JP2020198568A - Photographed video display system for vehicle - Google Patents

Abstract

To provide a photographed video display system for a vehicle, capable of suppressing degradation in visibility when noise invades into a frequency band of a color signal.SOLUTION: A photographed video display system 1 for a vehicle inputs a photographed video photographed by a camera 2 (photographing means) into a monitor 3 (video display means) through a coaxial cable 4 as an analog HD video signal including a video signal formed by superposing a color signal of a second frequency band different from a predetermined first frequency band on a brightness signal thereof to generate a screen output. A filter circuit 6d (interference signal detection means) detects an interference signal affected by a color signal of the analog HD video signal and when an interference signal is detected, a video processing circuit 6b (color killer means) display-outputs a white and black video on the monitor 3.SELECTED DRAWING: Figure 4

Description

The present invention relates to a captured image display system for a vehicle.

Some vehicles in recent years are equipped with a vehicle shooting image display system that displays a rear-view image on a rear-view mirror (room mirror) in the vehicle interior (Patent Document 1). In such a vehicle image display system, a camera for photographing the rear of the vehicle is installed at the rear of the vehicle, a monitor is built in a rearview mirror on the upper part of the windshield, and they are connected by wire.

In such a vehicle shooting video display system, the shooting data shot by the camera is converted into analog data and output, and the output analog HD (High Definition) video signal is transmitted via a transmission cable such as a coaxial cable or a twisted pair cable. Some of them are input to the monitor, converted back to digital data, and then displayed on the screen. In recent years, AHD (Analog) has been used as an analog video transmission method that can output higher resolution video than before while using the same transmission cable (3C-2V: JIS standard coaxial cable) as conventional analog cameras. High Definition), HD-TVI (High Definition Tranport Video Interface), etc. are also used. As the analog HD video signal used in such a transmission method, a composite video signal composed of a synchronization signal, a luminance signal, and a color signal as shown in FIG. 2 can be used.

JP-A-2018-207274

In the case of such a composite video signal, a color signal is superimposed on a frequency band higher than the luminance signal in a predetermined frequency band. Then, in a vehicle satisfying a certain specific condition, the radio wave of a high-power radio or the like causes noise in the frequency band of the color signal, causing color fringes and the like, which may greatly reduce the visibility.

An object of the present invention is to provide a captured image display system for a vehicle capable of suppressing a decrease in visibility when noise is included in a frequency band of a color signal.

Means for Solving Problems and Effects of Invention

In order to solve the above problems, the first of the captured image display systems for vehicles of the present invention is
Coaxially as an analog HD video signal including a video signal in which a color signal of a second frequency band different from the brightness signal of a predetermined first frequency band is superimposed on a shot video shot by the shooting means. It is a vehicle shooting video display system that inputs to the screen display means via a cable or twisted pair cable and outputs the screen.
An interference signal detecting means for detecting an interference signal in the second frequency band superimposed on the analog HD video signal, and
A color killer means for causing the screen display means to output a black-and-white image based on the luminance signal when the interference signal is detected by the interference signal detecting means.
It is characterized by having.

According to the above-described configuration of the present invention, when an interfering radio wave in the same frequency band as the color signal frequency band is received, the color display is stopped and a black-and-white image is output. That is, since the black-and-white image is output based on the undisturbed luminance information without using the disturbed color information due to the disturbed radio wave, the color stripes and the like that greatly deteriorate the visibility do not occur.

In order to solve the above problems, the second method of the captured image display system for vehicles of the present invention is
Coaxially as an analog HD video signal including a video signal in which a color signal of a second frequency band different from the brightness signal of a predetermined first frequency band is superimposed on a shot video shot by the shooting means. It is a vehicle shooting video display system that inputs to the screen display means via a cable or twisted pair cable and outputs the screen.
Interfering signal detecting means for detecting an interfering signal in the frequency band superimposed on the analog HD video signal, and
When the jamming signal is detected by the jamming signal detecting means, the frequency of the jamming signal is specified, the analog HD video signal is removed or attenuated at the specified frequency, and then input to the screen display means. Interfering signal removal means to make
It is characterized by having.

According to the configuration of the present invention, when an interfering radio wave in a frequency band superimposed on an analog HD video signal is received, the frequency is specified, and the analog HD video signal is removed or attenuated at the specified frequency. It is possible to greatly eliminate the influence of interfering radio waves and display color images that do not generate color stripes. In this case, the frequency band of the interference signal to be detected may be defined as within the second frequency band.

The jamming signal detecting means can be said to have detected the jamming signal when the analog HD video signal has an amplitude of a predetermined level or more. For example, it can be determined that the analog HD video signal is processed by a filter through which only the color signal band (second frequency band) passes, and the interfering signal is detected when the processed signal has an amplitude of a certain value or more. According to this configuration, the jamming signal is detected directly from the video signal of the analog HD video signal, so that the jamming signal can be reliably detected.

