Question

How fast does the uScopeGX scan a whole slide?

Answer

A number of selections and options contribute to scan performance. Additionally, there are a number of performance enhancements that are not always possible (like blank field detection/skipping)—we have avoided those for these benchmarks.

What objective magnification is used?

For most whole slide scanners, a 20x objective is used for timing and speed calculations. Since the uScopeGX is available in several different objective configurations, we completed these tests with each supported objective.

What light path is used (brightfield or polarized)?

The brightfield and polarized light paths available in the uScopeGX can affect scan speed due to the exposure and illumination settings.

What camera resolution is used?

Resolution of the camera is really about pixel mapping. The uScope camera operates in two different modes:

• Standard Definition (SD)
  Standard definition camera mode is 960x540 pixels with a pixel mapping of 0.5 microns per pixel (for a 20x objective).
• High Definition (HD)
  High definition camera mode is 1920x1080 pixels with a pixel mapping of 0.25 microns per pixel (for a 20x objective).

For these benchmarks, we scanned using both camera resolution modes.

Note
High definition (HD) mode scans are several times slower than standard definition (SD) mode scans. In some cases, high definition can approximate standard definition at the next higher magnification objective. For example, high definition scans at 20x are very close to the resolution of a standard definition scan at 40x.

How big is a "whole slide"?

The typical benchmark for a "whole slide" is a 15mm × 15mm area (about the size of a square cover slip). That is the scan area used for these tests. It is important to scan a 15mm x 15mm area that is completely covered with tissue in order to obtain accurate results. Scanning blank areas of the slide could skew the results due to blank detection/skipping algorithms that most scanners employ.

What focus method is used?

The uScope Navigator application allows you to select from among four (4) different focus methods when scanning a slide.

• Initial Focus uses a single focus plane for the entire scan.
• Predictive Focus chooses prediction points and create a focus map. This is the focus method used for these benchmarks.
• Fast Stack takes a few images (typically three) for each field in the region.
• Exhaustive Stack takes a deep stack of images for each field.

Note
Each focus method affects scan speed. Initial Focus and Predictive Focus are the fastest.

What about setup time?

Some scanners require more setup time than others. As a single-slide scanner, the uScope requires very little setup time. As the setup time varies from scanner to scanner, we have excluded it from these benchmarks.

What about process time?

All whole slide scanners require some processing to combine image fields/data and output the large scanned image. The uScope Navigator application combines fields while scanning the region of interest. So, the process time is mainly composed of filter time and image output time. The process time is included in the table below.

Scan/Process Times

The following table provides scan and process time (for a 15mm × 15mm region) for various uScopeGX Models by objective, light path, and camera mode.