Mosaic oblique images and methods of making and using same
View Patent ↗A method for creating an oblique-mosaic image from a plurality of source images is disclosed. Initially, a desired area to be imaged and collected into an oblique-mosaic image is identified and then a mathematical model of a sensor of a virtual camera is created, where the virtual camera has an elevation greater than an elevation of the area to be imaged. The mathematical model has an oblique-mosaic pixel map for the sensor of the desired area. A surface location is determined for each pixel included in the oblique mosaic pixel map, and at least one source oblique image pixel of the area to be imaged is reprojected for each pixel included in the oblique-mosaic pixel map to thereby create an oblique-mosaic image of the desired geographical area. The at least one single oblique-mosaic image is visually pleasing and geographically accurate. Further, techniques for compensating for building lean in oblique-mosaic images are disclosed.
1. A method for creating an oblique-mosaic image from a plurality of source oblique images, comprising the steps of:
identifying a desired geographical area to be imaged and collected into an oblique-mosaic image;
creating a mathematical model of a virtual camera having a sensor higher in elevation from which the source oblique images were captured and looking down at an oblique angle, the mathematical model having an oblique-mosaic pixel map for the sensor of the desired area encompassing multiple source images, wherein the virtual camera includes the parameters of a focal point, a focal length, and a size of a focal plane;
assigning a geographic coordinate to each pixel included in the oblique mosaic pixel map;
selecting source oblique images of the geographic coordinates captured at an oblique angle and compass direction similar to the oblique angle and compass direction of the virtual camera; and
reprojecting, using a mathematical elevation model to define a ground surface within the desired geographical area, at least one source oblique image pixel of selected source oblique images of the area to be imaged from the vantage point of the sensor of the virtual camera for each pixel included in the oblique-mosaic pixel map in a fan-like pattern from the focal point of the virtual camera to thereby create a geo-referenced oblique-mosaic image of the desired geographical area.
2. The method of claim 1 , wherein the step of assigning is further defined by projecting each pixel through the perspective of the virtual camera to determine a corresponding geographic coordinate for each pixel in the oblique-mosaic pixel map.
3. The method of claim 1 , wherein multiple source oblique images represent the same geographic coordinate.
4. The method of claim 3 , wherein the pixels of each source oblique image that represent the same geographic coordinate are compared to determine which source pixel is most representative of the geographic coordinate, the more representative pixel to be included in the oblique-mosaic image.
5. The method of claim 1 , wherein the step of reprojecting is further defined by reprojecting the pixel to match the size and shape of the represented geographic coordinate as taken from the elevation, compass direction, and oblique angle of the virtual camera.
6. The method of claim 1 , wherein the step of reprojecting is further defined by removing the effects of elevation from the source oblique images prior to reprojection and then adding the effects of elevation to the oblique-mosaic image after reprojection.
7. The method of claim 1 , further comprising the step of minimizing lean of vertical structures within the oblique mosaic image.
8. The method of claim 7 , wherein the step of minimizing lean of vertical structures within the oblique mosaic image is defined further as the steps of creating an elevation model from the source oblique images taking into account the vertical structures, and reprojecting at least one source oblique image pixel of the area to be imaged.
9. The method of claim 7 , wherein the step of minimizing lean of vertical structures is defined further as matching vertical structures in multiple source oblique images and shifting pixels apparent location in at least one of the source oblique images by a relative height above a ground model.
10. The method of claim 1 , wherein metadata is stored with the oblique-mosaic image.
11. A method for creating an oblique-mosaic image from a plurality of source oblique images, comprising the steps of:
identifying a desired geographical area to be imaged and collected into an oblique-mosaic image;
creating a mathematical model of a virtual camera having a sensor, where the virtual camera has an elevation greater than an elevation from which the source oblique images were captured and looking down at an oblique angle, the mathematical model having an oblique-mosaic pixel map for the sensor of the desired area encompassing multiple source oblique images, wherein the virtual camera includes the parameters of a focal point, a focal length, and a size of a focal plane;
determining a geographic coordinate for each pixel included in the oblique mosaic pixel map;
selecting source oblique images of the geographic coordinates captured at an oblique angle and compass direction similar to the oblique angle and compass direction of the virtual camera; and
reprojecting, using a mathematical elevation model to define a ground surface within the desired geographical area, at least one source oblique image pixel of selected source oblique images of the area to be imaged from the vantage point of the sensor of the virtual camera for each pixel included in the oblique-mosaic pixel map in a fan-like pattern from the focal point of the virtual camera to thereby create a geo-referenced oblique-mosaic image of the desired geographical area.
12. The method of claim 11 , wherein the step of determining is further defined by projecting each pixel through the perspective of the virtual camera to determine a corresponding geographic coordinate for each pixel in the oblique-mosaic pixel map.
13. The method of claim 11 , wherein multiple source oblique images represent the same geographic coordinate.
14. The method of claim 13 , wherein the pixels of each source oblique image that represent the same geographic coordinate are compared to determine which source pixel is most representative of the geographic coordinate, the more representative pixel to be included in the oblique-mosaic image.
15. The method of claim 11 , wherein the step of reprojecting is further defined by reprojecting the pixel to match the size and shape of the represented geographic coordinate as taken from the elevation, compass direction, and oblique angle of the virtual camera.
16. The method of claim 11 , wherein the step of reprojecting is further defined by removing the effects of elevation from the source oblique images prior to reprojection and then adding the effects of elevation to the oblique-mosaic image after reprojection.
17. The method of claim 11 , further comprising the step of minimizing lean of vertical structures within the oblique mosaic image.
18. The method of claim 17 , wherein the step of minimizing lean of vertical structures within the oblique mosaic image is defined further as the steps of creating an elevation model from the source oblique images taking into account the vertical structures, and reprojecting at least one source oblique image pixel of the area to be imaged.
19. The method of claim 17 , wherein the step of minimizing lean of vertical structures is defined further as matching vertical structures in multiple source oblique images and shifting pixels apparent location in at least one of the source oblique images by a relative height above a ground model.
20. The method of claim 11 , wherein metadata is stored with the oblique-mosaic image.