JPS6280143A - Visual confirmation auxiliary device for vehicle - Google Patents

Abstract

PURPOSE:To enable further clear display of a scene of a given region at night, by a method wherein, in relation to a photograph signal from CCD image sensor controbuting to a picture projected on a display device, and light corresponding to back scene light can be relatively reduced. CONSTITUTION:A CCD image sensor 10 is provided for collecting light from the given direction region of a vehicle, for example, a front region through a lens 22, collecting reflection light and back scene light generated when the region is intermittently irradiated with light from a lamp 20 to output a photograph signal Sv. The photograph signal Sv is generated in synchronism with outputs from a transmission clock generating circuit 3, a horizontal clock generating circuit 4, and a vertical clock generating circuit 5. According to an output from a monomulti MM 6, outputting an H level for a given time commencing with a rise of a clock signal from a light irradiation signal generating circuit 2, an AND circuit 7 is opened, and this causes a photograph signal right after irradiation with light to be inputted to a display device 18 through an accumulating circuit 16 and the like for display.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to the fn range, which is difficult for vehicle occupants to use. 52
It is related to a device that supplements recognition, and in detail, a CCD image sensor receives light from a predetermined direction area with respect to a vehicle, and 1l of pixels of about 1i are output from this CCD image sensor.
This invention relates to a vehicle FM='1 auxiliary device that displays an image parked at an image signal on a display device.

[Prior Art] First, a CCD image sensor (hereinafter simply referred to as C structure) is shown in FIG. 4, for example.

This C0D 10 is constructed on a semiconductor substrate such as silicon, and its basic elements are a photosensitive section 11 arranged in a matrix and each having a structure of a photoelectric conversion element such as a photodiode, and a photosensitive section. Vertical registers 12 for storing accumulated charges sent out at once from 11 columns, and horizontal registers for storing charges output in parallel from each vertical register 12 and serially outputting the charges as carrier image signals Sv in pixel units. It has a register 13. The transmission of the accumulated charge from the photosensitive section 11 is synchronized with the transfer lock signal CLt, the transmission of the charge from the vertical register 12 is synchronized with the vertical clock signal CLV, and the transmission of the accumulated charge from the horizontal register 13 in units of pixels is synchronized with the transfer lock signal CLt. The output of the signal Sv is performed in synchronization with the horizontal clock signal CLh. That is, the rate relationship of each clock signal is that of the transfer lock signal CLt.
For one clock, the vertical clock signal CLV is equal to the number of clocks in the vertical direction of the photosensitive section 11 (in this case, three clocks), and further, for each vertical clock signal CLv1 clock, the horizontal clock signal CLh is equal to the number of vertical registers 12. The period of the transfer lock signal Cut means the charge accumulation time in the photosensitive section 11.

In FIG. 4, the photosensitive section 11 has a 3.times.3 matrix structure, but in an actual CCD, it has a matrix structure of about 300.times.400 pixels.

Conventionally, a so-called vehicle visual recognition system, which uses a CCD as described above, removes the shadow of the driver's blind spot and displays the image on a display device such as a CRT display installed inside the vehicle. An auxiliary device is being considered (Japanese Patent Laid-Open No. 5
8-180346, etc.). This vehicle visibility aid device receives light from the blind spot area etc. using a CCD,
At that time, the configuration is such that an image is displayed on the display device based on the carrier signal of each pixel corresponding to each photosensitive section 11 outputted from this CCD.

[Problems to be Solved by the Invention] Incidentally, in order to project on a display device a scene in an area that is difficult for vehicle occupants to see at night, it is possible to use a vehicle visibility aid device as described above. If background light, such as light from a street lamp or the headlights of an oncoming car, is directly input to the CCD, even if the area to be checked is illuminated with light, the object in the area in the image displayed on the display device will not be visible. The problem is that it becomes difficult to see.

This is because conventional vehicle visibility aids do not take the above background light into consideration, and instead project an image on the display device based on all the dynamic image signals output from the CCD. Because there is.

Therefore, it is an object of the present invention to reduce the decoy image signals from the CCD that contribute to the image displayed on the display device, which correspond to the background light, relative to those which correspond to the light from the predetermined area. The goal is to be able to do so.

[Means for Solving the Problems] The present invention includes a CCD image sensor that receives light from a predetermined area of the vehicle, and a CCD image sensor that receives light from a predetermined area of the vehicle. The technical means for solving the above problem in the vehicle visibility aid device is to avoid the use of a light source device that intermittently irradiates the area in the predetermined direction with light at a predetermined period. At the same time, the cycle of transmitting accumulated charges from the photosensitive section in the CCD image sensor is set to be shorter than the light irradiation cycle of the light source device, and the turtle is irradiated with light from the light i device after a predetermined period of time has elapsed from the time of light irradiation. The apparatus is further provided with a prohibition means for prohibiting the jump signal output from the CCD image sensor from contributing to the image displayed on the display device.

