Massapoag Pond Photography

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Sep 2012

Counting Birds

Using software (imageJ) to count birds in a photograph

I'm an engineer that worked in the medical field for 25 years and always used the tools available to help to solve a problem. There is a great free program used in biomedical work from NIH called imageJ. One little part of the program is used for cell counting, after looking at the photo I figured the cell counting routine within imageJ would work great for solving this problem. It took all of less than a minute to get the answer of ~1100.

The program will work best with images with birds against the sky such as in the image that Steve Mirick posted. Most high contrast images should work well. Let me know how you make out!

Here is link to the photograph Steve Mirick posted a few weeks back for you to play with.

http://massapoag.org/images/SwallowQuiz.jpg

First you need to download the free program for your platform, you can grab it here. Be sure you already have a current version of Java installed on the computer.

http://rsbweb.nih.gov/ij/download.html

Steps to process the photograph. I find pictures worth 1000 words, so I'll show the steps with screen captures with a bit of text.

1. Open the photograph...File------->




2a. Convert the image to an 8-bit image… Image------>Type------>8-bit





2b. Result after converted to 8-bit grey scale image.





3a. Next we have to set the 'threshold'… Image------>Adjust------>Threshold…




3b. The program analyzes the image and guesses on a solution, most of the time the default values are fine. As you can see the program selected most of the birds and are denoted in red.




4. Now we are set to analyze the photograph…Analyze------>Analyze Particles…




5. The ‘Analyze Particles’ dialog box will popup, again most of the time the default values are fine. Click the 'OK' button.




6. The answer! After you selected 'Analyze Particles…' the program will count the birds. As you can see the count is 1100.




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