Overlay settings

The Overlay settings dialog can be displayed by opening the pop-up menu on a dialog with an overlay and selecting the Overlay menu and the Modify... menu item.

  • Popup Menu: Overlay->Modify...
  • In MPR mode: Overlay->Modify...

The Overlay Settings dialog

Active Overlay

select from the dropdown menu the specific overlay to be modified in the case of multiple overlays.

Palette

select the appropriate palette from the dropdown menu for the overlay selected in Active overlay. The different overlays may have different palettes.

Overlay description

a text string identifying the active overlay. By default, the descriptor is set equal to the SPM file descriptor, but this may be changed by the user after loading.

Opacity

The slide bar varies the degree of opacity (=1-transparency) of the overlay. 100 % opacity means maximum opacity (no transparancy). The opacity is varied only for the overlay specified in Active Overlay, and multiple overlays may have different degrees of opacity. The opacity may be varied in real time, allowing viewing with changing levels of opacity.

Window / pixel range

Sets the maximum / minimum window and pixel values which are rendered to screen. This is like the window level /width function for the image underlay, but instead of setting level/width values the max and min window values are set directly. For some image types (SPM images), the actual pixel values may include a scaling factor (e.g. to scale the resulting pixel range between 0.0 and 1.0), and for such images the pixel range displays the actual pixel range corresponding to the set window range. The pixel range can also be edited, and the window range will then be updated correspondingly. If the window->pixel scaling factor is 1.0 (which is the case for all non-Nifti images) the window and pixel ranges will be the same.

Hide Colorbar

The palette colorbar normally appears on the left of the image to aid interpretation during image examination. Check this box to hide the colorbar. This also hides the colorbar when the image with overlay is copied to the clipboard.

Hide Overlay

When checked, the overlay specified in Active overlay is temporarily hidden.

Invert palette

When checked, the overlay specified in Active overlay is inverted, e.g. the intensity scale is inverted so that the lowers image intensities are assigned to the highest palette values.

Flip overlay:

Enables the active overlay to be flipped up/down or left/right. NOTE: the geometry header is not modified when this operation is performed.

 

Delete overlay(s): 

Clicking the Delete overlay(s) button deletes all loaded overlays.

Close

Click Close to close the dialog and retain the selected settings

Related topics:

Modify image overlays