Spectral Mixture Analysis. Classification of mixed pixels

Classification of mixed pixels in remote sensing refers to the process of identifying and categorizing pixels in an image that contain multiple materials or land covers. These pixels are known as "mixed pixels" as they contain multiple spectral signatures, making it difficult to classify them using traditional classification techniques.

Spectral mixture analysis (SMA) is a technique used to classify mixed pixels. It is based on the principle that different materials reflect light differently and have unique spectral signatures in different parts of the electromagnetic spectrum. SMA uses a set of known spectral signatures for different materials, such as vegetation, water, soil, and rock, and compares them to the spectral reflectance of an image.

The technique then estimates the proportion of each material present in the image by analyzing the spectral reflectance of each pixel. This information can be used to map the distribution of different materials in an area and identify areas of interest, such as vegetation health or mineral deposits.

SMA can be applied to both multispectral and hyperspectral images, but it is more commonly used with hyperspectral data as it has a higher number of spectral bands and is more sensitive to small changes in reflectance. SMA can be used in a variety of applications, such as land use mapping, mineral exploration, and environmental monitoring.

Overall, classification of mixed pixels is a challenging task in remote sensing, but Spectral Mixture Analysis is a powerful tool that can help identify and quantify the different materials present in an image, thus allowing for a more accurate classification of mixed pixels. This information can be used to map the distribution of different materials in an area and identify areas of interest, such as vegetation health or mineral deposits.

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