Three-dimensional visualization of noun interpretation-volume rendering, voxel, body data, volume rendering algorithm

Volume Rendering is a technique for generating two-dimensional images on screen directly from three-dimensional data fields. The advantage is that it can explore the internal structure of the object, can describe the very shape of the object, the disadvantage is that the data storage is large, the computation time is longer.

voxel (Voxel), is the abbreviation of the volume element (volumepixel). As its name, is the smallest unit of digital data in three-dimensional space division, voxel for three-dimensional imaging, scientific data and medical imaging and other fields. Conceptually similar to the smallest unit of two-dimensional space-pixels, pixels are used in the image data of two-dimensional computer images. Some true three-dimensional displays use the body to describe their resolution, for example, to display a 512x512x512 voxel.

Body Data is a description of a data type , as long as the data containing the body details, can be called the body data. For example, there is a pile of concrete, which contains a number of carbon substances ( C), a number of water molecules ( H20), and an unknown chemical composition of the gel, you use this concrete to build a block brick, if there is a three-dimensional array , will brick X, Y, The distribution of the material in the c12>z direction is expressed, then the array can be called the body data.

The so-called polygon data , not the two-dimensional plane data, but that the data is only the surface details, there is no body details, the actual body data and polygon data is essentially the difference between the inclusion of the body details, not in the dimension.

In general, there are 2 sources of body data:

1. The results of scientific calculation, such as: finite element calculation and fluid physics calculation;

2. Instrument measurement data, such as: CT or MRI scan data, seismic survey data, meteorological testing data.

The international body rendering algorithms are mainly: Ray projection algorithm (ray-casting), error-cut-transform algorithm (SHEAR-WARP), frequency-domain volume rendering algorithm (Frequency domain) and snowball-throwing algorithm (splatting). The ray casting algorithm is the most important and common one. The reason, there are three points: first, the algorithm in the solution based on the ray scanning process, in line with human life common sense, easy to understand; second, the algorithm can achieve a better rendering effect, and the algorithm can be easily ported to the GPU for implementation, can achieve real-time rendering requirements.

Three-dimensional visualization of noun interpretation-volume rendering, voxel, body data, volume rendering algorithm