Fig. 4.

(A–D) Proximal gradient descent with TV regularization, $K=30$ iterations, for each layer 1 to 4. (E–H) Approximants generated from the experimental measurements with $K=1$. (I–L) Approximants generated from the experimental measurements with $K=8$. (M–P) Reconstructions from the DNN of each approximant E–H, respectively. (Q–T) Reconstructions from the DNN of each approximant I–L, respectively. (U–X) Idealized ground truth obtained from the sample specifications for layers 1 to 4. Note that the color bar range covers more than the range of the data, so there is no saturation effect on the images.