JP7475556B2 - Vehicle lighting control device and vehicle lighting control method - Google Patents

Description

The present disclosure relates to a vehicle lighting control device and a vehicle lighting control method.

The illumination imaging device described in Patent Document 1 aims to acquire an image of a subject in an environment where high-intensity light such as headlights is irradiated from an oncoming vehicle at night. In order to achieve the aim, the illumination imaging device removes an image of a part of a high-brightness subject captured with a light-emitting unit turned off from an image of the subject and a high-brightness subject captured with a light-emitting unit turned on, in which the image of the part of the high-brightness subject exceeds the dynamic range of the camera.

International Publication No. 2018/173715

For crime prevention purposes, some vehicles are equipped with highly sensitive cameras that can capture images even in dark places such as at night. It is possible to use these highly sensitive cameras to monitor the surroundings of the vehicle while it is in use.
However, unlike the above-mentioned environment, when the headlights of one's own vehicle are illuminated at night, if a high-sensitivity security camera for night-time parking is used to capture an image of the surroundings including the vehicle in front, there may be white areas in the captured image that exceed the limits of the dynamic range of the high-sensitivity camera, for example, an image of a white license plate may become completely white, resulting in a phenomenon known as whiteout.

The object of the present disclosure is to provide a vehicle lighting control device and a vehicle lighting control method that can reduce the occurrence of whiteout in captured images.

In order to solve the above-mentioned problems, the vehicle lighting control device disclosed herein is capable of capturing images in dark places and includes a detection unit that detects a first imaging pulse that specifies the timing at which a camera that is to capture images captures images according to a predetermined frame rate, a generation unit that outputs a control signal for duty controlling headlamps provided in the vehicle according to a predetermined duty ratio, and that changes the timing at which the headlamps are turned off when the first imaging pulse is detected and generates an extinguishing pulse to coincide with the timing of a second imaging pulse that follows the first imaging pulse, and a drive unit that drives the headlamps to be turned off in accordance with the extinguishing pulse.

The vehicle lighting control device disclosed herein can reduce the occurrence of whiteout in captured images.

1 is a functional block diagram of a vehicle lighting control device STS according to a first embodiment. FIG. 4 is a time chart of the vehicle lighting control device STS of the first embodiment. 1 shows a configuration of a vehicle lighting control device STS according to a first embodiment. 4 is a flowchart showing the operation of the vehicle lighting control device STS of the first embodiment. 11 is a time chart (part 1) of the vehicle lighting control device STS of the second embodiment. 13 is a second time chart of the vehicle lighting control device STS of the second embodiment. 10 is a flowchart of a vehicle lighting control device STS according to a second embodiment.

An embodiment of a vehicle lighting control device according to the present disclosure is described below.

Embodiment 1.
First Embodiment
A vehicle lighting control device according to a first embodiment will be described.

Functions of the First Embodiment
FIG. 1 is a functional block diagram of a vehicle lighting control device STS according to the first embodiment.

As shown in FIG. 1, the vehicle lighting control device STS of embodiment 1 includes an interface unit 11, a detection unit 12, a generation unit 13, and a drive unit 14 to control the lighting of the headlamp HL while checking the operation of the surveillance camera KK.

The detection unit 12 corresponds to the "detection unit", the generation unit 13 corresponds to the "generation unit", and the drive unit 14 corresponds to the "drive unit".

Surveillance camera KK corresponds to "camera" and headlamp HL corresponds to "headlamp."

Before explaining the vehicle lighting control device STS, we will explain the surveillance camera KK and headlamp HL.

The surveillance camera KK is a high-sensitivity camera capable of capturing images in dark places such as at night, and is mounted on a vehicle such as a private car (not shown) to monitor the surroundings including the area in front of the vehicle. The surveillance camera KK captures images at a predetermined frame rate (e.g., several tens of FPS (Frames Per Second)), and more specifically, captures images according to an imaging signal SS that defines the frame rate.

Figure 2 is a time chart of the vehicle lighting control device STS of embodiment 1.

