Brightness control method of illumination device, brightness control device and brightness control system

A brightness control method of an illumination device includes: obtaining a brightness of ambient light, determining an amount of supplementary light according to the brightness of the ambient light and target brightness if the brightness of the ambient light is less than the target brightness, and generating a first pulse signal according to the amount of supplementary light to control the illumination device to emit light.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 202110378398.2, filed on Apr. 8, 2021, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of electronic technologies, and in particular, to a brightness control method of an illumination device, a brightness control device and a brightness control system.

BACKGROUND

An advanced driving assistance system (ADAS) includes a driver monitoring system (DMS). In the DMS, in order to improve a display effect of a captured image, the DMS usually includes an illumination device for supplementing light. The brightness of the illumination device is usually adjusted according to the actual scenario.

SUMMARY

In an aspect, a brightness control method of an illumination device is provided. The brightness control method includes: obtaining a brightness of ambient light, determining an amount of supplementary light according to the brightness of the ambient light and a target brightness if the brightness of the ambient light is less than the target brightness, and generating a first pulse signal according to the amount of supplementary light to control the illumination device to emit light.

In some embodiments, after generating the first pulse signal according to the amount of supplementary light, the brightness control method further includes sending the first pulse signal to a driver device, so that the driver device controls, according to the first pulse signal, the illumination device to emit light.

In some embodiments, the brightness control method further includes sending a second pulse signal to the driver device to control the driver device to be turned on or off.

In some embodiments, sending the first pulse signal to the driver device, so that the driver device controls, according to the first pulse signal, the illumination device to emit light, includes: sending the first pulse signal to an integrating circuit, so that the integrating circuit outputs a current or a voltage to the driver device to drive the driver device to output a drive current to the illumination device.

In some embodiments, generating the first pulse signal according to the amount of supplementary light includes: obtaining a driving signal according to the amount of supplementary light, obtaining a duty cycle of the first pulse signal according to the driving signal and a correspondence between the driving signal and the duty cycle of the first pulse signal, and generating the first pulse signal according to the duty cycle of the first pulse signal.

In some embodiments, obtaining the driving signal according to the amount of supplementary light includes: obtaining, according to a following formula, a power converted into light in an output power of the illumination device when the illumination device is driven to emit light with the amount of supplementary light:

P⁢O⁢Yn=(P⁢O⁢Y2-P⁢O⁢Y1)(W2-W1)·Wn;
where POY2is a power, converted into light with a maximum brightness, in an output power of the illumination device when the illumination device is driven to emit the light with the maximum brightness, POY1is a power, converted into light with a minimum brightness in another output power of the illumination device when the illumination device is driven to emit the light with the minimum brightness, POYnis a power, converted into light with the amount of supplementary light, in yet another output power of the illumination device when the illumination device is driven to emit the light with the amount of supplementary light, n represents the driving signal corresponding to the amount of supplementary light; W2is the maximum brightness, W1is the minimum brightness, and Wnis the amount of supplementary light; and obtaining the driving signal according to the power converted into the light with the amount of supplementary light, and a correspondence between the driving signal and the power converted into the light with the amount of supplementary light.

In another aspect, a brightness control device of an illumination device is provided. The brightness control device includes a memory and one or more processor coupled to the memory. The memory is configured to store computer program codes including computer program instructions. At least one processor is configured to when executing the computer program instructions, perform: obtaining a brightness of ambient light, determining an amount of supplementary light according to the brightness of the ambient light and a target brightness if the brightness of the ambient light is less than the target brightness, and generating a first pulse signal according to the amount of supplementary light to control the illumination device to emit light.

In some embodiments, the at least one processor is further configured to perform: sending the first pulse signal to a driver device, so that the driver device controls, according to the first pulse signal, the illumination device to emit light.

In some embodiments, the at least one processor is further configured to perform: sending a second pulse signal to the driver device to control the driver device to be turned on or off.

In some embodiments, the at least one processor is configured to perform: sending the first pulse signal to an integrating circuit, so that the integrating circuit outputs a current or a voltage to the driver device to drive the driver device to output a drive current to the illumination device.

In some embodiments, the at least one processor is configured to perform: obtaining a driving signal according to the amount of supplementary light, obtaining a duty cycle of the first pulse signal according to the driving signal and a correspondence between the driving signal and the duty cycle of the first pulse signal, and generating the first pulse signal according to the duty cycle of the first pulse signal.

In some embodiments, the at least one processor is configured to perform: obtaining, according to a following formula, a power converted into light in an output power of the illumination device when the illumination device is driven to emit light with the amount of supplementary light:

P⁢O⁢Yn=(P⁢O⁢Y2-P⁢O⁢Y1)(W2-W1)·Wn;
where POY2is a power, converted into light with a maximum brightness, in an output power of the illumination device when the illumination device is driven to emit the light with the maximum brightness, POY1is a power, converted into light with a minimum brightness, in another output power of the illumination device when the illumination device is driven to emit the light with the minimum brightness, POYnis a power, converted into light with the amount of supplementary light, in yet another output power of the illumination device when the illumination device is driven to emit the light with the amount of supplementary light, n represents the driving signal corresponding to the amount of supplementary light; W2is the maximum brightness, W1is the minimum brightness, and Wnis the amount of supplementary light; and obtaining the driving signal according to the power converted into the light with the amount of supplementary light, and a correspondence between the driving signal and the power converted into the light with the amount of supplementary light.

In yet another aspect, a non-transitory computer-readable storage medium is provided. The computer-readable storage medium includes computer program instructions that, when run on a computer, cause the computer to perform the brightness control method as described above.

