Calibrating medical displays to DICOM standards is important for diagnostic accuracy and quality assurance. The human eye perceives light and color differently than digital displays. DICOM Part 14 specifies how pixel values should be displayed to match human vision. Regular calibration ensures displays accurately depict images over time as components like backlights degrade, and allows consistent viewing across clinical environments. Most LCD, LED, and OLED displays can be calibrated using software that generates lookup tables to map pixel values to luminance levels defined by DICOM standards.

1. Calibrating the most demanding professional displays
www.qubyx.com

2. Why calibrate
medical displays?
Hospitals and clinics have quality programs for medical
equipment. However, often the displays used for diagnostics and
reviewing are not part of those quality assurance programs.
No monitor, including medical ones, displays images perfectly.
Poor image quality results in fatigue of the doctors, more time

3. DICOM calibration
of displays in medical
environment
•
• What is light and how does it influence
image?
• What is DICOM GSDF Part14?
• Why calibrate displays to DICOM?
• How does calibration work?
• What displays can be calibrated?
• What are the required tools?

4. What is light?
Visible light is the electromagnetic radiation that can be seen by
the human eye.Light is visible in the wavelengths from 380 to
740 nm. When light is broken by a prism, different colors of the
white light become visible.

5. How do we see light?
Rod and con cells in the retina of the human eye are sensible to
light and can distinguish up to 10 million different color and
luminance shades. These cells form the images.
Non image building cells are the photosensitive ganglion cells,

6. What is DICOM Part14?
The DICOM Standard is developed and published by
the US organisation NEMA (National Electrical
Manufacturers Association).
The Part 14 of this standard discusses how pixel
values should be interpreted and displayed.
Part 14 also specifies a function that relates pixel
values to displayed luminance values. This function is
called GSDF (Gray Scale Display Function).

7. GSDF
Originally developed by the researcher Peter G.J. Barten and published as
"Contrast Sensitivity of the Human Eye and Its Effects on Image Quality".

8. Why calibrate
to DICOM GSDF?
• Adapt display to human eye. Human eye is not an digital device like a
computer is. The computer display, as the interface between the human and
the digital machine, must be adapted to the characteristics of the human eye.
• Re-calibrate over time. Computer displays tend to change over time, like
any other light source. Backlight lamps and RGB filters change. That is why
even a factory calibrated display needs to be re-calibrated over time to
continue matching the sensibility of the human eye.
• Make sure displays look the same. Consistency of images on various
displays is important for diagnostics. Calibration iensures that an image looks
the same in all services and on all workstation.
• Standardise display outputs. Calibrated displays meet the key quality
assurance standards in medical industry.
• Safety and quality. Increase diagnostic safety and improve quality
assurance.

9. Why calibrate
color of a display?
• human eye perceives
various color shades in a
different way
• a diagnostic image on a
color display is influenced
by color hues: reddish
gray shade will look
different from blueish
gray, so adjusting
luminance is not enough
• color calibration ensures
the same color
temperature on all driving
levels (different gray
levels) of the display

10. Why calibrate a display
regularly?
•
• display white level degrades
• display back light changes over
time
• display color filters change over
time
• regular verification and
adjustment of the white level of
the display is necessary

11. How does calibration work?
1. Measurements taken.Reference colors and gray levels are
displayed on the monitor and measured with a colorimeter or luminance
meter.
2. LUT generated. From the actual measured values and the known
Barten's formula target values a correction table called Look Up Table
(LUT) is generated.

12. What displays can be calibrated
to DICOM GSDF?
Almost any LCD, LED, or OLED display can be calibrated to DICOM GSDF to
compete with traditional medical displays.

13. Standardised Quality Assurance
In some countries the legal bodies enforce acceptance testing of diagnostic
and reviewing displays when they are installed, and constancy testing
for quality assurance on a regular basis.
Major QA standards are AAPM TG18, DIN 6868-57, DIN 6868-157,
JESRA X-0093 , IEC 62563-1
The tests performed within those standards consist of visual tests and
measurement tests, which verify conformance to the requirements of
the standards.

14. Controlled Environment
Apart from calibration and constant verification of the display it is important
to control the working environment:
• ambient light must be stable and remain within the acceptable range
• no direct reflection on the display panel should occur

15. calibrates any display
to DICOM GSDF.

16. performs
acceptance and constancy tests
to key medical standards

17. Download
A free 15-day trial of PerfectLum display calibration
and quality assurance software is available at
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