EP0796671A1 - Image acquisition system for parcel sorting - Google Patents

Image acquisition system for parcel sorting Download PDF

Info

Publication number
EP0796671A1
EP0796671A1 EP97400627A EP97400627A EP0796671A1 EP 0796671 A1 EP0796671 A1 EP 0796671A1 EP 97400627 A EP97400627 A EP 97400627A EP 97400627 A EP97400627 A EP 97400627A EP 0796671 A1 EP0796671 A1 EP 0796671A1
Authority
EP
European Patent Office
Prior art keywords
camera
sensor
upper face
conveying plane
height
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP97400627A
Other languages
German (de)
French (fr)
Other versions
EP0796671B1 (en
Inventor
Gilbert Micaletti
Claude Mitte
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Solystic SAS
Original Assignee
Alcatel Postal Automation Systems
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcatel Postal Automation Systems filed Critical Alcatel Postal Automation Systems
Publication of EP0796671A1 publication Critical patent/EP0796671A1/en
Application granted granted Critical
Publication of EP0796671B1 publication Critical patent/EP0796671B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C3/00—Sorting according to destination
    • B07C3/10—Apparatus characterised by the means used for detection ofthe destination
    • B07C3/14—Apparatus characterised by the means used for detection ofthe destination using light-responsive detecting means

Definitions

  • the invention relates to an image acquisition system for reading information on the upper face of objects moved on a conveying plane, comprising a high resolution camera mounted fixed above the conveying plane to scan the face. top of each object, this camera being equipped with a lens with motorized focusing mechanism.
  • an ultrasonic sensor determines the height of the plane corresponding to the upper surface of each package or package relative to the conveying plane to control the motor of the lens focusing mechanism at the moment when the camera begins to scan the upper surface of this object.
  • the camera is of the type with charge transfer photosensitive elements ("CCD") and the depth of field (at a fixed distance between the network of photosensitive elements and the object to be scanned) depends on two parameters: the magnification factor and the aperture of the objective.
  • the magnification factor ratio of dimensions between the object scanned and the image
  • the opening of the objective is limited taking into account the speed of conveying parcels or postal packages in sorting equipment (of the order of 1 to 2 m / s) and the light energy to be put used to light up packages during the shooting (2 kW is a maximum).
  • An opening of 2 seems to be a difficult limit to cross. Consequently, the maximum depth of field that can be obtained is of the order of 2 to 3 centimeters.
  • this image acquisition system cannot function properly if some or all of the packages have a top surface with significant surface irregularities (undulations, setbacks) resulting in height variations of the upper side of packages much larger than the depth of field of the objective and consequently the impossibility of recovering a clear image of the information. Furthermore, it is not possible to treat mail items arranged in an inclined manner on the conveying plane. However, this practice is generalized because it allows bulky mail items of the parcel or package type to be kept in a fixed position on a conveyor belt when these are moved at high speed (of the order of 1 to 2 m / s) .
  • the object of the invention is to propose a more sophisticated image acquisition system than that known previously.
  • an image acquisition system capable of adapting in real time to variations in height of the upper face of packages or packages which may be much greater than the depth of field (a priori fixed) of the lens of a high-resolution camera (typically variations of around forty centimeters compared to the two centimeters of depth of field of the lens) while these parcels or packages are moved at around 1.7 m / s.
  • the subject of the invention is an image acquisition system which comprises a sensor adapted to produce a signal representative of the height profile of the upper face of each object with respect to the conveying plane and in that means are provided for processing this profile signal so as to produce positioning instructions for the focusing mechanism in order to take account of variations in the height of the face of each object while the object is moving under the camera lens.
  • This sensor is preferably a laser rangefinder which has the advantage of having a good response on surfaces of different colors which is advantageous in the postal application.
  • another laser rangefinder is also provided for producing a signal indicative of the position of a movable lens placed at the rear of the objective and moved by a DC motor of the mechanism of focus.
  • the position signal is used to control the positioning setpoints so as to increase the precision of the focus adjustment.
  • the camera can be a camera with photosensitive elements with charge transfer (“CCD”) or with photosensitive elements with integration (“TDI”).
  • CCD photosensitive elements with charge transfer
  • TDI photosensitive elements with integration
  • the image acquisition system described below is intended to be connected to an optical character recognition system for the automatic reading of addresses on mail items of the parcel or package type, but the invention is not limited to this area of application.
  • the image acquisition system comprises a camera 1 fixedly mounted on a frame (not shown) above a conveying plane on which are moved postal packages 2a, 2b, 2c bearing on their face upper 3 of the postal address information represented by A for packet 2a. Note that this information can be printed on a label stuck on the upper side of each package as for package 2a.
  • the packets are moved at high speed on the conveying plane 4 in a certain direction D to pass under the camera 1.
  • Camera 1 is placed approximately 2 m above the conveying plane.
  • the objective 5 of the camera is equipped with a motorized focusing mechanism (not shown in the figure) which moves a movable rear lens 6 in a direction perpendicular to the conveying plane as indicated by the double arrow 7 to make a focused to move the area of sharpness.
  • the high resolution line scanning camera 1 is of the type with photosensitive elements 1A with charge transfer or with integration arranged transversely to the direction D to cover the entire width of the conveying plane. In the figure, the package lighting device for shooting is not shown.
  • a first laser rangefinder 8 for example the "MSL / 400" model having an excursion capacity of approximately 40 cm, is disposed above the conveying plane and upstream of the camera 1 in the direction D.
  • This rangefinder 8 sends a fine light beam at high frequency to the upper face of each packet and outputs a signal S representative of the height profile of this face with respect to the conveying plane.
  • Another laser rangefinder 9 for example the "M5L / 4" model having an excursion capacity of approximately 4 mm is mounted fixed relative to the objective 5 and is used to determine the position of a fixed reference target 10 of the lens 6.
  • a passage sensor 11, of the photoelectric cell type, is arranged upstream of the camera 1 in the direction D and downstream of the rangefinder 8. This sensor is used for detecting the passage of the front edge of a packet to synchronize the sending of setpoint commands to the motor of the focusing mechanism with the movement of the packets.
  • the motor is preferably a direct current motor making it possible to obtain a precise displacement of the movable lens (of the order of ten microns).
  • the objects 2b and 2c are moved on the conveying plane by being inclined because they are placed on supports 12 in the form of a ramp.
  • the height of the upper face of each package relative to the conveying plane varies over an interval greater than the depth of field of the objective. It is therefore necessary to carry out successive adjustments to move the area of sharpness by following the height profile of the upper face of a package as and when this package is moved under the camera lens.
  • An implementation of the image acquisition system was carried out. This makes it possible to process packets which are moved at a speed of 1.7 m / s with a target development time of less than 100 ms for a 40 cm excursion from the area of sharpness.
  • the latter produces an analog signal S as an output representative of the height profile of the upper face 3 of this packet.
  • This signal is digitized at a sampling frequency chosen to obtain approximately 300 measurement points for a packet length of approximately 40 cm.
  • the measurement points (succession of the different heights of the upper face in the direction D) are processed in real time by the processor 13 by using a table matching profile heights with setpoint data corresponding to as many adjustment positions of lens 6 and therefore of positions of the sharpness zone.
  • the package 2b moving according to the direction D towards the camera 1 is detected by the sensor 11 which then sends a detection signal T to the processor 13.
  • the processor 13 On reception of the signal T, the processor 13 sends the succession of setpoint data C to the motor 14 at a frequency depending on the speed of movement of the packet 2b under the camera lens and after a guard time dependent on the distance between the sensor 11 and the optical axis of the camera 1. In response to the reception of a setpoint data, the motor 14 moves the lens 6 to the desired position to carry out the required focusing. Furthermore, the position signal P produced by the rangefinder 9 is sent to the processor 13 to control the instructions sent to the motor 14.
  • a single lens is moved to focus, which makes it possible to obtain a very short focusing time and good reliability of the system.

