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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Introduction to the theory of belief functions:
An application to intelligent vehicles
Philippe XU1,2
Franck DAVOINE2
Thierry DENOEUX1
Huijing ZHAO2
1
1UMR CNRS 7253 HEUDIASYC
Université de Technologie de Compiègne
2LIAMA, CNRS
Peking University
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Mon parcours à l’ENS
• 2008-2011: ENS Cachan - Antenne de Bretagne Magistère Informatique et télécommunications
• 2009-2010: National Taiwan University Année d’échange (M1)
• Stage de recherches: • 2011: LIAMA, Peking University (Franck Davoine, Huijing Zhao)
Multi-sensor Based Object Detection in Driving Scenes
• 2010: LIAMA, Chinese Academy of Science (Franck Davoine)
Multi-modal Pedestrian Detection
• 2009: IRISA, VistaS (Patrick Pérez) Detection and Tracking of Moving Objets in Crowded Scenes
2
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Thèse
• 2011-…: HEUDIASYC (UTC), F. Davoine, T. Denoeux
Information Fusion for Urban Scenes Understanding
• LIAMA MPR: HEUDIASYC (CNRS), KLMP (PKU)
• ANR-NSFC PRETIV: HEUDIASYC (CNRS), KLMP (PKU), eMotion (INRIA), PSA Peugeot Citroën
• ICT-ASIA PREDIMAP: HEUDIASYC (CNRS), KLMP (PKU), SJTU (Shanghai), CSIS (University of Tokyo), MATIS (IGN), eMotion (INRIA), AITGC (Thailand)
3
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
LIAMA
4
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
LIAMA
Site internet: liama.ia.ac.cn
Projets de recherche:
• Multimodal Scene Understanding: MPR, CAVSA
• Massive Computing: LSPDS, YOUHUA
• Trustworth Software: ECCA, CRYPT, FORMES
• Shapes Modeling: CCM, cPlant, CAD, TIPE
5
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
HEUDIASYC
6
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
HEUDIASYC
• 9 CR CNRS + 41 Enseignants-Chercheurs + 72 Doctorants + …
• Labex MS2T: Maîtrise des Systèmes de Systèmes Technologiques
• Robotex: Equipement d’excellence
• Evaluation AERES: A+
7
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
8
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
9
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Fiction et réalité
10
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
I, Rodney Brooks, Am a Robot
Four basic capabilities that any true AGI (Artificial General Intelligence) should possess:
• The social understanding of an 8-year-old child
• The manual dexterity of a 6-year-old child
• The language capabilities of a 4-year-old child
• The object-recognition capabilities of a 2-year-old child
http://spectrum.ieee.org/computing/hardware/i-rodney-brooks-am-a-robot/1
11
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
I, Rodney Brooks, Am a Robot
Four basic capabilities that any true AGI (Artificial General Intelligence) should possess:
• The social understanding of an 8-year-old child
• The manual dexterity of a 6-year-old child
• The language capabilities of a 4-year-old child
• The object-recognition capabilities of a 2-year-old child
http://spectrum.ieee.org/computing/hardware/i-rodney-brooks-am-a-robot/1
12
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
I, Rodney Brooks, Am a Robot
Four basic capabilities that any true AGI (Artificial General Intelligence) should possess:
• The social understanding of an 8-year-old child
• The manual dexterity of a 6-year-old child
• The language capabilities of a 4-year-old child
• The object-recognition capabilities of a 2-year-old child
http://spectrum.ieee.org/computing/hardware/i-rodney-brooks-am-a-robot/1
13
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
I, Rodney Brooks, Am a Robot
Four basic capabilities that any true AGI (Artificial General Intelligence) should possess:
• The social understanding of an 8-year-old child
• The manual dexterity of a 6-year-old child
• The language capabilities of a 4-year-old child
• The object-recognition capabilities of a 2-year-old child
http://spectrum.ieee.org/computing/hardware/i-rodney-brooks-am-a-robot/1
14
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
DARPA Grand Challenge 2004
• Defense Advanced Research Projects Agency
• Barstow (California) -> Primm (Nevada)
• 240 km/10 heures
• $1 million
15
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Quinze participants
16
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Résultats
• Aucun véhicule ne termine le parcours
• Meilleur score: 11,78 km (CMU)
17
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
DARPA Grand Challenge 2005
• $2 million
• 23 participants
• 5 terminent le parcours
• 1er: Stanley (Stanford), 6h53min
• 2ème: Sandstorm (CMU), +11min
• 3ème: H1ghlander (CMU), +10min
• 4ème: Kat-5 (+20min), TerraMax (+5h)
18
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
More challenges
• DARPA Urban Challenge (2007)
• DARPA Robotics Challenge (2012-2014)
• Chine: The Future Challenge (every year since 2009)
19
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Google car
20
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Scène routière à Pékin
21
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Nos véhicules
22
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Compréhension de scène
23
Scene
Tree Sky Car Pedestrian Car Road Car Traffic light Car
Composed-of
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
24
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Raisonnement dans l’incertain
Dans de nombreux domaines des sciences appliquées, nous sommes amenés à raisonner à partir de connaissances imparfaites.
