Fig. 2: Testing the accuracy of WARP microscopy for NIH-3T3 cells.

a Phase-contrast image of an NIH-3T3 cell. b, c Monochromatic interference images of the same cell at 695 nm and 700 nm, respectively. Greyscale in arbitrary units. d Plot along the yellow line in the monochromatic images in b and c. A plot along the same line for the sum and difference images is also shown, with the match between zero-crossing points and maxima/minima used to establish the background. e Ratio of the sum and difference profile in d, after subtracting the background 2B from the sum. f Division image corresponding to the profile in e. g Displacement map generated from the division image via automated fringe counting and use of a lookup table. h Profile plot along the black diagonal line in g (black) and profile plot along the same line for a displacement map generated by wavelength-scanning ERISM (red). The black line is mostly hidden behind the red line due to the good agreement between both approaches. i Difference between the displacement map in g and the corresponding displacement map obtained by wavelength-scanning ERISM. Scale bars, 20 µm. Images are for a representative cell from three independent experiments.