JP2009253316A - On-vehicle camera and drive recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle camera and a drive recorder for stably and surely receiving light from a light emitting device such as a traffic signal machine flickering at the frequency of a commercial AC power source by a photodetector. <P>SOLUTION: The on-vehicle camera includes: a camera 1 with an electronic shutter for photographing the light emitting device repeatedly lighted and put out in a fixed cycle; an electrochromic filter 2 provided on the imaging side of the camera 1; and an electrochromic filter control part 6 for controlling the shade of the electrochromic filter 2. The electrochromic filter control part 6 determines surroundng brightness from the video signals or the like of the camera 1, forms ECF control signals, controls the shade of the electrochromic filter 2, controls incident light entering the camera 1, prevents the speed of the electronic shutter of the camera 1 from being faster than a fixed speed, and makes the period during which the electronic shutter is open longer than the put-out period of the light emitting device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an in-vehicle camera and a drive recorder, and more particularly, to an in-vehicle camera and a drive recorder that can reliably record a traffic signal image.

  Many light-emitting devices that emit light using a commercial AC power source use a light-emitting method that periodically turns on and off like a fluorescent lamp. The same applies to traffic signals using LEDs, and in Japan, it blinks at 50 Hz or 60 Hz.

  On the other hand, in a camera using a light receiving element such as a CCD (Charge Coupled Devices) or a CMOS (Complementary Metal Oxide Semiconductor), the charge accumulation period is repeated at a frequency close to the frequency of a commercial AC power source of 59.97 Hz. That is, when light strikes the light receiving element, a charge is accumulated in the light receiving element. If all the light receiving elements overflow with electric charges, the whole becomes white. For this reason, the electronic shutter is operated when a certain amount of electric charge is accumulated in order to adjust the amount of light.

  Specifically, the operation of the electronic shutter is realized by not transferring the electric charge accumulated in the light receiving element to the subsequent processing circuit. In this specification, closing the electronic shutter means not transferring the accumulated charge to the subsequent processing circuit, and opening the electronic shutter means transferring the accumulated charge to the subsequent processing circuit. Yes.

  This means that the electronic shutter operates at a frequency close to the frequency of the commercial AC power supply, whereas the light emitting device blinks at the frequency of the commercial AC power supply. Therefore, if the timing at which the light emitting device is lit and the timing at which the electronic shutter of the light receiving element is always matched, the light from the light emitting device reaches the light receiving device, but the timing at which the light emitting device is turned off and the light receiving device When the opening timing of the electronic shutter is correct, the light from the light emitting device does not reach the light receiving element. In that case, even if you look at the record of the drive recorder, the traffic light is off and you can't tell what color it was on.

  FIG. 6 is a timing chart illustrating the timing of turning on / off a traffic signal using a conventional LED and the opening / closing timing of an electronic shutter of a drive recorder. FIG. 6A shows a voltage waveform of a commercial AC power supply. FIG. 6B shows a waveform when the voltage waveform of the commercial AC power source is detected. FIG.6 (c) has shown the repetition state of the lighting period and light extinction period of the traffic signal apparatus using LED. Here, for the sake of simplicity, the LED is turned on when the voltage of the commercial AC power source in FIG. 6B exceeds a predetermined threshold (V0), and when the voltage drops below the predetermined threshold (V0). A description will be given assuming that the LED is turned off. FIGS. 6D to 6G show the open / close state of the electronic shutter of the drive recorder.

  FIG. 6D shows the opening / closing timing of the electronic shutter when the brightness around the road including the traffic signal is dark. For example, as shown in FIG. 7, on a night road, there is little light reaching the light receiving element. For this reason, the time during which the electronic shutter is open becomes longer. In FIG. 6D, the timing at which the LED is lit matches the timing at which the electronic shutter is opened, so that the LED light reaches the light receiving element, and the LED light is recorded in the drive recorder. As shown in FIG. 6E, even if the timing at which the LED is turned off coincides with the timing at which the electronic shutter is opened, the time when the electronic shutter is opened is longer than the time when the LED is turned off. The light reaches the light receiving element. And the light of LED is recorded on a drive recorder.