Abstract

The system comprises a high resolution camera (1) mounted above a conveyor belt (4) on which objects are placed, with their sides to be examined uppermost. The camera is fitted with an objective lens (5) with a motorised focussing mechanism operating with a sensor (8) which produces a signal representative of the height profile of the upper face of each object w.r.t. the conveyor plane. This profile signal serves to produce reference positions (C) for the focussing system, taking account of variations in the height of the upper surface of each object as it passes in front of the camera. The sensor used may be a telemetry laser, whilst the camera may be a CCD device and the motorised control operated by a DC electric motor.

Description

L'invention concerne un système d'acquisition d'images pour la lecture d'informations sur la face supérieure d'objets déplacés sur un plan de convoyage, comprenant une caméra à haute résolution montée fixe au dessus du plan de convoyage pour scruter la face supérieure de chaque objet, cette caméra étant équipée d'un objectif à mécanisme motorisé de mise au point.The invention relates to an image acquisition system for reading information on the upper face of objects moved on a conveying plane, comprising a high resolution camera mounted fixed above the conveying plane to scan the face. top of each object, this camera being equipped with a lens with motorized focusing mechanism.

Un tel système est déjà connu du document EP-0647479. Il est destiné plus particulièrement à la lecture automatique des adresses de destination de colis ou paquets postaux par reconnaissance optique de caractères, à partir des images, en vue d'effectuer un tri postal automatique. Dans ce système, un capteur à ultrasons détermine la hauteur du plan correspondant à la surface supérieure de chaque colis ou paquet par rapport au plan de convoyage pour commander le moteur du mécanisme de mise au point de l'objectif au moment où la caméra commence à scruter la surface supérieure de cet objet.Such a system is already known from document EP-0647479. It is intended more particularly for the automatic reading of the addresses of destination of parcels or postal packets by optical character recognition, from images, in order to carry out an automatic postal sorting. In this system, an ultrasonic sensor determines the height of the plane corresponding to the upper surface of each package or package relative to the conveying plane to control the motor of the lens focusing mechanism at the moment when the camera begins to scan the upper surface of this object.

