Monocular Depth Cues
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| Credit: Journal of Optical Networking |
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| Credit: Herzog, Renner, and Kai |
6. Atmospheric Attenuation
Objects farther away appear to be hazy and less distinct. Fine detail (e.g., sharp, clearly defined boundaries and other high frequency detail such as that common in texture mapped images) is more difficult to resolve in distant objects. Wavelengths near the blue end of the spectrum penetrate the atmosphere more easily than others (that is why the sky is generally blue), hence distant objects oftentimes have a bluish tint. This effect is sometimes also called Aerial Perspective or Texture Gradient.
The images at the top on the left are actual photographs in which many of these effects can be seen. Clearly fine detail such as windows in buildings is very difficult to see in distant objects. The image on the bottom is a computer-generated simulation of these effects.
