JP2556541B2 - Vehicle image information display device - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to a vehicle image information display device for reliably monitoring a landscape behind a vehicle, for example, a state relating to traveling of a following vehicle or the like. Is.

(Prior Art) In recent years, various so-called vehicular image information display devices have been proposed in which a surveillance camera is installed in the rear part of an automobile to monitor the scenery or the like behind the automobile (actually, the development of 54 -132224).

In such a conventional image information display device for a vehicle, a video signal from a surveillance camera installed in the rear portion of the automobile is input to a display device to display a landscape behind the automobile. In addition, the video signal from the above-mentioned surveillance camera is normally input to the squeezing adjustment circuit, and squeezing adjustment is executed according to the brightness of the scenery behind the vehicle based on this video signal to determine the amount of light incident on the surveillance camera. I am trying to adjust it.

(Problems to be Solved by the Invention) However, particularly when traveling at night,
When the strong light from the headlamp of the following vehicle enters the surveillance camera, the image signal of this strong light is input to the display. Among the images displayed on the display unit, the headlamps of the following vehicles are brighter than the surrounding landscape, so that they are dazzled by this particularly bright light, which causes a problem that the image on the display unit is difficult to see.

Therefore, if the amount of squeezing of the squeezing adjustment circuit is increased according to the brightness of particularly strong light from a headlamp or the like, the amount of light incident on the surveillance camera is adjusted so that it is reduced overall, so While the image of the headlamps displayed was easy to see, the surrounding images other than the headlamps became too dark, and there was a new problem that the following vehicle could not be reliably caught.

The present invention has been made in view of the above problems, and a vehicle image information display device capable of reliably and accurately catching a following vehicle by preventing dazzling by a headlamp of the following vehicle even when traveling at night. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) Means provided by the present invention in order to achieve the above object are as follows.
In a vehicle image information display device mounted on a vehicle for displaying an image behind a vehicle, the image signal including image pickup means for converting image information obtained two-dimensionally into a time-varying image signal and outputting the image signal. Comparing means for comparing the signal value of No. 1 with a preset reference value, and as a result of the comparison by the comparing means, when the video signal has a signal value exceeding the reference value, a comparison signal is outputted. Delaying the video signal by a signal generating means, an expanding means for generating an expansion signal for a predetermined time while the comparison signal is being output by the comparison signal generating means, and for a predetermined time after the output of the comparison signal is completed. Delay means and correction means for holding the luminance level of the video signal output from the delay means before the generation of the extension signal while the extension signal is being generated. The the gist.

(Operation) A vehicle image information display device mounted on a vehicle for displaying an image of the rear of a vehicle according to the present invention includes an image pickup means for converting image information obtained two-dimensionally into a time-varying video signal and outputting the image signal. When the video signal has a signal value exceeding the reference value as a result of comparison between the signal value of the video signal by the comparing means and the preset reference value, the comparison signal is output from the comparison signal generating means. To be done.

Further, while the comparison signal is being output and for a predetermined time after the output of the comparison signal is completed, the expansion means outputs the expansion signal.

Further, while the extension signal is being output, the correction means holds the luminance level of the video signal output from the delay means before the extension signal is generated.

In this way, the brightness of the area of the video signal in which the extension signal is output and the area of the extension signal before the delay time are corrected.

Embodiment An embodiment according to the present invention will be described in detail below with reference to the drawings.

First, the configuration will be described with reference to FIGS. 1, 2, and 4A and 4B. The surveillance camera 1 is installed in the rear part of the vehicle inside the window glass 2 and toward the rear, and sends out the landscape of the rear of the vehicle, for example, image information of the following vehicle. The surveillance camera 1 is connected to the dazzle prevention circuit 3, and the surveillance camera 1 sends video information about the scenery of the following vehicle to the dazzle prevention circuit 3.

