Model-based target classification using polarimetric similarity with coherency matrix elements

Abstract

Polarimetric similarity is a parameter for measuring the similarity between two scattering mechanisms. In this paper, we propose a novel model-based target classification technique using a compensated polarimetric similarity parameter between two coherency matrices. In general, the ensemble average coherency matrix elements have magnitude imbalance, thus the contribution degree to the polarimetric similarity differs for each element. We illustrate how to compensate the contribution degree, and then the proposed method is tested on L-band fully polarimetric ALOS-2/ PALSAR-2 data sets by using 4 theoretical scattering models (surface scattering, double-bounce scattering, volume scattering, and 22.5°oriented dihedral scattering). The classification results show that the new compensation scheme serves to better classification.

Improved Threat Detection in Walk-Through Security Scanning Using an Optimized Polarimetric Target Decomposition Method

“…This power mismatch may lead to a distorted decomposition result, since the total power P t is proportional to the sum of each scattering power. This imbalance, along with the large values of the diagonal elements of the coherency matrix compared to the other elements, were described in [15] and [16], respectively. Both authors suggested weighting factors for a compensation.…”

“…Both authors suggested weighting factors for a compensation. The source for the imbalance is not further investigated in [16] and the values for the weighting factors were calculated by the mean values of the coherency matrix entries from six different remote-sensing data sets. Each matrix element was then multiplied with the averaged inverse factor, putting all entries at a similar magnitude.…”

“…Next, due to four unknowns f s , f d , α, and β in the remaining three equations from (16), one parameter has to be set. Hence, again ( 21) is used for determination if single or double-bounce is dominating.…”