In yet another aspect, a computer program product is provided. The computer program product includes computer program instructions stored in a non-transitory computer-readable storage medium that, when run on a computer, cause the computer to perform the brightness control method as described above.

In yet another aspect, a brightness control system of an illumination device is provided. The brightness control system includes an ambient light detection device and a control device. The ambient light detection device is configured to detect a brightness of ambient light. The control device is coupled to the ambient light detection device and is configured to obtain the brightness of ambient light from the ambient light detection device, determine an amount of supplementary light according to the brightness of the ambient light and a target brightness if the brightness of the ambient light is less than the target brightness, and generate a first pulse signal according to the amount of supplementary light to control the illumination device to emit light.

In some embodiments, the brightness control system further includes a driver device coupled to the control device. The control device is further configured to send the first pulse signal to the driver device. The driver device is configured to control, according to the first pulse signal, the illumination device to emit light.

In some embodiments, the control device is further configured to send a second pulse signal to the driver device to control the driver device to be turned on or off.

In some embodiments, the brightness control system further includes an integrating circuit coupled to the driver device and the control device. The control device is further configured to send the first pulse signal to the integrating circuit. The integrating circuit is configured to outputs a current or a voltage to the driver device. The driver device is configured to output, as driven by the current or the voltage, a drive current to the illumination device.

In some embodiments, the control device is configured to: obtain a driving signal according to the amount of supplementary light, obtain a duty cycle of the first pulse signal according to the driving signal and a correspondence between the driving signal and the duty cycle of the first pulse signal, and generate the first pulse signal according to the duty cycle of the first pulse signal.

In some embodiments, the control device is configured to: obtain, according to a following formula, a power converted into light in an output power of the illumination device when the illumination device is driven to emit light with the amount of supplementary light:

P⁢O⁢Yn=(P⁢O⁢Y2-P⁢O⁢Y1)(W2-W1)·Wn;
where POY2is a power, converted into light with a maximum brightness, in an output power of the illumination device when the illumination device is driven to emit the light with the maximum brightness, POY1is a power, converted into light with a minimum brightness, in another output power of the illumination device when the illumination device is driven to emit the light with the minimum brightness, POYnis a power, converted into light with the amount of supplementary light, in yet another output power of the illumination device when the illumination device is driven to emit the light with the amount of supplementary light, n represents the driving signal corresponding to the amount of supplementary light; W2is the maximum brightness, W1is the minimum brightness, and Wnis the amount of supplementary light; and obtain the driving signal according to the power converted into the light with the amount of supplementary light, and a correspondence between the driving signal and the power converted into the light with the amount of supplementary light.

DETAILED DESCRIPTION

As used herein, the term “if” is optionally construed as “when” or “in a case where” or “in response to determining that” or “in response to detecting”, depending on the context. Similarly, the phrase “if it is determined that” or “if [a stated condition or event] is detected” is optionally construed as “in a case where it is determined that” or “in response to determining that” or “in a case where [the stated condition or event] is detected” or “in response to detecting [the stated condition or event]”, depending on the context.

The use of “applicable to” or “configured to” indicates an open and inclusive meaning, which does not exclude apparatuses that are applicable to or configured to perform additional tasks or steps.

For convenience of understanding, an application scenario of the embodiments of the present disclosure will be described first.

A driver monitoring system (DMS) is mainly to monitor whether there is a dangerous operation done by a driver in a process of driving a vehicle. Contents monitored by the driver monitoring system may include fatigued driving, not looking ahead for a long time, smoking, making or answering phone calls, hands off the steering wheel, not wearing a seat belt, etc. When the driver monitoring system detects the dangerous behavior of the driver, it will generate an alarm.

For example, the driver monitoring system includes an image acquisition device and a control device. The image acquisition device captures an image of the behavior of the driver, and the control device recognizes the captured image to determine whether there is dangerous driving. In order to ensure a display effect of the captured image, the driver monitoring system may further include an illumination device to supplement light for a shot environment of the image acquisition device. The brightness of the illumination device is adjusted according to the actual scenario.

In some embodiments of the present disclosure, a brightness control system of the illumination device is provided for controlling, for example, a brightness of the illumination device. As shown inFIG.1, the brightness control system1includes a control device10, a driver device11and an ambient light detection device12. The control device10is coupled to the driver device11and the ambient light detection device12. The driver device11is coupled to the illumination device14.

The illumination device14may be configured to emit light when a brightness of ambient light is low (e.g., lower than a target brightness), so as to supplement the ambient light. In this way, an image captured by the image acquisition device in the driver monitoring system may be clear and bright. For example, the illumination device14is an illumination lamp, such as a light-emitting diode (LED) lamp.

In some examples, the control device10and driver device11may be integrated into a single device or may be separate devices. For example, the driver device11is integrated into the control device10. In this case, the control device10is directly coupled to the illumination device14to control the brightness of the illumination device14.

Hereinafter, the description is made by considering an example where the control device10and the driver device11are separate devices. As for the case where the control device10and the driver device11are integrated into a single device, reference may be made to the description, which will not be repeated herein.

The ambient light detection device12is configured to detect the brightness of the ambient light and send the detected brightness of the ambient light to the control device10. For example, the ambient light detection device12is a light sensor. The light sensor detects light energy of ultraviolet light to infrared light, converts the light energy into an electric signal, and transmits the electric signal into the control device10.

The control device10is the core of the brightness control system1. The control device10may be a system on chip (SoC).