When the video signal from the surveillance camera 1 is input, the dazzling prevention circuit 3 includes a correction means for correcting a video signal corresponding to a landscape having a brightness higher than a predetermined level by a certain level or more than the brightness of the surrounding landscape. I have it. For example, in the video signal of the following vehicle, the video signal of a portion where the brightness of the headlamp or the like is significantly high is corrected to a level substantially the same as the signal level of the surrounding video signal. This dazzling prevention circuit 3
Is connected to the battery power source E via a switch SW1 which operates in conjunction with a switch (not shown) for turning on the headlamp of the host vehicle. Therefore, the switch SW1 sends the switch information 21a indicating that the headlamp is turned on to the dazzle prevention circuit 3. The dazzle prevention circuit 3 is connected to each of the display 5 and the squeezing adjustment circuit 7,
The dazzling prevention circuit 3 sends the dazzling prevention circuit output 3a to the display 5 and the squeezing adjustment circuit 7. The display 5 is a dazzling prevention circuit 3
From the dazzling prevention circuit output 3a, that is, the video signal in which the signal corresponding to the landscape having a brightness higher than the brightness of the surrounding landscape by a predetermined level or more is corrected as described above is input, and the rear of the vehicle is based on the input video signal. The scenery of, for example, the image of the following vehicle is displayed.

Further, when the squeezing adjustment circuit 7 receives the dazzling prevention circuit output 3a from the dazzling prevention circuit 3, it sends a signal to the surveillance camera 1 to adjust the amount of squeezing based on the input dazzling prevention circuit output 3a. The surveillance camera 1 is provided with a squeezing mechanism for adjusting the amount of light incident through the lens. The squeezing mechanism operates based on the signal from the squeezing adjustment circuit 7 described above, and the amount of incident light is Adjusted.

 Next, the internal structure of the dazzle prevention circuit 3 will be described.

The differentiating circuit 11 and the delay circuit 13 are connected to the surveillance camera 1, and each of the differentiating circuit 11 and the delay circuit 13 inputs the video signal 1a from the surveillance camera 1. The differentiating circuit 11 is formed of, for example, a capacitor and a resistor, and when the video signal 1a as shown in FIG. 3 is input, the video signal 1a is differentiated to extract the displacement amount, and the extracted signal 11a is extracted. Send out. The level shift circuit 15 is connected to the differentiating circuit 11, and when the level shift circuit 15 receives the differentiated signal 11a from the differentiating circuit 11, it shifts the signal level of the signal 11a as a whole, as shown in FIG. The shifted differential output 15a is transmitted.

Further, the level shift circuit 15 is connected to the comparison circuit 17, and sends the above-mentioned shifted differential output 15a to the comparison circuit 17. The comparison circuit 17 is formed of, for example, an operational amplifier and a reference value signal generation circuit for transmitting a reference value signal of a predetermined level to the reference input terminal of this operational amplifier, and the differential output 15a from the level shift circuit 15 Input to the comparison input terminal of the operational amplifier described above. Therefore, when the comparison circuit 17 receives the differential output 15a, the comparison circuit 17 compares the differential output 15a with the reference value of the predetermined level described above, and sends out the signal of the comparison result, that is, the comparison output 17a. Pulse expansion circuit 1
Reference numeral 9 is connected to the comparison circuit 17, and inputs the comparison output 17a from the comparison circuit 17. The pulse expansion circuit 19 includes, for example, a one-shot circuit formed by a multi-pibrator or the like, and a comparison output 17 which is a pulse signal.
When a is input, the extended signal 19a having a pulse width longer than the pulse width of the input comparison output that is input is transmitted. Switching circuit 2
Reference numeral 1 is connected to the pulse expansion circuit 19 and inputs the above-mentioned expansion signal 19a. This switching circuit 21 is a delay circuit 13
And the hold circuit 23, respectively. When the delay circuit 13 receives the video signal 1a from the surveillance camera 1,
A signal obtained by delaying the input video signal 1a by a predetermined time ΔT, that is, a delayed output 13a is sent to the switching circuit 21. When the hold circuit 23 receives the signal 21b from the switching circuit 21, it holds the input signal 21b and returns the held signal 23b to the switching circuit 21. The switching circuit 21 incorporates a plurality of switching means, performs signal switching between the delay output 13a and the hold output 23b, and sends the signal resulting from this switching as the dazzle prevention circuit 3a.

Next, the internal configuration of the switching circuit 21 will be described in detail with reference to FIG.

