1.问题：

undefined reference to cv::softdouble::operator

解决方法：

set(OpenCV_LIBS
    libopencv_core.a
    libopencv_imgcodecs.a
    libopencv_imgproc.a)

   修改为以下即可

set(OpenCV_LIBS
    libopencv_imgcodecs.a
    libopencv_imgproc.a
    libopencv_core.a         // <--- Put core last)