**4. Conclusions**

In this study, we conducted FE analysis using 2D and 3D models that simulated turbine blades for the cases where an internal crack detection method using a digital holographic microscope and digital height correlation method were applied to turbine blades. The results acquired are shown below.


**Author Contributions:** Conceptualization, N.T.; methodology, H.K., T.U. and N.T.; validation, H.K.; formal analysis, H.K. and J.S.; investigation, H.K. and J.S.; resources, N.T.; data curation, H.K. and J.S.; writing—original draft preparation, H.K. and J.S.; writing—review and editing, N.T. and T.U.; visualization, H.K. and J.S.; supervision, N.T.; project administration, N.T.; funding acquisition, N.T. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by JSPS KAKENHI Grant Number JP18H01337.

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