# US 2019/0377952 A1 · RGB-D Camera Based Tracking System and Method Thereof

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- Number: US 2019/0377952 A1
- Document ID: US20190377952A1
- Status: Published application
- Kind: A1
- Application number: 16/312,039
- Filed: 2017-06-26
- Published: 2019-12-12
- Earliest claimed: 2016-06-24
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Soohwan KIM; Benzun Pious Wisely BABU; Zhixin YAN; Liu REN
- Web page: https://patentgrep.com/patent/US20190377952A1

## CPC

- G06V 20/46: {Extracting features or characteristics from the video content, e.g. video fingerprints, representative shots or key frames}
- G06F 16/7837: {using objects detected or recognised in the video content}
- G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51)
- G06T 7/579: from motion
- G06T 2207/20072: Graph-based image processing
- G06T 2207/20076: Probabilistic image processing
- G06T 2207/30241: Trajectory
- G06T 2207/30244: Camera pose
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A visual SLAM system comprises a plurality of keyframes including a keyframe, a current keyframe, and a previous keyframe, a dual dense visual odometry configured to provide a pairwise transformation estimate between two of the plurality of keyframes, a frame generator configured to create keyframe graph, a loop constraint evaluator adds a constraint to the receiving keyframe graph, and a graph optimizer configured to produce a map with trajectory.

## Claims

### Claim 1

A method for computing visual Simultaneous localization and Mapping (SLAM) comprising:
generating, by a visual odometry module, a local odometry estimate;
generating, by a keyframe generator, keyframes;
creating keyframe graph;
adding constraint to the keyframe graph using a loop constraint evaluator; and
optimizing the keyframe graph with trajectory.

### Claim 2 (depends on 1)

The method of claim 1 further comprising:
generating a new keyframe between a keyframe and a current frame before generating a local odometry estimate.

### Claim 3 (depends on 2)

The method of claim 2 wherein adding constraint to the keyframe graph using a loop constraint evaluator is based on a loop closure;
wherein the loop closure is the return to previously visited locations.

### Claim 4 (depends on 3)

The method of claim 3, further comprising adjusting a pose graph based on edge heights of different constraints in the keyframe graph after optimization.

### Claim 5

A method of applying a probabilistic sensor model for a dense visual odometry comprising:
generating, by a keyframe generator, keyframes;
creating keyframe graph;
adding constraint to the keyframe graph using a loop constraint evaluator; and
optimizing the keyframe graph with trajectory

### Claim 6 (depends on 5)

The method of claim 5 further comprising:
generating a new keyframe between a keyframe and a current frame before generating a local odometry estimate.

### Claim 7 (depends on 6)

The method of claim 6 wherein adding constraint to the keyframe graph using a loop constraint evaluator is based on a loop closure;
wherein the loop closure is the return to previously visited locations.

### Claim 8 (depends on 7)

The method of claim 7, further comprising adjusting a pose graph based on edge heights of different constraints in the keyframe graph after optimization.

### Claim 9

A method of t-distribution for photometric errors and a probabilistic sensor model for geometric errors comprising:
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### Claim 10

A visual SLAM system comprising:
a plurality of keyframes including a keyframe, a current keyframe, and a previous keyframe;
a dual dense visual odometry configured to provide a pairwise transformation estimate between two of the plurality of keyframes;
a frame generator configured to create keyframe graph;
a loop constraint evaluator adds a constraint to the receiving keyframe graph; and
a graph optimizer configured to produce a map with trajectory.