From Microscope To Monitor A Proprietary Color Match Method from Leica Biosystems

Digital pathology is quickly growing across the globe as it offers increasing benefits to standardize and optimize the pathology lab workflow. Pathologists can now retrieve their cases in digital form and review and sign off cases using a PC and monitor. However, digital pathology companies offer many different monitors, depending on the company. Pathologists are often frustrated by the color variation of a digital image as it may not match the microscope color experience They often prefer a color that looks as close as possible to the typical experience using a microscope.

How can we color match the image viewed on the monitor to what is seen in the microscope?

The problem is that no company had calibrated the color of the histology stain to the color of the monitor and color of the whole slide image. Our innovation team worked together to solve this issue.

Image Capture RGB values versus Display (Monitor) RGB values

When an Aperio digital pathology scanner scans a slide it produces a whole slide image that contains calibrated red-green-blue (RGB) values because the image is a color image. When the image is viewed on a monitor, the monitor also has its own separate calibrated RGB values (for example sRGB calibration by the manufacturer) because it is a color monitor. The problem is that image capture RGB values generated during image acquisition do not match the monitor display RGB values.

Many customers simply assume image capture RGB values will match the monitor RGB values. But this is not the case. 

A novel solution to calibrate color using Histology slides (patent pending). 

The goal is to reproduce what is seen in the microscope so that the same information is presented to the pathologist. In order to do this, the scanner and monitor need to be matched properly in order to produce accurate color. Leica Biosystems innovation solved this by creating a novel method, which includes the following:

• Input color is measured on a histology slide using a patented spectral method (standard D50 light used in microscopes).
• Output color is measured on the monitor display. Small patches of a whole slide image are magnified on the monitor and a colorimeter/spectrophotometer is used to measure the color of light for each patch.
• The scanner and monitor display are then calibrated separately for accurate color.
• An ICC profile is created to convert between RGB values across scanner and monitor to produce accurate color.
• Each monitor brand and model has its own ICC profile, and Aperio viewers calibrate image color against that ICC profile for consistent visualization.

Pathologists Benefit as Monitor Color Matches Histology Slides and Microscope

As digital pathology ramps up its adoption across the globe, it is important to consider the color of the image that is displayed on the monitor as Pathologists prefer that the color match the microscope (D50 light passing histology stained slides). By utilizing Leica Biosystems novel calibration methodology an ICC profile has been created to convert between RGB and color so that when a Pathologist views the image on a monitor it matches the color to histology stained slides.

For Research Use Only. Not for Use in Diagnostic Procedures