Software for Evaluating Display Mura and Computing JND

The TrueMURA™ Display Mura Analysis License from Radiant Vision Systems allows additional tests for assessing display mura based on human visual perception. The visual recognition of uniformity variations and other defects in displays by humans is based on various factors such as size, shape, color, brightness and severity of deviations inside the display area.

The TrueMURA™ has been designed to enable automated visual inspection systems to precisely identify JND—artifacts just noticeable by a human observer—thus assessing display mura (non-uniform areas) such that a human observer’s perception of defect severity is simulated.

These algorithms can ignore mura imperceptible to human observers and find different forms of mura that can be failed or passed based on JND calculations or user-defined criteria.

The TrueMURA license forms part of the Radiant Vision Systems TrueTest™ Software series and supplements the various advantages of TrueTest Software to effectively conduct image-based measurements for chromaticity and luminance while adding particular tests to assess more than 15 types of display mura.

Advanced Image Analysis Algorithms for Computing JND

Image Credit: Radiant Vision Systems

Comprehensive Display Test Suite

The TrueMURA Software license offers various mura tests apart from what is provided in standard TrueTest Software. TrueMURA enables users to delineate a complete set of measurement parameters and set pass/fail criteria for several types, locations and severities of mura in an image. The software license offers particular tests for identification and measurement of mura types, such as:

TrueMURATest:

  • Butterfly mura
  • Black mura
  • Edge mura
  • Blob analysis
  • Spot mura
  • Corner light
  • Line mura
  • Diagonal line mura
  • LED mura

The following tests are available in standard TrueTest™ Software:

  • Spot pattern mura
  • Color edge mura
  • Polarizer deformation
  • Color mura
  • Diagonal pattern mura

Captured image of display with mura (top), shown with TrueMURA analysis applied (Black Mura analysis example) (bottom).

Captured image of display with mura (top), shown with TrueMURA analysis applied (Black Mura analysis example) (bottom).

Captured image of display with mura (top), shown with TrueMURA analysis applied (Black Mura analysis example) (bottom). Image Credit: Radiant Vision Systems

The TrueMURA test library is part of the TrueTest platform and any tests from this library can be added to a series (which are stored to enable multiple sequences to be created and recalled as required) and pass/fail settings and test parameters can be input for each test. The complete sequence can be automatically run end-to-end. Individual test results are displayed and can be recorded in a report.

Just Noticeable Differences

The TrueMURA Software from Radiant Vision Systems is the first commercial system to offer sophisticated image analysis algorithms for computing JND ('Just Noticeable Differences') in displays.

The tests supplement the defect analysis functions that are available already in Radiant Vision Systems’ TrueTest Automated Visual Inspection Software, which includes a comprehensive test suite to assess chromaticity, luminance and common display defects (such as lines, dead pixels, non-uniformity and much more).

The JND detection algorithm integrated into TrueMURA has been developed 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).

Advanced Image Analysis Algorithms for Computing JND

Image Credit: Radiant Vision Systems

JND analysis image (left) and outputs (right). TrueMURA analysis provides output of maximum, total, and single JND values.

JND analysis image (left) and outputs (right). TrueMURA analysis provides output of maximum, total and single JND values. Image Credit: Radiant Vision Systems

Complete Measurement Solution

The TrueMURA software can be used with a ProMetric Imaging Colorimeter or Photometer, thus offering several options to realize the pixel resolution, field of view, cost requirements and dynamic range for users’ application.

The TrueMURA is supported by Radiant Vision Systems’ worldwide support staff and distributor network, is field-proven and has been employed to test displays in the most advanced high-value devices across the world.

Advanced Image Analysis Algorithms for Computing JND

Image Credit: Radiant Vision Systems

TrueMURA License Key Features and Highlights

  • Includes tests for identifying more than 15 types of display mura and pass/fail on visual appearance
  • Colorimetric and photometric measurement is applied to values captured by imaging systems that mimic human visual perception of color and light
  • Supports R&D and production applications, ensuring cost efficiency and consistency of measurement data throughout manufacturing
  • Data analysis functions offered are cross-sections, bitmaps and isoplots
  • Objective and numerical assessment of display mura through algorithms for computing JND ('Just Noticeable Differences') based on U.S. Patent 7,783,130 licensed by Radiant from NASA

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