A Volume Optimization Method to Improve the Three-Stage Inversion Algorithm for Forest Height Estimation Using PolInSAR Data

This letter proposes a novel method to improve the results of the three-stage inversion algorithm, using polarimetric synthetic aperture radar interferometry. Since the accuracy of the estimated forest height is affected by the volume only coherence selection, finding the optimum coherence value is an important challenge for the conventional three-stage method. In the three-stage algorithm, a specific polarization state, HV, is usually used as the volume only channel. However, in this letter, an optimization algorithm is developed to find a more accurate volume only coherence on the coherence line. We used the experimental airborne SAR L-band single-baseline single-frequency polarimetric interferometry data to evaluate the proposed algorithm. The experimental results show the proposed optimized volume only coherence leads to 2.9-m improvement in the results of the three-stage inversion algorithm.