Viewer3D Help

Index

• Viewer3D (Intro)
• Shear-Warp
• Starting Viewer3D
• Menu Items
• Main Render Window
• Change Alphacolors Window

Viewer3D (Intro)

This viewer can be used to interactively view any kind of 3D image volumes like CT and MRI.
It includes:

Maximum intensity projections (MIP)	Volume Rendering (VR)
Colored Volume Rendering	Phong shaded Volume rendering.

Voxel opacity and color tables can be changed on the fly allowing also iso surface kind of renders.

Shear-Warp

The fast render algorithm which used is based on a c-code implementation of the Shear-Warp transform.

Instead of rotating the viewer rays the volume slices are sheared, and the rays go parallel through
the volume allowing 2D interpolation instead of 3D, and efficient caching of data

The intermediate image after rendering through the sheared slices must be warped to
get the correct final image.

Starting Viewer3D

Viewer3D can be called from the command window with the following inputs:

  VIEWER3D(V, RENDERTYPE, SCALES);

  inputs,

    V : 3D Input image volume, of type double, single, uint8, uint16 or uint32 

              (the render process uses only double calculations)

    RENDERTYPE: 'MIP' Maximum Intensity Render (default)

                'VR' Volume Rendering

                'VRC' Volume Rendering Color

                'VRS' Volume Rendering with Shading

    SCALES: The sizes(height, width, depth) of one voxel. (default [1 1 1])


When Viewer3D is called without inputs you can load a previous saved view.

The Matlab render functions are also available as MEX / c-code in mex_c-code.zip

Menu Items

File

• Load View : Load a previous saved render
• Save View : Save render data to a matlab file
• Save Picture : Save a "Screenshot" to an image file (.png or .jpg)

Render

• MIP : Maximum intensity projection rendering
• Greyscale : Greyscale volume rendering
• Color : Colored volume rendering
• Shaded : Phong shaded volume rendering
• Image 400x400 : Rendered viewer image size 400x400
• Image 800x800 : Rendered viewer image size 800x800

Config

• Change AlphaColor : Will display the AlphaColor Window, used to change opacity and color of voxels
• Shading Shiny, change Phong shading to make object look shiny
• Shading Dull, change Phong shading to make object look dull
• Shading Metal, change Phong shading to make object look metal

Info

• Help : Display this help document
• About : Display version an author information

Main Render Window

• Zoom: Right mouse button
• Pan : Center mouse button
• Rotate around Z: Left mouse button at boundary of renderimage
• Rotate around XY: Left mouse button in center of renderimage

Change Alphacolors Window

The graph is showing the histogram of the data, with on the x-axis the intensity values.
The curve shown is a mapping from intensity to alpha and color, with on the y-axis
the opacity of the voxel form zero (transparent) to one (solid)

• drag a point with the left mouse button in y direction down to make a voxel of a certain intensity more transparent.
• click with the left mouse button on the line between the poinst to create a new (control) point
• click on a control point with the right mouse button to remove it.
• click on a control point with the center mouse button to change its color