opencv was used for human face posture detection some time ago, but C# has always been used in previous programming, so the efficiency of C++and opencv really gives me a headache.So in April, I resolutely turned to Emgu.

Emgu can be called simply by adding a DLL reference, without the tedious configuration in c++ projects.

But when I used HaarCascade class, I pointed out an error like this: probably it meant that I couldn't find cvextern.dll's reference.

Then I tried to add the reference cvextern.dll manually, but the tip was:

A reference to cvextern.dll could not be added

I looked at emgu's instructions and did not say that I would add environment variables.However, I manually added the environment variable of emgu, and the program can be executed normally.

There is another solution: copy the cvextern.dll in the Emgu directory to the debug directory where the program is written, so that it can run successfully.