Originally Posted by
parabellum
Surely, before any information from shadows can be included you must know the height of the sun above the horizon, its position relative to the aircraft etc. also, just minor movement of the hand holding the smartphone will change the picture. Throughout this thread assumptions have been made without knowing any of the relevant trigonometry which has just been ignored.
Actually the trigonometry isn't complicated at all, particularly given some reasonable assumptions, such as:
a) the aircraft tracking more-or-less along the runway centreline up to the point where it rotates and becomes airborne, and
b) the sun staying in the same position in the sky for the duration of the takeoff roll
The point at which the aircraft rotates and becomes airborne can be readily discerned from the change in the angle that the wing L/E subtends with the horizon, the position of the wingtip/winglet relative to the runway edge marking and the distance between a point on the wing and its corresponding shadow on the runway.
Minor movements of the camera will have a negligible effect on any of those.