Ex: données en provenance de capteurs, d’experts, de modèles, …
25
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Data-related Fusion Aspects B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
26
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Data-related Fusion Aspects B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
27
« Je crois que Jean mesure 1,5
mètre. »
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Data-related Fusion Aspects B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
28
« Jean mesure entre 1,5 mètre
et 2 mètres. »
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Data-related Fusion Aspects B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
29
« Jean est grand. »
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Data-related Fusion Aspects B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
30
« Il est possible que Jean
mesure plus de 1,5 mètre. »
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Théories et imperfections B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”.
Information Fusion, vol. 14(1), pp. 28-44, 2013
31
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Théorie des probabilités
• La théorie des probabilités peut représenter:
• Incertitude aléatoire: interprétation fréquentielle
• Incertitude épistémique: interprétation subjective
• Problème en tant que modèle de l’incertitude épistémique (modèle Bayesien):
• Impossibilité de représenter l’ignorance (totale ou partielle)
32
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Représentation de l’ignorance
• Principle of Indifference: en l’absence d’information concernant une quantité X, une probabilité égale doit être mise sur toutes les valeurs possibles de X.
• Premier problème: une probabilité uniforme et l’ignorance sont représentées de la même manière.
33
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
L’exemple de l’eau et du vin
Soit une bouteille contenant un mélange d’eau et de vin.
La bouteille contient: • au moins autant d’eau que de vin,
• au plus deux fois plus d’eau que de vin.
Question: «Quelle est la probabilité que la bouteille contienne au plus 1.5 fois plus d’eau que de vin?»
34
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
L’exemple de l’eau et du vin
Avec 𝒓𝒆/𝒗 le rapport eau sur vin:
𝟏 ≤ 𝒓𝒆/𝒗 ≤ 𝟐;
loi de proba uniforme sur [𝟏, 𝟐];
𝑷 𝒓𝒆/𝒗 ≤ 𝟑/𝟐 = 𝟎. 𝟓.
Avec 𝒓𝒗/𝒆 le rapport vin sur eau:
𝟏 ≤ 𝒓𝒆/𝒗 ≤ 𝟐⟺ 𝟏/𝟐 ≤ 𝒓𝒗/𝒆 ≤ 𝟏;
loi de proba uniforme sur [𝟏/𝟐, 𝟏];
𝒓𝒆/𝒗 ≤ 𝟑/𝟐 ⟺ 𝒓𝒗/𝒆 ≥ 𝟐/𝟑
𝑷 𝒓𝒆/𝒗 ≤ 𝟑/𝟐 =
𝑷 𝒓𝒗/𝒆 ≥ 𝟐/𝟑 = 𝟐/𝟑.
Contradiction
35
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Limitation de la granularité
Ce que le conducteur
perçoit: une voiture
noire à l’arrêt sur la
droite.
Ce qu’un capteur laser perçoit:
présence d’un obstacle en forme de ‘L’.