As shown in FIG. 2, the switching circuit 21 comprises an AND circuit G and two switching means SW3 and SW5. One input terminal of the AND circuit G is connected to the switch SW1 and inputs the switching information 21a indicating that the switch SW1 has been operated. The other input terminal of the AND circuit G is connected to the pulse expansion circuit 19 and inputs the expansion signal 19a. The output terminal of the logical product circuit G is connected to each of the switching means SW3 and SW5, and the logical product output of the logical product circuit G controls the switching operation of the switching means SW3 and SW5. The movable contact S1 of the switching means SW3 is connected to each of the display 5 and the squeezing adjusting circuit 7. Also, switching means SW
The fixed contact S1 of 3 is connected to the movable contact S5 of the switching means SW5. In addition, the fixed contact S of the switching means SW3
1 is connected to the output terminal of the hold circuit 23. Further, the movable contact S5 of the switching means SW5 is connected to the delay circuit 13. In addition, fixed contact S of switching means SW5
7 is connected to the input terminal of the hold circuit 23.

Next, the control operation of the switching means SW3, SW5 based on the logical product output of the logical product circuit G will be described.

FIG. 2 shows the state when the logical product output of the L level is output from the logical product circuit G, and when the logical product output of the L level is transmitted from the logical product circuit G in this way. The delay output 13a from the delay circuit 13 is sent out as the dazzle prevention circuit output 3a via the fixed contact S1 and the movable contact S3 of the switching means SW3. Also, the AND circuit G
When a logical product output of H level is sent from, the switching means SW3 and SW5 are switched at the same time. That is,
The movable contact S3 of the switching means SW3 switches from the fixed contact S1 to the fixed contact S2. Further, the movable contact S5 of the switching means SW5 switches from the fixed contact S7 to the fixed contact S6. As a result, the delay output 13a from the delay circuit 13 is prohibited from being sent to the display unit 5, and the hold output 23b from the hold circuit 23 is output from the dazzling prevention circuit via the fixed contact S2 and the movable contact S3 of the switching means SW3. Sent as 3a.

Next, the operation of the embodiment according to the present invention will be described with reference to FIG.

 First, the operation during the daytime will be described.

A surveillance camera 1 attached to the rear portion of the vehicle sends a landscape behind the vehicle, for example, a video signal 1a of the following vehicle to a delay circuit 13. When the video signal 1a is input to the delay circuit 13, a signal delayed by a predetermined time ΔT, that is, a delayed output
13a is sent to the switching circuit 21. On the other hand, in the daytime, the switch SW1 is set to the open state in order to prohibit the lighting of the headlamp. Therefore, the switching information 2 from the switch SW1 is applied to one input terminal of the AND circuit G.
Since 1a is not input, the logical product circuit G sends out an L level logical product output. Therefore, the two switching means SW3 and SW5 built in the switching circuit 21 are set to the states shown in FIG. As a result, the delay output 13a from the delay circuit 13 is directly output to the dazzling prevention circuit output 3a.
Is sent to the display 5 and the squeezing adjustment circuit 7. When the display device 5 receives the dazzling prevention circuit output 3a, the display 5 outputs the dazzling prevention circuit output 3a, that is, the signal obtained by delaying the video signal 1a by a predetermined time ΔT. Is displayed. Further, when the squeezing adjustment circuit 7 receives the above-mentioned dazzling prevention circuit output 3a, the squeezing adjustment circuit 7 performs the squeezing adjustment of the surveillance camera 1 on the basis of this dazzling prevention circuit output 3a to adjust the amount of light incident on the surveillance camera 1.

 Next, the operation at night will be described.

When the switch SW1 is closed to turn on the headlamp during nighttime driving, a signal indicating that the switch SW1 is closed, that is, the H level switching information 21a is input to one input terminal of the AND circuit G. Send out. Further, when the surveillance camera 1 captures the image of the following vehicle traveling with the headlamps turned on and sends out the image signal 1a as shown in FIG. 3, such an image signal 1a is detected by the differentiating circuit 11 and the delay circuit 13. Given to each. Of the video signal 1a shown in FIG. 3, the signals 1b and 1c are signals due to the high-luminance portion due to the headlamp of the vehicle that follows. As shown in FIG. 3, the surveillance camera 1 inserts a negative pulse horizontal synchronizing signal at a predetermined cycle T into the video signal 1a. Such a video signal 1a is differentiated by the differentiation circuit 11 and then shifted by the level shift circuit 15. That is, as shown in FIG. 3, level shift is performed so that the lowest level of the differentiated horizontal synchronizing signal is 0 volt.

