Cover story: A transmission-matrix of a scattering medium describes the input-output relationship between an input wavefront and the output wavefront. Having the transmission-matrix of a scattering-medium (ex: frosted-glass) will enable one to see through it. In this work we propose a new technique to quickly calibrate the transmission-matrix of a scattering medium.


"Coherent Inverse Scattering via Transmission Matrices: Efficient Phase Retrieval Algorithms and a Public Dataset"
Chris Metzler*, Manoj K. Sharma*, Sudarshan Nagesh, Richard Baraniuk, Oliver Cossairt and Ashok Veeraraghavan
Intenational Conference on Computational Photography (ICCP), Stanford University, May 2017

Images :


Experimental setup: This is the experimental setup we used to acquire the transmission-matrix of the scattering-medium.






Comparison of phase-retrieval algorithms: This is a comparison of the phase-retrieval algorithms in the literature with respect to the oversampling factor .  prVAMP algorithm requires as few samples as the state-of-the-art algorithms.





Computation-times: The performance of the prVAMP algorithm is similar to the state-of-the art algorithm prSAMP but it requires much less-computational time.








Imaging results using transmission-matrices: Shown in the left-most columns the input speckle pattern (corresponding to the SLM patterns shown in right-most column) captured on the detector. After performing coherent inverse-scattering via the transmission-matrix, the images reconstructed and denoised are shown in columns 2 and 3 respectively.






Dataset: The dataset of the input SLM patterns and the corresponding speckle patterns are given here. Also the transmission-matrices corresponding to these scattering media as computed by the prVAMP algorithm can be downloaded at this site.


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