A method and an apparatus determines a geometry of a scene by projecting one or more output image into the scene, in which a time to project the output image is t1. Input images are acquired of the scene, in which a time to acquire each input image is t2, and in which t1>t2 and in which the input image includes a distinguishable stripe of pixels with an edge due to t1>t2. An amount of distortion of the edge is measured from a straight line to determine a geometry of the scene.