Then, the comparison circuit 17 compares the level of the reference value with the level of the level-shifted differential output 15a. Here, the level of the reference value is the differential output 15 as shown in FIG.
It is set to a value higher than the average level L1 'of a and lower than the signal level L2' that is prominent due to headlamps.

Of the differential output 15a as shown in FIG. 3, the operation when the first signal, that is, the peripheral differential output 15a other than the protruding signal 1b from the headlamp is input will be described.

Upon receiving the differential output 15a, the comparison circuit 17 compares the level L1 'of the differential output 15a with the reference value set to a value larger than the level L1', and the L-level comparison output 17a.
To the pulse expansion circuit 19. The pulse expansion circuit 19 is L
When the level comparison output 17a is input, the L level signal 19a
To the switching circuit 21. When the switching circuit 21 receives the L-level signal 19a, the delay output 13a from the delay circuit 13 is directly output to the dazzling prevention circuit output 3a as shown in FIG.
Is sent to the display 5 and the squeezing adjusting circuit 7.

In the switching circuit 21, as shown in FIG. 2, the movable contact S5 of the switching means SW5 is connected to the fixed contact S7, and the delay output 13a from the delay circuit 13 is held via the movable contact S5 and the fixed contact S7. It is output to the circuit 23. In the hold circuit 23, the delay output 13a of the video signal from the delay circuit 13
Is held at the brightness level before the generation of the extension signal.

Next, as shown in FIG. 3, when the comparison circuit 17 inputs the signal 1b or 1c of the level L2 'projected by the headlamp,
When the comparison circuit 17 inputs a signal corresponding to the headlamp, that is, a differentiated output 15a having a protruding level higher than the reference value level, the comparison output 17a becomes H level only for the duration of the protruding signal corresponding to this headlamp. To the pulse expansion circuit 19. When the pulse expansion circuit 19 receives the comparison output 17a, which is a pulse signal, it expands the pulse width of the comparison output 17a as shown by the dotted line in FIG. 3, and the expansion signal 19a having a pulse width wider than the pulse width of the comparison output 17a. To the switching circuit 21. In the switching circuit 21, as shown in FIG. 2, when the logical product circuit G inputs the H level extended signal 19a, the H level logical product is output only during the time corresponding to the H level signal duration of the extended signal 19a. The switching means
Send to SW3 and SW5. When the H level signal from the AND circuit G is input, the switching means SW3 and SW5 respectively perform a switching operation, and the movable contact S3 of the switching means SW3 switches from the fixed contact S1 to the fixed contact S2. Also,
Moving contact S5 of switching means SW5 is fixed contacts S7 to S6
Switch to. Therefore, the delayed output of the video signal from the delay circuit 13, that is, the transmission of the signal of high level L2 from the headlamp is prohibited. At this time, the hold circuit 23 displays the brightness level before the generation of the extension signal, that is, the low level.
The delay output 13a of L1 is held, and the movable contact S3 is switched from the fixed contact S1 to S2, so that the hold output 23b held in this hold circuit 23 prevents dazzling via the fixed contact S2 and the movable contact S3. It is sent to the display 5 and the squeezing adjusting circuit 7 as the circuit output 3a. Therefore, the display 5 is provided with the output 3a from the anti-glare circuit 3 in which the high level signal L2 from the headlamp is corrected to the same level as the surrounding signal level L1. Therefore,
The display 5 displays the image of the following vehicle in which only the image of the headlamp is corrected. Further, the squeezing adjusting circuit 7 corrects the high level L2 signal from the headlamp described above to the signal level L1 and then inputs it to the dazzling circuit output 3a, so that the high level L2 signal from the headlamp is corrected. The squeezing adjustment of the surveillance camera 1 is appropriately executed on the basis of the output 3a from the dazzling prevention circuit 3 which has been performed, and the amount of light incident on the surveillance camera 1 is appropriately adjusted.

