Imaging of object in cluttered environments (sponsored by ONR, NSF)

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This project investigates an adaptive imaging approach, namely that of a synthetic wideband, stepped CW transmitter and a multi-channel, adaptive array for receiving backscattered energy from short range objects in a full +/- 90 degree field of view. The method is a hybrid one, using conventional Fourier processing for range and is adaptive in angle. The results show how background clutter affects the angular resolution of the array due to the increase in rank of the signal plus clutter covariance matrix, whereas at the same time the rank of this matrix is reduced for closely spaced scatterers due to signal coherence. In addition to investigating some known angular enhancement methods, we study a method to enhance angular resolution in the presence of clutter by a projection, which seeks to reduce the received signal to a lower rank approximation, without using eigen decomposition, thus having an implementation advantage. This method allows more control over the angular resolution and the background clutter level.



Testing the 12-channel imaging array system in the anechoic chamber.

Image of one large dihedral and 3 cylinders using adaptive beam forming techniques.




Related publications






Sponsored by ONR, NSF