So let's start analyzing some images! As a tutorial for how to use Image J, you can follow the instructions below, and/or watch these videos: basics, labeling, exporting data.
1. Launch ImageJ. ImageJ may be installed in your computer lab, or alternatively, download and install a copy on your local computer via http://rsb.info.nih.gov/ij/. Laslty, you can run ImageJ in your web browser via QUBESHub, though you will have to sign up for a QUBESHub account. Click here for instructions.
2. Download this picture to start with. Save it on your local computer. [If using ImageJ from QUBESHUb, use instructions above for QUBESHub tool session file management.]
3. In ImageJ, go to "File", "Open" (menu selections will be indicated with italics throughout this lab), then select the image you just downloaded.
4. Let's learn to set the scale for an image, that is, to tell the computer how big things are in the image. Choose the straight line tool from the menu bar.
a. Use Control + , or Control - , to zoom in and out.
b. Zoom in on the scale bar, and carefully draw a line that is exactly 2 centimeters. To draw a line, click the left mousebutton, drag the line, then release the mouse button. If you screw up, just try again.
c. Now, select "Analyze", "Set Scale"... then type in "2" in the known distance box, and "cm" in the unit of length box. Hit OK.
d. Select "Analyze", "Set measurements", and unclick all the boxes. Here you can set what kind of measurements you want the software to calculate for you... but for now we just want length which it does automatically.
5. Success! Now let's measure! Zoom in on an ant, draw a line along its body, then hit "m" for measure. A window should pop-up, with a length and the angle of the line (which presumably you don't care about, but in some applications you might). Each time you draw a line and hit "m" a new data point will be added to this worksheet. It is easy to cut and paste these data into MS Excel or other spreadsheet/statistical software for analysis or graphing.
6. By choosing other tools (ellipse, polygons, etc.) and changing the "Set Measurements" setting, you can measure all kinds of features of the images. Try measuring the area of a leaf with the polygon tool, and remember to add "Area" to the "Set Measurements" settings.
7. If the image is too bright/dark or otherwise needs adjustments, go to "Image", "Adjust", and "Brightness/Contrast" or whichever parameter might help you. These adjustments can be very helpful to make dark ant legs show up against the dark background.Next->
image analysis basics image analysis instructions hypothesis formation regression basics regression instructions post-lab bibliography
image and video sets regression practice