2, the imaging signal SS is composed of imaging pulses Ps1, Ps2, Ps3, etc., which are multiple pulses that determine the timing at which the surveillance camera KK captures images, as shown in FIG. 2. The surveillance camera KK captures images during time T1, which is the pulse width of the multiple imaging pulses Ps1, Ps2, Ps3, etc. In other words, the surveillance camera KK does not capture images during time T2, which is the interval between the imaging pulses Ps1, Ps2, Ps3, etc.

As shown in Figure 2, the synchronization signal DS is a signal obtained by dividing the imaging signal SS (for example, by 1/5 to 1/10). The synchronization signal DS is composed of multiple synchronization pulses Pd1, Pd2, Pd3, .... The synchronization signal DS is synchronized with the imaging signal SS, and for example, the timing of the synchronization pulse Pd1 in the synchronization signal DS matches the timing of the imaging pulse Ps1 in the imaging signal SS, and similarly, the timing of the synchronization pulse Pd2 in the synchronization signal DS matches the timing of the imaging pulse Ps6 in the imaging signal SS.

Therefore, for example, if the division ratio is known, detecting the synchronization pulse Pd1 and detecting the imaging pulse Ps1 have the same meaning.

The imaging pulse Ps1 and the synchronization pulse Pd1 correspond to the "first imaging pulse", and the imaging pulse Ps2 corresponds to the "second imaging pulse".

The headlamp HL is mounted on the vehicle as described above, similar to the surveillance camera KK. As shown in Figure 2, the headlamp HL is controlled to be turned on and off by a control signal CS for duty controlling the illuminance of the headlamp HL by a duty ratio. Since the illuminance of the headlamp HL is regulated by law, the duty ratio is determined so as to satisfy the legal illuminance, taking into account the specifications of the headlamp HL.

The relationship between time T3, which is the pulse width of the off pulses Poff1, Poff2, Poff3, etc. in the control signal CS (before adjustment) and the control signal CS (after adjustment), and time T1, which is the pulse width of the imaging pulses Ps1, Ps2, Ps3, etc., is generally time T3 > T1.

Here, the control signal CS (before adjustment) is the original control signal CS, and there is no guarantee that the light-off pulse Poff1, etc. in the control signal CS (before adjustment) is synchronized with the imaging pulse Ps1, etc.

On the other hand, the control signal CS (after adjustment) is the control signal CS generated by the generation unit 13, or more precisely, the control signal CS whose phase has been adjusted by the generation unit 13. As a result, the light-off pulse Poff1 etc. in the control signal CS (after adjustment) are synchronized with the imaging pulse Ps1 etc., and for example, the light-off pulse Poff1 is synchronized with the imaging pulse Ps2.

The control signal CS (before adjustment) is composed of lighting pulses Pon1, Pon2, Pon3, etc. and extinguishing pulses Poff1, Poff2, Poff3, etc., as shown in Fig. 2. The headlamp HL is turned on during the lighting pulses Pon1, Pon2, Pon3, etc., of the control signal CS (before adjustment) (periods indicated by white circles in the figure), as shown in Fig. 2, while being turned off during the extinguishing pulses Poff1, Poff2, Poff3, etc., of the control signal CS (before adjustment) (periods indicated by black circles in the figure).

The control signal CS corresponds to a "control signal", the light-on pulse Pon corresponds to a "light-on pulse", and the light-off pulse Poff corresponds to a "light-off pulse".

Returning to Figure 1, we will continue to explain the vehicle lighting control device STS.

The interface unit 11 continuously receives the above-mentioned image capture signal SS (also shown in FIG. 2) and synchronization signal DS (also shown in FIG. 2) from outside the vehicle lighting control device STS. The synchronization signal DS may be generated based on the image capture signal SS.

The interface unit 11 functions, for example, as part of a CAN (Controller Area Network) and a LIN (Local Interconnect Network).

The detection unit 12 detects the synchronization pulses Pd1, Pd2, Pd3, etc. that constitute the synchronization signal DS. More specifically, as shown in FIG. 2, the detection unit 12 detects, for example, the rising edge REd or the falling edge FEd of the synchronization pulses Pd1, Pd2, Pd3, etc.

