OpenCV版本显示错误

Question

I had installed opencv 2.4.9 it worked fine but I was not able to use imgproc header and drawMarker functions so I decided to install opencv 4.1.0 and I ran the cmake and everything but when I check the opencv version using pkg-config --modversion opencv it shows 2.4.9. by the way, I use ubuntu 14.04 and want to use c++ with opencv.

Answer 1

This is a common mistake. People are installing opencv from the first link and it is generally installing opencv 2.4.9 automatically they do not decide the version while installing.

First thing you need to do is to uninstall opencv. There is a post in this link how to uninstall opencv. The way I prefered:

sudo apt-get autoremove opencv-doc opencv-data libopencv-dev libopencv2.4-java libopencv2.4-jni python-opencv libopencv-core2.4 libopencv-gpu2.4 libopencv-ts2.4 libopencv-photo2.4 libopencv-contrib2.4 libopencv-imgproc2.4 libopencv-superres2.4 libopencv-stitching2.4 libopencv-ocl2.4 libopencv-legacy2.4 libopencv-ml2.4 libopencv-video2.4 libopencv-videostab2.4 libopencv-objdetect2.4 libopencv-calib3d2.4 

Then you need to install opencv again. I strongly recommend you this link . Read that article carefully and do the steps. You can decide the opencv version in the line for example version 3.4.3:

git checkout 3.4.3