From this figure, it appears that the nonlinearities occurring in spectral bands ranging from $1400$nm to $2500$nm are of high intensity (see the plot associated with the oracle-LMM, in black dashed line) but are rather well described by the various nonlinear models.

![Two- and three-endmember orchard synthetic dataset. Reconstruction difference $\textrm{RD}_{\ell}$ as a function of wavelength for various linear/nonlinear mixing models: LMM (black), oracle-LMM (black, dashed line), FM (blue), oracle-FM (blue, dashed line), NM (magenta), GBM (red) and PPNM (green).[]{data-label="fig:synth_orchard_wavelength"}](results_simulated_orchard_error_wavelength_new.pdf){width="0.75\columnwidth"}

### Virtual forest

For the simulated forest scenes, the unmixing results are reported in Table \[tab:synth\_forest\_RMSE\]. These results are computed for four scene compositions, with increasing proportions from $20\%$ to $80\%$ of beech trees with respect to poplars (see paragraph \[sec:forest\]). The first three images provided a sequence of images with increasing nonlinearity, as shown by the RE obtained with the oracle-LMM, ranging from $2.11$ to $5.36$ ($\times
10^{-4}$). The fourth image, composed of $80\%$ of poplars and $20\%$ of beech trees, seems to be subject to nonlinearities of lower intensity, since the oracle-LMM RE is $3.15 \times 10^{-4}$.

As with the previous dataset, NM together with PPNM provides the best model fit for all images, i.e. with lowest RE, 