In practice, it is hardly realistic to achieve images with exposure times in steps of 0.02 ms with today’s cameras. Something that could be possible to achieve is contrast from exposure times with 1 ms steps, i.e., 1, 2, 3, … ms exposure times. In order to calculate a Doppler power spectrum with frequencies above 1 kHz from contrasts with only those exposure times, the contrasts for intermediate exposure times, including exposure times below 1 ms, have to be interpolated. In Fig. 6(a), the contrast that is interpolated from the points 0, 1, … 82 ms is compared to the original, high-resolution contrast. A logarithmic time scale is used in the plot where it is apparent that there are deviations between the interpolated and the original contrasts foremost between 0 and 1 ms. When calculating the Doppler power spectrum from those two contrast curves, it is apparent that especially frequencies above 1 kHz become highly distorted [Fig. 6(b)]. In this example, the original optical Doppler spectrum was based on single shifts with RBC speed of , 80% Doppler shifted light. A shape-preserving piecewise cubic interpolation (MATLAB) was used. The resulting perfusion estimates [Eq. (22)], which were calculated from the Doppler power spectra in Fig. 6(b), were 242 and 527, respectively.