Dans ce système connu, la caméra est du type à éléments photosensibles à transfert de charge ("CCD") et la profondeur de champ (à distance fixe entre le réseau d'éléments photosensibles et l'objet à scruter) dépend de deux paramètres: le facteur de grandissement et l'ouverture de l'objectif. En pratique, le facteur de grandissement (rapport de dimensions entre l'objet scruté et l'image) est d'environ 9 à 13 pour des objets du genre colis ou paquets postaux. Par ailleurs, l'ouverture de l'objectif est limitée compte tenu de la vitesse de convoyage des colis ou paquets postaux dans un équipement de tri (de l'ordre de 1 à 2 m/s) et de l'énergie lumineuse à mettre en oeuvre pour éclairer les colis ou paquets pendant la prise de vue (2 kW est un maximum) . Une ouverture de 2 semble être une limite difficile à franchir. En conséquence, la profondeur de champ maximale qu'on puisse obtenir est de l'ordre de 2 à 3 centimètres.In this known system, the camera is of the type with charge transfer photosensitive elements ("CCD") and the depth of field (at a fixed distance between the network of photosensitive elements and the object to be scanned) depends on two parameters: the magnification factor and the aperture of the objective. In practice, the magnification factor (ratio of dimensions between the object scanned and the image) is approximately 9 to 13 for objects of the parcel or postal packet type. Furthermore, the opening of the objective is limited taking into account the speed of conveying parcels or postal packages in sorting equipment (of the order of 1 to 2 m / s) and the light energy to be put used to light up packages during the shooting (2 kW is a maximum). An opening of 2 seems to be a difficult limit to cross. Consequently, the maximum depth of field that can be obtained is of the order of 2 to 3 centimeters.

En partant de ces contraintes, ce système d'acquisition d'images ne peut pas fonctionner correctement si certains ou l'ensemble des colis ou paquets ont une face supérieure présentant des irrégularités de surface importantes (ondulations, décrochements) entraînant des variations de hauteur de la face supérieure des colis ou paquets bien plus grandes que la profondeur de champ de l'objectif et par voie de conséquence l'impossibilité de récupérer une image nette des informations. Par ailleurs, il n'est pas envisageable de traiter des articles de courrier disposés de façon inclinée sur la plan de convoyage. Or cette pratique se généralise car elle permet de maintenir les articles de courrier volumineux du genre colis ou paquets en position fixe sur une bande de convoyage quand ceux-ci sont déplacés à haute vitesse (de l'ordre de 1 à 2 m/s).Based on these constraints, this image acquisition system cannot function properly if some or all of the packages have a top surface with significant surface irregularities (undulations, setbacks) resulting in height variations of the upper side of packages much larger than the depth of field of the objective and consequently the impossibility of recovering a clear image of the information. Furthermore, it is not possible to treat mail items arranged in an inclined manner on the conveying plane. However, this practice is generalized because it allows bulky mail items of the parcel or package type to be kept in a fixed position on a conveyor belt when these are moved at high speed (of the order of 1 to 2 m / s) .

Le but de l'invention est de proposer un système d'acquisition d'images plus perfectionné que celui connu antérieurement.The object of the invention is to propose a more sophisticated image acquisition system than that known previously.

En particulier, il s'agit de proposer un système d'acquisition d'images capable de s'adapter en temps réel à des variations de hauteur de la face supérieure de colis ou paquets pouvant être très supérieures à la profondeur de champ (à priori fixe) de l'objectif d'une caméra à haute résolution (typiquement des variations d'une quarantaine de centimètres à comparer aux deux centimètre de profondeur de champ de l'objectif) tandis que ces colis ou paquets sont déplacés à environ 1,7 m/s.In particular, it involves proposing an image acquisition system capable of adapting in real time to variations in height of the upper face of packages or packages which may be much greater than the depth of field (a priori fixed) of the lens of a high-resolution camera (typically variations of around forty centimeters compared to the two centimeters of depth of field of the lens) while these parcels or packages are moved at around 1.7 m / s.

A cet effet, l'invention a pour objet un système d'acquisition d'images qui comprend un capteur adapté pour produire un signal représentatif du profil de hauteur de la face supérieure de chaque objet par rapport au plan de convoyage et en ce qu'un moyen est prévu pour traiter ce signal de profil de façon à produire des consignes de positionnement pour le mécanisme de mise au point afin de prendre en compte des variations de la hauteur de la face supérieure de chaque objet tandis que l'objet se déplace sous l'objectif de la caméra.To this end, the subject of the invention is an image acquisition system which comprises a sensor adapted to produce a signal representative of the height profile of the upper face of each object with respect to the conveying plane and in that means are provided for processing this profile signal so as to produce positioning instructions for the focusing mechanism in order to take account of variations in the height of the face of each object while the object is moving under the camera lens.

