License to enable additional tests for evaluation of display mura according to human visual perception
Human visual recognition of uniformity variations and other defects in displays is dependent on many factors including brightness, color, shape, size, and severity of deviations within the area of the display. Developed to allow automated visual inspection systems to accurately identify JND—artifacts just noticeable by a human observer—TrueMURA™ evaluates display mura (areas of non-uniformity) in a way that simulates a human observer’s perception of defect severity. These algorithms can ignore mura that is imperceptible to human observers and identify various types of mura that can be passed and failed based on evaluation criteria.
Part of the Radiant Vision Systems TrueTest™ Software family, the TrueMURA license supplements the many benefits of TrueTest Software to efficiently perform image-based measurements for luminance, chromaticity, and adds specific tests to evaluate over 15 types of display mura.
Illustration of some identifiable mura types in TrueMURA.
A comprehensive display mura test solution from Radiant combines TrueTest Software with the additional TrueMURA license and a ProMetric® Imaging Colorimeter or Photometer to perform rapid, automated visual inspection of displays. TrueMURA uses a ProMetric imager to test all display characteristics simultaneously, capturing and processing data much faster and more accurately than a human inspector or a spot measurement device.
- ProMetric Imaging Photometer or Colorimeter
- TrueTest™ Automated Visual Inspection Software
- 3.0 GHz and 8 cores
- 16-32 GB RAM
- Windows® 7 or 10, 64 bit
- Dual-monitor video output
- Ethernet 100/1000 or USB 2.0
Comprehensive display test suite
The TrueMURA module provides several mura tests in addition to what is offered in standard TrueTest Software. TrueMURA allows users to define a complete set of measurement parameters and set pass/fail criteria for different types, locations, and severities of mura in an image. The software module includes specific tests for identification and measurement of mura types including:
Available in standard TrueTest™ Software:
- Color Edge Mura
- Color Mura
- Diagonal Pattern Mura
- Polarizer Deformation
- Spot Pattern Mura
Captured image of display with mura (top), shown with TrueMURA analysis applied (Black Mura analysis example) (bottom).
Part of the TrueTest platform, any tests from the TrueMURA test library can be added to a sequence (which are stored, so multiple sequences can be created and recalled as needed), and test parameters and pass/fail settings can be input for each test. The entire sequence can be run end-to-end automatically. Individual test results are displayed and can be recorded in a report.
Just Noticeable Differences
Radiant’s TrueMURA software module is the first commercial system to provide advanced image analysis algorithms for computing JND (“Just Noticeable Differences”) in displays. These tests augment the defect analysis functions already available in Radiant’s TrueTest Automated Visual Inspection Software, including a complete test suite to evaluate luminance, chromaticity, and common display defects (non-uniformity, dead pixels, lines, and more). The JND detection algorithm incorporated in TrueMURA is based on U. S. patent 7,783,130, “Spatial Standard Observer” (SSO) technology, licensed by Radiant Vision Systems from the National Aeronautics and Space Administration (NASA).
JND analysis image (left) and outputs (right). TrueMURA analysis provides output of maximum, total, and single JND values.
Complete Measurement Solution
TrueMURA can be used with any ProMetric Imaging Colorimeter or Photometer, providing multiple options to achieve the field of view, pixel resolution, dynamic range, and cost requirements for your application.
Supported by Radiant's global support staff and distributor network, TrueMURA is field-proven and has been used to test displays in the latest high-value devices worldwide.
TrueMURA License Key Features and Highlights:
- Applies photometric and colorimetric measurement to values captured by imaging systems that simulate human visual perception of light and color
- Includes tests to detect over 15 types of display mura and pass/fail on visual appearance
- Single display test platform from R&D to production reduces cost and variability in display image quality assessment
- Objective, numerical evaluation of display mura using algorithms for computing JND (“Just Noticeable Differences”) based on U.S. Patent 7,783,130 licensed by Radiant from NASA
- Data analysis functions including bitmaps, isoplots, and cross-sections
TrueMURA enables evaluation of displays beyond standard TrueTest software tests to evaluate mura defects according to human visual perception.
- Display mura characterization for evaluation and design
- Detection of display mura with pass/fail thresholding for automated visual inspection
- Production quality control of display devices