Dynamic scene analysis method, and associated analysis module and computer programme

Patent metadata

Field	Value
Publication number	US-10290116-B2
Application number	US-201515316779-A
Country	US
Kind code	B2
Filing date	Jun 2, 2015
Priority date	Jun 6, 2014
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

A method for analyzing a dynamic scene partitioned into cells which involves determining a probability of occupancy of a cell and a probability or probabilities of movement of the cell by solving the equation P(OV|ZC)=ΣA0−1V-1P(CA00−1VV−1Z)/ΣA00−1VV−1P(CA00−VV−1Z) comprising the determination of the speeds and positions of dummy particles in the grid depending on those determined at the (k−1)th iteration and the probability P(V|V−1); the determination of the particles located in each cell depending on the determined positions, and the solving of the equation, for a cell, is split into the solving of a static part corresponding to P(0=empty, V=0|ZC) and P(0=occupied, V=0|ZC) and the solving of a dynamic part corresponding to P(0=occ, V=vki,|ZC), i=32 1 to nk, in which nk is the number of particles determined in cell C for the kth iteration.

First claim

The invention claimed is:

1. A method for analyzing a dynamic scene observed with the aid of one or more sensors, the method comprising:
defining a grid that is partitioned into cells and corresponding to the observed scene;
collecting at least one new observation of the one or more sensors at a k th iteration;
determining, as a function of the new collected observation, a first probability of occupancy of each cell of the grid modeling the operation of the one or more sensors;
determining, for each cell, at the k th iteration, a second probability of occupancy of the cell and a set of probabilities of motion of the content of the cell as a function of the first probability of occupancy of the cell determined at the k th iteration,
wherein the second probability of occupancy of the cell and of the set of probabilities of motion of the content of the cell as a function of the first probability of occupancy of the cell determined at the k th iteration is determined based on:
C, an identifier of the cell considered;
A, an identifier of the cell which contained, at the (k−1) th iteration, what is contained in the cell considered at the k th iteration;
O, an occupancy state of the cell considered, from among the empty and occupied states;
O −1 , an occupancy state of the cell at the (k−1) th iteration;
V, a velocity of the cell considered;
V−1, a velocity of the cell at the (k−1) th iteration; and
Z, observations of the sensors from the first iteration up to the k th iteration;
wherein respective velocity and the respective position of a set of dummy particles in the grid are determined at the k th iteration as a function of the velocities, positions of the particles determined at the (k−1) th iteration and of a probability P(V|V−1);
the method comprises a step of determining the particles located in each cell as a function of the positions determined and in that the solving of an equation, for a cell, is split into the solving of a static part corresponding to P(0=empty, V=0|ZC) and P(O=occupied, V=0|ZC) and into the solving of a dynamic part corresponding to the P(O=occ, V=v i k ,|ZC), i=1 to n k , where n k is the number of particles determined in a cell C for the k th iteration; and
wherein the static part of the cell C at the k th iteration being determined as a function of the static part of the cell C determined at the (k−1) th iteration and of P(O|O −1 );
the probability of P(O=occupied, V=v i k ,|ZC) of the dynamic part of the cell C being determined at the k th iteration as a function of the probability P(O=occupied, V=v i k-1 ,|ZA) calculated at the (k−1) th iteration for the dynamic part of a cell A and of P(O|O −1 ),

where the particle p i determined in the cell C at the k th iteration with a velocity v i k-1 was situated in the cell A at the (k−1) th iteration with a velocity v i k-1 , and on completion of the k th iteration, one or more pairs (p i , (v i k , x i k )), where x i k the position of the particle p i at the k th iteration, are duplicated within a cell or deleted so that the number of pairs per cell is dependent on the dynamic part determined for the cell.

2. The method of claim 1 , further comprising selecting the pair to be duplicated or deleted, wherein the selection of said pair being carried out as a function of the probability P(O=occupied, V=v i k |ZC) is determined at the k th iteration, and where v i k is a velocity component of the pair.

