Some automated and semi-automated tools for linear feature extraction in two and three dimensions
A system for vector extraction comprising a vector extraction engine stored and operating on a network-connected computing device that loads raster images from a database stored and operating on a network-connected computing device, identifies features in the raster images, and computes a vector based on the features, and methods for feature and vector extraction.
1. A system for three-dimensional feature extraction from imagery of a surface, comprising:
a vector extraction engine operating on a computing device or network of computing devices;
wherein the vector extraction engine:
receives a stereoscopic raster image pair of the surface, the stereoscopic image pair comprising a first raster image and a second raster image;
identifies one or more image features that are homologous between the first raster image and second raster image;
computes a vector difference between the first raster image and the second raster image for each of the identified image features;
constructs a three-dimensional digital surface model of the surface based on the vector differences.
2. The system of claim 1 , further comprising a three-dimensional viewer operating on the computing device or network of computing devices;
wherein the three-dimensional viewer:
displays the surface on a user interface;
receives from the user interface a user-selected first point on the surface and a user-selected second point on the surface;
calculates a three-dimensional path along the digital surface model between the first point and the second point; and
displays a three-dimensional representation of the surface on the display showing the three-dimensional path along the surface.
3. The system of claim 2 , wherein the surface is displayed on the user interface as a two-dimensional representation.
4. The system of claim 2 , wherein the surface is displayed on the user interface as a three-dimensional representation.
5. The system of claim 2 , wherein the three-dimensional path is shown along the surface slightly raised from the three dimensional representation of the surface.
6. The system of claim 2 , wherein the three-dimensional path is calculated using a least-cost algorithm.
7. The system of claim 2 , further comprising additional user selected points on the surface between the first point and the second point, and wherein the three-dimensional path between the first point and the second point passes through each of the additional user selected points.
8. A method for three-dimensional feature extraction from image data of a surface, comprising the steps of:
receiving, using a vector extraction engine operating on a computing device or network of computing devices,
a stereoscopic raster image pair of the surface, the stereoscopic image pair comprising a first raster image and a second raster image; and
identifying, using a vector extraction engine stored and operating on a workstation computer, one or more image features that are homologous between the first raster image and second raster image;
computing a vector difference between the first raster image and the second raster image for each of the identified image features; and
constructing a three-dimensional digital surface model of the surface based on the vector differences.
9. The method of claim 8 , further comprising the step of operating a three-dimensional viewer on the computing device or network of computing devices;
wherein the three-dimensional viewer:
displays the surface on a user interface;
receives from the user interface a user-selected first point on the surface and a user-selected second point on the surface;
calculates a three-dimensional path along the digital surface model between the first point and the second point; and
displays a three-dimensional representation of the surface on the display showing the three-dimensional path along the surface.
10. The method of claim 8 , further comprising the step of displaying the surface on the user interface as a two-dimensional representation.
11. The method of claim 8 , further comprising the step of displaying the surface on the user interface as a three-dimensional representation.
12. The method of claim 8 , further comprising the step of showing the three-dimensional path along the surface slightly raised from the three dimensional representation of the surface.
13. The method of claim 8 , further comprising the step of calculating the three-dimensional path using a least-cost algorithm.
14. The method of claim 8 , further comprising the steps of receiving additional user selected points on the surface between the first point and the second point, and ensuring that the three-dimensional path between the first point and the second point passes through each of the additional user selected points.