advance.

[n00bzor]

Fixed : i was using snap instead of grab. 

[menghuihantang]

QUOTE (n00bzor @ Mar 20 2009, 06:07 AM)

Hey, i'm obviously trying to acquire images with a usb camera. Using LV8.5. Vision 8.5 and the usb drivers installed. My program is supposed to take pictures continously with the camera and dump testX.jpg in a folder, where X is the number of the picture taken.

Problem is it only works for 1 in 100 or 200 or 300 pictures (i can't seem to get a pattern, it's a random thing). I only get one valid image, the rest are black. I think it has to do with synchronising the camera with the vi. Any ideas? Thanks in advance.

I have the same problem too. I use the Microsoft LifeCam. But not as bad as 1 in 100, it returns a black image maybe once every 200 so. I don't know if it is a synchronising problem, but it is definitely related to the webcam settings. It seemed to me that every time the webcam snaps an image, it auto-adjusts itself for the environmental light and very likely it returns an error at this point. So I turned off its auto-white-balance and reset up other parameters like saturation, contrast. This helps a lot, but I don't know if it can help you.

Just in any case the webcam still returns a black image, I put a while loop around image snap routine which only stops after an non-black image is captured.

[deep]

QUOTE (n00bzor @ Mar 20 2009, 04:37 PM)

Hey, i'm obviously trying to acquire images with a usb camera. Using LV8.5. Vision 8.5 and the usb drivers installed. My program is supposed to take pictures continously with the camera and dump testX.jpg in a folder, where X is the number of the picture taken.

Problem is it only works for 1 in 100 or 200 or 300 pictures (i can't seem to get a pattern, it's a random thing). I only get one valid image, the rest are black. I think it has to do with synchronising the camera with the vi. Any ideas? Thanks in advance.

hi can u send me ur code........ i need it very urgently please