Maybe it is a False positive virus detection like the one detected by Avast in 2017. Because you don't provide any information about which anti-virus program you are using, the only general advice left is to update your virus checker and run a virus scan and/or use another anti-virus checker to see if the same virus is detected.
OpenCV is a C program of which Anti-virus programs are known to recognize the signature of the compiler used as the basis for a computer virus. You can possibly test the program online via VirusTotal to see what other Anti-Virus programs think.