执行命令 sudo apt-get install libopencv-dev

报错如下：

The following packages have unmet dependencies:
 libopencv-dev : Depends: libopencv-objdetect-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-highgui-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-legacy-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-contrib-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-videostab-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-superres-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libopencv-ocl-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libcv-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libhighgui-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
                 Depends: libcvaux-dev (= 2.4.9.1+dfsg-1.5ubuntu1) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

尝试解决方案：

1.执行命令 sudo apt-get -f install   xxx   该命令无效

2.sudo aptitude install  xxx. 该命令是有效的，要注意 不接受未安装方案，接受降级方案。搞定。