The control device10is configured to: receive the brightness of the ambient light detected by the ambient light detection device12; if the brightness of the ambient light is less than a target brightness, determine an amount of supplementary light according to the brightness of the ambient light and a target brightness; and generate a first pulse signal according to the amount of supplementary light, so as to control the illumination device14to emit light.

In some examples, the illumination device14is controlled by the driver device11to emit light. Therefore, after generating the first pulse signal, the control device10sends the first pulse signal to the driver device11. In this case, the control device10is further configured to send the first pulse signal to the driver device11, so that the driver device11controls, according to the first pulse signal, the illumination device14to emit light.

In order to reduce the power consumption of the brightness control system1, in some examples, the driver device11is turned on when the illumination device14is to emit light, and turned off when the illumination device14does not emit light. For example, the driver device11is turned on as driven by a high-level/low-level signal. In this case, the control device10is further configured to send a second pulse signal to the driver device11to control the driver device11to be turned on or off, so as to control the illumination device14to emit light or not to emit light.

Both the first pulse signal and the second pulse signal may be pulse width modulation (PWM) signals.

In these examples, the driver device11may be configured to output a drive current according to the first pulse signal when the driver device11is turned on, so that the illumination device14emits light as driven by the drive current.

For example, when the second pulse signal sent by the control device10to the driver device11is a first level (e.g., a high level) signal, the driver device11is turned on and outputs the drive current according to the first pulse signal. In this case, the illumination device14may be driven by the drive current to emit light.

For another example, when the second pulse signal sent by the control device10to the driver device11is a second level (e.g., a low level) signal, the driver device11is turned off, so as to stop outputting the drive current. In this case, the illumination device14does not emit light because no drive current is flowing therein.

In some examples, the driver device11is a driver chip. In this case, in order to make the driver chip operate normally, that is, in order to make the driver chip be turned on and output the drive current, and further to control the illumination device14to emit light as driven by the drive current, the control device10provides corresponding control signals (e.g., the first pulse signal and the second pulse signal) to the driver chip.

For example, as shown inFIG.1, the control device10provides control signals (e.g., the first pulse signal and the second pulse signal) to an EN pin, a PWMA pin, and an ISET pin of the driver chip. The EN pin and the PWMA pin of the driver chip are used for receiving the second pulse signal to control the driver chip to be turned on or off. The ISET pin of the driver chip is used for receiving the first pulse signal, so as to output the drive current to the illumination device14according to the first pulse signal. Generally, a magnitude of the drive current input to the illumination device14may be adjusted by adjusting a magnitude of the voltage or current at the ISET pin, thereby adjusting the light-emitting brightness of the illumination device14.

It will be noted that the pins of the driver chip may be different in different applications limited by application scenarios and a purpose of miniaturization of the driver chip. For example, the EN pin and the PWMA pin are multiplexed, and there is no Fault pin.FIG.1shows an example where the EN pin and the PWMA pin are multiplexed.

In addition, since the first pulse signal is a pulse width modulation (PWM) signal, the ISET pin of the driver chip may be in a current detection mode or a voltage detection mode.

In this case, in some examples, the brightness control system1further includes an integrating circuit15. The integrating circuit15is coupled to the control device10and the driver device11. The control device10is configured to send the first pulse signal to the integrating circuit15. The integrating circuit15is configured to convert the first pulse signal into a current or a voltage that may be detected by the ISET pin of the driver device11, so that the driver device11outputs a drive current according to the current or the voltage that may be detected by the ISET pin for driving the illumination device14to emit light.

As shown inFIG.1, if the ISET pin is in the voltage detection mode, the ISET pin is coupled to a fixed resistor R, and a drive current for driving the illumination device14to emit light may be obtained according to a relationship between a resistance of the fixed resistor R and the voltage output by the integrating circuit15.

FIG.2is a circuit diagram of a driver chip coupled to an integrating circuit according to some embodiments, and the driver chip may be applied to the driver device11shown inFIG.1.

As shown inFIG.2, the PWMA pin of the driver chip is used to receive a second pulse signal (e.g., an LED-STROBE pulse signal inFIG.2) sent by the control device10, and the driver chip is turned on or off according to the second pulse signal. The ISET pin is used to receive a first pulse signal (e.g., an LED-PWM pulse signal inFIG.2) sent by the control device10.

For example, the first pulse signal sent by the control device10may be input to the ISET pin of the driver chip through the integrating circuit15. After the first pulse signal is input to the integrating circuit15, the integrating circuit15may output a current or a voltage. Therefore, the ISET pin of the driver chip may detect the current or the voltage, so that the driver chip outputs a drive current according to the current or the voltage to drive the illumination device14to emit light.

In addition, the driver chip shown inFIG.2may be OZ585. For descriptions of functions of other pins of the driver chip, reference may be made to related contents in the prior art, which will not be repeated here.

FIG.3is a circuit diagram of an integrating circuit15according to some embodiments. The integrating circuit15may be applied in a situation where the ISET pin is in the voltage detection mode. That is, when the first pulse signal is input to the integrating circuit15shown inFIG.3, the integrating circuit15outputs a voltage.

For example, as shown inFIG.3, the integrating circuit15includes a first resistor R1, a second resistor R2, a first capacitor C1and a second capacitor C2. One terminal of the first resistor R1is coupled to a LED-PWM pulse signal terminal (i.e., a terminal for receiving the first pulse signal), and the other terminal of the first resistor R1is coupled to one terminal of the second resistor R2and one terminal of the first capacitor C1. The other terminal of the first capacitor C1is grounded. The other terminal of the second resistor R2is coupled to the ISET pin and one terminal of the second capacitor C2. The other terminal of the second capacitor C2is grounded.

