| 摘要 |
PROBLEM TO BE SOLVED: To improve the reality of rooftop surfaces of buildings in a three-dimensional map.SOLUTION: A normal projection image 102 as a raster image is generated by direct parallel projection or perspective projection of a 3D map database. From a projection image for processing obtained by projection in a state where colors of buildings in the 3D map database are unified and lighting is applied from right above, portions having high brightness are extracted, to generate a rooftop surface image 103 as a raster image representing rooftop surfaces of buildings. A normal projection image is clipped from an image resulting from contraction processing of the rooftop surface image 103 and is shaded to generate a rooftop texture. In addition, boundaries of the image resulting from contraction processing of the rooftop surface image 103 are extracted. These images and boundaries are combined with the normal projection image 102 to generate a 3D map image 106 in which a relief impression is given to flat rooftop surfaces, whereby the reality of a three-dimensional map can be improved. |