Ce capteur est de préférence un télémètre laser qui présente l'avantage d'avoir une bonne réponse sur des surfaces de différentes couleurs ce qui est intéressant dans l'application postale.This sensor is preferably a laser rangefinder which has the advantage of having a good response on surfaces of different colors which is advantageous in the postal application.

Suivant un mode de réalisation avantageux de l'invention, un autre télémètre laser est aussi prévu pour produire un signal indicatif de la position d'une lentille mobile disposée à l'arrière de l'objectif et déplacée par un moteur à courant continu du mécanisme de mise au point. Le signal de position sert à l'asservissement des consignes de positionnement de sorte à augmenter la précision du réglage de la mise au point.According to an advantageous embodiment of the invention, another laser rangefinder is also provided for producing a signal indicative of the position of a movable lens placed at the rear of the objective and moved by a DC motor of the mechanism of focus. The position signal is used to control the positioning setpoints so as to increase the precision of the focus adjustment.

La caméra peut être une caméra à éléments photosensibles à transfert de charge ("CCD") ou bien à éléments photosensibles à intégration ("TDI") . Dans ce second cas, il est possible de réduire soit la puissance d'éclairage nécessaire pour la prise de vue, soit de fermer le diaphragme de la caméra et donc d'augmenter la profondeur de champ de quelques centimètres ce qui permet de réduire le nombre de réglages à effectuer en temps réel pour la mise au point.The camera can be a camera with photosensitive elements with charge transfer ("CCD") or with photosensitive elements with integration ("TDI"). In this second case, it is possible to reduce either the lighting power necessary for the shooting, or to close the diaphragm of the camera and therefore to increase the depth of field by a few centimeters which allows to reduce the number adjustments to be made in real time for focusing.

Un exemple de réalisation de l'invention est décrit ci-après en détails en référence à la figure unique qui est un synoptique général du système d'acquisition selon l'invention.An exemplary embodiment of the invention is described below in detail with reference to the single figure which is a general block diagram of the acquisition system according to the invention.

Le système d'acquisition d'images décrit ci-après est destiné à être connecté à un système de reconnaissance optique de caractères pour la lecture automatique d'adresses sur des articles de courrier du genre colis ou paquets mais l'invention n'est pas limitée à ce domaine d'application.The image acquisition system described below is intended to be connected to an optical character recognition system for the automatic reading of addresses on mail items of the parcel or package type, but the invention is not limited to this area of application.

Sur la figure, le système d'acquisition d'images comprend une caméra 1 montée fixe sur un châssis (non représenté) au dessus d'un plan de convoyage sur lequel sont déplacés des paquets postaux 2a,2b,2c portant sur leur face supérieure 3 des informations d'adresse postale représentées par A pour le paquet 2a. A noter que ces informations peuvent être imprimées sur une étiquette collée sur la face supérieure de chaque paquet comme pour le paquet 2a.In the figure, the image acquisition system comprises a camera 1 fixedly mounted on a frame (not shown) above a conveying plane on which are moved postal packages 2a, 2b, 2c bearing on their face upper 3 of the postal address information represented by A for packet 2a. Note that this information can be printed on a label stuck on the upper side of each package as for package 2a.

Les paquets sont déplacés à haute vitesse sur le plan convoyage 4 suivant une certaine direction D pour passer sous la caméra 1.The packets are moved at high speed on the conveying plane 4 in a certain direction D to pass under the camera 1.

La caméra 1 est placée à environ 2 m au dessus du plan de convoyage. L'objectif 5 de la caméra est équipé d'un mécanisme motorisé de mise au point (non représenté sur la figure) qui déplace une lentille arrière mobile 6 suivant une direction perpendiculaire au plan de convoyage comme indiqué par la double flèche 7 pour faire une mise au point de façon à déplacer la zone de netteté.Camera 1 is placed approximately 2 m above the conveying plane. The objective 5 of the camera is equipped with a motorized focusing mechanism (not shown in the figure) which moves a movable rear lens 6 in a direction perpendicular to the conveying plane as indicated by the double arrow 7 to make a focused to move the area of sharpness.

La caméra 1 à balayage ligne haute résolution est du type à réseau d'éléments photosensibles 1A à transfert de charge ou à intégration disposé transversalement à la direction D pour couvrir la totalité de la largeur du plan de convoyage. Sur la figure, le dispositif d'éclairage des paquets pour la prise de vue n'est pas représenté.The high resolution line scanning camera 1 is of the type with photosensitive elements 1A with charge transfer or with integration arranged transversely to the direction D to cover the entire width of the conveying plane. In the figure, the package lighting device for shooting is not shown.

