Image Segmentation and Manipulation

Operators (multiply, divide, add, set to a fixed value, threshold, etc.) can be applied, singly or in combination, to each user-selected region to alter an image region's gray level(s). New operators and filters can be added that might, in specific cases, help select particular structures. The regions created in this module are pixel based, and copies of the regions along with the associated operators can be saved as a mask file. Regions and their operators can be later modified, cut, and pasted and the modified image and/or its mask set can be saved to a disk file for future use. A macro command tool is available to customize configurations of the editing tools.

Algebraic Image Manipulation (AIM) can be used for performing image algebra by treating images as simple variables in an equation. Image data can be loaded as one of four variables, a, b, c, and d. User-defined equations, such as out = (a + b)/2, can then be written to manipulate the input data sets as desired. AIM will interpret and execute these equations by performing pixel-by-pixel and slice-by-slice computations on the input images. Results can be computed for the entire data set, or for a selected slice for preview purposes.

IMPROMPTU (IMage PROcessing Module for Prototyping, Testing, and Utilizing image-analysis processes) provides a graphical user interface system for constructing, testing, and executing automatic image analysis processes. Elaborate image analyses can be performed by constructing a sequence of simpler image processing and analysis functions such as filters, edge detectors, and morphological operators. The interface currently links to a library (VIPLIB: Volumetric Image Processing function LIBrary) of 1D, 2D, and 3D image processing and analysis functions developed at Pennsylvania State University. These scripts, used in conjunction with VIDA's segmentation modules, can automate a series of processes that need to be applied to several data sets. Users can create and add customized functions to the library.

Vessel Segmentation can be used to segment connected vessels, such as airways or other major conduits, from 3D images. The module presents three windows corresponding to each of coronal, transverse, and sagittal views of the loaded data set. Users can draw masks (boundaries) in each of the three views such that the object of interest lies completely within the masks and then specify a threshold range to be used for segmentation. A seed point can be selected by clicking the mouse button somewhere on the object of interest, on one of the views to be used as the starting point for a 3D fill. The 3D fill algorithm starts at the seed point and continues to fill the structure as long as the contiguous voxels are within the specified threshold and the masked regions. To correct for undesired local fills (such as leaks) an edit facility is provided to locally edit a slice or the whole volume.

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