We can apply Wiener filtering to multi-dimensional signals including the Solvay photograph shown in Laboratory  Exercise 9.2. In this exercise the filter is applied independently to each of the three, noisy color channels {r, g, b}. Use the slider in the window to adjust the signal-to-noise ratio, SNR.

1. How does the Wiener-filtered restoration of a noisy version of the Solvay photograph compare to the original version and the noisy version?


2. At what SNR is the filter no longer useful? Compare the filtered version to the noisy version.


3. Why does the Wiener-filtered version seem to have less and less contrast as the SNR decreases?


4. Comparing the results in this exercise to those in Laboratory Exercise 10.1, do you consider Wiener filtering to be a universal solution, a panacea, to the problem of noise contamination? Explain your reasoning.