Remote sensing is done on the basis of measurement of emitted or reflected radiation from different bodies. Objects having different surface features reflect or absorb the radiation of light in various ways. The reflectance properties of a substance depend on the physical and chemical state of the material for example – presence of moisture on the surface of the material explains the roughness as well as the geometric circumstances. For example angle of incidence of sunlight. The most significant features of any materials that affect the color quality of the products are its structure, appearance and quality of the surface.
The difference in the colors helps to identify different materials easily just by analyzing the spectral reflectance patterns or spectral signatures of the material. These signatures can be seen in these spectral reflectance curves as a function of wavelength. The figure in the right column shows typical spectral reflectance curves.
The spectral reflectance curve of material has a significant reflectance in the visible portion of the electromagnetic spectrum that results from pigments on the surface of the material. Reflectance increases dramatically in the near infrared. Stressed areas of the product can also be detected because the stressed area has a low percentage of reflectance in the infrared. The reflectance curve of the material depends on the appearance due to the presence of moisture content, surface roughness, the texture of the material, or due to the presence of some particles on the l surface.Nowadays, the best way to measure the reflectance curve of different materials for color measurement is to make use of color measurement instruments. Testronix offers a broad range of device that quickly measures the spectral reflectance curve of the devices. For more information, visit: www.testronixinstruments.com/