If the delay time ΔT in the delay circuit 13 is set appropriately, for example, as shown in FIG. 3, the period T is set as a time longer than the duration of the H level of the H level comparison output 17a sent from the comparison circuit 17. By setting it to about 4 to 5%, it is possible to appropriately correct not only a high level signal from the headlamp but also a signal before such a high level signal.

Further, the H level of the comparison output 17a of the H level from the comparison circuit 17
Since the signal extension time of the level is extended by the pulse extension circuit 19a, it is possible to appropriately correct the subsequent signal following the high level signal by the headlamp or the like,
Dazzling can be prevented more reliably.

If the pulse expansion circuit and the delay circuit are not provided, for example, if the threshold value is set high, the brightness of the area around the headlamp cannot be sufficiently corrected. Therefore, although the brightness of the area around the headlamp can be corrected by lowering the threshold value, the area of the following vehicle such as a sidelight of the vehicle having a slight brightness is also corrected, and the obtained image The contrast becomes low.

On the other hand, the present invention has the pulse expansion circuit and the delay circuit, and therefore, the correction of the area after the generation time of the pulse by the headlamp is performed by the pulse expansion circuit and the correction of the area before the generation time of the delay circuit. It is possible to perform a fine brightness correction by using a function.

Further, the surveillance camera 1 may be configured by using a surveillance camera that transmits a video signal of a color signal.

When a surveillance camera that sends color signals together is used as the surveillance camera 1 in this way, a low-pass filter for removing the color signals is inserted between the differentiating circuit 11 and the surveillance camera. Good.

EFFECTS OF THE INVENTION As described above, according to the present invention, a video signal corresponding to a specific area having a brightness higher than a predetermined level and higher than the brightness of the surrounding image information is provided to the brightness before the generation of the specific area. By holding and correcting, for example, it is possible to surely prevent the dazzling by the headlamps of the following vehicle, and therefore, it is possible to accurately and accurately capture the state of the following vehicle in a comfortable state and to make it safer. You can drive. Further, by appropriately setting the delay time in the delay circuit, it is possible to appropriately correct, for example, a high level signal from the headlamp as well as a signal prior to such a high level signal.

Further, since the H level signal duration of the H level comparison output from the comparison circuit is expanded by the pulse expansion circuit, the subsequent signal following the high level signal by the headlamp or the like is also appropriately corrected. It is possible to prevent dazzling more reliably.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing the internal configuration of the switching circuit of FIG. 1, and FIG. 3 is a signal waveform diagram of each part of FIG. Figure 4 (A) is the first
FIG. 4 is an explanatory view of a vehicle equipped with the embodiment shown in the figure, and FIG. 4 (B) is an enlarged view of a circular frame portion of FIG. 4 (A). 1 ... Surveillance camera, 3 ... Dazzling prevention circuit 5 ... Indicator, 7 ... Squeezing adjustment circuit 11 ... Differentiation circuit, 13 ... Delay circuit 15 ... Level shift circuit 17 ... Comparison circuit, 19 ... Pulse expansion circuit 21 …… Switching circuit, 23 …… Hold circuit

Claims (1)

(57) [Claims] 1. An image information display device for a vehicle, which has an image pickup means for converting image information obtained two-dimensionally into a video signal which changes with time and outputs the image signal, and which is mounted on a vehicle for displaying an image of the rear of the vehicle. In the above, in the case where the signal value of the video signal is compared with a preset reference value, and the video signal has a signal value exceeding the reference value as a result of the comparison by the comparison means, the comparison is performed. A comparison signal generating means for outputting a signal, while the comparison signal is being output by the comparison signal generating means, and a predetermined time after the output of the comparison signal is finished,
Expansion means for generating an expansion signal; delay means for delaying the video signal for a predetermined time; and the video output from the delay means before the expansion signal is generated while the expansion signal is being generated by the expansion means. A vehicle image information display device comprising: a correction unit that holds the brightness level of a signal.