**5. Conclusions**

In conclusion, based on the round-trip TM, we have done some preliminary studies on imaging 3D objects hidden behind highly scattering media. A simple virtual complex amplitude object has been tested, and the results show that both the amplitude and the phase information of the object can be recovered. As an early study, this work may have potential reference value for the endoscopic imaging with more research.

**Author Contributions:** Funding acquisition, L.R. and Z.H.; Investigation, B.Z., C.X., Y.G., G.Z. and H.C.; Methodology, B.Z.; Supervision, L.R.; Validation, B.Z. and C.X.; Writing—original draft, B.Z.; Writing—review & editing, L.R.

**Funding:** This work was supported by the National Natural Science Foundation of China (Grant No. 61535015).

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


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