  However, on a road that travels in a bright place during the day as shown in FIG. 8, since the amount of light reaching the light receiving element is too large, the electronic shutter is operated at high speed, and FIG. 6 (f) and FIG. 6 (g). As described above, the time during which the electronic shutter is open is shortened. In FIG. 6F, the timing at which the LED is turned on coincides with the timing at which the electronic shutter is opened, so that the LED light reaches the light receiving element, and the LED light is recorded in the drive recorder. However, as shown in FIG. 6G, when the timing at which the LED is turned off coincides with the timing at which the electronic shutter is opened, the LED light does not reach the light receiving element, and the LED light is not recorded on the drive recorder. .

As a conventional method for solving this problem, a method has been proposed in which the traffic light extinguishing period is obtained and the electronic shutter is controlled so that the charge accumulation period of the CCD is longer than the traffic light extinguishing period. According to this method, even if the timing when the traffic light is turned off and the timing when the electronic shutter is opened, a certain amount of light enters the CCD. Can be recorded (see, for example, Patent Document 1).
JP 2007-161189 A

  However, the conventional method is required to perform the following procedures (1) to (6). That is, (1) It is identified whether there is a traffic signal in the screen shot by the drive recorder. (2) If there is a traffic signal on the screen being photographed, point the camera at the traffic signal as necessary. (3) Calculate the light extinction period of the traffic signal captured by the camera. (4) Based on the calculated traffic light extinction period, the time for which the electronic shutter of the camera should be opened is calculated. (5) Open the electronic shutter of the camera for the determined time. (6) If a traffic signal is reflected in the screen being shot, repeat (5) periodically.

  Repeating the steps (2) to (6) every time a traffic signal appears in the camera of the drive recorder in the procedure (1) places a load on the control device of the drive recorder. On roads with traffic signals, for example, automobiles run at a speed of 40 Km / h to 60 Km / h, so it cannot be determined that there is a traffic signal on the screen, or an electronic shutter for calculating the turn-off period, etc. It may happen that a series of calculations and controls are not in time.

  The present invention stably detects light from light-emitting devices including traffic signals blinking at the frequency of a commercial AC power source without detecting the presence or absence of traffic signals or calculating the turn-off time. It is an object to provide an in-vehicle camera and a drive recorder that can surely receive light with a light receiving element.

  In order to solve the above problems, the present invention can be applied to an electrochromic filter that applies an electrochromic phenomenon in which a substance reversibly changes color and light transmittance using an electric current or electric field as an external stimulus. Using an electrochromic filter (hereinafter abbreviated as ECF) that uses an electrochromic effect in which the light transmittance changes according to the voltage, the ambient brightness is judged from the video signal of the camera and the electronic shutter speed of the camera. Perform signal detection, weighting, peak / average switching, etc., create ECF control signals, control the density of ECF, control the incident light entering the camera, and the electronic shutter speed of the camera is faster than a certain level The period when the electronic shutter is open is the off period of the light-emitting device that is the subject. It is set to be long.

  As a result, when a traffic signal using an LED is photographed with an in-vehicle camera or a drive recorder, it is not possible to photograph or record at the timing when the traffic signal is extinguished.

  The present invention also provides a dedicated illuminance sensor in addition to the in-vehicle camera and the drive recorder adopting the above-described configuration, judges the ambient brightness from the illuminance sensor, detects the video signal, weights, and switches the peak / average value. , Etc., create ECF control signal, control the density of ECF, control the incident light entering the camera, the electronic shutter speed of the camera is not faster than a certain period, and the electronic shutter is open Is longer than the turn-off period of the light-emitting device that is the subject.

  This makes it possible to quickly determine the brightness of the surroundings, and when shooting traffic signals using LEDs with an in-vehicle camera or drive recorder, shoot or record at the timing when the traffic signal turns off. It can be lost.

In order to solve the above-described problem, the present invention provides a first mirror and a second camera that shoot a light emitting device that is repeatedly turned on and off at a constant or commercial AC power frequency cycle as a subject. Place the angle of view through the prism at the position where the angle of view matches, and set the first camera so that the electronic shutter speed does not become faster than a certain level with a camera with an extinction filter,
The second camera is a camera that does not have an extinction filter and is set so that the speed of the electronic shutter does not become higher than a certain level. Usually, the second camera is used for shooting, and in bright conditions, the first camera is switched to. In this way, the electronic shutter speed of each of the first camera and the second camera is not increased beyond a certain level, and the period during which the electronic shutter is open is longer than the period during which the light emitting device that is the subject is turned off. It is configured to be long.

  With this configuration, even when the surroundings are bright, the electronic shutter speed of the camera will not be faster than a certain level, and even if an AC-lit LED traffic light is photographed with this camera system, it is not possible to photograph the state where the traffic light is extinguished. Disappear. In addition, since there is no mechanical aperture, reliability when mounted on a vehicle is improved.

