Searching for a solution(tool) for comparing two images (1. expected image, 2. real time captured image) to identify difference with high accuracy for automation testing to integrate it with VB.net.

If it also supports OCR functionality then one more problem of mine will be solved.

  • Can you give us some example images of what exactly you want to compare/achieve? Do you need image compare or OCR? Or both? For image compare, try Sikuli or Kantu(has a VB.Net API), for a free OCR service to call from VB.net, try OCR.space
    – Bobby231
    Commented Feb 25, 2017 at 9:19

1 Answer 1


There are numerous ways to compare images from most programming languages. You could try the open-source library ImageMagick which also has a .Net implementation here. If the .Net library doesn't work you can always install the program itself and run it from a Process.start.

ImageMagick has extensive compare options, running a percentage match, display the difference if it fails. Check the compare functionality here: https://www.imagemagick.org/script/compare.php

Alternatives are:

  • Sikuli4Net: https://sourceforge.net/projects/sikuli4net/ (based on the Java Sikuli image-based testing tools)
  • Write your own image compare class (have a look at my image search class for VB.net, the search functions checks if an image exists with in another image and returns a point, if it returns a point two images are the same or the first contains the second. You should be able to rewrite this very easily to a compare function. I used this as a simple image-based testing tool for VB.net instead of using the overhead of something like Sikuli)

For the OCR part I would look at another library as suggested here: https://stackoverflow.com/questions/5552599/fast-ocr-in-vb-net

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