SEM images are most often displayed in a 2D view where valuable topographic and depth information is completely lost. However, stereomicroscopy opens up doors for researchers to finally uncover this hidden third dimension. This technique uses parallex-based stereoimaging where two images of the specimen are taken at slighly different angles. Below outlines a basic procedure to acquire high quality stereoimages.
Acquiring Images Using SEM
1. Load sample onto sample holder
a. Ensure sample is not too tall as this may become an issue during rotation-cut if necessary
2. Go to VP mode, high pressure, and small spot size to minimize charging
3. Find part of specimen you are interested in and get a good quality image.
a. Keep working distance as large as possible while maintaining a high quality image to allow for the most depth information
4. Find a defining feature and center that feature on your screen.
5. Go to the tab menu (indicated by small right pointing arrow on right side of image). Choose compucentric height.
6. A new window will open. Check again that your chosen feature is centered and then click Read.
7. Choose a tilt angle (default 5º). Click on Tilt. The stage will move to the desired angle. Re-center your chosen feature. Click Calculate.
8. You can choose to save this height for future measurements by clicking save. Return stage to original position. Your feature should now be centered.
9. Under the same tab menu, choose Rotate/Tilt
10. Check the box that says Scan Rot and set to 90º.
11. Go to the stage tab. Under the first drop-down menu, choose the option: compucentric mode= tilt.
12. Turn off protected Z to prevent stage from moving down each time the angle is changed.
13. With all settings in place, make sure one last time your chosen feature is centered. Click on photo to get high quality scan and save image as a .TIFF.
14. Then, go to the stage tab and rotate the sample ±6º depending on what features you want to see.
15. Ensure feature again is centered. If not, you may have to redo the compucentric height step.
16. Take another photo scan and save image as .TIFF.
17. Turn off comp scan rotation option.
18. Shut down SEM as you would normally.
Bringing Images Into Photoshop
1. Import both photos into Photoshop.
2. Go to Image>Mode>Grayscale for both photos.
3. Drag the tab of one of the photos out of the top menu.
4. Drag this file on top of other image still in Photoshop. This creates 2 layers.
5. Go to Image>Image Size and set width to 1920 pixels.
6. Go to the Crop option on the left hand side and choose 16:9 ratio. Crop out desired section of image. Both layers will be cropped.
7. Ctrl+R - this brings out the ruler function. Drag the vertical line ruler to the center of the image until it "clicks."
8. Ctrl+T - this allows you to transform the image. Drag the image taken at 0º to the left until it "clicks" at the halfway marked ruler. Drag the image taken at 6º to the right until it "clicks" at the halfway marked ruler.
9. Your image is now ready to be viewed using a 3D monitor!