The generating unit 13 generates the above-mentioned control signal CS (also shown in FIG. 2). More specifically, when the detecting unit 12 detects, for example, a synchronization pulse Pd1, the generating unit 13 adjusts the phase so that the timing of the light-off pulse Poff1 coincides with the timing of the imaging pulse following the imaging pulse Ps1, for example, the imaging pulse Ps2 immediately following the imaging pulse Ps1, and generates the light-off pulse Poff1.

The drive unit 14 controls the turning on and off of the headlamp HL using a drive signal KS for driving the headlamp HL in accordance with the control signal CS generated by the generation unit 13.

Configuration of First Embodiment
FIG. 3 shows the configuration of the vehicle lighting control device STS according to the first embodiment.

In order to perform the above-mentioned functions (shown in FIG. 1), the vehicle lighting control device STS of the embodiment includes a processor PC, a storage medium KB, a memory MM, an input unit NY, and an output unit SY, as shown in FIG. 3. More precisely, the vehicle lighting control device STS includes an input unit NY and an output unit SY as necessary.

The processor PC is the core of a well-known computer, making the hardware operate according to software.

The storage medium KB is composed of, for example, a hard disk drive (HDD), a solid state drive (SSD), and a read only memory (ROM). The storage medium KB stores a program PR. The program PR is a set of instructions that specifies the content of the processing to be executed by the processor PC.

The memory MM is composed of, for example, DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory).

The input unit NY is, for example, an interface that receives signals from outside the vehicle lighting control device STS.

The output unit SY is, for example, an interface that outputs a signal outside the vehicle lighting control device STS.

Regarding the relationship between the functions and configuration in the vehicle lighting control device STS, in hardware, the processor PC executes the program PR stored in the storage medium KB on the memory MM, thereby realizing the functions of each section from the interface section 11 to the drive section 14, and controlling the operation of the input section NY and the output section SY as necessary.

<Operation of the First Embodiment>
4 is a flowchart showing the operation of the vehicle lighting control device STS of embodiment 1. The operation of the vehicle lighting control device STS of embodiment 1 will be described below with reference to the flowchart of FIG.

Step ST11: While the interface unit 11 (shown in Figure 1) receives an imaging signal SS (shown in Figures 1 and 2) and/or a synchronization signal DS (shown in Figures 1 and 2) from outside the vehicle lighting control device STS, the detection unit 12 (shown in Figure 1) detects a synchronization pulse Pd1 in the synchronization signal DS, for example, at time t1, as shown in Figure 2.

Step ST12: In step ST11, when the detection unit 12 detects a synchronization pulse Pd1 at time t1, the generation unit 13 (shown in Figure 1) generates a light-off pulse Poff1 at time t2, as shown in the control signal CS (after adjustment) in Figure 2.

The generation unit 13 adjusts the phase of the control signal CS (before adjustment) so that the timing of the light-off pulse Poff1 that constitutes the control signal CS (after adjustment) matches the timing of the imaging pulse Ps2 that follows the imaging pulse Ps1 that is synchronized with the synchronization pulse Pd1, as shown in the control signal CS (after adjustment) in Figure 2, to generate the light-off pulse Poff1.

The generating unit 13 may start generating the above-mentioned off pulse Poff1, for example, simultaneously with the timing of the rising edge REs of the imaging pulse Ps2, or may start generating the off pulse Poff1 at a time T2 elapsed from the falling edge FEd of the synchronization pulse Pd1. That is, the generating unit 13 may at least match the falling edge FEc of the off pulse Poff1 with the rising edge REs of the imaging pulse Ps2.

The generation unit 13 completes the generation of the light-off pulse Poff1 by advancing the falling edge FEc.

Step ST13: In step ST12, when the generating unit 13 generates the extinguishing pulse Poff1 of the control signal CS (after adjustment), the driving unit 14 turns off the headlamp HL by the driving signal KS according to the extinguishing pulse Poff1. The surveillance camera KK captures an image of, for example, the area in front of the vehicle according to the imaging pulse Ps2, more specifically, according to the imaging pulse Ps2 that is located during the period when the headlamp HL is turned off.

