Viewer Control

The Viewer Control palette is a powerful tool for manipulating image appearance in the main window

Getting There

Three different methods exist for reaching the Viewer Control window.

The first method is to use the Viewer Control thumbnail in the Main Window.

The second method is to go to "Slice Control" under the Tools menu.

The third method is to use the keyboard shortcut "F5". For more on keyboard shortcuts in VQ, please see Keyboard Shortcuts.


The Viewer Control window provides a variety of options for manipulating the appearance of open data sets in the main window of the VQ. Options include Sliders (for slice selection), Color Controls and Voxel Values.


Adjustment of the x, y, and z sliders in the Sliders section changes the sagittal , coronal, and transverse slices, respectively, that are displayed in the main window. The slice numbers and crosshairs displayed on the main window also reflect the x, y, and z slider values. Please see the view options for more on the display settings for the main window.

Color Controls

The Color Controls display information about the datasets loaded at the Reference, Input 1 and Input 2 positions.

The checkboxes on the left toggle the visibility of the datasets in the Display. Next to these, the voxel values of each dataset at the current slice are displayed along with their respective units. (Note: if given proper Hounsfield or quantification calibration, the voxel values will be given in Hounsfield units or MBq). On the far right are spinboxes labelled "Intensity", which control the relative transparency of the dataset; decreasing the intensity value increases the transparency of the image.

Viewer Control in Multi-View

Multi View enables users to customize the layout of viewports in the Display. When in Multi View, additional controls become available in the Viewer Control which extend its normal functionality to the Multi View Display. Users may also select whether navigation is linked across viewports, or if viewports may be navigated independently of one another.

For more on setting up the Display in Multi View, see the Multi View page.

The general functionality of the Viewer Control does not change in Multi View. However, in Multi View, information in the Sliders and Color Controls is automatically updated to reflect information from the viewport through which the user is navigating. To update these with information from another viewport, there is a drop down menu in the upper left hand corner where the desired viewport may be selected. Alternatively, simply clicking on or navigating through another viewport in the Display will update the Viewer Control.

By default, the Viewer Control links all viewports in Multi View together. This means any navigation through the slices in one viewport is reflected in all other viewports automatically. Viewports may be unlinked by unchecking the "Link Views" checkbox in the upper right corner of the Viewer Control. Unchecking this box will succesfully unlink the viewports, and allow viewports to be navigated independently of one another.

If at any point you wish to reset all viewports to the same slice again, simply click the button located next to the "Link Views" box.

It is important to note that "Link Views" only affects the slice-by-slice navigation between viewports. Regardless of whether "Link Views" is checked, zooming and panning within each viewport will remain independent.

To reset the zoom and pan in a specific viewport, select the viewport you wish to reset (either by selecting it from the drop down menu or by clicking on the viewport) and click the button in the Viewer Control. This will reset only the viewport selected. To reset all viewports at once, click the button on the toolbar.