JFET_V2_N1_RP2 Mujahid Fahmy Al-Azzo Journal on Future Engineering and Technology 2230 – 7184 2 1 30 35 Modified covariance, Spectral estimation, Holographic technique A high resolution modified covariance method is applied to modeling an ultrasonic holographic imaging of concealed objects. In-line holography is used to increase the signal to noise ratio. Different concealing materials are used. The results are compared with the traditional, Fourier transform, method. The performance is investigated for different values of signal to noise ratio. August-October 2006 Copyright © 2006 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=965