Introduction

The VL Video Overlay Display is an "Editor" in MITK-speak, meaning that it fills the centre part of the screen, and provides a view of the data in the Data Manager. It is a custom viewer for providing augmented reality displays, merging rendered surface meshes and video data.

Usage

Imagine you have a video capturing device such as a laparoscope, connected via the Data Sources View (see Figure 1).

Figure 1: Physical layout of a tracked (e.g. NDI Polaris) laparoscope, viewing a pelvis phantom.

Then the VL Video Overlay Display can be used to provide augmented reality, merging video data with rendererd data (see Figure 2).

Figure 2: The VL Overlay Display merges laparoscopic video with rendered CT data (left) and displays a VTK 3D world (right).

The controls for the display itself are simple. See Figure 3.

Figure 3: The Controls.

On the left side of the screen are two check-boxes to display either left and/or right video channels.
To the right of the "left image:" checkbox, you see a combo box labelled "please select" allowing the user to select the left hand video image.
To the right of the "right image:" checkbox, you see a combo box labelled "please select" allowing the user to select the right hand video image.
To the right of the "transform:" label, you see a combo box labelled "please select" allowing the user to select a camera transformation.
The 'overlay opacity' controls the blending between video and virtual data.
The '3D viewer' checkbox toggles the 3D (right) window on/off.

Tracking Transformation

The "tracking" combo box enables the user to specify a tracking transformation. This should correspond to the world-to-camera matrix. So, if you are tracking a laparoscope you would normally compose the inverse of the tracker-to-laparoscope transform, followed by the hand-eye(camera) transform to give tracker(world)-to-camera.