IDEAs: how to interactively render large image series using GPU-based direct volume rendering

Question

I'm looking for idea's how to convert a 30+gb, 2000+ colored TIFF image series into a dataset able to be visualized in realtime (interactive frame rates) using GPU-based volume rendering (using OpenCL / OpenGL / GLSL). I want to use a direct volume visualization approach instead of surface fitting (i.e. raycasting instead of marching cubes).

The problem is two-fold, first I need to convert my images into a 3D dataset. The first thing which came into my mind is to see all images as 2D textures and simply stack them to create a 3D texture.

The second problem is the interactive frame rates. For this I will probably need some sort of downsampling in combination with "details-on-demand" loading the high-res dataset when zooming or something.

A first point-wise approach i found is:

1. polygonization of the complete volume data through layer-by-layer processing and generating corresponding image texture;
2. carrying out all essential transformations through vertex processor operations;
3. dividing polygonal slices into smaller fragments, where the corresponding depth and texture coordinates are recorded;
4. in fragment processing, deploying the vertex shader programming technique to enhance the rendering of fragments.

But I have no concrete ideas of how to start implementing this approach.

I would love to see some fresh ideas or ideas on how to start implementing the approach shown above.

Answer 1

If anyone has any fresh ideas in this area, they're probably going to be trying to develop and publish them. It's an ongoing area of research.

In your "point-wise approach", it seems like you have outlined the basic method of slice-based volume rendering. This can give good results, but many people are switching to a hardware raycasting method. There is an example of this in the CUDA SDK if you are interested.

A good method for hierarchical volume rendering was detailed by Crassin et al. in their paper called Gigavoxels. It uses an octree-based approach, which only loads bricks needed in memory when they are needed.

A very good introductory book in this area is Real-Time Volume Graphics.

Answer 2

I've done a bit of volume rendering, though my code generated an isosurface using marching cubes and displayed that. However, in my modest self-education of volume rendering I did come across an interesting short paper: Volume Rendering on Common Computer Hardware. It comes with source example too. I never got around to checking it out but it seemed promising. It is it DirectX though, not OpenGL. Maybe it can give you some ideas and a place to start.