Table 1 Data and timing efficiency.

Left: Comparison of the number of images and the amount of acquired image data between a lens-free on-chip microscope and a typical scanning optical microscope with a 20× objective lens. Right: Computation time corresponding to the full FOV (20.5 mm2) image reconstruction routine implemented in CUDA using an Nvidia Tesla K20c graphics processing unit (GPU) (released in November 2012). This total computation time can be further improved by more than an order of magnitude by using a GPU cluster.

Data efficiency comparisonTiming of lens-free image reconstruction
Lens-free microscopeSubroutineTime (s)
HDRPSRHeightsNo. of imagesData (GB)Read images from hard drive7.0
33633243.5Autofocus10.2
Conventional scanning microscope 20× (NA = 0.5)PSR91.0
Lateral scanAxial scanNo. of imagesData (GB)Image alignment54.6
9273671639.4Multi-height phase recovery94.6
Total257.4