Stuck Pixel on Canon 5DII

RalphM wrote on 5/19/2012, 2:36 PM

My daughter shot about 30 minutes of video only to find there is a stuck pixel on her camera sensor. It shows up as white.

Any thoughts on how to salvage this video?

Thanks,
Ralph

Comments

Tech Diver wrote on 5/19/2012, 3:04 PM

If you have a plugin like Boris Red you can use the clone filter that lets you copy any part of the image to another. In this case you may want to copy one of the four nearest-neighbor pixels. If you do not have that tool, you can duplicate the clip to a track that is above, create a mask that elimates everything but one pixel and then shift it over the dead pixel. Another approach is first apply a blur on the duplicate clip to get an average of the surrounding pixels and then create a mask as previously described. Note that since the dead pixel is white, you would have to slightly darken the blured image to compensate. Mathematically, the white pixel acts as a bias value to the average. Lastly, you could use the Vegas convolution filter, where you could convolve the following 3x3 kernel matrix to get a pixel that is the average its nearest neighbors. Again, this would be done on the duplicate track...

For the 4-nearest-neighbors, your normalized matrix would be:
0.0 .25 0.0
.25. 0.0 .25
0.0 .25 0.0

For the 8-nearest-neighbors, your normalized matrix would be:
.125 .125 .125
.125 0.0 .125
.125 .125 .125

If you auto normalize, just use a value of "1" instead of the .25 and .125 elements.

Hope this helps,
Peter

RalphM wrote on 5/19/2012, 6:53 PM

Thank you Peter. Don't have Boris, so we'll try one of the otherapproaches.

Ralph

amendegw wrote on 5/19/2012, 7:02 PM

See if this thread helps: http://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=765637Removing sensor dust on video[/link]

...Jerry

rs170a wrote on 5/19/2012, 7:29 PM

Ralph, see if the following tool (grabbed it from a Vegas forum some time ago) is of any help.
http://dl.dropbox.com/u/20488019/StuckVideoPixelRemover.zip

Mike

Tech Diver wrote on 5/19/2012, 7:54 PM

One of the advantages of the convolution filter is that you can control EXACTLY how the replacement pixel value is calculated. Notice how both of the matrices in my previous post have a center value of zero. That means that when calculating the value of the replacement pixel, the contribution of the bad pixel is zero. The value that is calculated is the average of the 4 or 8 nearest neighbors, which is known as bilinear interpolation. On my research cruises with Woods Hole Oceanographic Institution, we sometimes get pixel drop-outs in our image feeds from our submersibles and I apply the afore-mentioned algorithm in my image processing code to correct it.

I am actually quite surprised that a convolution filter is included in Vegas. If you are familiar with the process of convolving kernels, you can do neat things like first and second order partial derivatives, plus all sorts of custom smoothing.

Peter

RalphM wrote on 5/20/2012, 3:49 PM

Lots of good stuff here...

Many thanks to all,

Ralphy

chrismosner wrote on 2/15/2015, 10:25 AM

Hello Peter. I am hoping for a bit more detail on using the Convolution Filter to resolve a stuck pixel. Specifically, am I to create a mask that is but 1 pixel in area, as in your previous method, or a larger mask?

I currently have masked (positive) a small area in the duplicate track above the stuck pixel track. However, I still see a glowing pixel. How does the convo filter "know" that the pixel at the center of the matrix is the stuck pixel?

Thank you.

johnmeyer wrote on 2/15/2015, 11:45 AM

I created a YouTube tutorial several years ago that demonstrates how to remove a stuck pixel from a video. It works very, very well, and should give you a near-perfect result. It uses free software:

gjesion wrote on 2/15/2015, 4:55 PM

Try this: Open the event pan and crop window and create a mask around the bad pixel. Change apply to Fx to yes. Now add the median Fx and adjust until satisfied. I have used this technique many times and have found that it works quite well.

The only derog is that the median filter is slow.

Regards,
Jerry