Electronic control unit for a vehicle interior monitoring system and associated interior monitoring system

Abstract

Electronic control unit for a vehicle interior monitoring system and associated interior monitoring system. This electronic control unit (20) for a vehicle interior monitoring system comprises a first camera module (41), including a first camera control unit (121), connected to a first serialization module (141), and at least one second camera module (42, 43), including a second camera control unit (122, 123), connected to a second serialization module (142, 143), the electronic control unit (20) comprising a first deserialization module (181) connected to the first serialization module (141), and at least one second deserialization module (182, 183), each connected to each of the corresponding at least one second serialization module (142, 143),the electronic control unit further comprising a main control device (22) connected to the first and second deserialization modules, and configured to manage, via at least one of said first (181) and second (182,183) deserialization modules, an activation of each camera module with a time offset relative to another camera module. Figure: Fig. 1,

Description

Title of the invention: Electronic control unit for a vehicle interior monitoring system and associated interior monitoring system

[0001] The present invention relates to an electronic control unit for an interior vehicle monitoring system and an associated interior vehicle monitoring system.

[0002] The invention falls within the field of embedded surveillance systems, which use a plurality of camera modules for general surveillance, such as monitoring the passenger compartment, detecting vital signs, detecting the position of the driver and occupants or their location.

[0003] Each camera module used in such an embedded surveillance system generally includes a light source and an image sensor.

[0004] Such a system, such as the driver monitoring system (DMS) or the occupant monitoring system (OMS), can be used for example in advanced driver assistance systems (ADAS).

[0005] For effective monitoring inside the vehicle, under all conditions, including night driving, it is useful to sensitively activate a light source simultaneously with the image sensor to capture one or more images, forming a video, of the vehicle's interior. For example, in some applications, to avoid disturbing the driver, light sources in a spectrum different from that of visible light, such as infrared light sources, are used. However, for both infrared and visible light sources, activating a light source from a given camera module, even for a short period, can disrupt image acquisition by another camera module, introducing unwanted reflections or overexposure in the images captured by that other camera module.

[0006] The present invention aims to remedy the aforementioned problem.

[0007] To this end, the invention proposes an electronic control unit for an interior vehicle monitoring system, the interior monitoring system comprising a plurality of camera modules including:

[0008] -a first camera module, comprising a first light source and a first image sensor, the first camera module comprising a first camera control unit, connected to a first serialization module,

[0009] -at least one second camera module, comprising a second light source and a second image sensor, the second camera module comprising a second camera control unit, connected to a second serialization module,

[0010] the electronic control unit comprising a first deserialization module connected to the first serialization module, and at least one second deserialization module connected, each, to each of the at least one corresponding second serialization module, the electronic control unit further comprising a main control device connected to said first and second deserialization modules, the electronic control unit being configured to manage, via at least one of said first and second deserialization modules, an activation of each camera module with a time offset relative to another camera module.

[0011] Advantageously, the proposed electronic control unit allows the activation sequence of the camera modules of the plurality of camera modules to be controlled, so as to avoid the simultaneous activation of the light sources of two separate camera modules, and thus to ensure that the image acquisition quality is satisfactory under all conditions.

[0012] In embodiments of the invention, the electronic control unit comprises one or more of the following features, considered alone or in all technically possible combinations.

[0013] The main control device is configured to activate the first camera module, by means of a first trigger signal, sent via the connection between the first deserialization module and the first serialization module, to trigger the first camera control unit in order to activate the first light source and the first image sensor.

[0014] The first deserialization module is further configured to receive a synchronization signal from the first serialization module and to transmit the synchronization signal to a second deserialization module, said second deserialization module being configured to transmit said synchronization signal to the corresponding second serialization module of a second camera module, said second camera module being configured, upon receiving said synchronization signal, to obtain a second delayed trigger signal of said time offset, the second trigger signal being applied to activate said second camera module.

[0015] Each second deserialization module is configured to receive a synchronization signal from the second connected serialization module, and to transmit the synchronization signal to a subsequent second deserialization module connected to a subsequent second camera module, said subsequent second camera module being configured, upon receipt of said synchronization signal, to obtain a second subsequent trigger signal delayed by said time offset, the second subsequent trigger signal being applied to activate said second subsequent camera module.

