Sparkle measurement setup table for different (BlackMURA complaint) LMK systems
LMK Display Sparkle – High-Precision Measurement of Anti-Glare and Sparkle Effects
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. LMK Sparkle is part of the display package.
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Advantages & features at a glance
- IEC 62977-3-9 compliant (external link) 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
READ THE TECHNICAL ARTICLE: MEASURING DISPLAY SPARKLE ACCORDING TO STANDARDS WITH TECHNOTEAM
Would you like to find out more about the precise evaluation of visual fine structures and anti-glare coatings? Then discover our technical article (external link) and its extended version (external link). In it, we present our proven measurement methodology for IEC 62977-3-9-compliant sparkle analysis - developed in close cooperation with leading OEMs and already established as an industry standard.
Measuring principle & procedure
- Selection of the camera/lens combination and initial measuring distance
- Alignment using Live View and BlackMURA method
- Focusing directly on the display pixels (within the moiré area)
- Measurement of a green test image with luminance measurement camera (LMK)
- Automatic correction of unwanted influences (pixel structure, dust, moiré)
- 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.
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.
Typical curve of a distance-focus sparkle scan from LabSoft.
RELEVANT PRODUCTS AND APPLICATIONS
Publications
The Impact of Sensor Noise on the Reproducibility of Sparkle Values for Different Measurement Setups
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.
Sparkle measurements for an automotive specification: Evaluation method for flexible setup conditions
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.
Understanding and Achieving Reproducibility for the Evaluation of Display Sparkle Contrast
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.
Sparkle Measurements for an Automotive Specification: The Compromise between Reproducibility and Flexibility
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
- Type:
- Add-On
- Applications:
- Automotive Display
- Measurands:
- Light measurement
- Tasks:
- Development & Industry