Wednesday, 16 May 2018

calculations - Calculate camera tilt angle from 2D image



I want to calculate the camera's tilt angle from a photograph, without knowing anything about the camera (or lens). Suppose I can extrapolate the vanishing points (one-point or two-point perspective):


enter image description here


enter image description here


Is it possible to determine the tilt angle? Perhaps by measuring the distance between the vanishing point(s) and the centre of the image?




Answer



In my opinion, the best way to do this is using a 3D program.


Sketchup has a special feature to mark the vanishing points of an image and that sets the camera position.


https://help.sketchup.com/es/article/3000115


The image is from Sketchup webpage.


enter image description here


On Blender there is an addon to do this. It is explained on this video: https://youtu.be/nb6rSMAooDs?t=2m16s


And the addon is here: https://github.com/stuffmatic/blam




Once you find the vanishing points, the horizon which is the line between them establishes the position of "eye-level" or the actual "elevation" of the camera lens. Use that as valuable information to establish "tilt" angle of camera.



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