System and method for generating textured map object images

Patent metadata

Field	Value
Publication number	US-9679362-B2
Application number	US-201013977792-A
Country	US
Kind code	B2
Filing date	Dec 30, 2010
Priority date	Dec 30, 2010
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A method of producing a textured or pseudo-3D image of one or more map objects is provided comprising acquiring at least one image representing at least part of the one or more map objects. Laser scan data is acquired for the at least one map object, the laser scan data representing distances from a laser scanner to one or more points on at least one surface of the at least one map object. Texture or lighting data associated with the at least one map object is generated from the laser scan data, and the texture or lighting data and the image is processed in order to generate at least one textured or pseudo 3D image at least partially representing the one or more map objects.

First claim

The invention claimed is:

1. A method of producing a pseudo-3D image of one or more map objects, comprising:
acquiring, by a processor, an image representing at least part of map object;
acquiring, by the processor, laser scan data for the at least part of the map object, the laser scan data representing distances from a laser scanner to one or more points on at least one surface of the map object;
determining, by the processor, a normal map, the normal map comprising or being representative of one or more normal vectors of at least one point of the at least one surface of the at least one map object;
normalizing, by the processor, said one or more normal vectors;
generating, by the processor, from the normal map, a texture map associated with the at least one map object from the laser scan data, the texture map being representative of light reflected from and/or shadows on the at least one surface of the map object;
processing, by the processor, the texture map and the image by combining corresponding portions of the texture map and image in order to generate a pseudo 3D image representing the at least part of the map object.

2. The method according to claim 1 , wherein the map object comprises a building and the at least one surface of the map object comprises at least one building facade.

3. The method according to claim 1 , wherein the method comprises generating a depth map, the depth map comprising, or being representative of, at least one of: (i) distances from a position of the laser scanner to one or more points on the at least one surface of the at least one map object; and (ii) distances from the surface of the map object.

4. The method according to claim 3 , wherein the depth map comprises an image comprising a plurality of pixels, wherein at least one pixel value may be representative of at least one of: (i) the distance between the laser scanner and the surface of the map object; and (ii) the distance from the surface of the map object.

5. The method according to claim 3 , the method comprising filling in one or more gaps in the depth map for which no distance data is available to produce a gap filled depth map.

6. The method according to claim 1 , wherein the method comprises projecting at least one laser beam generated by the laser scanner onto the at least one surface of the map object, receiving a reflected laser beam, and determining data indicative of a distance of the laser scanner from at least one point on the at least one surface of the at least one map object.

7. The method according to claim 1 , wherein the normal map comprises an image, the image comprising one or more pixels, wherein one or more pixel values are representative of a normal vector associated with at least one point of at least one surface of the at least one map object.

8. The method according to claim 7 , wherein red, green and blue values of a pixel are representative of coordinates defining the normal vector for a point of the surface of the map object represented by that pixel.

9. The method according to claim 1 , wherein generating the normal map comprises, for at least one pixel of the depth map or gap filled depth map, taking the cross product of at least three closest points to the pixel on the depth map or gap filled depth map in order to determine a normal vector of a point of the surface of the map object associated with that pixel of the depth map or gap filled depth map.

10. The method according to claim 1 , wherein the generation of the texture or light map comprises providing or determining at least one light source position, providing or determining at least one normalized light direction vector representative of a direction of the light source from at least one point on the at least one surface of the at least one map object and taking the dot product of at least one normal vector represented by at least one point or pixel in the normal map and the at least one normalized light direction vector from the light source position to a point of the surface of the map object associated with the point or pixel of the normal map.

11. The method according to claim 1 , wherein the combination of the texture map and image is based on pixel values of the texture map and pixel values of the image being combined on a pixel by pixel basis.

12. The method according to claim 1 , wherein the or each one of the normalized one or more vectors is represented as a value between −1 and 1.

13. A non-transitory computer program element comprising computer program code means to make a computer execute the method of claim 1 .

14. A system for producing a pseudo 3D image of one or more map objects, the system comprising:
a memory;
a processor, wherein the processor is configured to:
acquire an image at least part of a map object,
acquire laser scan data of the at least part of the map object, the laser scan data representing distances from a laser scanner to one or more points on surface of the at least one map object,
determine a normal map, the normal map comprising or being representative of one or more normal vectors of at least one point of the at least one surface of the at least one map object,
normalize said one or more normal vectors,
generate, from the normal map, a texture map associated with the at least one map object from the laser scan data, the texture map being representative of light reflected from and/or shadows on the at least one surface of the map object, and
process the texture map and the image by combining corresponding portions of the texture map and image in order to generate a pseudo 3D image representing the at least part of the map object.

15. A system according to claim 14 , wherein the processor comprises a graphics processing unit (GPU).

16. The system of claim 14 , wherein the system is a mobile mapping system comprising at least one laser scanner.

17. The system of claim 14 , wherein the combination of the texture map and image is based on pixel values of the texture map and pixel values of the image being combined on a pixel by pixel basis.

18. The system of claim 14 , wherein the or each one of the normalized one or more vectors is represented as a value between −1 and 1.

Assignees

• Chmielewski Radoslaw Pawel
• Wysokinski Michal
• Tomtom Global Content Bv

Inventors

• Chmielewski Radoslaw Pawel
• Wysokinski Michal

Classifications

• G06T2207/10028

  Range image; Depth image; 3D point clouds · CPC title

• G06T15/80

  Shading · CPC title

• G06T15/50

  Lighting effects · CPC title

• G06T15/205

  Image-based rendering · CPC title

• G06T15/04

  Texture mapping · CPC title