[0016] The first deserialization module and at least one second deserialization module are connected via a low voltage differential signaling link, LVDS (Low Voltage Differential Signaling).

[0017] The indoor surveillance system comprises a plurality of secondary camera modules and the main control device is configured to:

[0018] -generate a first trigger signal to activate the first camera module, and send the first trigger signal to activate the first camera module via the first deserialization module, and

[0019] -generate at least one second trigger signal to activate the second camera module(s), each second trigger signal being delayed relative to the first trigger signal by an overall offset, the overall offset depending on the rank of the second camera module in the plurality of second camera modules, and send each second trigger signal via the corresponding second deserialization module to activate the second camera module.

[0020] The main control device sends each of said first and second trigger signals to a general input / output port, GPIO, of the corresponding first camera module and second camera module, via a GPIO port of the corresponding first and second deserialization module.

[0021] The main control device sends each of said first and second trigger signals in the form of I2C (“Inter Integrated Circuit” commands).

[0022] The invention also relates to an interior vehicle surveillance system comprising a plurality of camera modules including:

[0023] -a first camera module, comprising a first light source and a first image sensor, the first camera module comprising a first camera control unit, connected to a first serialization module,

[0024] -at least one second camera module, comprising a second light source and a second image sensor, the second camera module comprising a second camera control unit, connected to a second serialization module,

[0025] the indoor surveillance system further comprising an electronic control unit as briefly described above.

[0026] According to an optional feature, the first light source and / or each second light source is an infrared light source.

[0027] Other features and advantages of the present invention will become apparent from the following description, provided solely by way of non-limiting example, with reference to the accompanying drawings, in which:

[0028] [Fig-1] Fig. 1 schematically represents the main functional modules of an internal vehicle monitoring system according to the invention;

[0029] [Fig.2] Fig.2 schematically represents an indoor surveillance system of a vehicle according to a first embodiment;

[0030] [Fig.3] Fig.3 schematically represents an indoor surveillance system of a vehicle according to a second embodiment, and

[0031] [Fig.4] Fig.4 schematically represents an indoor surveillance system of a vehicle according to a third embodiment.

[0032] Fig. 1 is a schematic representation of an interior monitoring system 2 of a vehicle (not shown), referred to as "system 2" in the following description.

[0033] System 2 is suitable for all types of vehicles, in particular motor vehicles.

[0034] System 2 comprises a plurality of on-board camera modules, including a first camera module 4i and at least a second camera module 42.

[0035] In the example of [Fig.1], system 2 comprises a first camera module 4i and two second camera modules 42, 43.

[0036] In the general case, the plurality of camera modules can include any number N of camera modules from 4i to 4N. In the illustrated examples, N=3.

[0037] Each camera module has an associated rank in the plurality of camera modules, for example the first camera module 4i has rank 1, the second camera module 42 has rank 2, the second camera module 43 has rank 3, and more generally, the second camera module 4N has rank N.

[0038] Each camera module 4i to 4N includes a light source 6i...6N, an image sensor 8i...8N, a camera control unit 10i...10N and a serialization module 12p..12N, which are adapted to communicate via an internal communication bus.

[0039] According to one embodiment, each camera module further includes at least one 14p.. 14N connection port, associated with the 12p.. 12N serialization module, for example a general Purpose Input / Output (GPIO) connection port and / or an I2C (Inter-Integrated Circuit) connection port.

[0040] For the first camera module, the light source 6i can also be called the first light source, the image sensor 8i can also be called the first image sensor, the camera control unit 10i can also be referred to as the first camera control unit, the 12i serialization module can also be called the first serialization control module, and the 14i connection port can also be called the first connection port.

[0041] For each second camera module, the light source module can also be called the second light source module, the image sensor can also be called the second image sensor, the camera control unit can also be called the second camera control unit, the serialization module can also be called the second serialization control module, and the connection port can also be called the second connection port.

[0042] In one example, some or all of the light sources 6p...6N comprise one or more light-emitting diodes (LEDs). In a particular example, each light source 6i...6N is configured to emit light in a spectrum different from the visible light spectrum, such as the infrared light spectrum. In other words, in one example, each light source 6i...6n is an infrared light source.