In a case where the ISET pin of the driver chip is in the voltage detection mode, the driver chip has a large internal resistance. In this case, the LED-PWM pulse signal is input to the integrating circuit15shown inFIG.3in a form of voltage. After the LED-PWM pulse signal is input to the integrating circuit15shown inFIG.3, a voltage on the ISET pin may be determined according to the voltage of the LED-PWM pulse signal. According to the voltage on the ISET pin, the driver chip may output a drive current corresponding to the voltage of the ISET pin. That is, the driver chip may output a drive current according to the first pulse signal.

FIG.4is a circuit diagram of another integrating circuit15according to some embodiments. The integrating circuit15may be used in a situation where the ISET pin is in the current detection mode. That is, when the LED-PWM pulse signal is input to the integrating circuit15shown inFIG.4, the integrating circuit15outputs a current.

As shown inFIG.4, the integrating circuit15includes a third resistor R3, a fourth resistor R4, a fifth resistor R5and a transistor Q. One terminal of the third resistor R3is coupled to the ISET pin, and the other terminal of the third resistor R3is coupled to one terminal of the fourth resistor R4and a collector of the transistor Q. The other terminal of the fourth resistor R4is grounded. An emitter of the transistor Q is grounded, and a base of the transistor Q is coupled to one terminal of the fifth resistor R5. The other terminal of the fifth resistor R5is coupled to the LED-PWM pulse signal terminal.

After the LED-PWM pulse signal is input to the integrating circuit15shown in FIG.4, the transistor Q may be controlled by the LED-PWM pulse signal to operate in a cut-off region, a triode region or a saturation region. When the transistor Q operates in the cut-off region, the triode region or the saturation region, an equivalent resistance of the transistor Q is different, so that the current input to the ISET pin will change according to the equivalent resistance of the transistor Q. According to the current at the ISET pin, the driver chip may output a drive current, so that the driver chip outputs the drive current according to the first pulse signal.

In some examples, as shown inFIG.1, the brightness control system1further includes an image acquisition device13, such as a camera. The image acquisition device13is configured to capture an image at the ambient light, and send the image to the control device10. The control device10is further configured to analyze a clarity of the captured image and determine whether to obtain the brightness of the ambient light according to the clarity of the captured image. When and how to obtain the brightness of the ambient light will be described later.

In addition, the control device10may be a computer device, such as a terminal device or a server. The terminal device may be a palmtop computer, a notebook computer, a smart phone, a tablet computer, a desktop computer or a vehicle terminal, such as a transmission control unit. The server may be a single server, a server cluster composed of multiple servers, or a cloud computing service center. The integrating circuit15and the driver device11may also be integrated in the control device10.

FIG.5is a block diagram of a hardware structure of a control device according to some embodiments. The control device10may include a processor101, a memory102, an interface unit103and a power supply104. However, the control device10may include more or fewer components than that shown inFIG.5according to actual needs.

The processor101is a control center of the control device10, and is connected to various parts of the entire control device10through various interfaces and lines. The processor101is configured to perform various functions of the control device10and process data by running or executing software programs and/or modules stored in the memory102, and calling data stored in the memory102, so as to perform an overall monitoring function of the control device10.

The processor101may include one or more processing units. For example, the processor101may be integrated with an application processor and a modem processor. The application processor mainly processes the operating system, the user interface, the application programs, etc., and the modem processor mainly processes the wireless communication. It will be understood that the modem processor may also not be integrated in the processor101.

The memory102may be configured to store software programs and various data. In this case, the memory102may include a program storage area and a data storage area. The program storage area may store at least one operating system, at least one application program required by at least one function unit, and the like.

The memory102may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid state storage devices. For example, the memory102may be a non-transitory computer readable storage medium. For example, the non-transitory computer readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, or an optical data storage device.

The interface unit103is an interface for connecting an external device to the control device10. For example, the external device includes an external power supply (or a battery charger) port, a wired data port, a wireless data port, and a memory card port. The wired data port may be, for example, a universal serial bus (USB) interface or a network cable interface. The wireless data port may be, for example, a Wi-Fi interface, a Bluetooth interface, or a near field communication (NFC) interface. The interface unit103may be used to receive input information (e.g., data information) from the external device and transmit the received input information to one or more components of the control device10, or the interface unit103may be used to transfer data between the control device10and the external device.

The power supply104(e.g., a battery) may be configured to supply power to various components. The power supply104may be logically connected to the processor101through a power management system, so as to implement functions such as charging management, discharging management, and power consumption management through the power management system.

Some embodiments of the present disclosure provide a brightness control method of an illumination device. The brightness control method may be performed by the control device10of the brightness control system1shown inFIG.1. As shown inFIG.6, the brightness control method includes steps201to203.

In step201, the control device10obtains a brightness of the ambient light.

After detecting the brightness of the ambient light, the ambient light detection device12sends the brightness of the ambient light to the control device10, so that the control device10obtains the brightness of the ambient light.

In some examples, the ambient light detection device12detects the brightness of the ambient light in real time, and the control device10receives the brightness of the ambient light in real time. That is, regardless of day or night, the control device10will receive the brightness of the ambient light sent by the ambient light detection device12.

In some other examples, the ambient light detection device12detects the brightness of the ambient light in real time, but the control device10receives the brightness of the ambient light within a preset time period. The preset time period may be, for example, 18:00-6:00 (24-hour clock) per day. That is, the control device10only receives the brightness of the ambient light when the brightness of the ambient light is low. Of course, the ambient light detection device12may also only detect the brightness of the ambient light within the preset time period.

