BlackMura procedure: Top left: Alignment; Top right: Bright uniformity; Bottom left: Dark uniformity; Bottom right: Dark gradient
Display uniformity is an essential quality criterion for modern displays. Errors in production can lead to low-frequency non-uniformity and hotspots for all kinds of technologies. The BlackMURA standard is a measurement and evaluation procedure to quantify this loss of quality in a reproducible way. The standard, used mainly in automotive displays, was developed by the German Automotive OEM Group and the German Flat Panel Forum (DFF), which we have been members of for many years.
After a three-step alignment procedure, the measurement itself is very straightforward and consists of three steps:
- Measurement and evaluation of the white display uniformity
- Measurement and evaluation of the black display uniformity
- Evaluation of the black gradient based on the previously captured images
All TechnoTeam LMK cameras have been acknowledged as industry standards and thus meet the standard requirements such as spectral mismatch and uniformity flat field, which are essential for measuring BlackMURA.
Our live-view mode helps you to see changes in the alignment right away
Our LMK BlackMURA add-on is a field-proven solution for making BlackMURA-compliant measurements since the first release of the standard. The standard's complex alignment procedure is easy and comfortable using our camera's live view mode. With this add-on, you measure and evaluate according to the standard, and you can perform sensible adjustments where required. Examples are the gray value adjustment (e.g., for the DeepgrayMURA evaluation of OLED displays) or parameter modifications to account for different versions of the standard. In addition, our software allows for a vantage point uniformity evaluation based on a projective rectification. In contrast to the standard BlackMURA procedure, the spatial uniformity and viewing angle effects seen by an observer from a specific vantage point are considered in the evaluation. Via our SDK, each aspect of the procedure, including the alignment procedure — can be automatized. This is for instance done by our LMK Position robot, which allows performing all BlackMURA-related alignment tasks without the need for manual adjustments.
TechnoTeam has also created the first implementation of short-distance uniformity correction, which allows BlackMURA-like evaluations to be measured at no large distance from the display, which can save a lot of space in production.
This concept also greatly improves the results of image stitching techniques. It thus allows high-precision BlackMURA-like uniformity evaluations of, e.g., very long displays (e.g. pillar-to-pillar), either by using two cameras simultaneously or by laterally moving the camera.
DISPLAY PACKAGE
This add-on is part of the display package add-on. It can be ordered separately or in combination with the other display add-ons.
The other display add-ons are linked below.
Downloads
Publications
Short distance uniformity and BlackMURA measurements
Society for Information Display 2021
The increasing display sizes and changing form factors of displays, including automotive displays, lead to impractical measurement distances for lateral uniformity measurements. This contribution suggests and exemplarily applies two alternative and combinable methods to allow lateral uniformity measurements at low distances and describes an adjusted BlackMURA compliant validation procedure. The proposed methods are validated with a high-quality display device and are compared to results using the standard long-distance measurement procedure.
Distinguished Paper: Short Distance Uniformity and BlackMURA Measurements
Journal of the Society for Information Display
The increasing display sizes and changing form factors of displays, including automotive displays, lead to impractical measurement distances for lateral uniformity measurements. This contribution suggests and exemplarily applies two alternative and combinable methods to allow lateral uniformity measurements at low distances and describes an adjusted BlackMURA compliant validation procedure. The proposed methods are validated with a high-quality display device and are compared to results using the standard long-distance measurement procedure.
Repeatability and Reproducibility Considerations for BlackMURA Measurements
Proceedings of the International Display Workshops Volume 26 (IDW '19)
The “Uniformity measurement standard for Displays”, which is used for automotive applications, describes precise setup and alignment procedures to ensure reproducible measurement results. However, the influences of the tested device and the ILMD are not considered in detail. This contribution shows experiments and simulations to estimate these influences as well.
Conformity assessment with examples for BlackMURA measurements
Society for Information Display
To decide whether a display works according to the specification it is not only necessary to take the measurement values into account. The measurement uncertainty also plays a significant role in this decision. Besides some basic knowledge about the measurement uncertainty evaluation, the paper shows the main contributions and their influences for the key values of the BlackMURA standard. Using the rules of conformity assessment, the use of tolerance intervals and acceptance intervals is explained in detail to give all parties (OEMs, manufacturer of display and measurement system manufacturer) the chance to discuss their quality metrics in a reasonable manner.
Invited Paper: Recent Standardization Efforts and Measurement Procedures of German Automotive OEM and German Flat Panel Forum (DFF)
SID International Symposium 2016
The requirements of automotive displays differ to a large extent from consumer and industrial displays. In order to reduce the effort in specifying and evaluating high quality displays, German automotive OEMs, Tier 1/2 and the German Flat Panel Forum have launched a cooperation.
- Type:
- Add-On
- Applications:
- Automotive Display
- Measurands:
- Light measurement
- Tasks:
- Development & Industry