[0043] Each light source 61,... 6N and each image sensor 8i... 8N are configured to be activated (i.e. turned on) by the corresponding camera control unit 10i... 10N.

[0044] Each 12p.. 12N serialization module is configured to receive image / video data on a video input interface (not shown), the image / video data being represented as series of pixel matrices, and to transform the image / video data into series of bits.

[0045] Each of the plurality of camera modules 4p.. 4N is configured to communicate via a serial link 15p.. 15N with a corresponding deserialization module 18i ... 18n, each deserialization module 18p.. 18N having an I / O connection port 16p.. 16N.

[0046] According to one embodiment, each serial link 15p.. 15N is a physical LVDS (Low Voltage Differential Signaling) or Coax link, generally used for cameras.

[0047] According to one embodiment, each serial link 15p.. 15N is a Gigabit Multimedia Serial Link (GMSL for Gigabit Multimedia Serial Link) or a Fiat Panel Display Link (FPD-Link or Fiat Panel Display Link), for example GMSL1, GMSL2, FPD-Link3, FPD-Link4.

[0048] For example, each serialization module is a standard component, such as a CSL2 (Camera Serial Interface 2) to GMSL or FPD-Link serializer.

[0049] The system 2 further comprises an electronic control unit 20, including a main control device 22. The control device principal 22 is preferably implemented as a system on chip (SoC) and is configured to communicate, via a bidirectional communication bus, with each deserialization module 18i... 18N.

[0050] Preferably, the electronic control unit 20 includes the deserialization modules 18i... 18N, as well as the main control device 22.

[0051] The deserialization module 18i, connected to the serialization module 12i of the first camera module, is also called the first deserialization module.

[0052] Each deserialization module 182... 18N; connected to a corresponding serialization module 122... 12n of a second camera module 42 to 4N can also be called a second deserialization module.

[0053] Advantageously, the electronic control unit 20 is configured to manage, via the first deserialization module 18X or via the plurality of deserialization modules 18i...18N, the activation of each camera module with a time offset relative to another camera module.

[0054] Activation of a camera module includes activation of the light source, i.e., switching on the light source, and activation of the image sensor of the camera module.

[0055] The activation of a given camera module is followed by its deactivation (in particular, its light source is turned off) before any other camera module of the plurality of camera modules is activated.

[0056] The time delay is chosen so that only one light source is activated at a time. In other words, when one light source in a camera module is turned on, all other light sources in the other camera modules are turned off.

[0057] For example, the time lag D between the activation of two successive cameras of the plurality of cameras depends on the FPS (frames per second) parameter of each camera, for example less than or equal to 10 ms.

[0058] Advantageously, the electronic control unit 20 manages the sequential activation of the camera modules, which makes it possible to avoid any interference between the light sources of separate camera modules.

[0059] The time offset D ensures that when a subsequent camera is activated (i.e. its source is turned on), the previous camera is deactivated (i.e. its light source is turned off).

[0060] For example, the order of activation of the camera modules is the order of ranking.

[0061] For example, when the first camera module (rank 1) is activated first, the overall time lag between the activation of the first camera module 4i and the activation of the second camera module 42 (rank 2 camera module) is D, the overall time lag between the activation of the first camera module 4i and the activation of the second camera module 43 (rank 3 camera module) is 2xD, and so on, so that the overall time lag between the activation of the first camera module 4i and the activation of the second camera module 4N (rank N camera module) is (Nl)xD.

[0062] Therefore, the overall time lag between the activation of the first camera module and the activation of a given second camera module depends on the rank of the second camera module in the plurality of camera modules.

[0063] Several embodiments for managing the sequential activation of the camera modules are described below with reference to Figures 2 to 4.

[0064] According to a first embodiment, schematically illustrated in [Fig.2], the main control device 22 is configured to activate the first camera module 4b by means of a first trigger signal Si which is sent to the first deserializer 18i. The deserializer 18i transmits the first trigger signal Si via, for example, its GPIO port, and then through the serial link 15i to the corresponding first serialization module.

[0065] In this first embodiment, the first camera module 4i acts as the main synchronization module, and the synchronization of the activation of the second camera modules is then carried out in cascade.

