Fig. 1. Optical imaging path

Fig. 2. (a) Hologram of single particle; (b) normalized hologram of single particle; (c) focused image after reconstruction of single particle

Fig. 3. Horizontal step displacement measured by (a) Hough transform method and (b) holographic reconstruction focusing method for single particle

Fig. 4. Axial step displacement of single particle

Fig. 5. (a) Hologram of overlapped particles; (b) normalized hologram of overlapped particles; (c) focused image after reconstruction of overlapped particles

Fig. 6. Horizontal step displacement of overlapped particles

Fig. 7. Axial step displacement of overlapped particles