In yet some other examples, the ambient light detection device12detects the brightness of the ambient light in real time. The control device10obtains a clarity of an image captured under the ambient light. If the clarity of the image is less than a preset clarity, the control device10obtains the brightness of the ambient light.

For example, the ambient light detection device12detects the brightness of the ambient light in real time. The image acquisition device13captures an image under the brightness of the ambient light, and sends the image to the control device10. The control device10processes the image to determine the clarity of the image. If the clarity of the image is less than the preset clarity, the control device10obtains (e.g., receives) the brightness of the ambient light.

For another example, the ambient light detection device12detects the brightness of the ambient light in real time. The image acquisition device13captures an image under the brightness of the ambient light, processes the captured image to determine the clarity of the image and generates first prompt information for indicating the clarity of the image. Then, the image acquisition device13sends the first prompt information to the control device10, and the control device10determines the clarity of the image according to the first prompt information. If the clarity of the image is less than the preset clarity, the control device10obtains the brightness of the ambient light. The method of determining the clarity of the image is not limited, which may use the existing technology.

In step202, if the brightness of the ambient light is less than a target brightness, the control device10determines an amount of supplementary light according to the brightness of the ambient light and the target brightness.

It will be noted that the target brightness is a preset brightness. In the embodiments of the present disclosure, the picture of the image captured by the image acquisition device13under the target brightness is clear and bright.

For example, the target brightness is 30 cd/m2. If the brightness of the ambient light is 20 cd/m2, the amount of supplementary light is 10 cd/m2(that is, the amount of supplementary light is a difference between the target brightness and the brightness of the ambient light). That is, the brightness of light emitted by the illumination device14is 10 cd/m2, so that a total brightness of the brightness of the ambient light and the brightness of the light emitted by the illumination device14may reach the target brightness. As a result, the picture of the image captured by the image acquisition device13may be clear and bright.

In step203, the control device10generates a first pulse signal according to the amount of supplementary light, so as to control the illumination device14to emit light.

In some examples, as shown inFIG.7, step203includes steps203ato203c.

In step203a, the control device10obtains a driving signal according to the amount of supplementary light.

For example, the control device10obtains, according to the following formula, a power converted into light (i.e., an output optical power corresponding to light intensity) of the illumination device14in an output power of the illumination device14when the illumination device14is driven to emit light with the amount of supplementary light:

Where POY is a power converted into light in an output power of the illumination device14; POY2is a power converted into light in an output power of the illumination device14when the illumination device14is driven to emit light with the maximum brightness; POY1is a power converted into light in another output power of the illumination device14when the illumination device14is driven to emit light with the minimum brightness; POYna power converted into light in yet another output power of the illumination device14when the illumination device14is driven to emit light with the amount of supplementary light; n represents a driving signal corresponding to the amount of supplementary light; W2is the maximum brightness of the illumination device14, W1is the minimum brightness of the illumination device14, and Wnis the amount of supplementary light. It will be noted that the output power of the illumination device may be changed as the brightness of the light emitted by the illumination device is changed.

FIG.8is a graph illustrating an output power PO of an illumination device, and a photoelectric conversion efficiency PCE of the illumination device versus a drive current and voltage of the illumination device, according to some embodiments. It will be noted that each light-emitting brightness of the illumination device14corresponds to a respective brightness value of an object to be captured.

The power POY converted into light in the output power of the illumination device14satisfies the following formula: POY=PO×PCE, where PO is the output power of the illumination device14, and PCE is a photoelectric conversion efficiency of the illumination device14.

Combined withFIG.8and the formula POY=PO×PCE, a correspondence between the power converted into light in the output power of the illumination device14and the drive current of the illumination device may be determined.

It will be noted that before the brightness control system1is used, the brightness control system1may be debugged according to the actual situation. For example, the brightness control system1is debugged according to information such as a model of a vehicle actually used, a camera, an installation position of the illumination device14and a distance from the object to be captured, so that the brightness control system1may be reliably used.

For example, the debugging content includes determining a maximum operating current of the illumination device14under a condition of a completely dark room (e.g., a completely dark environment), according to a maximum brightness of the illumination device14, so as to set the maximum operating current of the illumination device14as a maximum current value output by the driver device11in subsequent use. That is, in subsequent use, the maximum current output by the driver device11cannot exceed the maximum operating current of the illumination device14.

In addition, when the maximum current value output by the driver device11is set, the aging of the illumination device14and a redundancy of a current value after the efficiency is reduced may also be considered.

For example, the debugging content further includes determining a minimum operating current of the illumination device14under a fully bright condition (e.g., under strong sunlight at noon), according to a minimum brightness of the illumination device14. In subsequent use, the minimum current output by the driver device11is not less than the minimum operating current of the illumination device14.

For example, in the natural environment where supplementary light is not required, the operating current of the illumination device14is 0 A (that is, the illumination device14is in an OFF state), and the required amount of supplementary light W1is zero. When the ambient light is at its darkest (which corresponds to a completely dark environment), the operating current of the illumination device14is 3.5 A (in this case, the light emitted by the illumination device14has the maximum brightness), and the required amount of supplementary light W2is 55 cd/m2.

After the power converted into light in the output power of the illumination device14is obtained when the illumination device14is driven to emit light with the amount of supplementary light, the control device10may obtain the driving signal according to the power converted into light in the output power of the illumination device14and a correspondence between the power converted into light in the output power of the illumination device14and the driving signal (e.g., a drive current) of the illumination device14.

