Lens Tracking (TCD + ST-Map) [Advanced]

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This page details the options for setting up tracking through the TCD protocol. Currently the only tracking system that can output TCD is EZtrack

1. Tracking Protocol

This dock is accessible from the Capture step.

Possible values:

• FreeD (d1)
• TCD <

2. Distortion Source

TCD carries calibrated lens data alongside the positional tracking. Focal length and sensor size are always taken from TCD directly, but there are two options to correct the lens distortion:

Possible values:

• Tracking
• ST-Map <

In "ST-Map" mode, the distortion coefficients for TCD are ignored. Instead, a special image called an ST-Map is used.

2.1. ST-Map Format

A St-Map encodes a mapping of (x,y) pixel coordinates, to describe a displacement.

Usually these are encoded in the red and green channels of the image:

For EZlineup however, we use a different format, in which the RG channels encode the distortion mapping, and the BA channels encode the undistortion mapping.

• the distortion map takes a straight image and applies the distortion to it
• the undistortion map takes a distorted image and straightens it

This encoding looks something like this (without the alpha channel):

The origin of the image is in the top left.

2.2. Load the ST-Map

Press the button on the right, indicated by a folder icon, to browse and pick a lens profile:

If the file was successfully loaded, its name will be displayed at the left of the button:

Note that a ST-Map only covers one specific Zoom/Focus position, you must do the entire line-up calibration at that FIZ setting for the ST-Map to be valid throughout.

3. Tracking Receiver

Warning

This assumes a tracking system has been configured on the camera to calibrate, and it currently sends FreeD data to the computer running EZlineup on a specific port.

3.1. IP

IP address of this computer. In most cases leave 0.0.0.0 (0.0.0.0 means "any IPv4 address at all"). If you want to make sure to only listen to the data on a specific network adapter, you can choose its IP instead from the list.

The IP list can be refreshed by clicking the refresh button, indicated by two arrows following each other.

3.2. Port

Port on which to receive TCD messages. This is the port that should be given along with the true IP address of the computer running EZlineup (not 0.0.0.0) to the tracking apparatus.

3.3. Camera ID

There is a Camera ID in TCD to identify multiple cameras sent on the same port. By default this is not filtered by EZlineup.

To activate Camera ID filtering, check the "Filter ID" box. You can then put the desired ID in the field on the left.

3.4. Start/Stop

Once IP, Port and filters have been configured, use this button to toggle the TCD receiver. The fact that the button is green only indicates that the receiver is running, not that it is actually receiving messages. To check this, you can look at the tracking values on the right, which should move if you move the camera.

In addition to that, there is a Frequency indicator under the button. It gives an estimate of the frequency at which messafges are received. If no messages are received the frequency will be zero.

While receiving, the tracking UI will become greyed out. To unlock it, press "Stop Receiving".