Un premier télémètre laser 8, par exemple le modèle "MSL/400" ayant une capacité d'excursion d'environ 40 cm, est disposée au dessus du plan de convoyage et en amont de la caméra 1 suivant la direction D. Ce télémètre 8 envoie un fin faisceau lumineux à fréquence élevée sur la face supérieure de chaque paquet et produit en sortie un signal S représentatif du profil de hauteur de cette face par rapport au plan de convoyage.A first laser rangefinder 8, for example the "MSL / 400" model having an excursion capacity of approximately 40 cm, is disposed above the conveying plane and upstream of the camera 1 in the direction D. This rangefinder 8 sends a fine light beam at high frequency to the upper face of each packet and outputs a signal S representative of the height profile of this face with respect to the conveying plane.

Un autre télémètre laser 9, par exemple le modèle "M5L/4" ayant une capacité d'excursion d'environ 4 mm est monté fixe par rapport à l'objectif 5 et sert à déterminer la position d'une cible de référence 10 solidaire de la lentille 6.Another laser rangefinder 9, for example the "M5L / 4" model having an excursion capacity of approximately 4 mm is mounted fixed relative to the objective 5 and is used to determine the position of a fixed reference target 10 of the lens 6.

Un capteur de passage 11, du type cellule photoélectrique, est disposé en amont de la caméra 1 suivant la direction D et en aval du télémètre 8. Ce capteur sert à détecter le passage du bord avant d'un paquet pour synchroniser l'envoi de commandes de consigne au moteur du mécanisme de mise au point avec le déplacement des paquets. Le moteur est de préférence un moteur à courant continu permettant d'obtenir un déplacement précis de la lentille mobile (de l'ordre de la dizaine de microns).A passage sensor 11, of the photoelectric cell type, is arranged upstream of the camera 1 in the direction D and downstream of the rangefinder 8. This sensor is used for detecting the passage of the front edge of a packet to synchronize the sending of setpoint commands to the motor of the focusing mechanism with the movement of the packets. The motor is preferably a direct current motor making it possible to obtain a precise displacement of the movable lens (of the order of ten microns).

Comme montré sur la figure, les objets 2b et 2c sont déplacés sur la plan de convoyage en étant inclinés du fait qu'ils sont placés sur des supports 12 en forme de rampe. Dans cette position, la hauteur de la face supérieure de chaque paquet par rapport au plan de convoyage varie sur un intervalle plus grand que la profondeur de champ de l'objectif. Il faut donc effectuer des mises au point successives pour déplacer la zone de netteté en suivant le profil de hauteur de la face supérieure d'un paquet au fur et à mesure que ce paquet est déplacé sous l'objectif de la caméra. Une réalisation du système d'acquisition d'images a été effectuée. Celui-ci permet de traiter des paquets qui sont déplacés à une vitesse de 1,7 m/s avec un temps de mise au point de l'objectif de moins de 100 ms pour une excursion de 40 centimètres de la zone de netteté.As shown in the figure, the objects 2b and 2c are moved on the conveying plane by being inclined because they are placed on supports 12 in the form of a ramp. In this position, the height of the upper face of each package relative to the conveying plane varies over an interval greater than the depth of field of the objective. It is therefore necessary to carry out successive adjustments to move the area of sharpness by following the height profile of the upper face of a package as and when this package is moved under the camera lens. An implementation of the image acquisition system was carried out. This makes it possible to process packets which are moved at a speed of 1.7 m / s with a target development time of less than 100 ms for a 40 cm excursion from the area of sharpness.

Le fonctionnement général de ce système d'acquisition est le suivant.The general operation of this acquisition system is as follows.

A mesure qu'un paquet tel que 2b passe sous le télémètre laser 8, celui-ci produit en sortie un signal S analogique représentatif du profil de hauteur de la face supérieure 3 de ce paquet. Ce signal est numérisé à une fréquence d'échantillonnage choisie pour obtenir environ 300 points de mesure pour une longueur de paquet d'environ 40 cm. Les points de mesure (succession des différentes hauteurs de la face supérieure suivant la direction D) sont traitées en temps réel par le processeur 13 en exploitant une table mettant en correspondance des hauteurs de profil avec des données de consigne correspondant à autant de positions de réglage de la lentille 6 et donc de positions de la zone de netteté. Le paquet 2b se déplaçant suivant la direction D vers la caméra 1 est détecté par le capteur 11 qui envoie alors un signal de détection T au processeur 13. Sur réception du signal T, le processeur 13 envoie la succession de données de consigne C au moteur 14 à une fréquence fonction de la vitesse de déplacement du paquet 2b sous l'objectif de la caméra et après un temps de garde dépendant de la distance entre le capteur 11 et l'axe optique de la caméra 1. En réponse à la réception d'une données de consigne, le moteur 14 déplace à la position voulue la lentille 6 pour effectuer la mise au point requise. Par ailleurs, le signal de position P produit par le télémètre 9 est envoyé au processeur 13 pour asservir les consignes envoyés au moteur 14.As a packet such as 2b passes under the laser rangefinder 8, the latter produces an analog signal S as an output representative of the height profile of the upper face 3 of this packet. This signal is digitized at a sampling frequency chosen to obtain approximately 300 measurement points for a packet length of approximately 40 cm. The measurement points (succession of the different heights of the upper face in the direction D) are processed in real time by the processor 13 by using a table matching profile heights with setpoint data corresponding to as many adjustment positions of lens 6 and therefore of positions of the sharpness zone. The package 2b moving according to the direction D towards the camera 1 is detected by the sensor 11 which then sends a detection signal T to the processor 13. On reception of the signal T, the processor 13 sends the succession of setpoint data C to the motor 14 at a frequency depending on the speed of movement of the packet 2b under the camera lens and after a guard time dependent on the distance between the sensor 11 and the optical axis of the camera 1. In response to the reception of a setpoint data, the motor 14 moves the lens 6 to the desired position to carry out the required focusing. Furthermore, the position signal P produced by the rangefinder 9 is sent to the processor 13 to control the instructions sent to the motor 14.