3. The method of claim 1 , wherein the total number of particles in the grid is constant during the iterations.

4. The method of claim 1 , wherein P(O=empty, V=0|ZC) is determined at the k th iteration, is denoted as P k (O=empty, V=0|ZC), and is determined as a function of the product of a first term dependent on the first probability of occupancy and of a second term, said second term being dependent on:
P k-1 ( O =occ, V= 0| ZC ).(1−ε)+ P k-1 ( O =empty, V= 0| ZC ).ε,

where ε=P(O=occ|O −1 =empty)=P(O=empty|O −1 =occ); and/or
coeff (v i k ).P k-1 (O=occupied, V=v i k-1 ,|ZA).(1−ε), where coeff (v i k ) is a decreasing function of ∥v i k ∥, and/or
a probability of appearance p a of a new object in the observed scene.

5. A device effective to analyze a dynamic scene observed with the aid of one or more sensors, the device is configured to:
define a grid partitioned into cells and corresponding to the observed scene;
collect at least one new observation of the one or more sensors at a k th iteration and determining, as a function of the new collected observation, a first probability of occupancy of each cell of the grid and that models the operation of the one or more sensors;
determine, for each cell, at the k th iteration, a second probability of occupancy of the cell and a set of probabilities of motion of the content of the cell as a function of the first probability of occupancy of the cell determined at the k th iteration,
wherein the device is adapted to determine said second probability of occupancy of the cell and the set of probabilities of motion of the content of the cell as a function of the first probability of occupancy of the cell determined at the k th iteration based on:
C, an identifier of the cell considered;
A, an identifier of the cell which contained, at the (k−1) th iteration, what is contained in the cell considered at the k th iteration;
O, an occupancy state of the cell considered, from among the empty and occupied states;
O −1 , an occupancy state of the cell at the (k−1) th iteration;
V, a velocity of the cell considered;
V−1, a velocity of the cell at the (k−1) th iteration;
Z, an observations of the sensors from the first iteration up to the k th iteration;
wherein the device is further configured to:
determine, at the k th iteration, the respective velocity and the respective position of a set of dummy particles in the grid as a function of the velocities, of the positions of the particles determined at the (k−1) th iteration and of the probability P(V|V−1);
determine particles located in each cell as a function of the positions determined and to split the solving of an equation, for a cell, into the solving of a static part corresponding to P(O=empty, V=0|ZC) and P(O=occupied, V=0|ZC) and into the solving of a dynamic part corresponding to the P(O=occ, V=v i k ,|ZC), i=1 to n k , where n k is the number of particles determined in the cell C for the k th iteration;
determine the static part of the cell C at the k th iteration as a function of the static part of a cell C determined at the (k−1) th iteration and of P(O|O −1 ); and
determine the probability of P(O=occupied, V=v i k ,|ZC) of the dynamic part of the cell C at the k th iteration as a function of the probability P(O=occupied, V=v i k-1 ,|ZA) calculated at the (k−1) th iteration for the dynamic part of a cell A and of P(O|O −1 ),
where the particle p i determined in the cell C at the k th iteration with a velocity v i k was situated in the cell A at the (k−1) th iteration with a velocity v i k-1 ;
wherein on completion of the k th iteration, duplicate or delete one or more pairs (p i , (v i k , x i k )), where x i k is the position of the particle p i at the k th iteration, within a cell so that the number of pairs per cell is dependent on the dynamic part determined for the cell.

6. The device of claim 5 , adapted to select said pair to be duplicated/deleted, as a function of the probability P(O=occupied, V=v i k |ZC) is determined at the k th iteration, and where v i k is a velocity component of the pair.

7. The device of claim 5 , wherein the total number of particles in the grid is constant during the iterations.

8. The device of claim 5

Assignees

• Inria Inst Nat Rech Informatique & Automatique
• Centre Nat Rech Scient
• Commissariat Energie Atomique

Inventors

• Laugier Christian
• Negre Amaury
• Perrollaz Mathias
• Rummelhard Lukas

Classifications

• G06N7/01

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• G06T2207/10016

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• B60T2201/022

  Collision avoidance systems · CPC title

• G06T7/70 Primary

  Determining position or orientation of objects or cameras (camera calibration G06T7/80) · CPC title

• G01S17/931

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