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| A virtual endoscopy system based on PC (continued) |
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| We have explored three primary acceleration techniques listed as follows: | |||
| 1. Object and image space coherences | |||
| There are coherences between adjoining rays cast from screen and one between adjacent sampled points along the same ray. So we have presented the algorithm, sampled points decomposing based ray casting for virtual endoscopy, to explore the coherences. | |||
| 2. Combination of volume rendering and surface rendering | |||
| Surface rendering can obtain fast rendering speed using 3D hardware accelerator, but it loses large detailed information about the 3D datasets after extracting triangles of iso-surfaces. So it can not acquire high quality images and can not be applied in VE. However, we can make use of the depths information produced by surface rendering to accelerate the ray casting algorithm. So we presented an interactive ray casting algorithm based on the w-buffer of PC graphics card. | |||
| 3. Using Intel IA-32 SIMD Instructions | |||
| Intel IA-32 SIMD technologies can execute several single floating-point computations in parallel, and it is very useful for volume rendering. We presented a novel imaging acceleration method with SIMD technologies, which can improve rendering speed several times without any specialized purpose hardware and time-consuming preprocessing. Combining SIMD technologies with threshold segmentation to reduce large empty samplings, the rendering speed is further more improved, more than 10 times faster than brute force ray casting. So we presented a fast volume rendering algorithm based on Intel SIMD and segmentation technologies. | |||
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