Digital holography; Image reconstruction techniques; Inverse problem; Terahertz imaging.
Abstract :
[en] THz digital holography with camera sensor in off-axis configuration suffers from difficult recording conditions. In order to obtain a high resolution on the object, the latter must be close to the sensor, yielding high recording angles. It was already shown that iterative reconstruction methods can be used to limit the impact of spurious fringes obtained in such schemes. In this paper, we propose an inverse problem-based reconstruction technique that jointly reconstructs the object field and the amplitude of the reference field. Regularization in the wavelet domain promotes a sparse object solution. A single objective function combining the data-fidelity and regularization terms is optimized with a dedicated algorithm based on an ADMM framework. Each iteration alternates between two consecutive optimizations using projections operating on each solution and one soft thresholding operator applying to the object solution. The method is preceded by a windowing process to alleviate artifacts due to the mismatch between camera frame truncation and periodic boundary conditions assumed to implement convolution operators. Experiments demonstrate the effectiveness of the method.
