Install python-opencv error: 'Unable to correct problems, you have held broken packages.'

When I tried to install opencv and python3-opencv for my HiFive Unleashed Rev A00, I got this error

root@buildroot:~# apt-get install libopencv-dev python3-opencv
Reading package lists… Done
Building dependency tree
Reading state information… Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libopencv-dev : Depends: libopencv-contrib-dev (= 3.2.0+dfsg-6+riscv64.1) but it is not going to be installed
Depends: libopencv-viz-dev (= 3.2.0+dfsg-6+riscv64.1) but it is not going to be installed
Depends: libopencv3.2-java (= 3.2.0+dfsg-6+riscv64.1) but it is not going to be installed
Depends: libopencv-contrib3.2 but it is not going to be installed
python3-opencv : Depends: libopencv-viz3.2 (= 3.2.0+dfsg-6+riscv64.1) but it is not going to be installed
Depends: libopencv-contrib3.2 but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

I also tried using

apt-get auto-clean
apt-get autoremove
apt update
apt upgrade

as requested from askubuntu.com. But nothing happened.

What image are you running? Why do you have apt-get commands available with a buildroot prompt?

I am working base on this tutorial.

[SOLVED]
I have downloaded and installed from source, include opencv and its dependencies