You cannot measure from your picture. Unfortunately you will need to learn a new for you technique called stereo measurements. Usually two pictures are needed plus some software (with good understanding a few measurements could be maid with no software).

https://en.wikipedia.org/wiki/Scanning_electron_microscope#3D_SEM_reconstruction_from_a_stereo_pair

http://www.samx.com/microanalysis/products/3D_TOPx.html

https://www.emsdiasum.com/microscopy/products/sem/3DSEM.aspx

You cannot measure from your picture. Unfortunately you will need to learn a new for you technique called stereo measurements. Usually two pictures are needed plus some software (with good understanding a few measurements could be maid with no software).

https://en.wikipedia.org/wiki/Scanning_electron_microscope#3D_SEM_reconstruction_from_a_stereo_pair

http://www.samx.com/microanalysis/products/3D_TOPx.html

https://www.emsdiasum.com/microscopy/products/sem/3DSEM.aspx

Dear Parthasarathi,

In addition to Vladimir Dusevich's post, I suggest you these 2 white papers:

• Tondare et al., "Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry ", 2017 - https://booksc.xyz/book/66995426/5ca368
• C. Mignot, "Color (and 3D) for Scanning Electron Microscopy", 2018 - https://www.cambridge.org/core/services/aop-cambridge-core/content/view/96EA3848313BFFF6437B17EFC6C01411/S1551929518000482a.pdf/color_and_3d_for_scanning_electron_microscopy.pdf

Regards

This is not presented as an accurate calculation. Refer to the previous answers for accurate calculations. If this is the only image you have an you need a visual guess, you have to make an assumption on where the base of the indentation is and the position of the top rim. Rotate the image so that it appears vertically aligned. Create a right triangle from the center to the top rim and compare the length of the depth to the scale. My approach is attached.

Dear Parthasarathi,

To get a more accurate estimate by hand, I highly recommend you refer to the figure 10 and its related text description from the following prior suggested paper:

• Tondare et al., "Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry ", 2017 - https://booksc.xyz/book/66995426/5ca368

To that end, you need some disparities in an accurate eucentric tilt setting where one stationary point “p” on the surface is chosen as the reference depth point.

Hoping it will be helpful to you

Thank you Vladimir, Stephane and Stephen Adams. Thank you for your suggestion and the manuscripts. As mentioned by Vladimir, I felt following approaches will helpful in estimating the depth.

1. Get the sequence of SEM image at different angles,

2. Develop a three dimensional grid,

3. we can find the depth (even volume in the dent) through MeshLAb.