- The "AFI" clip

About this Tutorial

A new feature in mokey v3 is the ability to import cleanplates. This is useful in cases where the background behind an object you want to remove is not revealed anywhere in the shot and hence mokey's remove algorithm can not remove the foreground object completely just by looking at the other frames in the shot.

For such cases you would paint one or more cleanplates in your favourite paint program, import these into mokey and then let mokey deal with painting out the object(s) in the other frames in the shot. So if you have a 500 frame shot you might have to paint 5-6 cleanplates - instead of all 500 frames!

In this example shot the goal is to remove the hair from the left hand side of each image. We have already painted a single cleanplate and will import this into the project such that mokey can use it to remove the hair in the other frames.

Loading

Specify that you want to load the AFI clip in the New Project Wizard and mask out the black borders of the frames using the following Mask settings: Top 75, Left 5, Right 5, Bottom 68.

Selections

In the first frame, create a background selection around the hair, and then create a selection for the hair itself. Note that the order of the selections is important - you tell mokey in what order the objects appear in the real world. The order can be changed by dragging the name of a selection, displayed in the corner of the rendering area, up or down.

Image 16 Selections in frame 1

Try to look at the garbage matte of the selections to see what effect this has - essentially, if 'layer 1' is in front of 'layer 2' it will subtract from the garbage matte of 'layer 2'.

Tracking and Removal

There is no motion in the clip, so set both selections to Doesn't Move in the Max Motion group in the tracker parameters. Track the selections through the clip. Switch to Remove.

Make sure Use Cleanplates is ticked and import the cleanplate by clicking on the Cleanplates… button. In the dialog that pops up, click on the 'open folder' button and select CLEAN_FC_MOKEY.0001.tga. Note that you can select multiple cleanplates by selecting multiple files. After having selected the file, you need to specify which frame in the clip the cleanplate corresponds to. In this case the default is correct, frame 1.

Select and remove the hair selection throughout the clip. This will copy pixels from the cleanplate into each frame.

Image 17 - Frame 1 with the hair removed

This is a simple example. If there is motion in the background, you can still use a single clean plate so long as the background can be tracked by mokey. If you want mokey to use the cleanplate(s) exclusively for object removal, you can specify Cleanplates instead of All in the Reference Frames switch.

For a clip with several hundred frames and motion in the background we recommend that you paint a number of cleanplates, evenly spaced throughout the clip. If you e.g. have a 200 frame shot, paint a cleanplate for frame 20, 70, 120 and 170.