As shown in Table 1 below, Table 1 shows the correspondence between the power POY converted into light in the output power of the illumination device14and the driving signal of the illumination device14.

On the basis of the above formula, when the illumination device14is driven to emit light with the amount of supplementary light, the power POYnconverted into light in the output power of the illumination device14may be obtained, and then the power POYnis compared with data in Table 1 to determine a driving signal (e.g., a drive current I).

It will be noted that Table 1 is illustrated by considering an example where the driving signal is a drive current.

In step203b, the control device10obtains a duty cycle of the first pulse signal according to the driving signal and a correspondence between the driving signal and the duty cycle of the first pulse signal.

The correspondence between the duty cycle of the first pulse signal and the driving signal is preset. For example, the correspondence between the duty cycle of the first pulse signal and the driving signal may be pre-stored in the control device10.

As shown inFIG.2, an ENA pin and a VIN pin of the driver chip are electrically connected to a power supply VDD, and the power supply VDD is configured to supply power to the VIN pin and provide an enable signal to the ENA pin, that is, to supply power and provide the enable signal to the driver device11, so that the driver device11operates normally.

As shown inFIG.9, the LED-PWM represents a first pulse signal (e.g., an LED-PWM pulse signal) input by the control device10to the integrating circuit15. For example, an operating frequency of the LED-PWM pulse signal is 100 kHz, and the duty cycle thereof is 60%, or the duty cycle thereof is 12%.

The ISET represents the voltage on the ISET pin of the driver device11. For example, in a case where the operating frequency of the LED-PWM signal is 100 kHz and the duty cycle thereof is 60%, the voltage on the ISET pin is 2V. For another example, in a case where the operating frequency of the LED-PWM pulse signal is 100 kHz and the duty cycle thereof is 12%, the voltage on the ISET pin is 0.4 V.

The VCSEL current represents a drive current output by the driver device11. For example, in the case where the operating frequency of the LED-PWM pulse signal is 100 kHz and the duty cycle thereof is 60%, the drive current output by the driver device11is 3 A. For another example, in the case where the operating frequency of the LED-PWM pulse signal is 100 kHz and the duty cycle thereof is 12%, the drive current output by the driver device11is 0.6 A.

It can be seen fromFIG.9that as the duty cycle of the LED-PWM pulse signal is different, a voltage value on the ISET pin of the driver device11is also different, so that the drive current output by the driver device11is also different. For example, when the duty cycle of the LED-PWM pulse signal is 60%, the voltage value on the ISET pin of the driver device11is 2 V, and correspondingly, the drive current output by the driver device11is 3 A. For another example, when the duty cycle of the LED-PWM pulse signal is 12%, the voltage value on the ISET pin of the driver device11is 0.4 V, and correspondingly, the drive current output by the driver device11is 0.6 A.

That is, assuming that the driving signal is 3 A, referring toFIG.9, it can be seen that the duty cycle of the first pulse signal is 60%. In this way, after the driving signal is obtained, the duty cycle of the first pulse signal may be obtained according to the correspondence between the driving signal and the duty cycle of the first pulse signal.

In step203c, the control device10generates the first pulse signal according to the duty cycle of the first pulse signal.

After obtaining the duty cycle of the first pulse signal, the control device10may generate the first pulse signal according to the duty cycle.

In some examples, as shown inFIG.10, the brightness control method further includes step204after step203is performed.

In step204, the control device10sends the first pulse signal to the driver device11, so that the driver device11controls, according to the first pulse signal, the illumination device14to emit light.

For example, with reference toFIG.1and the above embodiments, the control device10may generate a first pulse signal according to the amount of supplementary light, and send the first pulse signal to the ISET pin of the driver device11. After receiving the first pulse signal through the ISET pin, the driver device11outputs a drive current to the illumination device14to drive the illumination device14to emit light.

As described above, the control device10generates the first pulse signal according to the amount of supplementary light, and sends the first pulse signal to the ISET pin of the driver device11. The driver device11may output the drive current to the illumination device14according to the first pulse signal, so that the illumination device14emit lights as driven by the drive current. In this way, the brightness of the ambient light may be adjusted.

In some embodiments, step204may include: sending, by the control device10, the first pulse signal to the integrating circuit15, so that the driver device11outputs a drive current to the illumination device14according to the first pulse signal.

In this case, the control device10sends a first pulse signal to the integrating circuit15, and the integrating circuit15may adjust, according to the first pulse signal, the drive current that is to be output by the driver device11.

For example, as shown inFIG.2, an input terminal (i.e., an LED-PWM pulse signal terminal) of the integrating circuit15is connected to the control device10, and the output terminal of the integrating circuit15is connected to the ISET pin of the driver device11. When the control device10generates a different first pulse signal (e.g., an LED-PWM pulse signal), and sends the LED-PWM pulse signal to the input terminal of the integrating circuit15, the integrating circuit15may adjust the voltage on the ISET pin of the driver device11, so that the drive current output by the driver device11, i.e., the drive current output to the illumination device14is changed.

As described above, the first pulse signal may be a current or a voltage. For example, the first pulse signal is a voltage, and the integrating circuit15shown inFIG.3may be adopted. For another example, the first pulse signal is a current, and the integrating circuit15shown inFIG.4may be adopted.

With reference to the above embodiments, the control device10inputs an LED-PWM signal (i.e., a first pulse signal) with a duty cycle of 60% to the integrating circuit15, and the voltage output by the integrating circuit15is 2 V, that is, the voltage on the ISET pin of the driver device11is 2 V, so that the drive current output by the driver device11is 3 A. That is, when the drive current output by the driver device11is 3 A, the drive current may drive the illumination device14to emit light according to the amount of supplementary light.

