Method and apparatus for constructing three-dimensional map

Patent metadata

Field	Value
Publication number	US-10580206-B2
Application number	US-201715726017-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Mar 7, 2017
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

The present disclosure discloses a method and apparatus for constructing a three-dimensional map. A specific embodiment of the method includes: acquiring multiple frames of a monocular image containing a target object collected by a monocular camera, and constructing a three-dimensional map containing the target object and other objects in the monocular image based on the monocular image; determining an absolute scale of the target object, and determining a ratio of a relative scale corresponding to the target object to the absolute scale; and adjusting a scale of each object in the three-dimensional map to obtain a three-dimensional map meeting a preset condition based on the ratio. The method and apparatus provided by the present disclosure achieves the construction of a world coordinate system with absolute scales in a three-dimensional map constructed based on a monocular image.

First claim

What is claimed is:

1. A method for constructing a three-dimensional map, comprising:
acquiring a plurality of frames of a monocular image containing a target object collected by a monocular camera, and constructing a three-dimensional map containing the target object and other objects in the monocular image based on the monocular image, each object in the constructed three-dimensional map corresponding to a relative scale relative to a world coordinate system;
determining an absolute scale of the target object, and determining a ratio of the relative scale corresponding to the target object to the absolute scale, the absolute scale being an actual scale of the target object in the world coordinate system; and
adjusting a scale of each object in the three-dimensional map to obtain a three-dimensional map meeting a preset condition based on the ratio, the preset condition including: the each object in the three-dimensional map having the absolute scale;
wherein when the target object is a planar object, each type of the target object is preset with a corresponding absolute scale, the determining an absolute scale of the target object comprises: identifying a type of the target object, and using an absolute scale preset for the type of the target object as the absolute scale of the target object;
wherein the determining a ratio of the relative scale corresponding to the target object to the absolute scale comprises:
detecting an edge of the target object;
selecting points on the edge;
determining three-dimensional points in the three-dimensional map corresponding to the selected points on the edge;
calculating the relative scale corresponding to the target object based on coordinates of the three-dimensional points; and
determining the ratio of the relative scale corresponding to the target object to the absolute scale.

2. The method according to claim 1 , wherein when the target object is a non-planar object, before the acquiring the plurality of frames of a monocular image containing a target object collected by a monocular camera, the method further comprises:
performing a three-dimensional model construction for the target object to obtain a three-dimensional model of the target object, based on a characteristic point having a preset characteristic extracted from an image containing the target object, each three-dimensional point in the three-dimensional model having a coordinate in the world coordinate system, and the each three-dimensional point corresponding to a characteristic point and a preset characteristic of the characteristic point.

3. The method according to claim 2 , wherein the determining an absolute scale of the target object comprises:
detecting a profile of the target object;
extracting a characteristic point having a preset characteristic on the profile;
determining a three-dimensional point in the three-dimensional model of the target object corresponding to the extracted characteristic point, based on a matching relation between the preset characteristic of the extracted characteristic point and the preset characteristic corresponding to the three-dimensional point in the three-dimensional model of the target object; and
determining the absolute scale of the target object, based on a coordinate of the three-dimensional point in the three-dimensional model of the target object corresponding to the extracted characteristic point.

4. The method according to claim 3 , wherein the determining the ratio of the relative scale corresponding to the target object to the absolute scale comprises:
determining a three-dimensional point in the three-dimensional map corresponding to the extracted characteristic point;
determining the relative scale corresponding to the target object, based on the coordinate of the three-dimensional point in the three-dimensional map corresponding to the characteristic point; and
determining the ratio of the relative scale corresponding to the target object to the absolute scale.

5. An apparatus for constructing a three-dimensional map, comprising:
at least one processor; and
a memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform operations, the operations comprising:
acquiring a plurality of frames of a monocular image containing a target object collected by a monocular camera, and constructing a three-dimensional map containing the target object and other objects in the monocular image based on the monocular image, each object in the constructed three-dimensional map corresponding to a relative scale relative to a world coordinate system;
determining an absolute scale of the target object, and determining a ratio of the relative scale corresponding to the target object to the absolute scale, the absolute scale being an actual scale of the target object in the world coordinate system; and
adjusting a scale of each object in the three-dimensional map to obtain a three-dimensional map meeting a preset condition based on the ratio, the preset condition including: the each object in the three-dimensional map having the absolute scale;
wherein when the target object is a planar object, each type of the target object is preset with a corresponding absolute scale, the determining an absolute scale of the target object comprises: identifying a type of the target object, and using an absolute scale preset for the type of the target object as the absolute scale of the target object;
wherein the determining a ratio of the relative scale corresponding to the target object to the absolute scale comprises:
detecting an edge of the target object;
selecting points on the edge;
determining three-dimensional points in the three-dimensional map corresponding to the selected points on the edge;
calculating the relative scale corresponding to the target object based on coordinates of the three-dimensional points; and
determining the ratio of the relative scale corresponding to the target object to the absolute scale.

6. The apparatus according to claim 5 , wherein when the target object is a non-planar object, before acquiring the plurality of frames of a monocular image containing a target object collected by a monocular camera, the operations further comprise:
performing a three-dimensional model construction for the target object to obtain a three-dimensional model of the target object, based on a characteristic point having a preset characteristic extracted from an image containing the target object, each three-dimensional point in the three-dimensional model having a coordinate in the world coordinate system, and the each three-dimensional point corresponding to a characteristic point and a preset characteristic of the characteristic point.

7. The apparatus according to claim 6 , wherein the determining an absolute scale of the target object comprises:
detecting a profile of the target object;
extracting a characteristic point having a preset characteristic on the profile;
determining a three-dimensional point in the three-dimensional model of the target object corresponding to the extracted characteristic point, based on a matching relation between the preset characteristic of the extracted characteristic point and the preset characteristic corresponding to the three-dimensional point in the three-dimensional model of the target object; and
determining the absolute scale of the target object, based on a coordinate of the three-dimensional point in the three-dimensional model of the target object corresponding to the extracted characteristic point.

8. The apparatus according to claim 7 , wherein the determining the ratio of the relative scale corresponding to the target object to the absolute scale comprises:
determinin

Assignees

• Baidu online network technology beijing co ltd

Inventors

• Lin Yuan
• Chen Sili
• Dong Yuhua
• Zheng Binbin
• Yan Yijie
• Wu Zhongqin

Classifications

• G06T2200/08

  involving all processing steps from image acquisition to 3D model generation · CPC title

• G06T17/05 Primary

  Geographic models · CPC title

• G06T7/55

  from multiple images · CPC title

• G06T2207/10004

  Still image; Photographic image · CPC title

• G06T17/00 Primary

  Three-dimensional [3D] modelling for computer graphics · CPC title