Distortion correcting sensors for diagonal collection of oblique imagery

Abstract

A vehicle collects oblique imagery along a nominal heading using rotated camera-groups with optional distortion correcting electronic image sensors that align projected pixel columns or rows with a pre-determined direction on the ground, thereby improving collection quality, efficiency, and/or cost. In a first aspect, the camera-groups are rotated diagonal to the nominal heading. In a second aspect, the distortion correcting electronic image sensors align projected pixel columns or rows with a pre-determined direction on the ground. In a third aspect, the distortion correcting electronic image sensors are rotated around the optical axis of the camera. In a fourth aspect, cameras collect images in strips and the strips from different cameras overlap, providing large-baseline, small-time difference stereopsis.

1 . (canceled) 
     
     
         2 . A method comprising:
 operating a vehicle in a nominal heading;   capturing oblique imagery of a surface via one or more respective camera-groups comprising 4 particular camera-groups having respective particular plan angles of approximately 45, 135, 225, and 315 degrees with respect to the nominal heading, at least one of the 4 particular camera-groups comprising at least one camera comprising at least one distortion correcting electronic image sensor; and   wherein the at least one distortion correcting electronic image sensor comprises one or more one-dimensional collections of a plurality of pixel elements, and at least a particular one of the one-dimensional collections is oriented to align a projection of the particular one-dimensional collection with the nominal heading.   
     
     
         3 . The method of  claim 2 , wherein the one-dimensional collections correspond to one of a collection of rows and a collection of columns of the at least one distortion correcting electronic image sensor. 
     
     
         4 . The method of  claim 2 , wherein the capturing oblique imagery is in accordance with a down angle of the at least one camera, and the orienting is based at least in part on the down angle. 
     
     
         5 . The method of  claim 2 , wherein the orienting is in accordance with any one or more of increasing a swath width and increasing uniformity of projection of pixels onto the surface. 
     
     
         6 . The method of  claim 2 , further comprising:
 wherein the capturing oblique imagery comprises capturing a plurality of images from at least a first one of the respective camera-groups;   wherein the plurality of images is captured sequentially in a strip;   wherein the plurality of images is a first plurality of images, the strip is a first strip, the capturing oblique imagery further comprises capturing a second plurality of images from at least a second one of the respective camera-groups as a second strip, and the first strip and the second strip overlap with each other; and   wherein a first image in the first strip overlaps with a second image in the second strip, the first image is captured at a first period in time, the second image is captured at a second period in time, and the first period in time is distinct from the second period in time.   
     
     
         7 . The method of  claim 2 , wherein the vehicle is a flying vehicle and the surface is the ground. 
     
     
         8 . The method of  claim 2 , wherein the nominal heading is nominally an intercardinal direction. 
     
     
         9 . A method comprising:
 operating a vehicle in a nominal heading;   capturing oblique imagery of a surface via one or more respective camera-groups comprising 4 particular camera-groups having respective particular plan angles of approximately 45, 135, 225, and 315 degrees with respect to the nominal heading, at least one camera of at least one of the 4 particular camera-groups comprising at least one distortion correcting electronic image sensor; and   wherein the at least one camera has an associated Petzval surface, and the at least one distortion correcting electronic image sensor is rotated at an angle based at least in part on a position of the at least one distortion correcting electronic image sensor in the Petzval surface.   
     
     
         10 . The method of  claim 9 , further comprising:
 wherein the capturing oblique imagery comprises capturing a plurality of images from at least a first one of the respective camera-groups;   wherein the plurality of images is captured sequentially in a strip;   wherein the plurality of images is a first plurality of images, the strip is a first strip, the capturing oblique imagery further comprises capturing a second plurality of images from at least a second one of the respective camera-groups as a second strip, and the first strip and the second strip overlap with each other; and   wherein a first image in the first strip overlaps with a second image in the second strip, the first image is captured at a first period in time, the second image is captured at a second period in time, and the first period in time is distinct from the second period in time.   
     
     
         11 . The method of  claim 9 , wherein the vehicle is a flying vehicle and the surface is the ground. 
     
     
         12 . The method of  claim 9 , wherein the nominal heading is nominally an intercardinal direction. 
     
     
         13 . An apparatus comprising:
 one or more respective camera-groups comprising 4 particular camera-groups enabled to capture oblique imagery of a surface, the respective camera-groups enabled to operate in a vehicle in accordance with a nominal heading, the 4 particular camera-groups having respective particular plan angles of approximately 45, 135, 225, and 315 degrees with respect to the nominal heading, at least one camera of at least one of the 4 particular camera-groups comprising at least one distortion correcting electronic image sensor; and   wherein the at least one distortion correcting electronic image sensor comprises one or more one-dimensional collections of a plurality of pixel elements, and at least a particular one of the one-dimensional collections is oriented to align a projection of the particular one-dimensional collection with the nominal heading.   
     
     
         14 . The apparatus of  claim 13 , wherein each of the one-dimensional collections correspond to one of respective rows and respective columns of the at least one distortion correcting electronic image sensor. 
     
     
         15 . The apparatus of  claim 13 , wherein the capturing oblique imagery is in accordance with a down angle of the at least one camera, and the orienting is based at least in part on the down angle. 
     
     
         16 . The apparatus of  claim 13 , wherein the orienting is in accordance with any one or more of increasing a swath width and increasing uniformity of projection of pixels onto the surface. 
     
     
         17 . The apparatus of  claim 13 , further comprising:
 wherein the capturing oblique imagery comprises capturing a plurality of images from at least a first one of the respective camera-groups;   wherein the plurality of images is captured sequentially in a strip;   wherein the plurality of images is a first plurality of images, the strip is a first strip, the capturing oblique imagery further comprises capturing a second plurality of images from at least a second one of the respective camera-groups as a second strip, and the first strip and the second strip overlap with each other; and   wherein a first image in the first strip overlaps with a second image in the second strip, the first image is captured at a first period in time, the second image is captured at a second period in time, and the first period in time is distinct from the second period in time.   
     
     
         18 . The apparatus of  claim 13 , wherein the vehicle is a flying vehicle and the surface is the ground. 
     
     
         19 . An apparatus comprising:
 one or more respective camera-groups comprising 4 particular camera-groups enabled to capture oblique imagery of a surface, the respective camera-groups enabled to operate in a vehicle in accordance with a nominal heading, the 4 particular camera-groups having respective particular plan angles of approximately 45, 135, 225, and 315 degrees with respect to the nominal heading, at least one camera of at least one of the 4 particular camera-groups comprising at least one distortion correcting electronic image sensor; and   wherein the at least one camera has an associated Petzval surface, and the at least one distortion correcting electronic image sensor is rotated at an angle based at least in part on a position of the at least one distortion correcting electronic image sensor in the Petzval surface.   
     
     
         20 . The apparatus of  claim 19 , further comprising:
 wherein the capturing oblique imagery comprises capturing a plurality of images from at least a first one of the respective camera-groups;   wherein the plurality of images is captured sequentially in a strip;   wherein the plurality of images is a first plurality of images, the strip is a first strip, the capturing oblique imagery further comprises capturing a second plurality of images from at least a second one of the respective camera-groups as a second strip, and the first strip and the second strip overlap with each other; and   wherein a first image in the first strip overlaps with a second image in the second strip, the first image is captured at a first period in time, the second image is captured at a second period in time, and the first period in time is distinct from the second period in time.   
     
     
         21 . The apparatus of  claim 19 , wherein the vehicle is a flying vehicle and the surface is the ground.