How to use imagej to measure area

Getting to Know Measuring in ImageJ

In the Intro toImageJ section, you learned that a digital image is a string of numbers, displayed in a rectangular array, according to a lookup table.

You also learned about the three dimensions of an image — width, height, and bit depth. The power of image processing is its ability to make measurements in these dimensions:

Spatial measurements— Measurements of distance, area, and volume.

These involve the first two dimensions of the image, its width and height.

Density measurements— Measurements involving the third dimension, the pixel values. Pixel values can represent temperature, elevation, salinity, population density, or virtually any phenomenon you can quantify.

Before you can make meaningful measurements, you need to calibrate the image — that is, "tell" the software what a pixel represents in real-world terms of size or distance (spatial calibration)

how to measure cell length in imagej

how to calculate area in imagej