An image reconstruction algorithm based on a Wentzel–Kramers–Brillouin (WKB) approximation in the
frequency domain in terms of path integration is tested with both simulated and experimental data. The
algorithm can be used with full frequency domain data (amplitude modulation and phase shift), or partial
data (amplitude or phase shift). This algorithm reconstructs an image of photon density wave propagation factor k without knowing the optical parameters of the background medium. Reconstruction was performed for data sets of different modulation frequencies and different detector geometries. The reconstruction time on a SUN-SPARC 5 station was about 5 min for images with a 128×128 pixel size.