  The present invention uses a filter to reduce the amount of light so that the speed of the electronic shutter does not increase beyond a certain speed when the brightness near the traffic signal becomes brighter. As a result, the period during which the electronic shutter is open can be maintained longer than the period during which the LED is turned off. Therefore, even if the LED off period and the period during which the electronic shutter are open overlap, a certain amount of light is applied to the light receiving element of the camera. Will not be recorded at the timing when the LED traffic signal goes off.

  In addition, the present invention does not detect the presence or absence of a traffic signal or calculate the turn-off time as in the prior art, and light from a light emitting device such as a traffic signal flashing at the frequency of a commercial AC power supply. Can be provided with an in-vehicle camera and a drive recorder that can stably and reliably receive light with a light receiving element.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a main part of a drive recorder according to Embodiment 1 of the present invention. In the first embodiment of the present invention, an electrochromic filter (ECF) 2 is provided on the imaging side of the camera 1. The camera 1 is a digital camera using a light receiving element such as a CCD or CMOS, receives charges incident from the imaging side, accumulates charges, converts the accumulated charges into a digital signal, creates a video signal, and outputs an output line. 3 is sent to display means and transmission means (not shown). The camera 1 incorporates an electronic shutter (not shown), and the light amount is adjusted by the electronic shutter.

  The electrochromic filter 2 is a filter that uses the electrochromic effect that the light transmittance changes according to the applied voltage. By providing the electrochromic filter 2 on the imaging side of the camera 1, the required amount of light incident on the camera 1 is reduced. It can be reduced.

  The output line 3 is provided with a feedback node 4, which detects the video signal with the detector 5 and then inputs it to the ECF controller 6 that controls the contrast of the electrochromic filter 2. As a first step, the ECF control unit 6 determines the degree of light quantity of an image captured from the video signal captured by the camera 1, that is, whether the captured image is brighter or darker than a predetermined threshold. As a second stage, a control current that darkens the electrochromic filter 2 is sent out when the captured image is bright, and a current that does not darken the electrochromic filter 2 is sent out when the captured image is dark. The control current sent from the ECF control unit 6 is amplified by the amplifier 7 and applied to the electrochromic filter 2.

  Since the drive recorder according to Embodiment 1 of the present invention is configured as described above, the amount of light incident on the camera 1 without substantially operating the electrochromic filter 2 when imaging a dark scene. Adjust the image with the electronic shutter. When a bright scene is being imaged, the electrochromic filter 2 is operated to reduce the amount of light entering the camera 1 and adjust the electronic shutter to capture the image.

  FIG. 2 shows a timing chart of lighting and extinguishing timings of traffic signals using LEDs and opening / closing timings of the electronic shutter of the drive recorder according to Embodiment 1 of the present invention. FIG. 2A shows the voltage waveform of the commercial AC power supply. FIG.2 (b) has shown the waveform when the voltage waveform of a commercial alternating current power supply is detected. FIG.2 (c) has shown the repetition state of the lighting period and light extinction period of the traffic signal apparatus using LED. Here, as in FIG. 6C of the conventional example, the LED is turned on when the voltage of the commercial AC power source in FIG. 2B exceeds a predetermined threshold (V0), and is equal to or lower than the predetermined threshold (V0). The description will be made assuming that the LED is turned off when the voltage drops. 2D to 2G show the open / close state of the electronic shutter of the drive recorder.

  FIG. 2D and FIG. 2E show the opening / closing timing of the electronic shutter when the surrounding brightness including the traffic signal is dark. When the surrounding brightness is dark, the ECF control unit 6 sends a current that does not darken the electrochromic filter 2. The light incident on the camera 1 is adjusted by an electronic shutter (not shown) built in the camera 1.

  When the surrounding brightness is dark, the open period is set to be longer than the LED off period even when the electronic shutter operates. In FIG. 2D, since the timing at which the LED is turned on coincides with the timing at which the electronic shutter is opened, the LED light reaches the light receiving element, and the LED light is recorded in the drive recorder. As shown in FIG. 2E, even if the timing at which the LED is turned off coincides with the timing at which the electronic shutter is opened, the time during which the electronic shutter is opened is longer than the time when the LED is turned off. Although there are few, the light of LED reaches a light receiving element, and the light of LED is recorded on a drive recorder.