Step ST14: In step ST13, when the surveillance camera KK completes imaging based on the imaging pulse Ps2, the surveillance camera KK images the area in front of the vehicle with the headlamps HL turned on at times t3, t4, and t5, when the headlamps HL are turned on, in accordance with the imaging pulses Ps3, Ps4, and Ps5 that follow the imaging pulse Ps2.

Step ST15: In step ST14, when the imaging by the surveillance camera KK at times t3 to t5 is completed, a processing unit (not shown) performs, for example, averaging processing on the four images captured by the surveillance camera KK at times t2 to t5. The images subjected to the averaging processing may be stored, for example, in a memory unit (not shown) and may be displayed on a display unit (not shown). In addition, the image at time t2 may be used for monitoring in a dark place, and the images at times t3 to t5 may be used for monitoring in a bright place.

After step ST15: After time t6, the interface unit 11 to the drive unit 14 repeat the same operations as those from time t1 to t5 in steps ST11 to ST15.

Effects of the First Embodiment
As described above, in the vehicle lighting control device STS of the first embodiment, when the detection unit 12 detects the synchronization pulse Pd1 in the synchronization signal DS, the generation unit 13 adjusts the phase of the turn-off pulse Poff1 to generate the turn-off pulse Poff1 so that the timing of the turn-off pulse Poff1 coincides with the timing of the imaging pulse Ps2 following the imaging pulse Ps1 with which the synchronization pulse Pd1 is synchronized, and the drive unit 14 turns off the headlamp HL according to the turn-off pulse Poff1. As a result, the surveillance camera KK captures the surroundings including the front of the vehicle when the headlamp HL is turned off during the imaging pulse Ps2. As a result, it is possible to reduce the occurrence of so-called whiteout that may occur due to imaging with the headlamp HL turned on, and for example, in the image after the averaging process, the visibility of the whiteout can be reduced.
That is, whiteout is suppressed by adjusting the timing at which the headlamps HL are turned off, and there is no need to modify the camera control or configuration.

Embodiment 2.
Second Embodiment
A vehicle lighting control device according to a second embodiment will be described.

<Functions and configuration of the second embodiment>
The function and configuration of the vehicle lighting control device STS of the second embodiment are similar to the function (shown in FIG. 1) and configuration (shown in FIG. 3) of the vehicle lighting control device STS of the first embodiment.

<Operation of the Second Embodiment>
As described above, the vehicle lighting control device STS of the first embodiment causes the falling edge FEc of the light-off pulse Poff1 to coincide with the rising edge REs of the imaging pulse Ps2.

Unlike the vehicle lighting control device STS of embodiment 1, the vehicle lighting control device STS of embodiment 2 generates the falling edge FEc of the light-off pulse Poff1 earlier than the rising edge REs of the imaging pulse Ps2, and generates the rising edge REc of the light-off pulse Poff1 later than the falling edge FEs of the imaging pulse Ps2. In other words, the vehicle lighting control device STS of embodiment 2 adjusts the phase so that the light-off pulse Poff1 continues to turn off the headlamp HL over the time that the surveillance camera KK is taking pictures in accordance with the imaging pulse Ps2, and generates the light-off pulse Poff1.

Figure 5 is a time chart (part 1) of the vehicle lighting control device STS of embodiment 2.

Figure 6 is a time chart (part 2) of the vehicle lighting control device STS of embodiment 2.

Figure 7 is a flowchart of the vehicle lighting control device STS of embodiment 2.

The operation of the vehicle lighting control device STS of embodiment 2 will be explained with reference to the time charts of Figures 5 and 6 and the flowchart of Figure 7.

Step ST21: Similar to step ST11 in embodiment 1, the detection unit 12 detects a synchronization pulse Pd1 in the synchronization signal DS at time t1, as shown in Figures 5 and 6.

Step ST22: As shown in FIG. 6, the generation unit 13 generates the light-off pulse Poff1 by causing the control signal CS (after adjustment) to fall after a time (T2-(T3-T1)/2) has elapsed from the falling edge FEd of the synchronization pulse Pd1, so that the imaging pulse Ps2 includes the timing at which it is located in the center of the light-off pulse Poff1.

