Calibration Policies

Introduction

Calibration policies are used to define:

  1. Schedule and method : the calibration schedule and method.

  2. Settings: Used to configure luminance-related settings that should be applied to the display.

_images/policies_calibrationsettings_default.png

Calibration

QAWeb Enterprise provides you two methods to calibrate your displays:

  • Default: This is the calibration method recommended by Barco and provides sufficient accuracy to keep the displays calibrated.

  • Extended: If this option is selected, the calibration provide additional accurracy but will take longer.

If a modified calibration policy is assigned to a workstation, it may immediately execute the calibration on the applicable workstation component(s) (if a calibration with these parameters has not yet executed). The schedule (execution frequency) for subsequent calibrations can be set as desired. This is described in detail in the chapter How the task schedule determines the execution time of tasks.

Luminance Response function

The following luminance response functions can be selected:

  • DICOM GSDF: Apply the Greyscale Standard Display Function, as defined in DICOM part 14, in order to achieve perceptual linearity.

  • sRGB: Apply an sRGB luminance response function

  • Gamma 1.8/2.0/2.2/2.4: Apply a gammatized luminance response function

  • Custom: Apply an arbitrary luminance response function.

The file format (*.gam files) of the custom luminance response function needs to adhere to the below syntax. The first column is describing the luminance component. The second and third component are describing the color component, which are ignored by the application.

0    0       0
0.000434138  0.000434138     0.000434138
0.000868276  0.000868276     0.000868276
0.001302414  0.001302414     0.001302414
...
0.98989226   0.98989226      0.98989226
1    1       1

Note

Some display models are unable to perfectly show the low lights when using gamma 2.2 and gamma 2.4 due to the nature of these gamma curves. The lowest grey levels may be shown slightly too bright for some display models.

Gamut

This settings controls the color gamut of the display.

  • Native: Use the color gamut as natively available for the display.

  • sRGB: Apply the pre-defined sRGB color gamut

White point luminance

This setting controls the white point luminance of the display.

  • Preset/Recommended: The Barco-defined default for the specific display model will be applied.

  • cd/m²: Allows you to choose a custom white luminance value between 100 and 2000 cd/m². If the display cannot reach this target, it will apply the closest supported value.

White point chromaticity

This setting controls the white point chromaticity of the display. You can select one of the following options:

  • Preset:

    • Recommended: A Barco-defined default for the specific display model.

    • Bluebase: Simulates the bluebase film color temperature.

    • Clearbase: Simulates the clearbase film color temperature.

    • D65 / D75: Corresponds approximately to a color temperature of 6500 or 7500 Kelvin.

    • Native white: The native, unmodified color temperature of the LCD panel.

  • Kelvin: Allows you to choose a custom white point chromaticity value between 4000 and 10000 K.

  • xy: Allows you to choose a custom white point chromaticity value defined in xy coordinates.

Black point luminance

This setting controls the black point luminance of the display.

  • Preset/Recommended: A Barco-defined default for the specific type of display which uses the native black point of the display panel.

  • cd/m²: Allows you to choose a custom black luminance value between 0.01 and 10 cd/m²

SteadyColor

Barco’s SteadyColor™ technology was created to achieve consistency and perceptual linearity in the display of color images. With multiple internal sensors, display parameters are constantly monitored and adjusted to ensure that the perceptual difference between colors is proportional with their Digital Driving Level (DDL) difference. This setting controls how SteadyColor is applied to the display:

  • Standard: Calibrates the display system to meet the DICOM GSDF and guarantees consistent, perceptually linear distribution of color hues.

  • Full: Extends the standard perceptual linearization to equally distribute desaturated and saturated colors.

  • Off: Disables SteadyColor.

Note that the SteadyColor setting is only effective on selected Barco display systems that support SteadyColor technology. For all other display systems, this setting will be ignored.

ICC profile generation

Calibration of a display will include the generation of an ICC profile if it supports Barco SteadyColor technology. The ICC profile is registered in the operating system.