  On the other hand, when the periphery of the LED traffic signal is bright, the ECF control unit 6 sends out a current that darkens the electrochromic filter 2. When the electrochromic filter 2 is darkened, the amount of light incident on the camera 1 is reduced. After all, the same amount of light is incident on the camera 1 as when the periphery of the LED traffic signal is dark, so the electronic shutter built in the camera 1 is the same as when the periphery of the LED traffic signal is dark. In operation, the open period is longer than the LED off period.

  Therefore, as shown in FIG. 2 (f) and FIG. 2 (g), even when the vicinity of the LED traffic signal is bright, the electronic shutter is open longer than the time when the LED is off. The LED light reaches the light receiving element, and the LED light is recorded on the drive recorder.

(Embodiment 2)
In the second embodiment of the present invention, as shown in FIG. 3, a dedicated illuminance sensor 8 is further provided in the configuration of the in-vehicle camera and the drive recorder shown in the first embodiment, and the ambient brightness is determined from the illuminance sensor 8. Then, video signal detection, weighting, peak / average switching, etc. are made, ECF control signal is created, ECF density is controlled, incident light entering the camera is controlled, and the electronic shutter speed of the camera is constant In order not to be faster than this, the period during which the electronic shutter is open is made longer than the light-out period of the light emitting device that is the subject. The signal from the illuminance sensor 8 is detected by the detector 5 together with the video signal and output to the ECF control unit 6. The following operations are the same as those in the first embodiment.

  This makes it possible to quickly determine the brightness of the surroundings, and when shooting traffic signals using LEDs with an in-vehicle camera or drive recorder, shoot or record at the timing when the traffic signal turns off. It can be lost.

(Embodiment 3)
FIG. 4 shows a configuration diagram of a main part of a drive recorder according to Embodiment 3 of the present invention. In the third embodiment of the present invention, the camera with ND (ND) set so that the speed of the electronic shutter is not higher than a certain level in the camera with the dark filter (ND), and the speed of the electronic shutter in the camera without ND. An ND-less camera (B) 12 that does not become faster than a certain distance is arranged through the half mirror 13 at a position where the angle of view matches. Note that the neutral density filter reduces the amount of light entering the lens. By using this, the camera with the ND (A) 11 can reduce the shutter speed.

  A shared lens 14 is disposed in front of the half mirror 13. The light that has passed through the lens 14 is divided by a half mirror. Since a half mirror is used, the NDless camera (B) is reversed left and right so as to be a mirror image.

  The camera with ND (A) 11 is connected to the frame memory 15. Further, the camera without ND (B) 12 is connected to the synchronization control means 16 and the frame memory 15, and the camera with ND (A) 11 and the camera without ND (B) 12 are synchronously coupled. Therefore, the camera with the ND (A) 11 and the camera without the ND (B) 12 are switched at a vertical interval so that there is no synchronization disturbance at the time of switching. The video signal (A) 17 of the camera with ND (A) 11 and the video signal (B) 18 of the camera without ND (B) 12 are connected so as to be output to the video signal switching unit 19, respectively. Then, the switching video signal 20 switched by the video signal switching machine 19 is output to a display means or a transmission means (not shown).

  In the drive recorder according to the third embodiment of the present invention configured as described above, the video signal of the ND-less camera (B) 12 is normally captured with the ND-less camera (B) 12 under bright conditions. When the saturation state is approached, the video signal is detected and switched to the camera (A) 11 with ND at a vertical interval, and the video of the camera (A) 11 with ND is continuously output.

  Also, when the surrounding brightness becomes dark and the image of the NDless camera (B) 12 is released from saturation and returns to normal, the camera with the ND (A) 11 is switched to the NDless camera (B) 12 to shoot. To continue.

  With this configuration, even when the surroundings are bright, the speed of the electronic shutter of the camera does not increase beyond a certain level, and even if an AC-lit LED traffic light is photographed with this camera system, the traffic light does not turn off. In addition, since there is no mechanical aperture, reliability when mounted on a vehicle is improved.

  FIG. 5 shows a timing chart of lighting and extinguishing timings of traffic signals using LEDs and opening / closing timings of the electronic shutter of the drive recorder according to Embodiment 3 of the present invention. FIG. 5A shows a voltage waveform of a commercial AC power supply. FIG.5 (b) has shown the waveform when the voltage waveform of a commercial alternating current power supply is detected. FIG.5 (c) has shown the repetition state of the lighting period and light extinction period of the traffic signal apparatus using LED. FIG. 5A to FIG. 5C are the same as the contents of FIG. 2A to FIG. 5D to 5G show the open / close state of the electronic shutter of the drive recorder.

