Hi Ahmad
Just giving you some ideas, not sure if it could work, but it is an idea.
Most modern TVs support something which is called HDMI CEC, which means that appliances connected via HDMI can send commands to the TV. This is also how the Chromecast powers on your TV. Here you can find some more info on HDMI CEC: http://www.howtogeek.com/207186/how-to-enable-hdmi-cec-on-your-tv-and-why-you-should/
What if you could find a way to have your DENON AVR send a command via HDMI to power on your TV? You will have to find out: first, if your DENON AVR is able to send this command, and secondly how the openHAB binding can invoke this command. I did something similar via my Raspberry 3 with Kodi and my Philips TV: https://community.openhab.org/t/switch-on-philips-tv-with-hdmi-cec-via-kodi/19603
Have fun!