Dans le système d'acquisition d'images selon l'invention, une seule lentille est déplacée pour faire la mise au point ce qui permet d'obtenir un temps de mise au point très faible et une bonne fiabilité du système.In the image acquisition system according to the invention, a single lens is moved to focus, which makes it possible to obtain a very short focusing time and good reliability of the system.

Claims (8)

Un système d'acquisition d'images pour la lecture d'informations (A) sur la face supérieure (3) d'objets (2a,2b,2c) déplacés sur un plan de convoyage (4), comprenant une caméra à haute résolution (1) montée fixe au dessus du plan de convoyage (4) pour scruter la face supérieure de chaque objet, cette caméra (1) étant équipée d'un objectif (5) à mécanisme motorisé de mise au point fonctionnant avec un capteur (8) monté au dessus du plan de convoyage pour mesurer la hauteur de la face supérieure (3) de chaque objet par rapport au plan de convoyage, caractérisé en ce que ce capteur (8) est adapté pour produire un signal (S) représentatif du profil de hauteur de la face supérieure de chaque objet par rapport au plan de convoyage et en ce qu'un moyen (13) est prévu pour traiter ce signal de profil de façon à produire des consignes de positionnement (C) pour le mécanisme de mise au point afin de prendre en compte des variations de la hauteur de la face supérieure de chaque objet tandis que l'objet se déplace sous l'objectif de la caméra.An image acquisition system for reading information (A) on the upper face (3) of objects (2a, 2b, 2c) moved on a conveying plane (4), comprising a high resolution camera (1) fixed mounted above the conveying plane (4) to scan the upper face of each object, this camera (1) being equipped with a lens (5) with motorized focusing mechanism operating with a sensor (8 ) mounted above the conveying plane to measure the height of the upper face (3) of each object with respect to the conveying plane, characterized in that this sensor (8) is adapted to produce a signal (S) representative of the profile in height of the upper face of each object with respect to the conveying plane and in that a means (13) is provided for processing this profile signal so as to produce positioning instructions (C) for the setting mechanism point to take into account variations in the height of the upper face of each object while the object is moving under the camera lens. Le système selon la revendication 1, dans lequel le capteur (8) est un télémètre laser.The system of claim 1, wherein the sensor (8) is a laser rangefinder. Le système selon la revendication 1, incluant en outre un autre capteur (9) adapté pour produire un signal (P) indicatif de la position d'une lentille (6) mobile disposée à l'arrière de l'objectif et déplacée par le moteur (14) du mécanisme de mise au point, ce signal de position servant à un asservissement des consignes de positionnement.The system of claim 1, further including another sensor (9) adapted to produce a signal (P) indicative of the position of a movable lens (6) disposed behind the objective and moved by the motor (14) of the focusing mechanism, this position signal serving to control the positioning setpoints. Le système selon la revendication 3, dans lequel cet autre capteur (9) est un télémètre laser.The system of claim 3, wherein said other sensor (9) is a laser rangefinder. Le système selon la revendication 3, dans lequel le mécanisme motorisé de mise au point est équipé d'un moteur (14) à courant continu.The system of claim 3, wherein the motorized focusing mechanism is equipped with a DC motor (14). Le système selon la revendication 1, dans lequel la caméra (1) est une caméra à éléments photosensibles à transfert de charge ("CCD").The system of claim 1, wherein the camera (1) is a charge transfer photosensitive element ("CCD") camera. Le système selon la revendication 1, dans lequel la caméra (1) est une caméra à éléments photosensibles à intégration ("TDI").The system of claim 1, wherein the camera (1) is an integrated photosensitive element ("TDI") camera. Un équipement de tri postal automatique incluant un système d'acquisition d'images selon l'une des revendications 1 à 7 pour la lecture automatique d'adresses sur des paquets par reconnaissance optique de caractères.Automatic postal sorting equipment including an image acquisition system according to one of claims 1 to 7 for the automatic reading of addresses on packets by optical character recognition.
EP97400627A 1996-03-22 1997-03-20 Image acquisition system for parcel sorting Expired - Lifetime EP0796671B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9603606 1996-03-22
FR9603606A FR2746330B1 (en) 1996-03-22 1996-03-22 IMAGE ACQUISITION SYSTEM FOR PACKET SORTING

