Analog camera field acquisition.

[AndyN]

I am trying to pull maximum performance out of my analog camera. I have a 1405 frame grabber and the camera is RS 170 monochrome NTSC. Real-Time LV 2009 SP1. Unfortunately I have to use it for motion tracking and there is no way at this point to upgrade the hardware. I want to have the image  with minimum blur and as fast as I can get.

Before I can to the questions, a small intro. RS 170 transfers at every 1/60s the odd field (odd lines) and then after next 1/60s the even field. Then the framegrabber combines both to make it a full image frame providing 30fps and so on. When motion happens, due to different acquisition times, the odd and even fields are being acquired and different times and the picture looks blurry ( the combing effect). Someone correct me please if  any of that is wrong.

Now, why not look at the even and off fields and have a 60fps at 640x240? I am almost sure that my framegrabber wont allow me grab the field as soon as they come separately. Is that true?

So what about just looking at one field? Even or odd? I do not know how the framegrabber is serving it to me. Lets say I set the mode to only odd fields. Do I get the odd field immediately after it arrives to the frame grabber or after it gets both odd and even and then it gives me the odd field? In this case I would get the field with the 1/60s delay, which is bad for me. The start field is the odd field .

[ChristopheC]

You can use IMAQ Interlace, located in the Image Manipulation palette, to extract the odd and even field from the image returned by the camera.

[GuenterMueller]

I haven't been working with analog cameras for a while, so I am not fluent in how to do it. But I have been doing field acquisitions and I got each field immediately as it came in. Making a frame of two fields is just a service that the frame grabber can do for you.  I do not know if you can set a 1405 to a field acquisition mode that transfers exclusively even/odd fields.

[AndyN]

Guenter,

My 1405 can do either odd fields or even fields but it seems it cannot do both, which does not make much sense to me. I do not want it to make a frame.
If it can I do not know how to do it.  

There is no benefit for me in splitting the frame as it  gives me 30 Hz and I can as well ditch the least recent field.

In perfect world I would like to access both fields ( even, odd, even, odd, even odd....) as soon as they come to the framegrabber, not when the are combined together..

[toto26]

Hello,

I don't think the hardware allows you to have odd and even frames alternatively @60Hz. But If you dou it with programatically by deinterlacing your frames, you will get the same, and will be able to recreate a 60Hz video.

Anyway, the amount od data is exactly the same, either you have 320*480*60=8.78MB/s, either you have 640*480*30=8.78MB/s

so it doesn't change nothing as your hardware is unable to go faster.

Regards

[BruceAmmons · Accepted solution]

I looked at an old program that uses analog video.  I am pretty sure the 1405 was supported by it, but not positive.  The only thing I had to do to change to 60 Hz field mode was change the property "Interlace Mode" to Field.

I understand your pain.  Good luck.

Bruce

[AndyN]

I know I can recreate the video but I do motion servoing as well and  between the odd and even fields I would like to comand the servo.  By servoing the camera I efectively change what happens in the next field/frame and that is the whole point.

[AndyN]

Can you put some more light on iit Bruce?

I did change that option but there is another option that tells which field and the choices are: odd, even , all; and it says only 12XX suppports all...

[BruceAmmons]

I guess whatever hardware I was using supported "all".  If it says your hardware won't do it, there isn't much you can do.  I was probably using a 1411 or 1409, and they must have supported "all".  I don't understand the 12XX reference.  I would try "all" anyway and see what happens, but I am guessing you already did that.

I did my changes programatically in LabVIEW, so I didn't have anything for the sub-options.

Bruce

[kellam]

If you go into MAX, under Acquisition Parameters for the channel, I believe if you change "Mode" to "Field" and "Acquire Field" to "Alternate", you should get what you want.