In addition to chlorophyll, the pallisade parenchyma contains other pigments, such as carotenoids, anthocyanins and others, which are also responsible for the absorption of light. Because of those pigments, most of the visible electromagnetic energy is absorbed, especially in the blue and red region. Absorption in the green regions is slightly weaker, which is why vegetation appears green to our eyes. As a result, very little energy escapes the pallisade parenchyma and is reflected back towards the sky. On the other hand, near infrared (NIR) energy is not affected by those pigments and almost completely penetrates the pallisade parenchyma. When it reaches the spongy parenchyma, the presence of air spaces causes the refraction of the NIR energy in various directions. This results in approximately half the energy exiting the leaf from the lower epidermis and the other half from the top epidermis, towards the sky.