Help with shot flipping and sign replacement technique

[macool]

I was given a shot of an empty desert road where the camera pans from right to left over to an old gas station+motel. I need to flip the shot and then replace the two Motel signs so they read correctly (un- flipped and tracked exactly).

The flipping is basic….. its the sign replacement that I am having difficulty with a correct technique. Can anyone give me some advisse as to handle this shot cleanly and accurately? Thanks again!

[Saran Sirikasamsap]

are the signs flat ? like billboards ? is the shot online-n-downloadable somewhere ?

[Tobin]

i had to do a similar shot quite a while ago.
we flipped the shot of a car (also a pan) where we had to replace the licence plate.

i asked one of our grafik designers to rebuild the licence plate in photoshop (in an higher resolution then the screenshot which quality was poor and would have suffered from undistortion anyway).

i then tracked the new plate over the old one with a classic cornerpin (combustion). fairly easy stuff if you have the signs made ready…

hope this helps

timor

– omgraphix –

[Aaron]

Here is a link to a still of my frames, again the shotis flipped and sign needs to read correctly as well as track correctly. Thanks!

http://www.imagemozilla.com/viewer.php?id=467770motelsign.jpg

[raj kumar]

depending on the jerkiness of your camera move this should be pretty straight forward, and like anything there’s a few ways of going about it.

what i’d do is pick up a still of your end frame. take it into photoshop and paint out those two signs. once you’re happy with the clean plate, pull the signs off the original plate and put them over your clean plate. so now your end frame should look as you want it. take it into your machine (what were u using?)

do a close feathered mask around the area around the signs onto your shot, starting at the last frame. Then back-track your signs into your shot, addding a bit of grain to combat the fact you’ve used a still.

To be honest you might want to try tracking the signs in seperately, so that any slight mis-matches in movements aren’t mimicking eachother.

hope that helps.

[Tobin]

i second what muiisal wrote,

you might also want to try 3d tracking the shot and replacing the signs in a 3d environment (fusion 5 is perfect for stuff like this) especially the sign where you can lock through.
of course you need to remove the signs first a 3d track can be handy for that as well.
it´s good to know what focal length was used and what kind of camera (chip size). your shot looks very distorted, make sure you undistort the footage before 3d tracking…

hope this helps.

timor

[Anonymous]

That looks like fun!

If you’re looking for a 2D sollution I would first “undistort” the image. That lense distortion lokks like a doozie. Then (once for each sign) you could stabilize the image such that the sign sits in center of frame. Then, in theory, you could handle the sign replacement with a four corner displacement. And then undo your stabilization to return the original motion.

By stabilizing the image around the corner of the sign you won’t have to match any camera motion just the shape change of the signs as the camera moves.

Good luck, post your finals when your done.

CE Raum

[Author]

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