Different kinds of image application features

The aerial remote sensing photos used this time include color infrared, natural color and black-and-white (panchromatic) aerial photos, and their application characteristics are different. Figure 8.3 shows the comparison of three types of aerial photos.

Figure 8.3 Three types of aerial photos

Color infrared photography

In color infrared aerial photographs, objects with strong reflection values for green, red and infrared light are represented by blue, green and red respectively. For example, the green plastic shed on the ground is blue in color infrared photos; Green plants (healthy) with high near-infrared reflectivity appear red. Because the blue light band is filtered out during photography, the influence of atmospheric scattering is reduced, and the color saturation is high and the image is clear. Moreover, due to the addition of near infrared channels, the resolution of water, vegetation and other ground objects is greatly improved.

8.2.2.2 color photography

Color photographic images can better show the natural colors of urban scenery, but due to the serious scattering of blue light when it passes through the atmosphere, the color tones of color aerial photographs are unsaturated, blue-green, and the spectral resolution is reduced.

8.2.2.3 ordinary black and white photography

Black-and-white aerial photographs have the advantages of low cost, high spatial resolution and clear texture features, and can be used to study urban changes. However, compared with color infrared aerial photos, black-and-white aerial photos contain less information.