FR2800895A1 - BUS PASSENGER COUNTING SYSTEM AND METHOD - Google Patents

Abstract

Passenger counting system comprises one or more digital cameras (3) mounted at each vehicle access or exit points such that its field of vision (5) totally covers the access area. The camera(s) are associated with a presence detector (8) and both are connected to an electronic calculator or computer which processes the captured images to detect any movement and associate it with physical persons. The procedure also relates to a method for detection and counting the number of passengers on board the bus. The presence detector can be an infrared, laser, or radar type detector.

Description

BUS PASSENGER COUNTING SYSTEM AND METHOD

  The present invention relates to a system and method for counting, as well as detecting, passengers for

  bus, coach or any group transport vehicle.

  In the area of group transport, knowing the number of passengers entering and leaving the vehicle, especially at different places on the bus away from the driver's eyes, is important for dynamic vehicle control. Knowing the instantaneous load weight of the vehicle can be used to control the braking and steering of the vehicle. In addition, for any vehicle for transporting people, such as coaches, buses, school buses for example, it is necessary to detect obstacles appearing at the doors and likely to interfere with the operation of the door closing mechanisms. Regarding the counting of passengers in a public transport vehicle, there are four current counting modes: - counting by carpet with electrical contacts; - active proximity metering by infrared or ultrasonic barriers; - passive proximity counting by infrared pyrometry;

  - camera counting and image processing.

  The first mode of counting by carpet uses five electrical contacts, distributed under the surface of the carpet, which react according to the weight of the person who walks on the carpet. This solution is unreliable because some children may not be taken

  because of their low weight.

  The second infrared barrier counting method generally uses 2 to 4 infrared cells, which

  are attached to the edge of the doors and at the top of the doors

  this. This mode is also unreliable because, depending on the albedo of the people, the cells may not detect people who do not reflect any signal in return. The non-detection of people is due to the absorption of infrared by the fabrics of their clothes. In the case of counting by ultrasonic barriers, the emitted beam can be dispersed for the physical shape of people, because the

ultrasound is specular.

  The infrared pyrometry counting mode is used more particularly in banks. It is based on the same principle as counting by infrared barriers, but the wavelengths used in pyrometry are 3 to 5 microns and 8 to 12 microns, while the wavelengths used in

  infrared barriers are 0.7 to 0.9 microns.

  For these first two modes, it is not possible to differentiate, using a single sensor, the people entering the vehicle from those leaving it. In addition, the counting accuracy is greater than 6%. However, the current objective of public transport organizations, such as the Régie Autonome des Transports Parisiens, is to achieve an accuracy of 1 to 2%, that is to say to detect 98 people out of 100

passing.

  The fourth counting mode uses a camera which aims vertically at a checkerboard mark placed on the ground. Counting is carried out using an integrated circuit which

  includes image processing with neural networks.

  This fourth mode, described in particular in French patent FR 2 739 208 of FAIVELY TRANSPORT, makes it possible to

  distinguish the direction of movement of people.

  Regarding the passenger detection function at the bus doors, it can be provided for example by pneumatic pressure sensors or by piezoelectric sensors equipping the edges of the doors associated with means for measuring the current of the

  electric motors for closing the doors.

  An electrical signal is sent to the dashboard of the

  vehicle to authorize the driver to start.

  However, due to the inaccuracy of measuring the pressure difference between the two pneumatic edges of each door, or that of the electric current of the motors driving the doors, an obstacle such as an arm or a foot of a passenger remaining in the door may go undetected and get stuck while the driver starts his vehicle. We can only detect solid non-deformable objects trapped in the doors, because small deformable obstacles such as a child's hand or arm do not strongly oppose the mechanical forces of the doors and the current consumed in the motors. door control

  not exceed a threshold set beforehand.

  The invention aims to solve these two problems by proposing a camera counting and detection system coupled with presence detection means.

to confirm and remove the doubt.

  For this, a first object of the invention is a system for counting and detecting passengers in a public transport vehicle, comprising at least one device for acquiring images, means for the display of these images by the driver. and an on-board electronic computer controlling in particular braking, gearbox and closing actuators of the vehicle doors, characterized in that it comprises: - an image acquisition device from one or more digital cameras , miniature format installed in the mechanical structure of the vehicle, at each passenger access door and whose field of vision encompasses the entire access area; a presence detector associated with the image acquisition device of each access door of the vehicle, the detection field of which is directed towards the border between the interior and the exterior of the vehicle; - an on-board electronic computer, called a vision computer, ensuring the processing of the images from each acquisition device, intended to detect moving regions and to make them correspond to the

natural persons detected.