C’est peut-être une voiture, ou un bus, ou un camion, ou un bâtiment, etc…
36
-15 -10 -5 0 5 10 150
5
10
15
Voiture
Obstacle
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Théorie des fonctions de croyance Theory of belief functions
• Autres dénominations: • Théorie de Dempster-Shafer (Dempster-Shafer theory)
• Théorie de l’évidence (Evidence theory)
• Modèle des croyances transférables (Transferable belief model)
• Quelques grands noms: • Dempster (1968)
• Shafer (1976)
• Smets (1980-1990)
37
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Fonction de masse
• Soit X une variable à valeur dans un ensemble fini 𝛀 (cadre de discernement).
• Fonction de masse: 𝒎:𝟐𝛀 → 𝟎; 𝟏 telle que
𝒎(𝑨)
𝑨⊆𝛀
= 𝟏
• m(A) représente la croyance concernant l’appartenance de X à l’ensemble A, mais à aucun sous-ensemble strict de A.
38
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Exemple d’un capteur laser
• Un capteur laser peut mesure la présence d’obstacle. 2 cas possibles: 𝛀 = {𝑶,𝑶 }.
• Le capteur n’est pas parfait, la mesure est fausse dans 20% des cas.
• Représentation de l’information quand le laser mesure la présence d’un obstacle:
𝒎 𝑶 = 𝟎. 𝟖, 𝒎 𝛀 = 𝟎. 𝟐
• La masse 0.2 n’est pas allouée à {𝑶 }, aucune information ne soutient l’absence d’obstacle!
39
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Raffinement
• Un cadre de discernement peut être raffiné en partitionnant un ou plusieurs de ses éléments.
• Ex: Obstacle = {voiture, piéton}.
• Cadre de discernement: 𝛀 = {𝑽, 𝑷, 𝑶 }.
• La masse est simplement conserver sur l’ensemble des éléments raffinés.
𝒎 𝑽,𝑷 = 𝟎. 𝟖, 𝒎 𝛀 = 𝟎. 𝟐
40
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
41
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Combinaison conjonctive
• Règle de Dempster non-normalisée:
𝒎𝟏⨅𝒎𝟐 𝑨 = 𝒎𝟏(𝑩)𝒎𝟐(𝑪)
𝑩∩𝑪=𝑨
• Règle de Dempster normalisée:
𝒎𝟏⨁𝒎𝟐 𝑨 =
(𝒎𝟏⨅𝒎𝟐)(𝑨)
𝟏 − 𝑲𝟏𝟐𝒔𝒊 𝑨 ≠ ∅
𝟎 𝒔𝒊 𝑨 = ∅
𝑲𝟏𝟐 = (𝒎𝟏⨅𝒎𝟐)(∅): degré de conflit entre les deux sources d’information.
42
Soient 𝒎𝟏 et 𝒎𝟐 deux fonctions de masse sur 𝛀 induites par deux sources d’information indépendantes.
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Exemple du capteur laser
• Information issue du laser:
𝒎𝟏 𝑽, 𝑷 = 𝟎. 𝟖,𝒎𝟏 𝛀 = 𝟎. 𝟐.
• Nouvelle source d’information:
𝒎𝟐 𝑷,𝑶 = 𝟎. 𝟔,𝒎𝟐 𝛀 = 𝟎. 𝟒.
43
{𝑽𝒐𝒊𝒕𝒖𝒓𝒆, 𝑷𝒊é𝒕𝒐𝒏} 0.8
𝜴 0.2
𝑷𝒊é𝒕𝒐𝒏,𝑶𝒃𝒔𝒕𝒂𝒄𝒍𝒆
0.6
{𝑷𝒊é𝒕𝒐𝒏} 0.48
𝑷𝒊é𝒕𝒐𝒏,𝑶𝒃𝒔𝒕𝒂𝒄𝒍𝒆
0.12
𝜴 0.4
𝑽𝒐𝒊𝒕𝒖𝒓𝒆, 𝑷𝒊é𝒕𝒐𝒏 0.32
𝜴 0.08
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Belief and plausibility functions
44
• bel(A) = degree to which the evidence supports A.
• pl(A) = degree of support that could be assigned to A if more specific information became available.
