EndmembersPure

Endmemberspure is a term used in the field of spectral unmixing and remote sensing to describe spectra that are considered pure endmembers—spectral signatures of a single material with minimal mixing or variability. In hyperspectral imagery, pixels often represent mixtures of materials, and endmembers serve as reference signatures for unmixing algorithms. The concept of EndmembersPure emphasizes endmember sets that are uncontaminated by mixtures, providing a stable basis for analysis and interpretation.

A pure endmember is typically a spectrum that corresponds to a single material under relatively consistent illumination and viewing conditions. In practice, endmemberspure may be obtained from high-quality measurements in the field or laboratory, or from carefully curated spectral libraries. These pure signatures are used as inputs to linear or nonlinear unmixing models to estimate the abundance of each material within mixed pixels, and to support material identification and mapping.

Methods to obtain endmemberspure include targeted field campaigns, laboratory spectrometry, and curated library creation, often accompanied by preprocessing steps such as atmospheric correction, instrument calibration, and spectral resampling. Automated endmember extraction algorithms—such as first-order purity measures or geometrical techniques—aim to identify spectra that approximate the concept of purity within a dataset, though the notion remains somewhat idealized due to natural variability.

Applications span geology, agriculture, environmental monitoring, and mining, where accurate pure endmember references improve material discrimination and abundance estimation. Challenges include spectral variability due to surface conditions, illumination, and sensor noise, as well as the difficulty of obtaining truly pure references in heterogeneous environments.