[0066] Upon receiving the first trigger signal Si, the first serialization module 12i transmits the first trigger signal Si to the first camera control unit 10i, which then activates the first light source 6i and the first sensor 8p. After the image acquisition carried out by the first sensor 8i, the first light source 6i is turned off, the first camera control unit 10i is further configured to generate a return synchronization signal Si-o, which is transmitted via the first serialization module 12i and the serial link 15i to the first deserialization unit 18i.

[0067] The first deserialization unit 18i is configured to receive the synchronization signal and to transmit said synchronization signal via, for example, its GPIO port to a second deserialization module of a second selected camera module, for example the second camera module 42, of rank 2 in the plurality of camera modules.

[0068] The second camera module 42 is configured to receive the synchronization signal Sro, to add for example a time offset D by the second camera control unit 102 to the received synchronization signal to obtain a second trigger signal S2, the second trigger signal being applied to activate the second camera module 42.

[0069] After image acquisition by the second sensor 82, the second camera control unit 102 is also configured to generate a return synchronization signal S2-o, which is transmitted via the second serialization module 122 and the serial link 152 to the second deserialization unit 182.

[0070] When the system includes a plurality of second camera modules, the operations are repeated sequentially, according to a predetermined order of activation of the second camera modules, for example according to their corresponding rank.

[0071] According to one embodiment, considering any two successive 4k and 4k+isuccessive camera modules, the second 18k deserialization module is configured to receive the Sk-o synchronization signal from the second 12k serialization module, via the 15k serial link.

[0072] The second 18k deserialization module is configured to transmit the synchronization signal to the second 18k+i deserialization module. The second 18k+i deserialization module is then configured to transmit the synchronization signal to the corresponding 12k+i serialization module of the 4k+i camera module.

[0073] The second 4k+ camera module is configured to receive the Sk-o synchronization signal, to add, for example, the time offset D to the received synchronization signal in order to obtain a second trigger signal Sk+i, the second trigger signal being applied to activate the second 4k+ camera module. When image acquisition is completed by the last camera module, the S3-o synchronization signal is sent back to the main control device 22.

[0074] Advantageously, the first embodiment includes only physical communications using serial communication links.

[0075] According to a second embodiment, illustrated in [Fig. 3], the main control device 22 is configured to generate successive trigger signals Si to SN to successively activate each of the camera modules 4i to 4N, in a predetermined order, respectively a first trigger to activate the first camera module and a plurality of successive second trigger signals to successively activate the plurality of second camera modules. Each camera module is activated for a given duration not exceeding the time offset D.

[0076] More generally, two successive trigger signals Sk and Sk+i are generated by applying the time offset D, and sent to the respective corresponding deserialization modules 18k and 18k+i.

[0077] Each deserialization module is configured to transmit the trigger signal to the corresponding serialization module in order to activate the corresponding camera module.

[0078] According to the second embodiment, the trigger signals Si... SN are transmitted via the general purpose input / output (GPIO) connection ports which link the deserialization module 18i...18N and the corresponding serialization module 12p...12N of each camera module 4b...4N. Each serialization module 12i...12N sends, upon receipt, the trigger signal to the camera control unit 10i...10N to activate the camera module.

[0079] Advantageously, in this second embodiment, the delay of the trigger signals is managed by the main control device; no management synchronization signal is required in the camera modules. Consequently, the activation of the camera modules is ensured even if an error occurs in one of the camera modules out of the plurality of camera modules.

[0080] According to a third embodiment, illustrated in [Fig. 4], the main control device 22 is configured to generate successive trigger signals Ci to CN to activate each of the camera modules 4i to 4N successively, in a predetermined order. Each camera module is activated for a given duration not exceeding the time offset D.

[0081] In this embodiment, the generated trigger signals are in the form of I2C (Inter-Integrated Circuit) commands which are transmitted via the I2C connection ports of the deserialization modules 18i...18N to the corresponding I2C connection ports of the serialization modules 12i...12N of the camera modules 4p...4N. Each serialization module 12i...12N is configured to send, upon receipt, a data setting signal Si...SN to the camera control unit 10i...10N in order to activate the camera module.

[0082] As in the second embodiment, two successive trigger signals Ck and Ck+i are generated by applying the time offset D and sent to the respective corresponding deserialization modules 18k and 18k+i.