[Operation] The light source device intermittently irradiates light to a region in a predetermined direction of the vehicle at a predetermined period. In the process, the CCD image sensor receives reflected light and background light from the object in the area, and sequentially outputs one image signal corresponding to the reflected light, but this CCD image sensor sends out accumulated charges from the photosensitive part. Since the cycle of light irradiation is set to be shorter than the light irradiation cycle from the light source device, in the process of outputting the imaging signal, the accumulated charge is sent out from the photosensitive section a plurality of times in response to -times of light irradiation. Each time light is irradiated from the light source device, the prohibiting means prohibits the dancing signal output from the CCD image sensor from contributing to the image displayed on the display device after a predetermined period of time has elapsed from the irradiation time. Then, the first image signal outputted from the CCD image sensor immediately after the light irradiation includes a counter-light component from the target object, while most of the other image signals correspond to background light. Therefore, most of the 1lil image signals whose contribution to the image is prohibited by the above-mentioned prohibition means correspond to background light. Therefore, regarding Wi image signals contributing to the image displayed on the display device, those corresponding to the background light are reduced relative to those corresponding to the light from the predetermined area.

[Embodiments of the invention] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an example of a vehicle visibility aid device according to the present invention.

In the same figure, 1o is a CCD having a configuration similar to that shown in FIG.
For example, it is disposed at an appropriate position in the vehicle so as to receive light from the area in front of the vehicle via the lens 22. Reference numeral 20 denotes a lamp that emits light and heat a to the area in the predetermined direction, and can also serve as a headlamp when illuminating the area in front of the vehicle.

1 is the predetermined period! This is a reference oscillation circuit that outputs a quasi-clock signal. 2 is a light irradiation device that performs predetermined frequency division processing on the 1QtI clock signal from the reference oscillation circuit 1 and outputs a clock signal (light irradiation signal) with a period TO of about 1/100 sec and a dignity ratio of about 1150. A signal generation circuit 21 is an initial circuit that receives a clock signal from the light irradiation signal generation circuit 2, and the circuit 20 intermittently irradiates light in synchronization with the clock signal.

3, 4, 5 Huge comparison to CCD101C? 7.
Feed lock signal CLt1 horizontal O-lock signal CLh.

These are a transfer lock generation circuit, a horizontal clock generation circuit, and a vertical clock generation circuit that output a vertical clock signal @CLV. Each of the clock generation circuits 3, 4.5 generates a clock signal of a predetermined period based on the reference clock signal from the reference oscillation circuit 1, and in particular generates a transfer lock signal from the transfer lock generation circuit 3. The period Tt of CLt is the period To of the output signal from the light irradiation signal generation circuit 2.
The horizontal clock signal @C is set to about 1150.
Each cycle Th and TV of Lh and vertical clock signal CLV
are set based on the period Tt of the transfer lock signal CLt and the rate relationship of each clock signal in C0D10 described above.

6 is a monostable multivibrator (hereinafter simply referred to as MM) that outputs an H level signal for a predetermined time T (l) from the rise of the clock signal from the light irradiation signal generation circuit 2, and the predetermined time T set in this MM6 is (I is slightly longer than the period Tt of the transfer lock signal CLt.

7 is a gate circuit, and this gate circuit 7 receives the carrier signal Sv from the CCD 10 when the output of MM6 is at H level.
It has the function of sending out to the subsequent stage.

15 is a video clock signal generation circuit that performs a predetermined frequency division process on the reference clock signal from the reference oscillation circuit 1 and outputs a video clock signal with a predetermined cycle Ts; 16 is a visual signal that is passed through the gate circuit 7; This is a carrier signal accumulation circuit that accumulates the carrier signal and outputs the accumulated carrier signal to the subsequent stage every time the clock signal from the video clock signal generation circuit 15 rises. 17 is 1lii image signal storage + a circuit 1
A video signal generation circuit 18 generates a video signal based on the 1lii image signals sequentially outputted from 6, and 18 is a display device installed at an appropriate position in the vehicle interior. Images based on video signals are displayed.

Next, the operation of the above device will be explained based on the timing chart shown in FIG.

-ngf++-20 intermittently irradiates light onto a predetermined direction area of the vehicle at a period TO. Furthermore, this irradiated light is 10
Since it repeats blinking at about 01-1z (To is about 1/100 sec), it appears to the human eye as continuous light. In this process, the CCD 10 receives the reflected light and backlight from the counter-dye in the area, and responds with l! 1 signal signal S type output.

Furthermore, if we look at the operation of CGDlo in detail, lamp 20 (7) light heat? 1 lap 1flTo (!: CCD 10
Since the relationship with the transfer lock period T[ is approximately To=50·Tt, the photosensitive section 11 in the CCD 10 accumulates charge and sends out the accumulated charge at a rate of 50% for one irradiation of the lamp 20. Repeat several times. As the accumulated charges are sent out, the accumulated charges move in synchronization with the vertical clock signal CLv and the horizontal clock signal CLh, and carrier image signals Sv in pixel units are sequentially output from the CCD 10. Here, immediately after the lamp 20 irradiates light once, charges corresponding to the reflected light from the object in the area and the background light are accumulated in the photosensitive section 11 of the C0D10, and when the transfer lock CLt is applied, the charges are accumulated. The accumulated charges are sent out from the photosensitive section 11 all at once. From then on, until the next light irradiation, the charge accumulated in the photosensitive section 11 of the CCD 10 corresponds to the background light, so the transfer lock signal CLt, vertical clock signal CL■, and horizontal clock signal The R image signal S■ outputted from the CCD 10 by the synchronous operation based on each clock signal of CLh corresponds to the background light. Therefore, when light is emitted from the lamp 20 intermittently at the period TO as described above, at that time C
The carrier signal Sv output from the CD 10 includes a component corresponding to the reflected light from the target object only immediately after the light irradiation, and thereafter until the next light irradiation. This corresponds to the background light (see the waveform of the imaging signal Sv in FIG. 2).