  A second object of the invention is a method of counting passengers implemented by such a system, comprising the following steps: - e1: acquisition of images at each access door of the vehicle; - e2: segmentation of the regions of each image; - e3: detection of image segments qualified as "candidates"; - e4: comparison of each "candidate" segment to a probable size criterion (CT); - e5: determination of image segments of "candidates for human presence"; - e6: confirmation of the presence of "hot bodies" in some of these latter image segments; - e7: selection of image segments qualified as "candidates for human presence suitable for counting"; - e8: counting of the number of passengers present in the vehicle, by subtraction from the number of passengers

  number of outgoing passengers.

  Other characteristics and advantages of the invention

  will appear on reading the description of a

  exemplary embodiment, illustrated by the following figures which are: FIG. 1: a schematic section of a vehicle at the level of a door, equipped with at least one camera and a presence detector; FIG. 2: a functional diagram of a counting system according to the invention, in a vehicle; FIGS. 3 and 4: two functional diagrams of image processing according to the counting method of the invention. The different elements bearing the same references in the different figures fulfill the same

  functions for the same results.

  The counting system according to the invention comprises an image acquisition device from one or more digital matrix cameras, of the CCD - Charge Coupled Device -, or CMOS Complementary Oxide Semiconductor -, or APS-CMOS - Active type. Pixel Sensor CMOS -, miniature format, installed in the mechanical structure of the bus-type vehicle, at each passenger access door, either at the front of the vehicle for the passenger entry flow and at the back for the output stream. Adequate lighting means can be associated with the cameras, in order to illuminate the scene happening in the vicinity of

each door.

  The images from the cameras are processed by an on-board electronic computer, with a microprocessor provided with an all-or-nothing input / output circuit to alert the driver of the vehicle. This calculator is intended to detect moving regions such as

  of travelers walking past the camera.

  This detection is improved and confirmed by at least one presence detector, of thermal infrared or radar type (of wavelength between three and

  five microns, or eight and twelve microns).

  The schematic section of the vehicle 1 in FIG. 1 is a cross section at the level of a door 2. A CCD camera 3 is placed inside the bus, under the ceiling light 4 above the opening area of the door. Its field of vision 5, with a diameter on the ground close to 1.5 meters for example, represented in dotted lines, encompasses the entire access area of the bus, i.e. the steps

access 6.

  A second camera 30 can be placed outside the bus 1 so that their two fields of vision 5 and 50 are complementary and cover the entire opening area of the door 2 allowing passenger access. As shown in the functional diagram on page 2, they are connected to an electronic computer 7 called vision ensuring the processing of images in order to detect moving regions. The regions are segmented in relation to the fixed background represented by the bus steps seen from above, or the doors

side views.

  To make the identification of people and their packages more reliable, for example, for each access door of the bus, a presence detector 8, of the thermal infrared or radio frequency (radar or laser) type, is associated with the cameras and placed at side of one of the two cameras. Its detection field 9 is narrow, with a diameter on the ground close to 20 cm for example, and directed towards the border between the inside and the outside of the bus at the level of the passenger access door. It is connected to the vision computer 7 in order to configure the correspondence between the regions segmented by image processing and the presence of physical persons that it has detected. Thermal detection confirms detection by segmentation

  before the actual count.

  The system according to the invention therefore comprises two devices as described above, a first installed at the level of the entry door 2 of the passengers and a second at the level of the exit 20, the computer carrying out the instant counting of the number of passengers present inside the vehicle. In addition, the calculator can estimate the total weight of the

  vehicle payload at all times.

  The method of counting the passengers actually present in the vehicle, implemented by the computer 7, comprises, as shown in the functional diagram in FIG. 3, a first step e1 of acquiring images at each door access. The processing of these digital video signals consists of a second step e2 of segmenting the regions of each image, followed by a third step e3 of detecting image segments qualified as "candidates", by a known morphological method for example. A fourth processing step e4 compares each candidate segment with a probable size criterion CT to determine the segments qualified as "candidates

  to a human presence "in a fifth step e5.

  If the presence detector confirms the presence of "hot body" in some of these latter segments, during a step e6, a seventh step e7 delivers a selection of image segments qualified as

  "candidates for human presence, suitable for counting".

  Finally, in the eighth step e8, the computer can count the passengers present on the bus, by subtracting from the number of incoming passengers, estimated from a device placed above the front door, the number of outgoing passengers, estimated from another device placed above the exit door. The calculator can also estimate

  the total weight of the vehicle's payload.

  The vision computer 7 is connected by a serial link to the central electronic computer 12 of the vehicle, to which it communicates the number of passengers as well as the estimate of the instantaneous total load of the vehicle in order to optimize the braking parameters and / or gearbox by piloting

actuators 13.

