Transform node deals with translation, rotation and scale as well as tracking, warping and motion blur. Sometimes you want to animate these values just by using one transform node, but sometimes it’s better to use rotation or scale node separately to understand the process better.

2D tracker

Tracker node: container of pixel in x and y
– Allows you to extract animation data from the position, rotation, and size of an image.
– Using expressions, you can apply the data directly to transform and match-move another element.
– To stabilize the image you can invert the values of the data and apply them to the original element
– We can also make several tracking nodes from the main Tracker node to automatically make the scene stable, match the movement, and either reduce or add shakiness.

General process for tracking an image:

1. Connect a Tracker node to the image you want to track.
2. Use auto-tracking for simple tracks or place tracking anchors on features at keyframes in the image.
3. Calculate the tracking data.
4. Choose the tracking operation you want to perform: stabilize, match-move, etc.

– 2D track: x & y
– 2.5: still x & y but in 4 points to mimic a sense of perspective. Use planartracker for this.
– 3D: XYZ

– inner tracking square: track the main shape/point
– outer tracking square: find movement around the inner square to track it

Sometimes we should treat the original plate to obtain better tracks, if the scene is too noisy or grainy. In this case, we use a ‘Denoise’ node to make the noise or grain less, helping the tracker read the changes between frames better. We can also use tools like ‘Laplacian’, ‘Median’, or ‘Grade Contrast’ to fix the grain issue.

1. Denoise plate (denoise node – median node).
2. Increase contrast with grade node.
3. Lapalachian node can help in certain case to lock better tracks.
   

It’s always important to use a Quality Control (QC) backdrop to make sure the tracking and any added rotoscoping is done right.

I attempted to do this assignment twice, as the first time I was really confused of the process and messed up the nodes. Doing it the second time made me realize that I first need to track the 4 points on the phone to create a Transform_stabilize node. This comes before the first Merge operation, following with a Transform_matchmove from the same tracking. Doing this ensures that the phone mockup is merged correctly with the tracked points.

I was not satisfied with the roto of the fingers at first because of the green spill. In this particular node setup as well haven’t touched on green spill operation, yet I managed to compensate for it by using Filter_Erode node with a slight blur to the edges to make the roto not too obvious.

I also used Erode node for the phone mockup as it doesn’t fully cover the green screen at the top of the phone, no matter how accurately I tried to adjust the CornerPin2D.

Homework feedback:
– My final work is good but personally I was not satisfied with the roto of the finger as it is still woobly, I want to learn how to roto better in the future.
– I learned that I could have used Curve Editor to smooth out my animation by using curve editor to control animation from linear to flow
– x → f → press h on in & out points (for easy in & out)
– y → f → press h on in & out points to smooth animation or move curve