FIGURE 4-19 Anisotropy factors for three wavelengths measured in perennial ryegrass with a field goniometer. Red displays the strongest BRDF, green is intermediate, and near-infrared is weakest. Adapted from Sandmeier (2004, fig. 3-3).

shadowed zones. Thus, CIR images that contain active vegetation, water bodies, and shadowing are often high contrast—quite bright and dark portions with little mid-range of brightness. Furthermore, darkening of water and shadows tends to exaggerate the appearance of sun glint and the hot spot (Fig. 4-18).

Numerous laboratory and field studies have demonstrated that the BRDF effect displays strong spectral variation for vegetated surfaces (Sandmeier, 2004). This is a consequence of multiple scattering effects within vegetation canopy and selective absorption of certain wavelengths. In general, high-absorbing red light shows the strongest response, whereas high-reflecting near-infrared is the weakest, and green is intermediate (Fig. 4-19).

100 Photography Tips

100 Photography Tips

To begin with your career in photography at the right path, you need to gather more information about it first. Gathering information would provide you guidance on the right steps that you need to take. Researching can be done through the internet, talking to professional photographers, as well as reading some books about the subject. Get all the tips from the pros within this photography ebook.

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