The slide scanner provides the user with a digital image of the whole slide, why it also called "whole slide scanner" or "digital slide scanner". And the images produced are named "digital slides" or "virtual slides".
How to produce a "virtual slide"
Modern slide scanners utilize the principle of so-called line-scanners. These kind of scanners work in contrast to point scanners with an array of optical sensors to scan the image row by row. Afterwards the slide scanner software stitch the digital images of these lines (called "swathes") together to produce one digital image.
The optical system of slide scanners
Slide scanners for scientific slides contain optical systems comparable to light microscopes but optimized to the needs of optical sensors. Similar to microscopes the user can choose between different magnifications and adapt brightness. Typical scientific slide scanners offer magnifications for creating virtual slides between 5x and 40x.
Characteristics of virtual slides
Virtual slide files – also called digital slides - can easily reach sizes of several gigabyte. Within such an image it is possible for the user to navigate through the complete scientific specimen. Additionally the user can zoom-in and zoom-out within the probe.