Effect of the fill factor of CCD pixels on digital holograms: comment on the papers 'Frequency analysis of digital holography' and 'Frequency analysis of digital holography with reconstruction by convolution'

In digital holography, holograms are digitally recorded by a CCD camera and stored in a computer’s memory. The reconstruction of the recorded wave field from the digitally stored hologram is realized numerically by the computer.123 This technique has found numerous applications, especially in 3-D microscopy,45 encryption,6 pattern recognition,7 and surface contouring.8 The process of digital holography by recording an interference pattern with a CCD array, and storing it in a computer to numerically reconstructing it can be interpreted as a coherent optical imaging system, which can be analyzed by Fourier optics and can be characterized by a point spread function (PSF). Such an analysis has been reported in recent publications written by Kreis.910 In this work, we indicate some shortages in Kreis’ analysis. At the same time we describe our new treatment and some new analytical results.