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Prise de décision
∅ {𝑃} {𝑉} {𝑂 } {𝑃, 𝑉} {𝑃, 𝑂 } {𝑉, 𝑂 } Ω
𝑚 0 0.48 0 0 0.32 0.12 0 0.08
𝑏𝑒𝑙 0 0.48 0 0 0.8 0.6 0 1
𝑝𝑙 0 1 0.4 0.2 1 1 0.48 1
45
{𝑽𝒐𝒊𝒕𝒖𝒓𝒆, 𝑷𝒊é𝒕𝒐𝒏} 0.8
𝜴 0.2
𝑷𝒊é𝒕𝒐𝒏,𝑶𝒃𝒔𝒕𝒂𝒄𝒍𝒆
0.6
{𝑷𝒊é𝒕𝒐𝒏} 0.48
𝑷𝒊é𝒕𝒐𝒏,𝑶𝒃𝒔𝒕𝒂𝒄𝒍𝒆
0.12
𝜴 0.4
𝑽𝒐𝒊𝒕𝒖𝒓𝒆, 𝑷𝒊é𝒕𝒐𝒏 0.32
𝜴 0.08
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
46
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Contexte multi-capteurs
47
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Objectifs
48
Scene
Tree Sky Car Pedestrian Car Road Car Traffic light Car
Composed-of
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Perceptions différentes du monde
Données issues des capteurs:
Sorties des détecteurs d’objets:
49
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Vue d’ensemble du système
• Plusieurs capteurs fournissent en données un ou plusieurs modules de traitement.
• Utilisation de blocs de traitement indépendants dans leur propre espace de raisonnement.
• Les sorties des modules (fonctions de masse) sont combinées sur un cadre de discernement unifié au niveau d’une image sursegmentée.
50
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Combinaison de modules
51
Ground Ground
Vegetation Vegetation
Sky Sky
Vegetation Vegetation
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Sky
Combinaison de modules
52
Ground Ground
Vegetation Vegetation
Sky
Vegetation Vegetation
Grass Road Tree/Bush Sky Obstacles
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Sky
Combinaison de modules
53
Ground Ground
Vegetation Vegetation
Sky
Vegetation Vegetation
Grass Road Tree/Bush Sky Obstacles
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Plan
1. Etat de l’art de la robotique moderne
2. Théorie des fonctions de croyance
a) Représentation de l’incertitude
b) Combinaison d’informations
3. Application aux véhicules intelligents
a) Contexte multi-capteurs et multi-classes
b) Résultats expérimentaux
54
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
General mass function
• Input: • Learned model M of a class C
• Observation X of an object S
• Observation-to-model measure d(X,M)
• Two distance thresholds 𝑑− and 𝑑+
• Output: mass function of 𝛀 = {𝑪, 𝑪 } a) If 𝑑− > 𝑑(𝑋,𝑀) → 0 then 𝑚( 𝐶 ) → 1.
b) If 𝑑− ≤ 𝑑(𝑋,𝑀) ≤ 𝑑+ then 𝑚({Ω}) → 1.
c) If 𝑑+ < 𝑑 𝑋,𝑀 → +∞ then 𝑚( 𝐶 ) → 1.
55
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
General mass function
𝒎 𝑪 = 𝜶𝒆−𝜸
𝒅𝒅−−𝒅
𝜷
𝒊𝒇 𝒅 < 𝒅−
𝟎 𝒐𝒕𝒉𝒆𝒓𝒘𝒊𝒔𝒆
𝒎 𝑪 = 𝜶𝒆−𝜸
𝒅+
𝒅−𝒅+
𝜷
𝒊𝒇 𝒅 > 𝒅+
𝟎 𝒐𝒕𝒉𝒆𝒓𝒘𝒊𝒔𝒆
𝒎 𝛀 = 𝟏 −𝒎 𝑪 −𝒎( 𝑪 )
56
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Mass function profile
57
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Mass distribution
Distance to model
Mass f
unction
m(f Cg)
m(f Cg)
m(+)
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Pignistic probability distribution
Distance to model
Pig
nis
tic p
robabili
ty
BetP(f Cg)
BetP(f Cg)
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Special case: 𝑑− = 𝑑+
58
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Mass distribution
Distance to model
Mass f
unction
m(f Cg)
m(f Cg)
m(+)
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Pignistic probability distribution
Distance to model
Pig
nis
tic p
robabili
ty
BetP(f Cg)
BetP(f Cg)
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Special case: 𝑑− = 0
59
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Mass distribution
Distance to model
Mass f
unction
m(f Cg)
m(f Cg)
m(+)
0 5 10 150
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Pignistic probability distribution
Distance to model
Pig
nis
tic p
robabili
ty
BetP(f Cg)
BetP(f Cg)
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Stereo based ground detection
Road plane estimation: 𝑨𝒖 + 𝑩𝒗 + 𝑪𝒅 + 𝑫 = 𝟎
Robust estimator RANSAC.
