Fig. 1. Combination of the MPM and the DH-PSF. The two rotating spots created by the SPM are replicated to four copies [10].

Fig. 2. Field evaluation of the proposed sensor. The blue/white crosses at x₀, x₁, x₂ mark the image positions, where a reference image stack is acquired. The red cross marks the current measurement position. For ∆x′ = 0 the calibration and measurement position is identical.

Fig. 3. Field measurements at calibration positions x₀ = 0 mm, x₁ = 5 mm, x₂ = 10 mm, x₃ = 15 mm, x₄ = 20 mm and x₅ = 25 mm with ∆x = 0 mm, meaning that the measurements are taken at the same position as the calibration. To show all field measurements in one plot, the signals are shifted by an offset of 0.1 mm times index i of x_i, so the measurements at field position x₀ are shown in the lowest and at x₅ in the highest plot.

Fig. 4. Changing intensity distribution of one defocused DH-PSF spot depending on field position. Images (a) to (f) show one spot at calibration positions x₀, x₁, x₂, x₃, x₄ and x₅. The spot is always at the same defocus position of z = 20 mm.

Fig. 5. Field measurements at calibration position x₃ = 15 mm with different offsets ∆x₁ = 0.2 mm, ∆x₂ = 0.4 mm, ∆x₃ = 0.6 mm and ∆x₄ = 1.0 mm. Blue dotted lines show the curves without jumps and detrended.

Fig. 6. 2D correlation energy distribution for ∆x₄. Each point (x, y) in the image represents the maximum correlation energy between measurement image #x and reference image #y. The blue dotted line illustrates a perfect linear relationship between measurement and reference.