Does Vision Builder support line scan cameras?

[Leo Chan]

I have Vision Builder version 2.6, and am interested in using a line scan camera on an applications similar to a web inspection app.

Has anyone used line scan cameras with Vision Builder? If so, do I need to upgrade to a newer version of Vision Builder?

Thanks

Leo

[GiGe]

Hi,

Using Line scan cameras with Vision Builder will be fine as long as your driver is compatible with Vision Builder 2.6.  Vision builder 2.6 will work our current drivers. You will probably need to get a camera file for your line scan camera. What camera and driver are you using?  

  Keep me posted.

Have a great day,

GG

[Robert_Eastlund]

Dear Leo,

I have some experience with linescan cameras and Vision Builder AI v2.6 and v3.0.  Both releases can acquire images from linescan cameras.  You can externally trigger the start of each frame, but neither version of VBAI directly supports external synchronization of the camera's line rate with an external trigger signal/encoder.  Possibly with the exception of the firewire linescan cameras, if you need to synchronize the line rate of the camera with an encoder signal, you will need to create a custom LabVIEW step for the image acquisiti

Firewire Linescan Cameras:  With VBAI v2.6, I worked with two firewire A linescan cameras, ISG Chips 1K and 2K CMOS linescan cameras, see http://www.graftek.com/pages/linescan.htm.  Aside from a few caveats, the cameras are relatively easy to work with.  These cameras build a 2D image in their onboard memory and transfer the complete image to the host PC.  The size of the image is predefined by the user.  The image can be one or thousands of lines in size (height).  There are two issues.  First, in the free running mode, the line rate of the camera and its exposure time are slaved together.  Next, there have been issues with the external synchronization of the line rate with VBAI v2.6 and v3.0.  However, the v3.01 of VBAI is shipping, so the issue of the external synchronization of the line rate most likely has been resolved.  If the external synchronization issue has been resolved, then the ISG cameras will allow for both triggering the start of each frame and external synchronization of the line rate of the camera.

Additional notes: The 1K CMOS linescan camera has 7.8 x 125 micron pixel.  This oblong pixel provides great sensitivity, but it also makes it difficult to acquire a geometrically correct image.  Also, ISG recently released a new 2K CCD linescan camera.  Both the 2K CMOS and 2K CCD cameras have square pixels.  I have made a brief test of their 2K CCD with VBAI v3.0 and it seems to work well enough.

Camera Link Linescan cameras:  I have not tested a Camera Link linescan camera with VBAI v2.6.  I have tested a Dalsa Spyder2 2K linescan camera with VBAI v3.0 and an NI PCI-1426 framegrabber, see http://www.graftek.com/pages/linescan.htm.  These tests lead me to believe that all of the available Camera Link linescan cameras will work with VBAI v3.0 or later.  Again, neither v3.0 or v3.01 directly supports the external synchronization of the camera’s line rate.

If you are going to use a Camera Link linescan camera with VBAI, there are three modes available for acquiring the image: triggered acquisition, grab and multiple camera acquisition.

Triggered acquisition-  For most users, the best choice will be to use the trigged acquisition mode.  Here, triggered acquisition means that the frame grabber will begin building an image each time it receives an external trigger signal.  Once the trigger is sent, the time it takes to receive the image for processing is determined by predefined line rate and height of the image.

Grab-  In the standard grab mode, the frame grabber will be continuously building an image, so every time you return to the image acquisition step, you will receive the next available image from the frame grabber.  Depending on the length of your image processing sequence, the line rate and height of the image, several images may have been built and discarded by the frame grabber before you have returned to the image acquisition step.  If your image processing steps take less time to complete than the formation of the next image, then this may not be a problem...

Multiple camera acquisition- In the multiple camera acquisition mode, image acquisition will begin after a delay of some length...

If you are in the grab mode or the multiple camera acquisition mode, and if the image you are acquiring takes more than 1000 milliseconds to acquire, then you will need a VBAI patch to successfully acquire the image.  This patch is only available for VBAI v3.0 or later.  I strongly recommend upgrading to VBAI v.3.0.  If you would like to discuss in greater depth or need the VBAI patch, I can be reached at 512-416-1099 or eastlund@graftek.com.

Regards,

Robert Eastlund

[Brad]

Although it is true that VBAI does not currently support trigger each line in the IMAQ acquisition step, you could get around this if you are using one of the newer IMAQ boards that support using an external trigger directly routed to the control lines.  The 1426, 1427, 1429, and 1430 all support this feature and you just have to go to MAX and configure the control line the camera is expecting the trigger to come from to an External Trigger Line (or RTSI) and then supply the encoder signal or whatever external trigger signal you want to be the trigger each line signal to that line on the frame grabber.  You also need to make sure the camera file is set to a mode that supports trigger each line.

Hope this helps,

Brad