Multi-View Aerial Imaging
A method for capturing a multi-view set of images of an area of interest, the multi-view set of images comprising, for each of a plurality of points within the area of interest, at least one nadir image and at least four oblique images from four substantially different viewing directions, the method comprising moving a dual-scan scanning camera along a survey path above the area of interest, and capturing, within selected intervals along the survey path and using the dual-scan scanning camera, subsets of the multi-view set of images of the area of interest along pairs of opposed non-linear scan paths.
1 . A method for capturing a multi-view set of images of an area of interest, the multi-view set of images comprising, for each of a plurality of points within the area of interest, at least one nadir image and at least four oblique images from four substantially different viewing directions, the method comprising moving a dual-scan scanning camera along a survey path above the area of interest, and capturing, within selected intervals along the survey path and using the dual-scan scanning camera, subsets of the multi-view set of images of the area of interest along pairs of opposed non-linear scan paths.
2 . The method of claim 1 , wherein the dual-scan scanning camera comprises two scanning cameras facing in substantially opposite directions, the method comprising capturing, within each selected interval along the survey path and using each scanning camera, a respective subset of the multi-view set of images of the area of interest along a respective non-linear scan path, each image in the subset having a unique viewing angle and viewing direction pair.
3 . The method of claim 2 , the method comprising, for each image within the subset, rotating a scanning mirror in an optical path of the corresponding scanning camera about a spin axis according to a spin angle, the spin axis tilted relative to a camera optical axis, the spin angle corresponding to a unique viewing angle and viewing direction pair.
4 . The method of claim 2 , the method comprising, for each image within the subset, rotating a scanning mirror in an optical path of the corresponding scanning camera about a spin axis according to a spin angle, the spin axis aligned with a camera optical axis, and tilting the scanning mirror according to a tilt angle, the spin angle and tilt angle pair corresponding to a unique viewing angle and viewing direction pair.
5 . The method of claim 2 , the method comprising, for each image within the subset, rotating a camera assembly of the corresponding scanning camera about a spin axis according to a spin angle, the spin axis aligned with a camera optical axis, and tilting a tilting mirror in an optical path of the scanning camera according to a tilt angle, the spin angle and tilt angle pair corresponding to a unique viewing angle and viewing direction pair.
6 . The method of claim 2 , the method comprising, for each image within the subset, rotating a camera assembly of the corresponding scanning camera about a spin axis according to a spin angle, the spin axis substantially orthogonal to a camera optical axis, and tilting a tilting mirror in an optical path of the scanning camera according to a tilt angle, the spin angle and tilt angle pair corresponding to a unique viewing angle and viewing direction pair.
7 . The method of claim 1 wherein each non-linear scan path comprises a smooth curve.
8 . The method of claim 1 wherein each non-linear scan path comprises two linear segments.
9 . The method of claim 1 wherein the two linear segments are substantially orthogonal.
10 . The method of claim 2 , wherein the two scanning cameras share a single camera assembly.
11 . The method of claim 10 , comprising multiplexing the single camera assembly between the two scanning cameras by rotating a multiplexing mirror in the optical paths of both scanning cameras between two operative positions.