Balancing colors in a scanned three-dimensional image
A method of balancing colors of three-dimensional (3D) points measured by a scanner from a first location and a second location. The scanner measures 3D coordinates and colors of first object points from a first location and second object points from a second location. The scene is divided into local neighborhoods, each containing at least a first object point and a second object point. An adapted second color is determined for each second object point based at least in part on the colors of first object points in the local neighborhood.
1. A method of optically scanning and measuring a scene, the method comprising:
providing a first scanner, the scanner including a first light emitter for emitting a first light onto the scene, a first light receiver for receiving a first portion of the first light from the scene, and a first processor, the first scanner having a first angle measuring device, a second angle measuring device and a distance meter;
providing a second scanner, the second scanner including a second light emitter for emitting a second light onto the scene, a second light receiver for receiving a portion of the second light from the scene, and a second processor;
measuring with a first scanner in a first scanner location three-dimensional (3D) coordinates and a color for each of a plurality of first object points in the scene based at least in part on the emitting of the first light, an angle measured by the first angle measuring device, an angle measured by the second angle measuring device and a receiving of the first portion with the distance meter;
measuring with the second scanner in a second scanner location 3D coordinates and a color for each of a plurality of second object points in the scene based at least in part on the emitting of the second light and the receiving of the second portion;
selecting a plurality of areas within the scene, each area being defined by a plurality of cells and including at least one first object point from the first plurality of object points and further including at least one second object point from the second plurality of object points;
determining an adapted second color for each second object point, wherein in each of the plurality of areas the adapted second color is based at least in part on a statistical distribution of the colors of the at least one first object point in the area;
storing the 3D coordinates and the color for each first object point; and
storing the 3D coordinates and the adapted second color for each second object point.
2. The method of claim 1 , wherein the cells are determined by subdividing a measured space with a three-dimensional grid.
3. The method of claim 1 , wherein the cells have a cube shape.
4. The method of claim 3 , wherein the cubes have an edge length between two centimeters and a decimeter.
5. The method of claim 1 , wherein the cells have a tetrahedron shape.
6. The method of claim 1 , further comprising:
determining for each area of the plurality of areas a first color distribution, the first color distribution based at least in part on a relative frequency of color values of the first object points in the area; and
determining for each area of the plurality of areas a second color distribution, the second color distribution based at least in part on a relative frequency of color values of second object points in the area.
7. The method of claim 6 , further comprising determining a target distribution based at least in part on the first color distribution.
8. The method of claim 7 , wherein the adapted second color for each second object point is based at least in part on the target distribution.
9. The method of claim 7 , wherein the target distribution is further based at least in part on the second color distribution.
10. The method of claim 7 , wherein the target distribution is based at least in part on a first number of points in the first color distribution and a second number of points in the second color distribution.
11. The method of claim 7 , wherein the determining of the adapted second color further includes determining an adapted first color for each first object point, the adapted first color being based at least in part on the target distribution.
12. The method of claim 7 , further comprising adjusting the color of at least one second object point in a first cell of the plurality of cells based at least in part on a distance from the second object point to an adjacent cell of the plurality of cells and on the target distributions of the first cell and the adjacent cell.
13. The method of claim 1 , further comprising displaying a color image on a display of at least a portion of the first object points and the second object points.
14. The method of claim 13 , wherein the display is selected from a group consisting of a planar display, a panoramic display, and a 3D display.
15. The method of claim 1 , wherein in the selecting of the plurality of areas, each area includes a reference point.
16. The method of claim 15 , further comprising selecting the reference point from among the second object points.
17. The method of claim 15 , wherein the adapted second color of the reference point is based at least in part on colors of and distances to the first object points in the scene.