Logo removal using Mocha AE and After Effects
The other day, I was asked to remove some logos that were attached to the side of a piece of machinery that I shot for a recent film. This was a bit irksome as they were very prominent in the shot and the shot was a pan and tilt shot. Some of the logos started in shot and moved out of shot. Others started out of shot and moved in shot. Argh!
Not easy to remove. If the shot had been largely stationary, then it wouldn’t be a problem.
I turned to After Effects and particularly to the bundled Mocha AE tracking software. It really is quite a remarkable piece of kit and got me out of this particular problem pretty easily – once I’d figured out a solution.
I’d seen the blurring of detail before with a corner pinning effect. Essentially, an area of the image is isolated and blurred to disguise the details.
This is what I had to start with.
Step 1 – Tracks the position of the logos
The first step is to track the logos on and off the screen using the Mocha planar tracking tools. This is a fairly straightforward affair but sometimes the targets wander off and you need to correct them back into place. For the logos that appear on screen later in the clip, you can track these backwards. The logos that wander off screen are OK to track forwards.
Step 2 – Transfer the position data into an After Effects composition
This data is then copied onto the clipboard and pasted into your After Effects composition. I extracted the Corner Pin data.
Step 4 – Create a blurred copy of the footage
Essentially, the trick is to blur a copy of the master shot and cut out a portion to cover the existing logos.
Step 5 – use the corner pin date extracted from Mocha
Using the data extracted from Mocha you can isolate when the logo is moving across the frame and blur away the logo. I used the Corner Pin data from Mocha, on a black solid. This was then used as a track matte to form a cutout of the blurred footage layer. If you simply paste the clipboard data on a solid, the corner pin effect is automatically applied along with all the coordinates. I then transferred the data into the Power Pin effect to make use of the extending edge facilities of the plugin.
Step 6 – Tweak the blurred layer to make it unobtrusive
Next, blur the logo some more and desaturate it to create a bland and unobtrusive ‘panel’ to cover the moving logos. My strategy was to make the area with the logo in it, look like some sort of frosted window panel on the machine.
Step 7 – Tidy up the edges
I then went back to Mocha and isolated the frame around the blurred section to help tidy up the region.
This was then put back into after effects to tidy up the edges.
