1 of 13

Javed Ahmad1,2 , Matteo Toso2, Matteo Taiana2, Stuart James2, Alessio Del Bue2

Multi-view 3D Objects Localization

From Street-Level Scenes

Published at ICIAP 2022

1Università degli Studi di Genova

2Istituto Italiano Di Tecnologia

​

2 of 13

3D Scene Perception

Automate Mapping [1]

Augmented Reality [2]

Autonomous Driving [3]

Robot Vision System [4]

[1] Mapillary.com

[2] MEMEXProject.eu

[3] Motional.com

[4]Universal-Robots.com

​

3 of 13

3D Scene Perception – Multi-View Scenario

Challenges:

  • Crowdsourced
  • Varying camera positions
  • Illumination changes
  • Object scale

 

 

 

 

 

 

 

 

 

 

 

z

4 of 13

Multi-view 3D Object Localization – The Problem

“ Localize street-level static objects in 3D scene as perceived by multiple camera images ”[1]

​

Objects:

Benches, Street-signs, street-lights, traffic-lights & signs, Trash-cans, Lamppost Manholes, etc.

​

Source of Data:

Crowdsourced , a service by Mapillary[2]

​

Challenges:

    • Unknown cameras
    • Illumination changes
    • Varying camera positions
    • Different scale of objects

[1] Ahmad, J., Toso, M., Taiana, M., James, S., & Del Bue, A. (2022, May). Multi-view 3d objects localization from street-level scenes. In International Conference on Image Analysis and Processing (pp. 89-101). Cham: Springer International Publishing.

[2] https://www.mapillary.com/

5 of 13

Multi-view 3D Object Localization – The Dataset

Dataset: Mapillary Street-level Scenes

API: Mapillary Python SDK [1]

Access Data: Define Radius , Number of Images

​

[1] Mapillary Python SDK, mapillary api v4. https://www.mapillary.com/developer/apidocumentation, accessed: 2021-12-15

Barcelona Center

London Center

Paris Center

Genova Porto Antico

Mapillary Meta Data:

  • Instance Segmentation
  • GPS Position

6 of 13

Multi-view 3D Object Localization – The Preprocessing

How to use these crowd-sourced multiple images for 3D objects localization?

​

We need to know the exact positions and orientations of the cameras in the scene!

​

We reconstructed the scene using structure from motion (SfM) [1]

Porto Antico, Genova

Piazza Corvetto, Genova

Vienna Central Area

[1] Schonberger, Johannes L., and Jan-Michael Frahm. "Structure-from-motion revisited." Proceedings of the IEEE conference on computer vision and pattern recognition. 2016

​

7 of 13

Genova

Dataset: Mapillary

Metainfo: Instance Segmentation

Step 1: Preprocessing

Step 2: Estimating 3D Objects

 

Refined

3D points

 

SOR

2D Dets.

 

 

 

 

 

 

 

 

 

Filter Static Objects

2D Polygons

2D Bounding Boxes

Access Objects’ 3D Points and Metainfo

Step 3:

Matching 2D Detections

Multi-view 3D Object Localization – Proposed Approach

 

Sparse Reconstruction

Meta Data

Scene Data

 

Camera Parameters

 

8 of 13

Porto Antico, Genova

 

 

 

Multi-view 3D Object Localization – Visualizations

9 of 13

A Scene From Vienna

 

 

 

Traffic Sign

Street light

Traffic Sign

Store sign

Multi-view 3D Object Localization – Visualizations

10 of 13

Multi-view 3D Object Localization – Visualizations

Performance if there is occlusion

Performance if object changes the texture

11 of 13

Multi-view 3D Object Localization – Failure vs Best

Failure Case

Best Case

12 of 13

Metrics

3D Intersection Over Union (3D IOU)

2D Intersection Over Union (2D IOU)

Measures

3D:- TP, FP and FN to compute precision and recall

2D:- TP, FP and FN to compute mean average precision (mAP)

Comparison

Mapillary’s method of objects derived from multiple detections in multiple images [1]

[1] Mapillary Python SDK, mapillary api v4. https://www.mapillary.com/developer/apidocumentation, accessed: 2021-12-15

TP: True Positive FP: False Positive FP: False Negative

Projected

G.T 3D Box

2D Detection

Multi-view 3D Object Localization – The Evaluation

13 of 13

Conclusions

​

​

We addressed the challenge of 3D object localization by integrating sparse reconstruction with 2D detection information, yielding significant advancements with vital implications for augmented reality.