How to remove line noise from videos?

wolverine wrote on 9/15/2003, 12:51 PM

I use Canon Ultura DV cam. The problem is that after shooting continuously for 5-10 minutes there will be blue horizontal lines flash across the images, this problem can get very seious in that there may be hundreds of such lines apparing at one time. If I shotdown the machine for 30" then the problem goes away. It will come back after another 5-0 minutes shooting.

After capturing the video to my PC using the Vegas 4 these annoying lines were still there. Therefore the question:

Is there a way to remove these lines and repair the images using Vegas 4? If Vegas 4 can not do it, is there anything else that may help?

Thanks.

Comments

BrianStanding wrote on 9/15/2003, 12:59 PM

Yikes! Sounds like a bad CCD in the camera, or something similar. I hope you can get the camera checked out, or you have another camera that's more reliable.

Repairing the damage may be difficult. How long do the lines last? If only for a frame or two, you may be able to delete the offending frames and use motion blur to interpolate a new frame based on the surrounding ones. If longer than a few frames, you may be out of luck.

Chienworks wrote on 9/15/2003, 1:09 PM

This is a guess and a very long shot, but here goes ... are the lines very thin, maybe only 1 pixel thick? If so, it might be possible that they are only on one field. You could try rendering the affected portions to a new file at half size (360x240 for NTSC) with the quality set for draft. This will skip every other scan line and effectively eliminate one of the fields of each frame. If this eliminates the wrong field then you can set the clip's properties to upper field first to swap fields (i think).

You might get better results rendering to 720x240, but then you'll also have to muck about with aspect ratios.

Anyway, this is just a random thought that may or may not apply to the problem at all.

wolverine wrote on 9/15/2003, 3:30 PM

Yeah the camera may have a bad CCD. The funny thing is that this problem occurred right after one year's ownership, which means right after the warranty expired! Sounds Canon is a master in design their products so they just last the duration as warranty!

Anyhow, the reason I am trying to find a solution is because I have several minutes' recording that had this problem on many of my tapes. This typically occurs when I set the camera up to record without any human intervetion and it runs for more than a few minutes. If possible I would like to salveage those parts.

Being a person who had no clue about video editing, I think it should be relatively easy theritically to have a program for this purpose: that is, first the program needs to identify all blue horizontal lines and remove them, then the software needs to interpolate each picture to fill the lines. I wonder if Photoshop or other picture editing software will have this kind capabilities. Any suggestion?

BrianStanding wrote on 9/15/2003, 3:36 PM

How many seconds / frames of bad footage are we talking about?

JJKizak wrote on 9/15/2003, 4:29 PM

Virtual Dub has a filter for removing vertical old film lines but I don't know
if they will remove horizontal lines.

JJK

wolverine wrote on 9/15/2003, 4:39 PM

Several minutes on each tape on about 7-8 tapes, so the total could be 30 minutes or so clips scattered throught out the 7-8 hours of recording.

craftech wrote on 9/15/2003, 4:54 PM

Depending upon what it is that you shot, can you get by with a photo sequence to replace the bad video footage. Perhaps you can let the audio play (assuming it is OK) while a photo sequence related to the general theme is playing as a substitute.

Secondly, in terms of the camera. Have you tried a head cleaning cassette?

John

wolverine wrote on 9/15/2003, 5:11 PM

John:

If there is no solution then I will just have to cut portions of video that had this problem.

I never thought using cleaning tapes because I thought it could not be the cause, because the machine functions well for a few minutes then the problem will start. I always imagined it is something related to heat, that is, after several minutes, some picture elements (CCD) gets hot and started to malfunction. However, as you probably can see I am not very knowledgable in this field so if dirty recording head could be a problem then I will buy a cleaning tape and clean it.