It will be noted that since parameters of components of the integrating circuit15have certain errors, in actual implementation, there may be certain errors in the voltage output by the integrating circuit15, which is a normal situation. Therefore, the output current of the illumination device14finally obtained according to the brightness control method is subject to the actual situation.

For example, in actual implementation, as shown inFIG.11, after the control device10inputs a first pulse signal with an operating frequency of 100 kHz and a duty cycle of 60% to the integrating circuit15, an output voltage of the integrating circuit15is 1.98 V. That is, the voltage on the ISET pin of the driver device11is 1.98 V. After the control device10inputs a pulse signal with an operating frequency of 100 kHz and a duty cycle of 12% to the integrating circuit15, the output voltage of the integrating circuit15is 396 mV. That is, the voltage on the ISET pin of the driver device11is 396 mV.

In some examples, in a case where the driver device11is turned on as driven by a high-level or low-level signal, as shown inFIG.12, the brightness control method further includes step205.

In step205, the control device10sends a second pulse signal to the driver device11to control the driver device11to be turned on or off.

In this case, the control device10sends a second pulse signal (e.g., an LED-STROBE pulse signal) to the driver device11to trigger the operating state of the driver device11. When the driver device11receives the second pulse signal sent by the control device10, the operating state of the driver device11is an ON state or an OFF state.

For example, a port of the control device10through which the control device10outputs the second pulse signal is an I/O port. The control device10may control the driver device11to be turned on when the output second pulse signal is at a high level, thereby controlling the illumination device14to emit light. Alternatively, the control device10may control the driver device11to be turned on when the output second pulse signal is at a low level, thereby controlling the illumination device14to emit light, which is not limited in the embodiments of the present disclosure.

The following description will be made by considering an example where the driver device11is turned on when the second pulse signal output by the control device10is at a high level, and the driver device11is turned off when the second pulse signal output by the control device10is at a low level.

For example, the control device10sends the second pulse signal at the high level to the driver device11. The driver device11is turned on in response to the second pulse signal, and outputs a drive current to the illumination device14to control the illumination device14to emit light. For another example, the control device10sends the second pulse signal at the low level to the driver device11. The driver device11is turned off in response to the second pulse signal, and thus the illumination device does not emit light.

As shown inFIG.9, LED-STROBE (PWMA) represents the LED-STROBE pulse signal (i.e., the second pulse signal) input by the control device10to the PWMA pin of the driver device11. For example, when the LED-STROBE pulse signal is at a high level, the driver device11is controlled by the LED-STROBE pulse signal to be turned on.

For example, with reference toFIG.2and the above embodiments, the control device10sends the LED-STROBE pulse signal (i.e., the second pulse signal) to the PWMA pin of the driver device11to control the driver device11to be turned on. After the driver device11is turned on, the control device10sends the first pulse signal to the ISET pin of the driver device11to adjust the drive current that is to be output by the driver device11, so that the illumination device14emits light as driven by the adjusted drive current.

It will be noted that, the control device10may output the first pulse signal according to the amount of supplementary light first to the ISET pin of the driver device11, and then output the second pulse signal to the PWMA pin of the driver device11to control the driver device11to be turned on, so that the illumination device14emits light with the amount of supplementary light. In this case, a duration of the ISET pin of the driver device11in an ON state may be set to be greater than a duration of the PWMA pin of the driver device11in an ON state.

In this way, the voltage on the ISET pin may be stable when the driver device11is normally turned on, and thus every time the driver device11is in the ON state, the voltage signal on the ISET pin may be a voltage signal required by the driver device11to operate, which makes the driver device11output a drive current. As a result, the illumination device14emits light, and the brightness of the illumination device14is equal to the amount of the supplementary light.

FIG.13is a timing diagram of signals through the PWMA pin and the ISET pin according to some embodiments. As shown inFIG.13, the duration of the ISET pulse signal through the ISET pin in an ON state is greater than the duration of the PWMA pulse signal through the PWMA pin in an ON state. For example, the PWMA pin will not be turned on until the ISET pin is turned on for t1.

In order to achieve that the duration of the ISET pulse signal through the ISET pin in ON state is greater than the duration of the PWMA pulse signal through the PWMA pin in ON state, an operating frequency of the ISET pin may be set to be greater than that of the PWMA pin. For example, the operating frequency of the ISET pin is 100 kHz, and the operating frequency of the PWMA pin is 60 Hz.

In the brightness control method provided by the embodiments, the control device10compares the brightness of the ambient light with the target brightness, determines the brightness of the supplementary light, i.e., the amount of supplementary light, and generates the first pulse signal according to the amount of supplementary light. Then, the control device10controls the illumination device14to emit light according to the first pulse signal. Since the first pulse signal is used to control the brightness of the illumination device14and the first pulse signal corresponds to the amount of supplementary light, when the illumination device14emits light according to the first pulse signal, the brightness of the light emitted by the illumination device14is the same as the amount of supplementary light, so that the brightness of the light emitted by the illumination device may be adjusted in real time according to the brightness of the ambient light.

The above contents mainly describe the solutions provided by the embodiments of the present disclosure from the perspective of interaction among the control device10, the driver device11, the ambient light detection device12and the illumination device14in the brightness control system1of the illumination device14. It will be understood that in order to implement the above functions, the control device10, the driver device11, the ambient light detection device12, the illumination device14, and the like include respective hardware structures and/or software modules for executing the functions. Those skilled in the art will easily realize that the embodiments may be implemented in hardware or a combination of hardware and computer software in conjunction with the units and algorithm steps of each example described in the embodiments disclosed herein. Whether a function is performed by hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled may use different methods to implement the described functions for each specific application, but such implementations should not be considered as exceeding the protection scope of the present disclosure.

