Possible sync problem with PCI-1409

[hspec]

We are using a PCI-1409 to acquire images from a product we produce that outputs a RS-170 composite signal. I am using Labview to build the test application. The problem we see is that a single black line is always present at the bottom of the 640X480 image. We have also observed the black line shifted 3 pixels up from the bottom (when this happens there is also some distortion apparent in the image - as if the line order is not right).  We also see the black bar at the bottom of the image when using Vision Assistant. We don't see these problems on a standard monitor.

Is this a hardware problem or software?

Any help would be greatly appreciated,

Howard Spec

CMC Electronics

Canada

[MarcoPolo5]

Most likely the problem is with the acquistion widow setting in Measurement and Automation Explorer for your 1409.

Try adjusting the top offset - this is the number of lines the 1409 is offsetting from the top of the frame sync signal from the camera - perhaps it is too large and the image is being shifted up and creating a black line at the bottom.

Most standard RS-170 monitors adjust automatically for video signal, the 1409 requires a manual adjustment - which allows greater control over how you want to specifically capture the video.

I hope that helps out.

[hspec]

Marc,

I tried changing the top offset from 21 to 20/22 and this did not get rid of the line. In one case it removed it (but I got a blank line at the top) and the other produced two blank lines at the bottom. I did notice that when I switched to even field first the line shifted up one. I think that this indicates that the even field is missing the last line if data. My only concern is that I have seen (in my application) the missing line shifted up three with the image generally distorted (as if the interlace was mixed up). I did not see this on the monitor. I want to be absolutly sure that there is a problem with our camera (and not the acquisition hardware/software) before I raise this issue with the engineering department. Can you think of anything that might cause this field/line mix-up?

I could send you some images if it would help.

Thanks for your help,

Howard

[MichaelChaney]

Hi Howard,

If the black line shifts up one when you change the field order and moves when you change the top offset, then it appears that the even field could be missing the last line of data.  Changing the top offset is simpling moving the image up and down exposing the blanking interval.  I can't think of anything else related to the 1409 or the driver that could be causing this.  One way to verify the correct operation of you 1409 would be to connect a composite test signal generator and see if you still get the black line.