In other SNAP modes where the left mouse button is used for other tasks, you can still move the crosshairs by using the middle mouse button, or by holding the Alt key on the keyboard and using the left mouse button. We will make use of probing later in this tutorial. The action of clicking on a voxel in the image to check its greylevel intentensity value is called probing. Since we have not done any segmentation yet, the segmentation label at every voxel has numeric value 0 and is called "Clear". The grey level intensity of the voxel and the segmentation label corresponding to it are displayed in the tool options sub-panel of the control panel: You will notice that the common cursor formed by the blue dashed lines always points to the same voxel in all three slice views. This lets you move around the image in three dimensions, without moving the mouse away from the slice window! Remember that you can use the scroll wheel of your mouse to change the slice currently displayed in the slice window under the mouse. You can also hold down the left mouse button and move the mouse around the slice for faster navigation. Left-click on any one of the three slices. Select the crosshairs tool in the IRIS toolbox (shown below) Thus, you can easily examine the orthogonal views of the image in the neighborhood of any pixel. When you click on one of the slices, the other two slices are adjusted so that the pixel where you clicked becomes the point of intersection of the three slices. Navigating the Image in Crosshairs ModeĬrosshairs mode is used to quickly focus all three slide views onto a location in the image. As we will see shortly, the common cursor makes it easy to examine the volumetric image near any particular voxel. These blue lines indicate the intersection between orthogonal slices.
#Zoom it press it snap it windows
As you manipulate the scroll bars, you will notice that the blue lines in the other two slice windows are moving. Make sure that the mouse cursor is inside of the slice window that you want to interact with.Ī key feature of SNAP is that the three slices are not viewed independently, but rather linked by a common cursor. If your mouse has a scroll wheel, you can use it to change the slice instead.
Use the scrollbars to change the currently displayed slice in one of the three slice windows. Under each scrollbar is located a slice counter, which shows the index of the displayed slice and the total number of slices in the direction perpendicular to the slice. Notice that a scrollbar is located next to each slice window. These three slice windows display three views of the image volume, in the orthogonal axial, coronal, and sagittal planes. Let's focus our attention on the three of the four dark windows that are displaying slices of the volumetric image (the fourth window is used for 3D display and will be discussed later). Once you have successfully loaded an image, the SNAP main window should look like this:
#Zoom it press it snap it how to
In this section of the tutorial you will learn how to use two of these tools in the IRIS toolbox: the crosshairs tool and the zoom/pan tool, which provide different ways to quickly navigate through the three-dimensional image.
#Zoom it press it snap it manual
The segmentation label sub-panel is used to select the labels used for manual and automatic segmentation, and the 3D toolbox provides additional tools used to interact with the three-dimensional rendering of the segmented structures. The contents of the tool options sub-panel depend on the tool that is currently selected in the IRIS toolbox. These interaction modes are called tools for short. The IRIS toolbox contains four buttons, which are used to select different modes of interaction with SNAP. It is divided into four sub-panels, which are labeled "IRIS Toolbox", "Tool Options", "Segmentation Label", and "3D Toolbox". The control panel for this mode is displayed to the right. Examining the Control Panel.Īfter loading a grey image, SNAP puts itself into manual segmentation mode.
This section requires approximately 10 minutes to complete. It assumes that you have successfully loaded an image following the instructions in the previous section.
This section shows you how to interact with a three-dimensional image in SNAP.
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