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Point of Interest (POI). The point of interest is the fixed point that is being stabilized. If you are pegging a shot, the point of interest is the one point on the image that never moves.
POI Deltas (Adjust tab). These values allow you to intentionally move the POI around, either to help reduce the amount of zoom required, or to achieve a particular framing effect. If you create a rotation, the image rotates around the POI.
Stabilization Track. This is roughly the path the POI took—it is a direction in 3- D space, described by pan/tilt/roll angles—basically where the camera (POI) was looking (except that the POI isn’t necessarily at the center of the image).
Reference Track. This is the path in 3-D we want the POI to take. If the shot is pegged, then this track is just a single set of values, repeated for the duration of the shot.
Separate Field of View Track. The image preprocessor system has its own field of view track. The image prep’s FOV will be larger than main FOV, because the image prep system sees the entire input image, while the main tracking and solving works only on the smaller stabilized sub-window output by image prep. Note that an image prep FOV is needed only for stabilization, not for pixel-level adjustments, downsampling, etc. The Get Solver FOV button transfers the main FOV track to the stabilizer.
Separate Distortion Track. Similarly there is a separate lens distortion track. The image prep’s distortion can be animated, while the main distortion can not. The image prep distortion or the main distortion should always be zero, they should never
both be nonzero simultaneously. The Get Solver Distort button transfers the main distortion value (from solving or the Lens-panel alignment lines) to the stabilizer, and begs you to let it clear the main distortion value afterwards.
Stabilization Zoom. The output window can only be a portion of the size of the input image. The more jiggle, the smaller the output portion must be, to be sure that it does not run off the edge of the input (see the Padded mode of the image prep window to see this in action). The zoom factor reflects the ratio of the input and output sizes, and also what is happening to the size of a pixel. At a zoom ratio of 1, the input and output windows and pixels are the same size. At a zoom ratio of 2, the output is half the size of the input, and each incoming pixel has to be stretched to become two pixels in the output, which will look fairly blurry. Accordingly, you want to keep the zoom value down in the 1.1-1.3 region. After an Auto-scale, you can see the required zoom on the Adjust panel.
Re-sampling. There’s nothing that says we have to produce the same size image going out as coming in. The Output tab lets you create a different output format, though you will have to consider what effect it has on image quality. Re-sampling 3K down to HD sounds good; but re-sampling DV up to HD will come out blurry because the original picture detail is not there.
Interpolation Filter. SynthEyes has to create new pixels “in-between” the existing ones. It can do so with different kinds of filtering to prevent aliasing, ranging from the default Bi-Linear, 2-Mitchell, to the most complex 3-Lanczos. The bi-linear filter is fastest but produces the softest image. The Lanczos filters take longer, but are sharper—although this can be drawback if the image is noisy.
Tracker Paths. One or more trackers are combined to form the stabilization track. The tracker’s 2-D paths follow the original footage. After stabilization, they will not match the new stabilized footage. There is a button, Apply to Trkers, that adjusts the tracker paths to match the new footage, but again, they then match that particular footage and they must be restored to match the original footage (with Remove f/Trkers) before making any later changes to the stabilization. If you mess up, you either have to return to an earlier saved file, or re-track.
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