The Problem of Missing Ridges
This page shows a comparision of two fractal mountain images with different intersection estimation algorithms. Both images have an horizontal view angle of 0.1°.|
missing-ver1 (000d 08h:10m:04s
): This is the first version. It tried to estimate the maximum/minimum value of a fractal terrain for an interval of given length. While the image was nice, different magnification scales reveiled different outlook of the mountain silhouettes. This bad effect were an indication, that there was something wrong with the estimation algorithm and some ridges were lost. |
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missing-ver2 (000d 02h:59m:10s
): This is the second version. For each tested interval it estimates the maximum possible terrain height by linear extrapolation of the interval border heights. This algorithm is much faster than the previous one and does miss virtually no ridges. The great change of the appearance is easily visible in this image. The background, that is same in both cases, proves that both sceneries are identical. Please note the fine ridge and its shadow at the lower left of the image. |
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