The jamming signal detecting means can be said to have detected the jamming signal when it has an amplitude of a predetermined level or more during the blanking period of the analog HD video signal. For example, among analog HD video signals, only signals in a blanking period (for example, a vertical blanking period or a horizontal blanking period excluding a color burst period) in which a high-frequency signal does not exist are passed, and then processed by a filter and processed. It can be determined that the interfering signal is detected when the later signal has an amplitude of a certain value or more. According to this configuration, since the interfering signal is detected not from the video signal included in the analog HD video signal but from the blanking period in which the high frequency signal is not present contained in the analog HD video signal, the interfering signal can be reliably detected. ..

The jamming signal detecting means detects the jamming signal when it has an amplitude of a predetermined level or more in a wired energizing means different from the coaxial cable or the twisted pair cable to which the analog HD video signal is transmitted. Can be done. For example, when a line (power line, control line, etc.) in which no analog HD video signal does not exist is processed by a filter that passes only the color signal band (second frequency band), and the processed signal has an amplitude of a certain level or more. It can be determined that the jamming signal has been detected. According to this configuration, the interfering signal is not detected directly from the analog HD video signal, but is indirectly detected from the power supply current or the control signal of the camera, monitor, or the like. Since there are no high-frequency signals in the power supply current and control signals, interfering signals can be detected reliably.

The figure which showed typically an example of the vehicle which carries the photographed image display system for a vehicle of this invention. The graph which showed the signal waveform of the color bar signal which is an example of an analog HD video signal simply. The graph which showed the frequency band of the luminance signal and the color signal of the analog HD video signal of FIG. 2 simply. The block diagram which showed the electric structure of the photographed image display system for a vehicle of FIG. 1 simply. The graph which showed the signal waveform when only the color signal was gated from the analog HD video signal of FIG. 2 simply. The block diagram which simply showed the electrical structure of the photographed image display system for a vehicle different from FIG.

Hereinafter, the first embodiment of the present invention will be described with reference to the drawings.

The vehicle shooting video display system 1 shown in FIG. 1 captures the shot video shot by the camera 2 (shooting means) as an analog HD video signal via a coaxial cable 4 (wired communication means) and monitors 3 (screen display means). It is a system that inputs to and outputs to the screen, and is installed in the vehicle 100. The vehicle 100 here is a vehicle that is longer in the front-rear direction than an ordinary vehicle, and is a freight vehicle (truck) provided with a cargo bed for freight transportation.

The camera 2 is an analog HD camera. The shooting of the camera 2 is performed as a digital camera, but the shooting data is once converted to an analog method so that it can be transmitted by the coaxial cable 4 (at least 3C2V can be used), and then converted back to digital data on the monitor 3 side. And play it back. The analog conversion method here is one of an AHD (Analog High Definition) method, an HD-TVI (High Definition Transport Video Interface) method, and an HDRCVI (High Definition Composite Video Interface) method.

The analog HD video signal output from the camera 2 is a composite video signal having a video signal in which a color signal is superimposed on a synchronization signal, a color burst signal, and a luminance signal, similarly to the NTSC composite video signal. FIG. 2 is an example of a composite video signal output from the camera 2, and shows a color bar signal of one line in the horizontal direction. This horizontal 1-line signal is provided with a horizontal blanking period on the leading side, and within that period, the horizontal synchronization signal (pulse) for synchronizing the horizontal scanning lines and the color signal are correctly demolished. A color burst signal (a sine wave of about 10 to 70 MHz) that serves as a reference for the phase to be reproduced is included. Further, the composite video signal is provided with an effective video period following the horizontal blanking period, and within that period, the luminance signal of the first predetermined frequency band (luminance signal band) is different from that. It has a video signal (sine wave) on which color signals of two frequency bands (color signal bands) are superimposed. Further, the composite video signal is followed by a signal of the next horizontal line of 1 to such a signal of 1 line in the horizontal direction, and the composite video forming one screen composed of the composite video signals of each of these horizontal lines. A vertical blanking period is provided at the beginning of the signal.

Here, as shown in FIG. 3, the color signal is in a higher frequency band than the luminance signal. Specifically, the frequency of the color signal is 17 MHz or more and 25 MHz or less, and the frequency of the luminance signal is 18 MHz or less.

As shown in FIG. 1, the coaxial cable 4 is a well-known wired communication means for connecting the camera 2 and the monitor 3, and is extended so that a plurality of cables are connected via a connecting portion 5 such as a connector. .. The coaxial cable 4 can also be a wired communication means such as a twisted pair cable.