Publications (2)

Publication Number Publication Date
EP0796671A1 true EP0796671A1 (en) 1997-09-24
EP0796671B1 EP0796671B1 (en) 2001-05-09

Family

ID=9490459

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97400627A Expired - Lifetime EP0796671B1 (en) 1996-03-22 1997-03-20 Image acquisition system for parcel sorting

Country Status (6)

Country Link
US (1) US6122001A (en)
EP (1) EP0796671B1 (en)
JP (1) JPH10187952A (en)
DE (1) DE69704738T2 (en)
ES (1) ES2157051T3 (en)
FR (1) FR2746330B1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19851284A1 (en) * 1998-11-06 2000-05-11 Siemens Ag Device for image acquisition of package surfaces
WO2002003105A2 (en) * 2000-07-05 2002-01-10 Psc Scanning, Inc. Autofocus apparaturs and method of using the same
WO2002092246A1 (en) * 2001-05-16 2002-11-21 Siemens Aktiengesellschaft Device for reproducing images
US6963074B2 (en) 2001-06-21 2005-11-08 Psc Scanning, Inc. Omni-directional optical code reader using scheimpflug optics
CN112561882A (en) * 2020-12-16 2021-03-26 深圳市六合智能感知系统科技有限公司 Logistics sorting method, system, equipment and storage medium

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4251312B2 (en) * 2002-03-08 2009-04-08 日本電気株式会社 Image input device
JP2005064633A (en) * 2003-08-08 2005-03-10 Hitachi Ltd Business form reader
US20050226489A1 (en) * 2004-03-04 2005-10-13 Glenn Beach Machine vision system for identifying and sorting projectiles and other objects
US9424634B2 (en) 2004-03-04 2016-08-23 Cybernet Systems Corporation Machine vision system for identifying and sorting projectiles and other objects
ES2289633T3 (en) * 2004-10-11 2008-02-01 Sick Ag DEVICE AND PROCEDURE FOR SURVEILLANCE OF MOVING OBJECTS.
US7809158B2 (en) * 2005-05-02 2010-10-05 Siemens Industry, Inc. Method and apparatus for detecting doubles in a singulated stream of flat articles
JP4807402B2 (en) * 2008-11-14 2011-11-02 日本電気株式会社 Image input device
US9554094B1 (en) 2012-11-30 2017-01-24 Cognex Corporation System and method for determining a displaced substrate with a vision system
EP2763105B1 (en) 2013-01-31 2018-08-22 Neopost Technologies Image acquisition system for processing and tracking mail pieces
CN109002796B (en) * 2018-07-16 2020-08-04 阿里巴巴集团控股有限公司 Image acquisition method, device and system and electronic equipment

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3736288A1 (en) * 1987-10-27 1989-05-11 Leuze Electronic Gmbh & Co Method for reading and decoding bar codes on semiconductor surfaces
US4920255A (en) * 1988-10-31 1990-04-24 Stephen C. Gabeler Automatic incremental focusing scanner system
EP0620051A1 (en) * 1993-04-16 1994-10-19 Materiel Pour L'arboriculture Fruitiere (M.A.F.) S.A. Method and device for automatic sorting of products, especially of fruit or vegetables
EP0647479A2 (en) * 1993-10-12 1995-04-12 Galai Laboratories Ltd. Parcel sorting system

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4700427A (en) * 1985-10-17 1987-10-20 Knepper Hans Reinhard Method of automatically steering self-propelled floor-cleaning machines and floor-cleaning machine for practicing the method
IS1666B (en) * 1991-02-19 1997-11-14 Marel Hf Method and apparatus for determining the volume, shape and weight of fish or other parts
US5440648A (en) * 1991-11-19 1995-08-08 Dalsa, Inc. High speed defect detection apparatus having defect detection circuits mounted in the camera housing
US5668887A (en) * 1992-05-29 1997-09-16 Eastman Kodak Company Coating density analyzer and method using non-synchronous TDI camera
US5650813A (en) * 1992-11-20 1997-07-22 Picker International, Inc. Panoramic time delay and integration video camera system
US5696591A (en) * 1996-01-05 1997-12-09 Eastman Kodak Company Apparatus and method for detecting longitudinally oriented flaws in a moving web

