Measurement of a visibility. Two panels on the top-left: front/rear pair of grids for one subcollimator. Close inspection shows that they have slightly different pitch and orientation. The combined transmission for an on-axis point source yields a Moire pattern (bottom-left panel). A simulation for an off-axis source shows the location of detected photons (top-right panel), as seen by a detector with four large pixels (blue). Accumulated counts in the four pixels are shown in the center-right panel. Differences among these counts (bottom right) yield the real and imaginary components of the Fourier component independent of background. The sum over the four pixels yields the flux (+background), independent of the visibility. There is also a cross check that is independent of the visibility, flux, and background.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.