A high-speed 3D image generating apparatus for generating and displaying a three-dimensional (3D) image of a display object arranged as an object of image generation in a 3D space and projected onto a projection plane according to volume data representing a distribution of a visual attribute at each position of the 3D space and rendering parameters determining characteristics of the image to be displayed, comprising:
- volume data acquiring means for acquiring the volume data;
- volume data storage means for storing therein the acquired volume data;
- input means for inputting the rendering parameters;
- 3D image generation process means, including a plurality of processors, for estimating a quantity of calculations necessary for the creation process of the 3D image according to a portion of the volume data stored in said volume data storage means, subdividing the generation process into sub-processes and thereby substantially equalizing the quantities of calculations respectively allocated to the plural processors, concurrently executing the sub-processes by the plural processors according to the volume data stored in said volume data storage means and the rendering parameters input thereto, and generating a 3D image;
- and
- image output means for visualizing the generated 3D image,
- wherein the 3D image generation process means sequentially performs the steps of:
- resampling the voxel value of the volume data representing the 3D space in a normal direction beginning at a first pixel group arranged in the projection plane with an interval larger than a pixel interval of pixels for which the 3D image generation process is to be executed on the projection plane, the resampling interval being larger than the pixel interval,
- deciding a first position group including a position at which the voxel value attained as a result of the resampling step exceeds a preset threshold value and a position which is on the normal line and which are least apart from the projection plane on the normal line,
- deciding a second position group including a position on a normal line passing each pixel of a second pixel group including pixels other than those of the first pixel group and a position interpolated according to positions of the first position group associated with one or more pixels of the first pixel group in the periphery of the pertinent pixel, and
- subdividing voxel data of voxels at respective positions of the first and second position groups into as many subdata items as there are processors.