What is Display Sparkle?

High-frequency visual disturbances such as Display Sparkle or DeepGreyMura impair the perceived uniformity of a display. These can be particularly pronounced with anti-glare coatings (AGL). Together with leading OEMs, TechnoTeam has therefore developed a standardized method for sparkle analysis that is now regarded as an industry benchmark.

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Advantages & features at a glance

  • IEC 62977-3-9 compliant and integrated into OEM specifications
  • Sparkle measurement directly possible at any stage of development
  • Full compatibility with all TechnoTeam LMK5 & LMK6 luminance cameras (from 16 mm lens)
  • Reproducible results thanks to frequency filter & distance focus scan
  • Live view & automatic alignment with BlackMURA methodology

Measuring principle & procedure

  1. Selection of the camera/lens combination and initial measuring distance
  2. Alignment using Live View and BlackMURA method
  3. Focusing directly on the display pixels (within the moiré area)
  4. Measurement of a green test image with luminance measurement camera (LMK)
  5. Automatic correction of unwanted influences (pixel structure, dust, moiré)
  6. Sparkle value is calculated in % in accordance with standards

Thanks to algorithmic frequency conversion, the results remain stable and comparable even with variable optical magnification.

Tabelle_Setup4.png

Sparkle measurement setup table for different (BlackMURA complaint) LMK systems

Distance focus scan for optimum image sharpness

A special feature is the distance focus scan developed by TechnoTeam. This automatically determines the point of maximum sparkle sharpness - exactly where the sparkle effect is most strongly perceived by the human eye. This is done either via an optional motorized linear axis or manually. Alternatively, a LMK Position system can be used as well.

Ralfs_Kurve6.png

Typical curve of a distance-focus sparkle scan from LabSoft.

 

LMK BlackMURA

LMK BlackMURA

Add-on for low-frequency uniformity measurements according to standard
LMK Display Resolution

LMK Display Resolution

Add-on package for resolution capability (sharpness) measurements
LMK Sticking Image

LMK Sticking Image

Add-on package for sticking image measurements
LMK Conoscope

LMK Conoscope

Add-on for viewing angle luminance and contrast measurements
LMK DeMURA

LMK DeMURA

Software for pixel-level luminance measurements
LMK Reflection

LMK Reflection

Add-on for fast, precise & standard-compliant reflection measurements

Downloads

AN1001 — Reproducible quantification of display sparkle
LMK Display brochure

Publications

International Display Workshop (IDW 2022)

This contribution examines the influence of ILMD noise on the reproducibility of different sparkle evaluation setups. Sparkle measurements at different sampling rates and aperture numbers are simulated for different ILMD sensors. Especially at low sparkle levels, the SNR can become very critical for some evaluation techniques such that the number of measurements needs to be increased significantly to ensure reproducibility among the different ILMD sensors.
Authors: I. Rotscholl, U. Krüger
The Impact of Sensor Noise on the Reproducibility of Sparkle Values for Different Measurement Setups

Journal of the Society for Information Display

This contribution proposes a sparkle evaluation based on a spatial frequency filter, taking into account various setup influences. Furthermore, the effect of flexible setup conditions on the reproducibility of measurement results is investigated. The procedure and concepts are derived for sampling resolutions between 15 and 30 cpx/mm with display pixel pitches between 183 and 224 ppi and validated by a round-robin experiment with different test devices, including glass and foil-based Anti-Glare Layers. The findings serve as a basis for the measurement conditions of an automotive display sparkle measurement specification.
Authors: I. Rotscholl; A. Schlipf; C. Rickers; U. Krüger
Sparkle measurements for an automotive specification: Evaluation method for flexible setup conditions

International Conference on Display Technology (ICDT 2020)

The reproducible quantification of anti-glare layer based display sparkle with Imaging Luminance Measurement Devices (ILMD) is essential for testing and conformity assessment of many displays aiming at outdoor applications. This study systematically researches relevant setup and system influences of a Fourier space-based sparkle evaluation. These include 13 different antiglare layers, two displays with different PPI, and several different system setups featuring 12 different camera/lens combinations and more than 10000 individual luminance images. Based on the resulting sensitivities, the measurement procedure is optimized with respect to the achieved reproducibility. The resulting procedure serves as basis to define a new automotive specification for reproducible sparkle measurements and may do so for other applications, that need to quantify sparkle in a reproducible way.
Authors: I. Rotscholl; j. Rasmussen; C. Rickers; J. Brinkmann; B. Liu; U. Krüger
Understanding and Achieving Reproducibility for the Evaluation of Display Sparkle Contrast

International Display Workshop (IDW 2021)

This contribution evaluates a frequency-filter based sparkle evaluation and investigates the compromise between reproducible measurement results and flexible setup conditions. It bases on measurements with two displays and 9 AGLs. The findings serve as basis for the measurement conditions of an upcoming automotive display sparkle measurement specification
Authors: Ingo Rotscholl; A. Schlipf, C. Rickers, U. Krüger
Sparkle Measurements for an Automotive Specification: The Compromise between Reproducibility and Flexibility
Type:
Add-On
Applications:
Automotive Display
Measurands:
Light measurement
Tasks:
Development & Industry