Using free software, you can measure part sizes with a resolution of less than a mil ( 1/1000 inch or about 25 microns ).
Great for identifying mystery micro-screws, electronics, camera parts, or even measuring plants or insects.
Tips and tricks for mounting parts, scanning, aligning the image, and taking measurements.
I'll give you links to other resources where people are using scanners for measurements and would like to hear from you about any ideas or feedback on how to get better results.
Step 1: Free Software for Measurement
The Notes and Resources step of this instructable gives links to notable image measuring software. Three free choices are IrfanView, The GIMP, and ImageJ. All are easy to use for basic measurements.
For simple measuring of lengths, I prefer IrfanView graphics software.
Keep in mind that The GIMP is excellent and is my main image editor. It is worth your time to learn it as a free alternative to Photoshop.
ImageJ is a scientific and math miracle. Easy to use, but loaded with incredible features. Thanks to i'bler aman0311 for suggesting this.
IrfanView is Windows-only freeware. It is easy to load and use. It is kept up-to-date by its author Irfan Skiljan.
Be sure to download it from the official site IrfanView or from a trusted site like C|Net or tucows.
It installs quickly and easily. It's very light on resources, and is easy to learn.
Step 2: The GIMP
It runs on Windows, Mac, or Linux.
It's very powerful, and for basic measuring is easy to use, though not as simple as IrfanView.
You can download the GNU Image Manipulation Program from the official GIMP site or from C|Net and other trusted sources.
You can also use Photoshop, Picasa and many other programs to directly measure scanned parts.