Some embodiments of the present disclosure provide a brightness control device of an illumination device. The brightness control device includes a memory and one or more processor coupled to the memory. The memory is configured to store computer program codes including computer program instructions. At least one processor is configured to when executing the computer program instructions, perform: obtaining a brightness of ambient light, determining an amount of supplementary light according to the brightness of the ambient light and a target brightness if the brightness of the ambient light is less than the target brightness, and generating a first pulse signal according to the amount of supplementary light to control the illumination device to emit light.

In some embodiments, the at least one processor is further configured to perform: sending the first pulse signal to a driver device, so that the driver device controls, according to the first pulse signal, the illumination device to emit light.

In some embodiments, the at least one processor is further configured to perform: sending a second pulse signal to the driver device to control the driver device to be turned on or off.

In some embodiments, the at least one processor is configured to perform: sending the first pulse signal to an integrating circuit, so that the integrating circuit outputs a current or a voltage to the driver device to drive the driver device to output a drive current to the illumination device.

In some embodiments, the at least one processor is configured to perform: obtaining a driving signal according to the amount of supplementary light, obtaining a duty cycle of the first pulse signal according to the driving signal and a correspondence between the driving signal and the duty cycle of the first pulse signal, and generating the first pulse signal according to the duty cycle of the first pulse signal.

In some embodiments, the at least one processor is configured to perform: obtaining, according to a following formula, a power converted into light in an output power of the illumination device when the illumination device is driven to emit light with the amount of supplementary light:

P⁢O⁢Yn=(P⁢O⁢Y2-P⁢O⁢Y1)(W2-W1)·Wn;
where POY2is a power, converted into light with a maximum brightness, in an output power of the illumination device when the illumination device is driven to emit the light with the maximum brightness, POY1is a power, converted into light with a minimum brightness, in another output power of the illumination device when the illumination device is driven to emit the light with the minimum brightness, POYnis a power, converted into light with the amount of supplementary light, in yet another output power of the illumination device when the illumination device is driven to emit the light with the amount of supplementary light, n represents the driving signal corresponding to the amount of supplementary light; W2is the maximum brightness, W1is the minimum brightness, and Wnis the amount of supplementary light; and obtaining the driving signal according to the power converted into the light with the amount of supplementary light, and a correspondence between the driving signal and the power converted into the light with the amount of supplementary light.

Some embodiments of the present disclosure provide a non-transitory computer-readable storage medium. The computer readable storage medium stores therein computer programs that, when run on a computer (e.g., a brightness control device of the illumination device), cause the brightness control device of the illumination device to perform the brightness control method described in any of the above embodiments.

For example, the computer-readable storage medium may include, but is not limited to: a magnetic storage device (e.g. a hard disk, a floppy disk, or a magnetic tape, etc.), an optical disk (e.g. a compact disk (CD), a digital versatile disk (DVD), etc.), a smart card or a flash memory device (e.g. an erasable programmable read-only memory (EPROM), a card, a stick or a key drive, etc.). The various computer-readable storage media may represent one or more devices and/or other machine-readable storage media for storing information. The term “machine-readable storage media” may include, but are not limited to, wireless channels and various other media capable of storing, containing, and/or carrying instructions and/or data.

Some embodiments of the present disclosure provide a computer program product including computer programs carried on a non-transitory computer-readable storage medium. When run on a computer (e.g., a brightness control device of the illumination device), the computer program product causes the brightness control device of the illumination device to perform the brightness control method described in any of the above embodiments.

The non-transitory computer-readable storage medium and the computer program product have the same beneficial effects as the brightness control methods as described in some embodiments of the present disclosure, which will be not described herein again.

From the above description of the embodiments, those skilled in the art may clearly understand that for convenience and brevity of description, only the above functional module division is used as an example for illustration. In practical applications, the above functions may be assigned to different functional modules as needed. That is, the internal structure of the device is divided into different functional modules to implement all or part of the functions described above.

In several embodiments provided in the present disclosure, it will be understood that the disclosed devices and methods may be implemented through other manners. For example, the device embodiments described above are only illustrative. For example, the modules or unit division is only a logical functional division. In actual implementation, there may be other division manners. For example, multiple units or components may be combined or integrated into another device, or some features may be omitted or not implemented. On the other hand, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the component(s) shown as units may be one physical unit or multiple physical units, that is, they may be located in one place, or may be distributed to multiple different places. Some or all of the units may be selected according to actual needs to achieve the purposes of the solutions in the embodiments.

In addition, the functional units in the embodiments of the present disclosure may be integrated into one processing unit. The units may exist physically alone, or two or more units may be integrated into one unit. The above integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

If the integrated unit is implemented in the form of the software functional unit and sold or used as an independent product, it may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present disclosure may essentially or a part of the technical solutions contributing to the prior art, or all or part of the technical solutions may be embodied in the form of software products. The software product is stored in a storage medium, and includes several instructions to make a device (which may be a single-chip microcomputer, a chip, etc.) or a processor to perform all or part of the steps of the methods described in the embodiments of the present disclosure.

The foregoing descriptions are merely specific implementations of the present disclosure. However, the protection scope of the present disclosure is not limited thereto. Changes or replacements that any person skilled in the art could conceive of within the technical scope of the present disclosure shall be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.