Image Processor
Starting with a volumetric dataset from the MR VIEWER base module, IMAGE PROCESSOR tools support segmentation, boundary mesh generation, and cortical unfolding. The output may be made available to VISUALIZER for 3D rendering, or to SOURCE ESTIMATOR for realistic headshape modeling and cortical surface restriction.

Functionality

Image Processing Toolkit

• Basic image processing functions include thresholding, inversion, region growing, masking.
• Convolution filters include median, difference of Gaussians, Kirsch, Prewitt, Sobel, Marr-Hildreth.
• Segmentation functions include region growing, edge detection, outlining, erosion, dilation, and assimilation. Stop markers may be set manually.
• Histograms may be obtained for entire images or selected portions (regions of interest).
• Wizards are available for common tasks, including segmentation and mesh generation (see below), to automate parameter selection and sequencing for complex procedures. A scripting language is available for program automation of repeated tasks.

Surface representation/Mesh Generation

• Automatic mesh generation using a "shrink-wrapping" algorithm tiles a selected surface (e.g. the cortex) with a polygonal mesh. 3D rendering is available with VISUALIZER.
• Cortical inflation may be obtained from the cortex mesh with cortex curvature information explicitly retained for visualization.
• Boundary element model calculations may be performed on the surface mesh representations using SOURCE ESTIMATOR.
• Mesh Generation Wizard lets you construct a tiled surface or volume from any region creted by MR Viewer. You may then view this wireframe in the Visualizer module.
• Mesh Reduction allows you to retain the topology of the wireframe while lowering the mesh order (tile size).

Segmentation

• The Segmentation Wizard is a new feature that automates tissue classification within an MR volume. Some features are described below.
• Brain Extraction Tool (BET) is an automated algorithm for finding the brain within a a volumetric dataset.
• Hidden Markov random field algorithm automates cortical tissue classification into disjoint regions (e.g., CSF, gray matter, white matter). 
• Inner/Outer Skull and Scalp Wizards complete the picture, enabling you to generate a complete finite element model for the MR volume.

Input/Output

• User Interface. A conventional Microsoft Windows style graphical user interface is used throughout. Dynamic linking of graphical display windows permits selections in one window to update others automatically.

Intermodule Communication

• Input. Requires MR VIEWER.
• Output. SOURCE ESTIMATOR may be used for source estimation. VISUALIZER may be used for topographic mapping on realistic head surface.

File I/O

• Input/Output. Requires MR VIEWER.

Other I/O

• Graphics may be transferred to clipboard for use by other graphics programs or for insertion into word processors.

Documentation

• Printed. User manual, including file formats.
• On-line. User manual and tutorial available as context sensitive hypertext.