  When the surrounding brightness including the traffic signal is dark, as shown in FIGS. 5D and 5E, the non-ND camera (B) 12 has an open period even when the electronic shutter operates. It is set to be longer than the period when the LED is off.

  In FIG. 5D, the timing at which the LED is lit matches the timing at which the electronic shutter is opened, so that the LED light reaches the light receiving element, and the LED light is recorded on the drive recorder. As shown in FIG. 5E, even if the timing at which the LED is turned off coincides with the timing at which the electronic shutter is opened, the time during which the electronic shutter is opened is longer than the time when the LED is turned off. Although there are few, the light of LED reaches a light receiving element, and the light of LED is recorded on a drive recorder.

On the other hand, when the periphery of the LED traffic signal is bright, the camera (A) 11 with ND is used, so the amount of incident light is reduced, and the same amount of light as when the periphery of the LED traffic signal is dark is incident. A) As for the electronic shutter of 11, the open period becomes longer than the period when the LED is turned off, as in the case where the periphery of the traffic signal LED is dark.
Therefore, as shown in FIG. 5 (f) and FIG. 5 (g), even when the surroundings of the LED traffic signal are bright, the time when the electronic shutter is open is longer than the time when the LED is off. The LED light reaches the light receiving element, and the LED light is recorded on the drive recorder.

  The present invention can be applied to an in-vehicle camera and a drive recorder, a digital camera, a digital video camera, and the like for photographing a light emitting device including a traffic signal using an LED blinking with a commercial AC power supply.

1 is a configuration diagram of a main part of a drive recorder according to Embodiment 1 of the present invention. The timing chart which shows the opening / closing timing of the electronic shutter of the drive recorder which concerns on Embodiment 1 of this invention, and the blink timing of LED of a traffic signal Main part block diagram of the drive recorder which concerns on Embodiment 2 of this invention Main part block diagram of the drive recorder which concerns on Embodiment 3 of this invention Timing chart showing opening / closing timing of electronic shutter and blinking timing of LED of traffic signal of drive recorder according to Embodiment 3 of the present invention Timing chart showing the timing of opening and closing the electronic shutter of a conventional drive recorder and the blinking timing of the LED of a traffic signal The figure which shows the use environment of the conventional drive recorder The figure which shows the use environment of the conventional drive recorder

Explanation of symbols

1 Camera 2 Electrochromic filter (ECF)
5 Detector 6 ECF Control Unit 7 Amplifier

Claims (4)

A camera with an electronic shutter that shoots a light-emitting device that repeatedly turns on and off at a constant or commercial AC power supply frequency cycle as a subject;
An electrochromic filter provided on the imaging side of the camera;
Electrochromic filter control means for controlling the density of the electrochromic filter,
The electrochromic filter control means determines the ambient brightness from the video signal of the camera and the speed of the electronic shutter of the camera, creates an ECF control signal, controls the shading of the electrochromic filter, and enters the camera By controlling the incident light,
An in-vehicle camera characterized in that the electronic shutter speed of the camera does not become faster than a certain level so that the period during which the electronic shutter is open is longer than the light-out period of the light emitting device. An illuminance sensor is further provided in the configuration according to claim 1,
By determining the ambient brightness by the illuminance sensor, creating an ECF control signal, controlling the shading of the electrochromic filter, and controlling the incident light entering the camera,
An in-vehicle camera characterized in that the electronic shutter speed of the camera does not become faster than a certain level so that the period during which the electronic shutter is open is longer than the light-out period of the light emitting device. Arrange the first camera and the second camera to shoot the light-emitting device that repeats turning on and off at a constant or commercial AC power supply frequency period as a subject at a position where the angle of view matches through a half mirror or prism,
The first camera is set so that the electronic shutter speed is not faster than a certain level with a camera with a dark filter,
The second camera is set so that the speed of the electronic shutter is not faster than a certain level with a camera without an extinction filter,
Usually, shooting with the second camera, and switching to the first camera under bright conditions, the electronic shutter speed of each of the first camera and the second camera is faster than a certain level. The vehicle-mounted camera is configured such that the period during which the electronic shutter is open is longer than the light-out period of the light emitting device as the subject. The drive recorder carrying the vehicle-mounted camera in any one of Claims 1-3.

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