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Provides an example application encompassing the following features and capabilities: |
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an Express-standard module that periodically increments an output value |
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an Express-standard module that accepts series of image files and outputs a 3D uniform field |
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an Express-standard module that generates a bounding area of a 3D structured field |
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an Express-standard module that resamples a field to reduce (or increase) its size |
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an Express-standard module that creates a surface, or 3D contour, of constant value |
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an Express-standard module that defines all of the necessary components for the display portion of a graphics application |
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combine a series of 2D MRI scans into a 3D volume for examination |
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combine images representing seismic data into a volume |
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| combine images representing atmospheric data into a volume and incorporate animation of additional data |
In AVS/Express, you begin building an application by finding the objects you need in the Libraries section of the Network Editor and then dragging them into the application workspace. This process is called instancing. When you instance an object, the AVS/Express Object Manager executes the functionality associated with that object.
So in this case, where the Image2Volume object represents a complete (albeit simple) application, instancing it causes it to execute the completed Image2Volume application. To learn more about instancing objects, see AVS/Express Concepts, Getting Started with AVS/Express, Section 2.2 Instance Objects in the Network Editor.
This section introduces you to direct interaction with the data in the DataViewer.
Ttry out the Transform and Reset buttons, which are not specific to this demo; they can be included in any DataViewer you create for your own visualization applications. Activate each control by clicking its button; see its name and description by hovering the mouse button over it.
These buttons are found along the top of the DataViewer portion of the application window.
The first four buttons provide the standard scene-manipulation controls: rotate, scale, translate in X/Y and translate in Z. Activate a control by clicking it and then dragging in the viewer area.
The next four buttons provide various reset functions that restore the defaults for various application states.
The following section briefly covers the controls in the various editors for individual modules within the Image2Volume demo.
Read_Img2Vol reads in a series of image file slices, builds these slices into a 3D volume and outputs the data as a 3D uniform field.
The module's Editor provides controls for specifying the base filename (e.g. MyImageFile) and tail (e.g. .TIF) and expects an index number as the unique component of each filename (e.g. MyImageFile2.TIF). The start and end index numbers are specified in the last two text-input fields.
The File Format and Output Format provide a choice of standard formats.
The isosurface module creates a surface of constant value, or a 3D contour.
The Isosurface Editor controls specify which data component to use for the isosurface, the value represented by the resulting surface, and whether to map cell components onto the resulting surface.
Click the map components checkbox to uncheck it; the surface turns white because cell data is not being mapped to it. Recheck the map cell components checkbox. The iso slider determines the value to display for the chosen iso component: the resulting isosurface indicates the presence of that value. The map components checkbox determines whether the (in this case lone) cell data will be mapped to the isosurface as color ranges representing value ranges.
The downsize module resamples a field to either reduce or increase its size. You can see its effects easily in the Image2Volume demo.
The Integer Sliders checkbox specifies whether the downsize factor sliders are constrained to output integer values. Move each slider and observe the results.
Before leaving this editor, set the sliders back to their original values of 4, 4, 4.
Bounds draws the bounding box around the data field we're viewing.
Turn on and off the various options and observe the results.
To exit the Image2Volume application
If you wish to continue, skip to the next section and come back to these instructions when you are finished working.
For this section, please switch to the Network Editor Window. The Network Editor looks like this:
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You can view the sub-components of any module by double-clicking directly on it; close any opened module by double-clicking its title bar. You can see man-page style help on any module by right-clicking it and choosing Help from the resulting contextual menu.
Loop's purpose generally is to continually output an incrementing value. In the Network Editor view of Image2Volume, it is not visibly connected to any other modules but it applies to the cyclic "animation" of the surface, which is generated by continually incrementing the isosurface level value.
This is the source of the fundamental information in this demo -- the series of image files to be converted to a volume. As described above, ReadImg2Vol accepts a series of image files for which the base filename, file format, and start and end indices are defined by you or the end user; it converts that file series into a volume. In Image2Volume, ReadImg2Vol passes its output to both Bounds and Downsize for further processing.
Bounds uses the information it receives from ReadImg2Vol about the resulting volume to construct a properly sized bounding box, with components displayed according to your specifications and/or user interaction at runtime. It passes the resulting box to Uviewer3D for viewing.
Downsize uses user-input parameters to either enlarge or reduce the volume file by resampling it upward or downward, and passes the result to Isosurface.
Isosurface takes the output of ReadImg2Vol (by way of downsize) and sends it to UIViewer3D for display as an isosurface.
For education, research and analysis in medicine, volume visualization is a well-established tool. AVS/Express has the built-in ability to combine a series of 2D images such as scans into a volume, and to introduce an orthoslice for moving dynamically through the scanned images while still viewing the volume. Further, AVS/Express allows integration of multiple data types from different sources so that sophisticated correlations can be derived from a relatively simple custom application. Incorporation of particle animation, for example to depict the flow of blood or oxygen, is just one of many possible extensions.
Seismic volumes constructed from slices provide an advantage particularly when augmented with color-mapping of value ranges: concentrations of a particular value/color stand out clearly and can be examined more closely using orthoslices that intersect at the area of concentration. Similarly, isosurfaces can be imposed in the same visualization to isolate value ranges for display as surfaces.
AVS/Express' ability to incorporate multiple disparate data types makes it an ideal tool for building weather data visualizations. Terrain information can combine with wind vector, humidity and temperature data to create a compelling and informative representation of a regional weather system for analysis and education.
