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Image verification point considerations

Technote (FAQ)


When do you record an image verification point (imageVP) in an IBM Rational Functional Tester (RFT) script?


You see that the imageVP fails unexpectedly. The actual and the baseline image look exactly the same.


Use image verification, if image verification is the only option. Use another verification method if possible.

The reason is that image verification is a strict pixel to pixel comparison. RFT compares every pixel in the actual with the corresponding pixel in the baseline. Differences arise from external factors. RFT depends on the pixels that the graphics card sends. In time the graphics card might send a slightly different pixel set. You cannot see the differences with naked eye.


  • In RFT you can adjust the verification tolerance, to get less unjust failures. See the following technote

    1647451: Playback yields failing image verification without difference in Comparator
  • In application monitoring when you run the script repeatedly, you see that the imageVP fails multiple times. You need to investigate if RFT incorrectly issued a verification point failure or that the actual and baseline are really different. Therefore the recommendation is to use another verification method.

Document information

More support for: Rational Functional Tester
Test Applications

Software version: 8.0, 8.1, 8.2, 8.3, 8.5

Operating system(s): Windows

Reference #: 1657104

Modified date: 22 November 2013

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