Pitts S2-C pilot reported cockpit canopy separation during takeoff. Pilot rejected take off.

Narrative

During take off the canopy opened and departed the aircraft.The flight began uneventfully; I conducted a pre-flight; got in the airplane and started normal. Taxi to run up area and waited for the oil to warm up before performing my run-up check and before take off checks. Once that was completed I requested taxi instructions from ground and I asked if I can take XXR at intersection 1; which ground accepted. Once I was holding short I informed tower that I was ready and was given a take off clearance. I performed the last minute before take off items and taxied into the runway. I began my take off run and as I lifted the tail off the ground; the canopy violently swung open and departed the aircraft. I executed an immediate abort without issue and informed ATC of my intentions and potential FOD on the runway. I was given instructions back to parking and proceeded without any issued back to my hangar. The airport informed that they would meet me there with the missing items. I received my broken canopy with the handle in the lock position. As far as I could recall I made sure the canopy to be properly locked. I have a video of my taxiing showing the canopy locked. I'm not sure as to why it opened.