板子上面安装rknn-toolkit问题

我使用命令 pip3.6 install -r requirements-cpu.txt 提示如下问题：

Collecting flask>=1.0.2 (from -r requirements-cpu.txt (line 10))
  Using cached https://files.pythonhosted.org/p ... y2.py3-none-any.whl
Collecting dill==0.2.8.2 (from -r requirements-cpu.txt (line 11))
  Using cached https://files.pythonhosted.org/p ... dill-0.2.8.2.tar.gz
Collecting opencv-python>=3.4.3.18 (from -r requirements-cpu.txt (line 12))
  Could not find a version that satisfies the requirement opencv-python>=3.4.3.18 (from -r requirements-cpu.txt (line 12)) (from versions: )
No matching distribution found for opencv-python>=3.4.3.18 (from -r requirements-cpu.txt (line 12))


请问怎么解决呢？

requirement文件是给PC机安装环境用的，板子上不需要这个。
开发板安装环境请参考wiki人工智能章节

好的，谢谢。