Testing a Color Chart with User-Defined Colors in NI Video Measurement Suite

Updated May 14, 2018

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Software

  • Video Measurement Software

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NI Video Measurement Suite

Issue Details

I am using NI Video Measurement Suite (VMS) and I would like to perform a measurement on a color bar test pattern. However, the color bar chart that I am testing has customized colors. I would like to be able to define the colors used for the color bar measurement in VMS in order to perform a test with my custom test pattern. How can I test a customized color bar chart?
 

Solution

The Colour Bar measurement in VMS compares measured levels in the test line to the expected levels for eight colors in a standard color bar test pattern (white, yellow, cyan, green, magenta, red, blue, black). An example of the color bar chart expected by VMS is shown below. More information about the color bar measurement and the expected levels can be found in the NI Video Measurement Suite Help under Fundamentals » Video Measurements.



The Colour Bar measurement in VMS is designed to be used with this test pattern, and the expected color levels it uses for the measurements returned cannot be changed. However, there are still a few ways you can perform meaningful tests in VMS with a non-standard color bar chart.
  1. Use a reference image to establish what the expected measurements are for your test signal, as described in Using the MacBeth ColorChecker Chart. The color sections in your test pattern must be divided into six sections of equal width, as defined by the Colour Bar test, in order to use this method. After observing the actual measurements returned for your test pattern, you can choose to set your test limits around the measured results. 
  2. Use the Level Meter measurement to measure the expected levels for your test pattern and then compare measured test results to the standards you establish. The Level Meter measurement returns the amplitude levels of a section of the test line. You will need to take a separate level meter measurement for each color section in your test pattern. 
  3. Use the LabVIEW API for VMS to create a Vectorscope plot to visualize the levels of a custom color bar chart using the Level Meter test in VMS. The Community Example Building Customized Color Bar Chart - VMS includes a modified version of VideoMASTER Vector Plot Controls.vi that can be used with any customized color bar chart. The Vector Plot controls are limited by default to only the standard colors shown in the image above, but can be modified in LabVIEW, allowing the user to separate and customize the individual elements of the control.

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