Particle Size Analysis using ImageJ Software

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Setup[edit | edit source]

Helpful video (Made by someone else): https://www.youtube.com/watch?v=JQAZ--c9YfI

1. Items Required:

  A. Particles
  B. Ruler (or Scale on Image)
  C. Camera (Cell Phone or Digital) that can take high quality photos
  D. High Contrast Background, either white or black depending on particle color

ImageJ Instructions Setup.png

Installing FIJI (Fiji Is Just ImageJ):[edit | edit source]

Download link: https://fiji.sc/

Taking Photos:[edit | edit source]

  A. Place the particles and a ruler on a plain high contrast background.
  B. Make sure the particles are not touching each other, you will get bad results. 
  C. Make sure the light is soft, and there are no shadows being created by the particles. Here is a good example:

ImageJ Instructions Taking Image.png

ImageJ Analysis[edit | edit source]

3. Open the ImageJ Software

4. Open image

  E. File > Open > Select Image

5. Save as something memorable

  F. File > Save as > “PLA Pellet Distribution 6-1-2018”

6. Set Scale on Image

  G. Select Line Tool 
  H. Hold control and scroll to zoom
  I. Draw line on ruler a set distance (ex. From 50 to 60mm) – Click and Drag

ImageJ Instructions Draw Line.png

  J. Go to Analyze > Set Scale 
  K. Set known distance and units (ex. 10mm)
  L. Select OK, and your image in now calibrated to scale.

7. Draw Rectangle around particles

ImageJ Instructions Rectangle.png

8. Duplicate image by going to Image > Duplicate. It will open a new window with just the particles in the image.

ImageJ Instructions Duplicate.png

9. Set Image as 8 bit by going Image > Type > 8 Bit

ImageJ Instructions 8 bit.png

10. Set bandpass filter by going Process > FFT > Bandpass Filter. Hit OK without changing any settings.

ImageJ Instructions Bandpass Filter.png

11. You are now ready to perform a particle distribution; the previous steps were to get the image ready for analysis.

12. Adjust the threshold by going to Image > Adjust > Threshold

13. Move the two bars until you get black where the particles are, and a white background, it is ok if there is specks still showing, we will ignore those in the next steps. Example shown:

ImageJ Instructions Threshold Settings.png

14. Hit apply

15. Analyze the particle size by going Analyze > Analyze Particles

16. Set size to about the size you would expect, this can be tweaked to make sure that the specks are not being counted. You can also tweak the circularity of the particles as well. Go to Show > Outlines to output a picture of what the software is measuring

17. Check: Display Results and Include holes

ImageJ Instructions Analyze Particles.png

18. Results are shown in a new window, as well as the image showing the particles that are actually being measured. Make sure that particles are not being counted as two together, this will skew area results.

ImageJ Instructions Results.png

19. The results window can be saved to a text document, where they can be formatted and analyzed further.

20. Done!

External links[edit | edit source]