Step ST23: As shown in Figures 5 and 6, the drive unit 14 turns off the headlamp HL only during the period of the extinguishing pulse Poff1, and the surveillance camera KK captures images according to the imaging pulse Ps2 during the period when the headlamp HL is off.

Step ST24: Similar to step ST14 in embodiment 1, the surveillance camera KK captures images in accordance with imaging pulses Ps3, Ps4, and Ps5 during the period when the headlamp HL is on.

Step ST25: As in step ST15 in embodiment 1, the processing unit performs averaging processing on the four images captured at times t2 to t5, and the images subjected to the averaging processing are stored in a storage unit (not shown), and a display unit (not shown) may display the images subjected to the averaging processing. In addition, the image at time t2 may be used for monitoring in a dark place, and the images at times t3 to t5 may be used for monitoring in a bright place.

Effects of the Second Embodiment
As described above, in the vehicle lighting control device STS of embodiment 2, similar to the vehicle lighting control device STS of embodiment 1, the surveillance camera KK captures images in accordance with the imaging pulse Ps2 while the headlamp HL is turned off in accordance with the off pulse Poff1, and therefore, similar to the vehicle lighting control device STS of embodiment 1, the occurrence of so-called whiteout can be reduced.
That is, whiteout is suppressed by adjusting the timing at which the headlamps HL are turned off, and there is no need to modify the camera control or configuration.

In the vehicle lighting control device STS of the second embodiment, in addition to the above-mentioned effects, the light-off pulse Poff1 is generated so that the timing when the surveillance camera KK is taking an image according to the imaging pulse Ps2 includes the timing at which the light-off pulse Poff1 is located in the center. This allows the surveillance camera KK to take an image without the headlamp HL being turned on while taking an image according to the imaging pulse Ps2, making it possible to more reliably reduce the occurrence of the above-mentioned whiteout.

The above-described embodiments may be combined without departing from the spirit and scope of the present disclosure, and components in each embodiment may be appropriately deleted or modified, or other components may be added.

The vehicle lighting control device disclosed herein can be used, for example, to capture images of the surroundings of a vehicle with the vehicle lights on.

11 Interface unit, 12 Detection unit, 13 Generation unit, 14 Drive unit, CS Control signal, DS Synchronization signal, HL Headlamp, KB Storage medium, KK Surveillance camera, KS Drive signal, MM Memory, NY Input unit, PC Processor, Pd Synchronization pulse, Poff Off pulse, Pon On pulse, PR Program, Ps Imaging pulse, SS Imaging signal, STS Vehicle lighting control device, SY Output unit.

Claims (4)

a detection unit that detects a first imaging pulse that defines a timing at which a camera capable of capturing an image in a dark place captures an image according to a predetermined frame rate;
a generation unit that outputs a control signal for duty controlling a headlamp provided in a vehicle with a predetermined duty ratio, and that changes a timing for turning off the headlamp when the first imaging pulse is detected, and generates an extinguishing pulse so that the timing coincides with a timing of a second imaging pulse that follows the first imaging pulse;
a driving unit that drives the headlamp to be turned off in accordance with the turn-off pulse;
A vehicle lighting control device comprising: the generation unit generates the light-off pulse by adjusting the timing so that the second imaging pulse includes a timing at which the second imaging pulse is located at the center of the light-off pulse.
The vehicle lighting control device according to claim 1 . a detection unit detects a first imaging pulse that specifies a timing for a camera capable of capturing an image in a dark place and capturing an image according to a predetermined frame rate;
a generation unit outputs a control signal for duty controlling a headlamp provided in a vehicle with a predetermined duty ratio, and generates an extinguishing pulse by changing a timing for turning off the headlamp when the first imaging pulse is detected so that the timing coincides with a timing of a second imaging pulse following the first imaging pulse;
A driving unit drives the headlamp to be turned off in accordance with the turn-off pulse.
A method for controlling vehicle lighting. the generation unit generates the light-off pulse by adjusting the timing so that the second imaging pulse includes a timing at which the second imaging pulse is located at the center of the light-off pulse.
The vehicle lighting control method according to claim 3.

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