Tracing trees in User-guided mode(3D)

See tutorial: Trace neurons in 3D with user-guided and smart manual tracing

Before you start

  • Open an image stack or single images.
  • Make image adjustments if necessary to clearly see the trees you intend to trace.
  • If you want to associate trees with a specific color channel, select the channel using either the Channel panel on the left side of the 3D environment or the Image Adjustment tool (on the Image and Workspace ribbons) in the 2D window.
  • Select your preferred image display (3D Volume [default] or Image Slice).
  • Click the Tree button to display the Trace Trees panel and select User-guided.
  • If needed, adjust the image view for tracing:
    • Zoom in/out by scrolling the mouse wheel.
    • Pan to position the image by pressing shift and dragging with your mouse.

When working with multiple images, make sure that the image you want to use for tracing is checked in the Image Organizer.

Tracing options in User-guided mode

Tracing

To undo your last click, press CTRL-Z.

About the user-guided tracing methods

The tracing methods are based on algorithms that work by tracing along the dendrites/axons one point at a time, and by producing three measurements at each point: (X,Y,Z) coordinate, thickness, estimated position of the next point.

  • Directional Kernels: With this method, four directional kernels are matched to the image data. For a given point within the tree, the algorithm identifies the best positions and orientations for the top, bottom, left, and right kernels surrounding the point. The positions and orientations results are combined to estimate the next point to trace. Points are estimated until a set of stopping criteria is met.

    For details on the algorithm, see Rapid automated three-dimensional tracing of neurons from confocal image stacks (Al-Kofahi, Lasek, Szarowski, Pace, Nagy, Turner, and Roysam, 2002).

  • Rayburst Crawl: This method performs rayburst sampling measurements to obtain the diameter and centroid of the cross-section of the tree. Successive measurements are used to position the nodes that define its centerline. Points are estimated until a set of stopping criteria is met.

    For details on the rayburst sampling algorithm see Rayburst sampling, an algorithm for automated three-dimensional shape analysis from laser scanning microscopy images (Rodriguez, Ehlenberger, Hof, & Wearne, 2006).

  • Voxel Scooping: This algorithm generates clusters of voxels iteratively along the tree. These clusters are then used to position the nodes that define the centerline of the tree. As in the other methods, points are estimated until a set of stopping criteria is met.

    For details on the algorithm, see Three-Dimensional Neuron Tracing by Voxel Scooping (Rodriguez, Ehlenberger, Hof, & Wearne, 2009).

 

See also Tracing trees in Smart manual mode (3D), Tracing trees in automatic mode (3D), Editing trees (3D)