As shown in FIG. 4, the monitor 3 is connected to the coaxial cable 4 via the display control unit 6. The monitor 3 here is provided on the rearview mirror 9 fixed to the upper center of the windshield in the vehicle interior together with the display control unit 6. A half mirror (not shown) is arranged on the front surface (driver side) of the rearview mirror 9, and a monitor 3 is arranged behind the half mirror (not shown). When the monitor 3 is OFF, the reflected image reflected on the mirror surface of the half mirror is visually recognized, and when the monitor 3 is ON, the vehicle rear image captured by the camera 2 is visually recognized through the half mirror.

The display control unit 6 includes a video decoder circuit 6a and a video processing circuit 6b, which function as image forming means. When the video decoder circuit 6a receives an input of an analog HD video signal, the video decoder circuit 6a decodes the input and extracts information on the brightness, hue, and color of each pixel, and the video processing circuit 6b extracts image data based on the extracted information. Is formed and input to the monitor 3 to be displayed on the screen.

On the other hand, the display control unit 6 has a gate circuit 6c and a filter circuit 6d, which function as interference signal detecting means. Further, the display control unit 6 includes a video decoder circuit 6a and a video processing circuit 6b, which function as color killer means. Specifically, when the gate circuit 6c receives the input of the analog HD video signal of FIG. 2 or the like, as shown in FIG. 5, the gate circuit 6c has a blanking period (horizontal block excluding the color burst period) in which no effective video exists. Pass the ranking period and vertical blanking period). The filter circuit 6d (bandpass filter) passes only the signal of the second frequency band (color signal band) of the passed blanking period, and detects the presence or absence of an amplitude of a certain value or more. Then, the filter circuit 6d determines that the jamming signal has been detected when the amplitude exceeds a certain level (jamming signal detecting means), and outputs a black-and-white image based on the brightness signal to the screen on the monitor 3. A well-known color killer signal is input to the video decoder circuit 6a or the video processing circuit 6b. As a result, the video processing circuit 6b causes the monitor 3 to output a black-and-white video based on the luminance signal of the analog HD video signal to the screen (color killer means).

As a result, when a strong interfering radio wave such as a high-power radio is received, the monitor 3 does not display an image having poor visibility including color stripes, and instead displays a black-and-white image without color. Black-and-white images have no color expression, but are more visible than color images that include color stripes.

For high-frequency interfering radio waves such as high-power radios, the transmission path (coaxial cable 4) from the camera 2 to the monitor 3 is long, the opening into which the windshield on which the monitor 3 is installed is wide, and the metal area of the vehicle body is large. Due to such a thing, color stripes are generated in the image of the monitor 3. In a freight vehicle that is long in the front-rear direction such as a truck, when an analog HD video signal is to be transmitted from the rear part of the vehicle to a monitor 3 on the front side of the vehicle interior such as a navigation screen or a room mirror, a long coaxial cable 4 is used. In some cases, the video signal must be transmitted from the camera 2 to the monitor 3 by using the coaxial cable 4 extended by the connecting portion 5. Naturally, if the transmission path is long, the analog HD video signal is easily affected by high-frequency interfering radio waves, and the connection portion 5 is particularly susceptible to the influence. Further, if the opening into which the windshield fits is wide like a truck, when a high-frequency interfering radio wave is received, an eddy current is generated in a metal portion surrounding the opening, and the analog HD video signal is easily affected by this eddy current. Furthermore, large vehicles such as trucks are more susceptible to high-frequency jamming radio waves than ordinary automobiles because the area of metal parts that form the outer surface is large. As described above, in a vehicle such as a truck that is easily affected by high-frequency interference radio waves, there is a possibility that color stripes may occur in the color image displayed on the monitor when receiving strong high-frequency interference radio waves. However, according to this embodiment, when it is detected that an interference signal is superimposed on an analog HD image signal due to a high-frequency interference radio wave of a predetermined level or higher, the color information that causes color fringes is discarded and a black-and-white image is produced. Since the display is switched, it is possible to avoid the difficulty of seeing due to the occurrence of color stripes.

Although the first embodiment of the present invention has been described above, this is merely an example, and the present invention is not limited thereto. For example, various changes can be made based on the knowledge of those skilled in the art, such as omitting some constituent requirements or adding other constituent requirements in the first embodiment.

Hereinafter, other examples and modifications of the present invention will be described. The same functional parts as those in the above embodiment and similar functional parts will be designated by the same reference numerals, and detailed description thereof will be omitted. Further, the above-described embodiment and the following examples and modifications can be appropriately combined and carried out within a range that does not cause a technical contradiction.

Hereinafter, the second embodiment of the present invention will be described.

