When is each approach applicable?

Consider  the two cases:

Figure 4.

In Case I, the mixing of radiation reflected by the separate components on the ground takes place in the sensor: This case can be treated by the linear approach.

In Case II, the mixing of radiation takes place in the scene: This case requires the use of non-linear methods.

Click here if you want to learn how the linear spectral unmixing works  

Click here if  you want  to learn how the non-linear spectral unmixing works