[0083] Advantageously, in this third embodiment, the delay of the trigger signals is managed by the main control device, without the need to manage the time lag in the camera modules. Consequently, the management of the activation camera modules is ensured even if an error occurs in one of the camera modules out of the plurality of camera modules.

Claims

Demands

1. Electronic control unit (20) for an interior vehicle monitoring system, the interior monitoring system comprising a plurality of camera modules including: - a first camera module (4J), comprising a first light source (6i) and a first image sensor (8i), the first camera module (4i) comprising a first camera control unit (12J), connected to a first serialization module (14J), - at least a second camera module (42, 43), comprising a second light source (62, 63) and a second image sensor (82, 83), the second camera module (42, 43) comprising a second camera control unit (122, 123), connected to a second serialization module (142, 143), the electronic control unit (20) comprising a first deserialization module (181) connected to the first serialization module (14J), and at least a second deserialization module (182,183),each connected to each of at least one corresponding second serialization module (142,143), the electronic control unit (20) further comprising a main control device (22) connected to said first (181) and second (182,183) deserialization modules, the electronic control unit (20) being configured to manage, via at least one of said first (181) and second (182,183) deserialization modules, an activation of each camera module with a time offset relative to another camera module.

2. Electronic control unit according to claim 1, wherein the main control device (22) is configured to activate the first camera module (4J, via a first trigger signal (Si), sent via the connection between the first deserialization module (18i) and the first serialization module (14i), to trigger the first camera control unit in order to activate the first light source (6i) and the first image sensor (8i).

3. Electronic control unit according to claim 2, wherein the first deserialization module (181) is further configured to receive a synchronization signal from the first serialization module (14J, and to transmit the synchronization signal to a second deserialization module (182), said second deserialization module (182) being configured to transmit said synchronization signal to the corresponding second serialization module (142) of a second camera module (42), said second camera module (42) being configured, upon receipt of said synchronization signal, to obtain a second trigger signal (S2) delayed by said time offset, the second trigger signal being applied to activate said second camera module (42).

4. Electronic control unit according to claim 3, the indoor surveillance system comprising a plurality of second camera modules, and each second deserialization module being configured to receive a synchronization signal from the connected second serialization module, and to transmit the synchronization signal to a subsequent second deserialization module connected to a subsequent second camera module, said subsequent second camera module being configured, upon receipt of said synchronization signal, to obtain a subsequent second trigger signal delayed by said time offset, the subsequent second trigger signal being applied to activate said subsequent second camera module.

5. Electronic control unit according to any one of claims 2 to 4, wherein said first deserialization module (181) and at least one second deserialization module (182,183) are connected via a low-voltage differential signaling link, LVDS.

6. Electronic control unit according to claim 1, wherein the main control device (22) is configured to: - generate a first trigger signal (S1) to activate the first camera module (4J), and send the first trigger signal to activate the first camera module (4i) via the first deserialization module (181), and - generate at least one second trigger signal (S2, S3) to activate the second or each of the second camera modules (42, 43), each second trigger signal being delayed relative to the first trigger signal of a global time shift, the global time shift depending on a rank of the second camera module in the plurality of second camera modules, and send each second trigger signal via the corresponding second deserialization module (182,183) to activate the second camera module (42,43).

7. Electronic control unit according to claim 6, wherein the main control device (22) sends each of said first and second trigger signals to a general input / output port, GPIO, of the corresponding first camera module and second camera module, via a GPIO port of the corresponding first and second deserialization module.

8. Electronic control unit according to claim 6, wherein the main control device (22) sends each of said first and second trigger signals in the form of I2C (“Inter-Integrated Circuit”) commands.

9. Interior vehicle surveillance system comprising a plurality of camera modules including: - a first camera module (4i), comprising a first light source and a first image sensor, the first camera module comprising a first camera control unit, connected to a first serialization module, - at least a second camera module (42, 43), comprising a second light source and a second image sensor, the second camera module comprising a second camera control unit, connected to a second serialization module, the interior surveillance system further comprising an electronic control unit (20) according to claims 1 to 8.

10. Indoor surveillance according to claim 9, wherein the first light source (6i) and / or each second light source (62 63) is an infrared light source.

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