Comparing image reconstruction algorithms for microwave camera featuring ultra wide band sensor

In this paper, we present numerical and experimental results on Ultra-wide band (UWB) imaging comparing multi-step quantitative and single-step qualitative image reconstruction algorithms. Two quantitative schemes have been evaluated involving two different ways of calculating the gradient. In the first case, the gradient is calculated using the adjoint state method, while the second algorithm uses the central difference method aided by Broyden´s technique for gradient updating. Meanwhile, the qualitative algorithm is radar based, and utilizes an enhanced version of the delay and sum which combines focusing quality, and multiply pair to identify significant scatterers. The methods and procedures were tested using both simulation and experimental phantoms. Results of detecting millimeter scaled targets for each algorithm are compared and discussed.