At the top of the Stradwin application there is a row of menus then a row of tool buttons. At the bottom, there is a slider which can be used to scroll through the individual frames of a data set.

Below the slider are three message panels. The left hand panel gives transitory information about what some menu items and controls do. The middle panel gives system messages about what Stradwin is doing, for example when initialising a position sensor. The right panel contains the current data file name (.sw), and the path to the folder in which that file is located.

The images are displayed in a central section of the Stradwin application with a user-configurable background colour. The top half of this section is divided in two, with the image window on the left and the 3D window on the right. The image window displays ultrasound or DICOM images, either live directly from the video source, or from recorded data. The images can be zoomed to any level, using an interpolation technique appropriate to the amount of zoom.

The 3D window shows the location of everything in 3D space. Each frame is depicted as a soccer goal-post shape, with the probe face (or top of the image) at the crossbar. The current frame, as selected by the frame slider, is shown in red and the other frames are shown in white.

There are a few key presses which affect the visualisation, particularly in the 3D window:

This disables or enables display of frames in the 3D window, which is sometimes useful when saving screenshots of this window.
In the image window, this toggles the interpolation technqiue and can hence show the underlying data pixels.
This toggles display of centres-of-gravity for surfaces in the 3D window.
This shows the current orientation of the 3D window as a text string which can be copied, pasted and edited. It can hence be used to set the viewpoint to a pre-defined value.

The bottom half of the central image display area can either be divided into two to show two orthogonal reslices, or used as a single large window displaying other information.

There are two further panels in the application called the tasks window and the visualisation window. If your screen is less than 1280 pixels wide, these will both be displayed one above the other down the left side of the application (and in addition Stradwin will use a smaller icon set). For larger screens, the default layout places the task window down the left of the application and the visualisation window down the right. It is possible to change the default layout of these two windows using the GUI menu.

The task window supports the various different tasks that you might wish to perform using Stradwin. This includes things like calibration, recording and drawing segmentation contours. The visualisation window controls the type of image that is displayed in the lower part of the central image display area.

In live mode, the 3D window also provides a wire-frame to indicate the valid volume of the position sensor being used. A small sphere shows the position of the electrical centre of the position sensor. If this sphere is inside the volume, the position sensor should work. When the Polaris is being used, the wire frame changes to amber and then eventually to red, to indicate that the sensor is being moved out of the valid volume.

When live mode is switched off, the 3D window can display segmentation contours, landmarks and surface rendered visualisations in three dimensions. The combination of task page and visualisation page that you have selected determines exactly which things are displayed at any instance.

The relative sizes of each of these windows can be changed at any time by dragging the bars which separate them.