In the second embodiment, the configuration of the display control unit 6 is different from that in the first embodiment. That is, as shown in FIG. 6, the filter circuit 6e is attached to another wired energizing means (for example, the camera 2 or the monitor 3) different from the coaxial cable 4 or the like through which the analog HD video signal captured by the camera 2 is transmitted. It is connected to the power line to be connected). In the case of FIG. 6, the filter circuit 6e (bandpass filter) is connected to the power supply line that supplies the drive power to the camera 2. The filter circuit 6e determines that an interfering signal has been detected and determines the frequency of the interfering signal when the energizing current of the power supply line has an amplitude of a predetermined level or more in the frequency band superimposed on the analog HD video signal. Identify. Then, the filter circuit 6e controls the filter circuit 6f (notch filter) into which the analog HD video signal is input so as to remove or attenuate only the signal having the frequency of the specified interfering signal and allow the other frequencies to pass as they are. Input the signal. The analog HD video signal from which the signal having the frequency of the interfering signal has been removed or attenuated is processed in the same manner as in the first embodiment by the video decoder circuit 6a and the video processing circuit 6b, and is displayed on the screen on the monitor 3. .. As a result, the monitor 3 displays a color image in a state in which the influence of the jamming signal (jamming radio wave) is removed or reduced and no color stripes are generated. In the second embodiment, the filter circuits 6e and 6f function as disturbing signal detecting means and disturbing signal removing means.

In the second embodiment, the filter circuit 6f (notch filter) is an analog filter that acts on the analog signal, but it may be a digital filter that acts on the digital signal after AD conversion.

Hereinafter, modifications of the present invention will be described.

For example, in the first embodiment and the second embodiment, the detection methods of the interfering signals may be exchanged.

Further, the interference signal is not detected directly from the analog HD video signal input from the camera 2 to the display control unit 6, but indirectly detected based on other information different from the analog HD video signal. It may be. For example, as shown in the second embodiment of FIG. 6, another different from the coaxial cable 4 (wired communication means) through which the analog HD video signal is transmitted, such as the power line connected to the camera 2 and the monitor 3. In the wired energizing means, the interfering signal may be detected when the amplitude is equal to or higher than a predetermined level in the frequency band superimposed on the analog HD video signal.

Although the monitor 3 of the above embodiment is provided in the rearview mirror 9, other monitors may be used as long as they are arranged in front of the driver. For example, it may be a navigation screen of an in-vehicle car navigation device.

1 Vehicle shooting video display system 100 Vehicle 2 Camera (shooting means)
3 Monitor (screen display means)
4 Coaxial cable (wired communication means)
5 Connection unit 6 Display control unit (interference signal detection means, color killer means, interference signal removal means)
9 room mirror

Claims (6)

Coaxially as an analog HD video signal including a video signal in which a color signal of a second frequency band different from the brightness signal of a predetermined first frequency band is superimposed on a shot video shot by the shooting means. It is a vehicle shooting video display system that inputs to the screen display means via a cable or twisted pair cable and outputs the screen.
An interference signal detecting means for detecting an interference signal in the second frequency band superimposed on the analog HD video signal, and
A color killer means for causing the screen display means to output a black-and-white image based on the luminance signal when the interference signal is detected by the interference signal detecting means.
A shooting video display system for vehicles, which is characterized by being equipped with. Coaxially as an analog HD video signal including a video signal in which a color signal of a second frequency band different from the brightness signal of a predetermined first frequency band is superimposed on a shot video shot by the shooting means. It is a vehicle shooting video display system that inputs to the screen display means via a cable or twisted pair cable and outputs the screen.
Interfering signal detecting means for detecting an interfering signal in the frequency band superimposed on the analog HD video signal, and
When the jamming signal is detected by the jamming signal detecting means, the frequency of the jamming signal is specified, the analog HD video signal is removed or attenuated at the specified frequency, and then input to the screen display means. Interfering signal removal means to make
A shooting video display system for vehicles, which is characterized by being equipped with. The vehicle capture image display system according to claim 2, wherein the frequency band of the interference signal to be detected by the interference signal detecting means is defined as being within the second frequency band. The first or third aspect of the present invention, wherein the interfering signal detecting means detects the interfering signal when the analog HD video signal has an amplitude of a predetermined level or more in the second frequency band. Photographed video display system for vehicles. The interfering signal detecting means according to any one of claims 1 to 4, wherein the interfering signal is detected when the analog HD video signal has an amplitude of a predetermined level or more during the blanking period. Video display system for vehicles. The jamming signal detecting means detects the jamming signal when the coaxial cable or another wired energizing means different from the twisted pair cable to which the analog HD video signal is transmitted has an amplitude of a predetermined level or more. The vehicle shooting image display system according to any one of claims 1 to 4.

Images