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3736288A1 (en) * 1987-10-27 1989-05-11 Leuze Electronic Gmbh & Co Method for reading and decoding bar codes on semiconductor surfaces
US4920255A (en) * 1988-10-31 1990-04-24 Stephen C. Gabeler Automatic incremental focusing scanner system
EP0620051A1 (en) * 1993-04-16 1994-10-19 Materiel Pour L'arboriculture Fruitiere (M.A.F.) S.A. Method and device for automatic sorting of products, especially of fruit or vegetables
EP0647479A2 (en) * 1993-10-12 1995-04-12 Galai Laboratories Ltd. Parcel sorting system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19851284A1 (en) * 1998-11-06 2000-05-11 Siemens Ag Device for image acquisition of package surfaces
WO2000027549A1 (en) * 1998-11-06 2000-05-18 Siemens Production And Logistics Systems Ag Device for recording pictures of parcel surfaces
WO2002003105A2 (en) * 2000-07-05 2002-01-10 Psc Scanning, Inc. Autofocus apparaturs and method of using the same
WO2002003105A3 (en) * 2000-07-05 2003-01-23 Psc Scanning Inc Autofocus apparaturs and method of using the same
US6689998B1 (en) 2000-07-05 2004-02-10 Psc Scanning, Inc. Apparatus for optical distancing autofocus and imaging and method of using the same
WO2002092246A1 (en) * 2001-05-16 2002-11-21 Siemens Aktiengesellschaft Device for reproducing images
US7215363B2 (en) 2001-05-16 2007-05-08 Siemens Ag System and method for scanning a surface of a moving object
US6963074B2 (en) 2001-06-21 2005-11-08 Psc Scanning, Inc. Omni-directional optical code reader using scheimpflug optics
CN112561882A (en) * 2020-12-16 2021-03-26 深圳市六合智能感知系统科技有限公司 Logistics sorting method, system, equipment and storage medium
CN112561882B (en) * 2020-12-16 2023-05-12 深圳市六合智能感知系统科技有限公司 Logistics sorting method, system, equipment and storage medium

Also Published As

Publication number Publication date
EP0796671B1 (en) 2001-05-09
DE69704738T2 (en) 2002-02-07
FR2746330A1 (en) 1997-09-26
DE69704738D1 (en) 2001-06-13
US6122001A (en) 2000-09-19
ES2157051T3 (en) 2001-08-01
FR2746330B1 (en) 1998-04-17
JPH10187952A (en) 1998-07-21

Similar Documents

Publication Publication Date Title
EP0796671B1 (en) Image acquisition system for parcel sorting
US8285026B2 (en) Method and system for use in inspecting and/or removing unsuitable objects from a stream of products and a sorting apparatus implementing the same
US6484066B1 (en) Image life tunnel scanner inspection system using extended depth of field technology
EP0224437B1 (en) Optical apparatus with a radiant beam for the automatic control of the bending operation during the bending with a press brake
FR2666315A1 (en) DEVICE FOR CONTROLLING AND REGULARIZING THE SPACING OF PARCELS, PACKAGES OR SIMILAR OBJECTS, ESPECIALLY POSTAL PARCELS.
FR2461944A1 (en) METHOD AND APPARATUS FOR EXAMINING THE OUTER ASPECT OF A FULL CYLINDRICAL OBJECT
CA2251323A1 (en) Surface defect inspection system and method
FR2539519A1 (en) AUTOMATIC FOCUSING DEVICE FOR A CAMERA
FR2482719A1 (en) APPARATUS FOR DETECTING MICROSCOPIC DUST ON NON-POLISHED SURFACES
US7215363B2 (en) System and method for scanning a surface of a moving object
EP2791660A1 (en) A system and a method for individually inspecting objects in a stream of products and a sorting apparatus comprising such system
FR2806504A1 (en) IMAGE CAPTURE DEVICE
WO2002088756A1 (en) Method and device for evaluating a parameter of a moving object
FR2700611A1 (en) Method and device for dimensionally controlling the profile of long products
FR2664525A1 (en) Slice-handling robot with optical sensor
JP2022162529A (en) Detection of flow of moving object
JP2003503865A (en) Packet surface imaging device
FR2939908A1 (en) DEVICE AND METHOD FOR SCANNING AN OBJECT BY A BEAM
CN114374771B (en) Film scanning device
EP0229581A1 (en) Device for the automatic focusing of a microscope
NL9000622A (en) Analytical cytology system for detection of small particles - uses systems for illumination, detection, focussing and image forming
FR2610421A1 (en) Rotating-mirror optical beam deflector for laser printer
EP2553659B1 (en) Device for processing objects, having real-time monitoring of object image quality; sorting machine; and method
JP4099689B2 (en) Document offset detection device
FR2605751A1 (en) Device for automatically focusing a microscope

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE ES GB IT

17P Request for examination filed

Effective date: 19980127

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: MANNESMANN DEMATIC POSTAL AUTOMATION S.A.

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

17Q First examination report despatched

Effective date: 20000918

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES GB IT

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20010509

REF Corresponds to:

Ref document number: 69704738

Country of ref document: DE

Date of ref document: 20010613

ITF It: translation for a ep patent filed

Owner name: GUZZI E RAVIZZA S.R.L.

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2157051

Country of ref document: ES

Kind code of ref document: T3

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020320

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020321

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20021001

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20020320

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20030410

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050320