  As shown in the functional diagram of FIG. 4, the detection of a passenger trapped in an access door is also carried out by the electronic computer 7 which compares, during a step e9, the image If coming from the camera indoor, or indoor and outdoor cameras when the device has two, after closing the door with a

  Ir reference image taken just before closing.

  The method then determines an image qualified as "candidate", at step elo. Then, the computer performs a step el, of confirmation of the presence of a "hot body" in some of these "candidate" images.

  by the infrared presence detector.

  In such a case, the vision computer 7 sends a signal, during a step e12 of triggering an alert to an interface, for example an indicator light placed in the driver's field of vision. It also sends, during an additional step el3, the image of the access door after closing on a display screen 11 placed in the driver's field of vision, on the dashboard for example. The driver can thus verify for himself the presence of an obstacle trapped in the door. Finally, it sends its confirmation signal to the central computer 12 of the vehicle which then controls the opening of the door where a person is detected trapped, in

  driving the door motor 14, during a step el4.

  The advantage of the system lies in particular in the multiple use of passive surveillance cameras in the vehicle access areas, in particular for counting, detecting passengers or objects trapped in the doors, or even for

  direct monitoring of entry and exit doors.

  This system will reduce the cost of purchasing components, improve the assembly process and increase the intrinsic performance of public transport vehicles thanks to excellent precision.

passenger counting.

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Claims (13)

R E V E N D I C A T I O N S   1. A system for counting and detecting passengers in a public transport vehicle, comprising at least one device for acquiring images, means for displaying these images by the driver and an on-board electronic computer controlling in particular actuators for braking, gearbox and closing the vehicle doors, characterized in that it comprises: - a device for acquiring images from an o10 or more digital cameras (3), of miniature format located in the mechanical structure of the vehicle, at each access door (2) for passengers and whose field of vision (5) encompasses the entire access area; - a presence detector (8) associated with the image acquisition device of each vehicle access door, the detection field of which is directed towards the border between the interior and exterior of the vehicle; - an on-board electronic computer (7), said to be of vision, ensuring the processing of the images from each acquisition device, intended to detect moving regions and to make them correspond to the natural persons detected.   2. System according to claim 1, characterized in that each image acquisition device, at each access door of the vehicle, comprises two cameras (3, 30) one of which (3) is placed at the interior of the vehicle and the other (30) is placed outside so that their two fields of vision (5, 50) are complementary and cover the entire area door opening.   3. System according to one of claims 1 or 2,   characterized in that lighting means are associated with the image acquisition device, intended   to illuminate the scene at each access door.   4. System according to claim 1, characterized in that the presence detector (8) is of the thermal infrared type. 5. System according to claim 1, characterized in that the presence detector (8) is of the type radio frequency, radar or laser.   6. System according to claim 1, characterized in that the electronic vision computer (7) comprises an all-or-nothing input-output circuit connected to a driver alert interface.   7. System according to claim 6, characterized in that the alert interface is an indicator light (10) placed in the field of vision of the driver of the vehicle.   8. System according to claim 1, characterized in that the electronic computer (7) of vision is connected, by a serial link, to the central electronic computer (12) of the vehicle to which it communicates the number of passengers present in the vehicle and the estimate of the total instantaneous load for the control of the brake and gearbox actuators. 1 3 9. Passenger counting process implemented by   a system according to one of claims 1 to 5,   characterized in that it comprises the following steps: - e1: acquisition of images at each access door of the vehicle; - e2: segmentation of the regions of each image; - e3: detection of image segments qualified as "candidates"; - e4: comparison of each "candidate" segment to a probable size criterion (CT); - e5: determination of image segments of "candidates for human presence"; - e6: confirmation of the presence of "hot bodies" in some of these latter image segments; - e7: selection of image segments qualified as "candidates for human presence suitable for counting"; - e8: counting of the number of passengers present in the vehicle, by subtraction from the number of passengers   number of outgoing passengers.   10. Method for detecting passengers trapped in an access door of a vehicle, by a system according to one   of claims 1 to 5, characterized in that it   comprises the following steps: - e9: comparison of the image (If), acquired at each access door of the vehicle, after the closing of said doors with a reference image (Ir) taken just before this closing; - elo: determination of images qualified as "candidates"; - el,: confirmation of the presence of "hot body" in these "candidate" images.   11. Detection method according to claim 10 by   a system according to one of claims 1 to 7,   characterized in that it comprises an additional step (e12) of triggering an alert to a   interface, such as an indicator light (10).   12. Detection method according to claim 10, characterized in that it comprises an additional step (e13) of sending the image of the access door after closing on a display screen   (11) placed in the driver's field of vision.   13. Detection method according to claim 10, characterized in that the step of sending the confirmation signal, originating from step (el1), to the central computer (12) of the vehicle, then controls the opening of the door while driving its motor (14), during a stage additional (el4).