NGM1 eyepiece reticles, Mertz

The Mertz Graticule (36 Points) - NGM1

Used to estimate the three-dimensional surface areas or the surface density of a component in a given volume, when the component does not have a random orientation. It comprises a test system with parallel curved lines used for measuring the intersection of points.

In this simplest form, stereology is the science where information about a three dimensional object is obtained from only a two-dimensional section of that structure.

Measurements are usually made with these graticules in the following manner:

1. An adequate representation of sections of a specimen is obtained.
2. The graticule is superimposed upon the specimen (or micrograph/projected image of the section).
3. Finally, the interaction between the superimposed graticule and the test sections are recorded.

An overall introduction is given by: L.B. Brianrty. "Stereology: Methods for Quantitative Light and Electron Microscopy."

Reference

• W.A. Mertz. "Mikroskopic" Vol. 22 1967 pp 132-142.