60
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Stereo ground detection
• Plane model: Π: 𝑛 ∙ 𝑃 + 𝑑 = 0
• Distance: 𝑑 𝑆, Π = mean𝑃𝑖∈𝑆
𝑑(𝑃𝑖 , Π)
• Variance: 𝛾 =1/var𝑃𝑖∈𝑆
𝑑(𝑃𝑖 , Π) , 𝛽 = 2
• 𝛼 = ratio of visible pixels in S
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Stereo ground detection
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0 0.2 0.4 0.6 0.8 10.92
0.93
0.94
0.95
0.96
0.97
0.98
0.99
1
Recall
Pre
cis
ion
Stereo: Ground detection
d-=0, d+=8
d-=0, d+=16
d-=0, d+=Inf
d-=8, d+=8
d-=8, d+=16
d-=8, d+=Inf
d-=16, d+=16
d-=16, d+=Inf
Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Stereo based method: 𝒅− = 𝟖, 𝒅+ = 𝟏𝟔
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
LIDAR based method
Multi-layered LIDAR:
• Cells cut by rays correspond to road.
• Laser impacts far away from the ground are obstacles.
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
LIDAR based method
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Monocular base method
• Features: Walsh-Hadamard coefficient over 8x8 patches
• Learning: Distribution over visual words (500 clusters)
• Observation: Each segment is represented by a distribution of visual words
• Distance: Distribution (histogram) distance
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Texton based road classification
𝒕− = 𝟔, 𝒕+ = 𝟔
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Vegetation detector
𝒕− = 𝟔:
𝒕− = 𝟎:
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Temporal propagation
Optical flow based approach
• For each segment St at time t is associated a segment St+1 at time t+1 defined as the one pointed by the mean flow of the pixels in St.
• The mass mt+1 is: 𝒎𝒕+𝟏 𝑨 = 𝜶𝒎𝒕 𝑨 , 𝒊𝒇 𝑨 ⊊ 𝛀
𝒎𝒕+𝟏 𝛀 = 𝟏 − 𝒎𝒕+𝟏(𝑨)𝑨⊊𝛀
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Détection du sol
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
Conclusion & Future works
• Framework adapted to multi-sensors fusion • Flexible to include new classes • Fusion is done locally over an over-segmented
image
• Future works: • Improve monocular based approach • Add new sensors (GPS, maps), new classes (moving) • Find a general approach to generate mass function
from “black box” detection tools • Global understanding
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Introduction to the theory of belief functions. An application to intelligent vehicles – 04/02/2013
References
• G. Shafer: “A mathematical theory of evidence”. Princeton University Press, 1976.
• P. Smets: “Belief functions: the Disjunctive rule of combination and the generalized Bayesian Theorem”. International Journal of Approximate Reasoning, vol. 9, pp.1-35, 1993.
• T. Denoeux: “A k-nearest neighbor classification rule based on Dempster-Shafer theory”. IEEE Transactions on Systems, Man and Cybernetics, vol. 25(5), pp.804-813, 1995.
• T. Denoeux: “The cautious rule of combination for belief functions and some extensions”. Proceedings of FUSION, 2006.
• T. Denoeux and P. Smets: “Classification using Belief functions: the Relationship between the case-based and model-based approaches”. IEEE Transactions on Systems, Man and Cybernetics, vol. 36(6), pp.1395-1406, 2006.
• B. Khaleghi et al.: “Multisensor data fusion: A review of the state-of-the-art”. Information Fusion, vol. 14(1), pp. 28-44, 2013.
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