On the other hand, the output of MM6 remains at the H level for a predetermined period of time T (+) from the light irradiation time every time the lamp 20 is irradiated with light, and the output of MM6 remains at the H level for a predetermined period of time T (J is set slightly longer than the above-mentioned transfer lock period Tt). , CCD 1 passing through gate circuit 7
The imaging signal SV from 0 is only the one immediately after the light irradiation.

Therefore, the carrier signal storage circuit 16 receives C immediately after the light irradiation.
Imaging signals output from the CD 10 are accumulated. Then, this accumulated imaging signal is transferred to the video signal generation circuit 17 every predetermined period TS in synchronization with the clock signal from the video clock signal generation circuit 15, and after being converted into a predetermined video signal, the video signal is The image based on the display device 18
will be displayed on the screen.

In the vehicle visibility aid device like this embodiment, the lamp 20
Only the visualization signal Sv1 outputted from the C0D10 immediately after the light irradiation from the target object, that is, the 1liilS signal containing a component corresponding to the reflected light from the target object, is displayed on the display device 18.
Since most of the other imaging signals, that is, the 1lil image signal corresponding to the background light, do not contribute to the image, the display device 18 shows a clearer image of the target object. An image will be obtained.

Note that the amount of charge accumulated in each photosensitive section 11 of the CCD 10 is proportional to (intensity of light entering tJ4) x (storage time), so in order to obtain a clearer image, the lamp 20 Increasing the intensity of the light emitted from the CCD10
The accumulation time in each photosensitive section 11, that is, the transfer lock period Tt, is made shorter, and the set time T of MM6 is changed accordingly.
9 should also be shortened. As a result, regarding the signal output from the CCD 10 immediately after light irradiation from the lamp 20, the component corresponding to background light is reduced by the shorter accumulation time, and the reflected light from the target object is reduced. The reduction in the component corresponding to There is a possibility that the charge generated exceeds the allowable amount of C0D10 and blooming occurs in the iq image, so in order to prevent this, it is necessary to shorten the transfer lock period Tt.

FIG. 3 is a diagram showing measures to further reduce the influence of background light.゛This is characterized by placing an optical chic 30 made of PLZT, B501 liquid crystal, etc. in the front part of C0DIO, and a drive circuit 31 transmits light through a shutter 30 in synchronization with the irradiation timing of the lamp 20 mentioned above. state and non-transparent state. As a result, the C0D 10 enters the light receiving state only when the lamp 20 irradiates the light. Therefore, the reflected light from the object irradiated by the lamp 2o passes through the optical shutter 30 as it is, while the continuous background light is reduced by the operation of the optical shutter 30.

In FIG. 3, 32 is a photomultiplier, and 33 and 34 are condensing lenses.

[Effects of the Invention] As explained above, according to the present invention, imaging from a CCD that contributes to an image displayed on a display device (regarding the r This makes it possible to reduce reflected light relative to the corresponding one, so it is possible to eliminate the influence of background light and display scenes more clearly at night in areas that are difficult to see. An auxiliary device can be realized.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the vehicle visibility aid device according to the present invention, Fig. 2 is a timing chart showing the status of each part signal in Fig. 1, and Fig. 3 is a diagram showing the timing chart for further eliminating the influence of background light. FIG. 4 is a diagram showing the basic structure of an interline transfer type CCD image sensor. 1...Reference oscillation circuit 2...Light irradiation signal generation circuit 3...Transfer lock generation circuit 4...Horizontal clock generation circuit 5--Touch clock generation circuit 6...Monostable multivibrator (MM)7...
・Gate circuit 10...CCD image sensor (CCD) 11...
Photosensitive section 12...I correction register 13...Horizontal register 16...Image signal storage circuit 18...Display device 20...Lamp 21...Drive circuit Patent applicant Nissan Motor Co., Ltd. N3 gate, 31

Claims (1)

[Claims] In a vehicle visibility aid device, a CCD image sensor receives light from an area in a predetermined direction with respect to a vehicle, and displays an image on a display device based on an imaging signal in units of pixels output from the CCD image sensor. a light source device that intermittently irradiates light to the region in the predetermined direction at a periodic rate, and a period for transmitting accumulated charge from a photosensitive section in the CCD image sensor is set to be shorter than a light irradiation period of the light source device; Each time light is irradiated from the light source device, a prohibition means is provided for prohibiting an imaging signal output from the CCD image sensor from contributing to an image displayed on the display device after a predetermined period of time has elapsed from the light irradiation time. Features of this vehicle visibility aid device.