Image stabilization and uniformity
Displays used for medical imaging need to remain stable and consistent over time. Sensors and uniformity technologies are required to ensure compliance with medical standards. Over the years, manufacturers have developed a number of technologies to stabilize the luminance of medical monitors.
Display systems may incorporate backlight sensors, front of screen sensors, or fixed or mechanical sensors. The most accurate measurements are achieved with fixed high-precision front of screen luminance photometers. These provide accurate and traceable measurements of the complete DICOM curve over the full lifetime of the display. DICOM states that high-precision photometers must be used to perform Quality Assurance. A NIST traceable photometer, such as the I-Guard sensor from Barco, is permanently attached to the display face and is internally baffled to exclude extraneous light sources.
LCD monitors suffer from inherent uniformity imperfections, which cause arbitrary patterns called noise. These unwanted non-uniformities may have a negative influence on the accuracy and efficiency of medical image readings, as they make it difficult to discriminate subtle image features. Dedicated solutions, like Barco’s Per Pixel Unifomity (PPU) and Uniform Luminance Technology (ULT), address these non-uniformities by characterizing the non-uniformity (spatial noise pattern) of the display. ULT does not alter the content of the medical image - it simply removes distracting noise in the display, in color and grayscale, resulting in improved diagnostic quality.