This contrast loss is most critical in the dark areas of the screen because it may actually make critical information in a medical image a lot less visible.
When your phone or tablet screen is exposed to the bright sunlight, it will be very hard to read. Walk outside on a sunny day with your phone or tablet. This will result in an overall contrast loss. Because an LCD screen is also a surface, ambient light will reflect on your display's screen surface as well. Why is ambient light compensation so important when viewing medical images?Īmbient light which is present in a diagnostic reading room (and any other environment of course) reflects onto surfaces back into our eyes. Without DICOM calibration (native curve): Without going too much into detail on DICOM, the images below should give you a better visual idea of what DICOM really does: That visible luminance difference between two subsequent digital driving levels consists of Just Noticeable Differences. Only this way we can be sure that a low-contrast pathology (such as for instance a lung nodule) is going to be easily discernable by the radiologist. In practice, this means that consecutive digital driving levels correspond with an equally visible luminance difference. DICOM takes into account the contrast sensitivity of the human eye. The intention of the DICOM calibration is to have a visual consistency on how a given digital image appears. For each pixel, the display controller sends out a pixel value between 0 and 255 which is then converted by the display into visible light. Each of the 256 shades of gray is called a Digital Driving Level (DDL). This image can consist of 256 different shades of gray. a light box next to the diagnostic display)Ībout Just Noticeable Differences and Digital Driving LevelsĪssume an 8-bit grayscale image. Light from the environment shining into the eyes of the viewer (e.g.In a diagnostic reading room context: Ambient light is the surrounding light in a reading room which can influence diagnostic reading: How the ambient light compensation is appliedĭefinition: Ambient light is the light which is present in an environment.
LIGHT DISPLAYS HOW TO
How to calculate the reflected ambient light?.How do we compensate for ambient light when DICOM calibrating a display?.Why is ambient light compensation so important when viewing medical images?.About Just Noticeable Differences and Digital Driving Levels.
0 kommentar(er)
