Radar scattering from an illuminated object is often highly dependent on th
e target-sensor orientation. In typical synthetic aperture radar (SAR) imag
ery, the information in the muiti-aspect target signatures is diffused in t
he image-formation process. In an effort to exploit the aspect dependence o
f the target signature, we employ a sequence of directional filters to the
SAR imagery, thereby generating a sequence of subaperture images that recov
er the directional dependence of the target scattering. The scattering stat
istics are then used to design a hidden Markov model (HMM), wherein the ori
entation-dependent scattering statistics are exploited explicitly This appr
oach fuses information embodied in the orientation-dependent target signatu
re under the assumption that both the target identity and orientation are u
nknown. Performance is assessed by considering the detection of tactical ta
rgets concealed in foliage, using measured foliage-penetrating (FOPEN) SAR
data.