  Objective quality assessment of digital holograms has proven to be a
challenging task. While prediction of perceptual quality of the recorded 3D
content from the holographic wavefield is an open problem; perceptual quality
assessment from content after rendering, requires a time-consuming rendering
step and a multitude of possible viewports. In this research, we use 96 Fourier
holograms of the recently released HoloDB database to evaluate the performance
of well-known and state-of-the-art image quality metrics on digital holograms.
We compare the reference holograms with their distorted versions: (i) before
rendering on the real and imaginary parts of the quantized complex-wavefield,
(ii) after converting Fourier to Fresnel holograms, (iii) after rendering, on
the quantized amplitude of the reconstructed data, and (iv) after subsequently
removing speckle noise using a Wiener filter. For every experimental track, the
quality metric predictions are compared to the Mean Opinion Scores (MOS)
gathered on a 2D screen, light field display and a holographic display.
Additionally, a statistical analysis of the results and a discussion on the
performance of the metrics are presented. The tests demonstrate that while for
each test track a few quality metrics present a highly correlated performance
compared to the multiple sets of available MOS, none of them demonstrates a
consistently high-performance across all four test-tracks.
