CSU Monterey Bay - Kibak - BIO 310  

Lab Exercise for Image J

  
 
 

First we will try this software on a practice image so we all get the same results... then we will try it on our image data.

  • Download example01.jpg
  • Open ImageJ
  • Open the example01.jpg
  • GoTo Image --> Type --> 8-bit
  • Should turn Gray

 
 
 

Set measurement scale:

  • carefully draw line accross red plastic at right angle to edge.
  • Choose Analyze --> Set Scale
  • Change the "Known Distance" to 5.0
  • Change the "Unit of Length" to mm
  • select Global
  • click "OK"
  • Draw a line at the other end of the red plastic to convince yourself that you are able to measure correctly (the software should measure it as 5 mm).
 
 

  • Now "threshold" the image by choosing
    Process --> Binary --> Threshold

    To calculate the area of your lemna leaves, enclose the area with the rectangular selection tool.

 

 
 

Now choose Analyze --> Analyze Particles

  • Enter 50 as the minimum particle size (this is an example of why you need to include software settings in your "Methods" section.
  • Toggle "Show:" "Outlines"
  • Check "Display Results"
  • Check "Clear Results Table"
  • Check "Summarize"
  • Click "OK"
 
 
The outline of the analyzed areas is automatically drawn and the data window should give an area of about 8 mm^2
 
This is very powerful software but not that easy to use. There are other ways to measure area and you can even set the software up to exclude areas below a certain size and above a certain size. Imagine how easy it would be to count fertilized versus unfertilized sea urchin eggs!