Manual interlacing problem

[Shimonek]

I have a custom camera that is interlaced, but does not use a field ID. It uses a control line connected to external trigger #2 of my PCI-1424 card to differentiate its fields (Hi Odd, Low Even). I’ve attempted to use an “IMAQ Trigger Read” and capture two separate video streams then put them into an array and manually interlace them without any luck. Is there an easier way?

Thanx,
Shimonek

[RManion]

Hi Shimonek,

Depending on how your camera is set up, it may be possible for you to interlace the frames by just making changes to your camera file. However, this would require you to have two taps for your camera. Each tap would send data for one field (odd / even). If your camera only sends one tap, and the frames are sent one after another, the 'trigger/manual interlace' method you are working on may be your best bet. Are you attempting to record a single picture or video? If it is in fact possible to manually interlace the frames, I do not believe that the frame rate will be very good. Because of all the additional processing, it will be much slower, possibly 5-10 fps at best.

More information regarding the format that the camera transfers pixels could help here. However, it is possible that you will need to try your proposed software solution due to this unique camera.

Hope this helps,

Robert

[Shimonek]

Thank you for your response.

I am trying to capture video. 5 – 10 fps would be wonderful, as of now I’m getting 0.25 fps. I am filling a single buffer with both fields (1 complete frame) then sending the image to an array then manually interlacing. I wanted to use the external trigger (Enable C), but it doesn’t work and none of the tech support people at NI appear to know how to set up the camera file correctly to make this data line available. As of now I don’t think this external line will buy me anything anyway, my problem is the lack of speed in data manipulation.

Thanx
Shimonek

[RManion]

Hi Shimonek,

It sounds as though I was overly optimistic in my estimation of 5-10 fps. Based on your computer hardware it is possible that .25 may be the best you can do. Manually interlacing the image is a computationally intensive process and will certainly slow down the frames per second. Because your digital camera has only one tap, I do not believe it will be possible to modify a camera file such that it will automatically interlace the images. You might want to try creating a custom camera file. Within the attributes sections, set interlaced to be true. If it is possible to automatically interlace the images, it will be by modifying or creating your own camera file.


Robert

[RManion]

After a little bit more thought, I think you should be able to use a camera file that sets the acquisition up for a digital camera with interlaced frames. Give it a try... the camera file generator could be helpful. It is a free download available at:

http://sine.ni.com/apps/we/nioc.vp?cid=14207〈=US

There is a link to the ftp site towards the middle of that page.

Worst case scenario, at least you can use the IMAQ interlace images VI to do the interlacing for you. (rather than interlacing arrays by hand)

Robert