EmguCV cvextern System.DllNotFoundException

Question

I am trying to run the example of LicensePlateRecognition in EmguCV 3.1. But I always get the error System.DllNotFoundException and the message is that \"cvextern.dll cannot

Answer 1

I found this page after encountering a similar problem when upgrading a project from Emgu 3.1.0.2282 to 3.1.0.2504-r16.12

In my case it was because my Win10 computer did not have Visual C++ Redistributable for Visual Studio 2015 installed.

More specifically, in Emgu 3.1.0.2282 the "x86" and "x64" folders contained msvcr120.dll and msvcp120.dll, while in 3.1.0.2504 those folders now contain vcruntime140.dll and msvcp140.dll.

The new dependency isn't mentioned in the changelog or installation instructions, and there was no indication that cvextern.dll was failing because of the visual C runtime - only the error bin\Debug\x64\cvextern.dll failed with error code 126: The specified module could not be found

I've not needed to copy DLL files around to fix this: my bin directory contains only the Emgu.CV.UI and Emgu.CV.World DLL files, plus the "x86" and "x64" folders (containing 4 DLLs each). I mention this to steer people away from all the advice Google will pull up which was intended for older versions of Emgu.