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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for watching around a vehicle
and more particularly to an apparatus for allowing a driver within a
vehicle such as an automobile to observe scenes and the like on both left
and right sides of the vehicle.
The present invention also relates to an apparatus for watching around a
vehicle by picking up an image in a dead angle area around the vehicle in
order to display the image within the vehicle.
2. Description of the Related Art
When an automobile approaches an intersection, it will be necessary for a
driver to ensure safety on left and right sides. At any intersection
offering poor lateral visibility, however, the driver has had to cause the
vehicle to enter the intersection zone a little bit so as to make sure of
safety on left and right sides. At that time, the driver needs to pay
careful attention to moving the vehicle into the intersection zone and
also making sure of safety by directly watching scenes on both the left
and right sides after entering the intersection zone, which has mentally
given the driver a burden.
In order to reduce the aforementioned burden, there has recently been
proposed a visual observation apparatus in such a system as to mount an
image pick-up unit on the hood, front grill and bumper of an automobile
and by using the image pick-up unit to take in scenes on left and right
sides of the vehicle so that images about left and right sides thereof may
simultaneously be displayed on a display unit provided within the vehicle.
Moreover, there has also appeared an apparatus for displaying a mask image
that is divided into left and right images in order to improve the
discriminability between the left and right images in a case where the
left and right images are simultaneously displayed on the display unit.
The masking systems disclosed in JP-A-10-104765 have adopted as what marks
off the left image from the right one by compounding each of the left and
right images and a window type mask using a trimming image and as what
limits a range of pick-up visual fields corresponding to the mask
position. The mask area of a mask image has heretofore been displayed in a
single color such as black.
In such a case that the mask area is displayed in a dark color of black or
the like, the drawback is poor visibility in that though the boundary
between the left and right images and the mask image is distinctly
recognized because the left and right images are brightly displayed in the
daytime time zone, a dark portion (black portion) of each of the left and
right images becomes greater in a time zone where the outside of the
vehicle is dark and this makes it difficult to clearly recognize the
boundary between the left and right images and the mask image.
In addition, it will be unnecessary to display both the left and right
sides by means of any display device during normal cruising other than,
for example, entering any intersection providing poor lateral visibility.
In order to reduce power consumption, there has also been proposed an
apparatus for stopping the supply of power to power supply circuits and
image output circuits of the image pick-up unit such as CCD cameras
whenever the vehicle travel speed, or the vehicle speed exceeds a
predetermined level.
In the conventional apparatus for watching around a vehicle, however,
electric power is supplied simultaneously to the power supply switch of an
image pick-up means such as a CCD camera and an image output circuit in
cases where the vehicle is traveling at a predetermined speed or lower,
which results in taking a certain time to start the power supply within
the image pick-up unit such as a CCD camera and to initialize an internal
microcomputer and an LSI; namely, taking as long as about one second.
During this time, the operation of an image signal tends to become
unstable and as a normal signal is not output, a noise image is displayed
in a display unit. The shortcoming is that display quality is
deteriorated.
By the way, an apparatus for watching around a vehicle of the sort
mentioned above is used to watch around a vehicle by causing images around
the vehicle to be displayed during the travel of the vehicle on narrow
streets offering poor visibility. However, the display of such images
becomes unnecessary during the travel of the vehicle offering unobstructed
view. Therefore, it is needed to switch the on and off states of
displaying images around the vehicle by the apparatus for watching around
a vehicle.
Consequently, an operating switch for switching the on and off states of
the display of images around a vehicle is provided in the prior art to
such an apparatus for watching around a vehicle so that a driver may
operate the switch (first prior art).
Further, information on spots with poor visibility is included in car
navigation maps to allow an apparatus for watching around a vehicle to
decide whether the display of images around a vehicle will be needed on
the basis of positional information indicating the present position of the
vehicle by means of the information on spots with poor visibility, GPS and
the like, whereby switching the on and off states of image display can be
conducted automatically (second prior art).
However, the first prior art develops a problem arising from troublesome
operation of switching the on and off states of the display of images
around the vehicle.
With respect to the second prior art, though switching the on and off
states of the display of images around the vehicle is automatically
conducted, information on spots with poor visibility is needed to be
included in the map information. Moreover, the problem is that an
expensive system is also needed to detect the present position of the
vehicle with precision in order to precisely decide whether or not the
display of peripheral images will be needed, which results in increasing
equipment cost.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an apparatus
for watching around a vehicle so designed to improve the visibility of the
boundary between picked-up images and a mask image.
Another object of the present invention is to provide an apparatus for
watching around a vehicle by effectively preventing a noise image from
being displayed on a display unit in order to improve display quality at
the same time.
Still another object of the present invention is to provide a low-cost
apparatus for watching around a vehicle capable of switching the on and
off states of the display of images around a vehicle precisely and
automatically depending on the visibility around the vehicle.
To technically solve the foregoing problems, there is provided an apparatus
for watching around a vehicle according to the invention using an image
pick-up unit to be mounted on the exterior of the vehicle to pick up
images of the surroundings of the vehicle so that the images thus picked
up thereby together with a mask image which is superimposed on the
picked-up images can be displayed on a display unit provided within the
vehicle, which is characterized in that the apparatus for watching around
the vehicle includes a light-to-dark decision unit for deciding the
lightness outside the vehicle; the display color of the mask image is
switchable from one to another; and the display color of the mask image is
set switchable from one to another according to a light-to-dark decision
signal from the light-to-dark decision unit.
The apparatus for watching around a vehicle functions as what picks up both
left and right surroundings of the vehicle, causing the left and right
images thus picked up to be displayed on the display unit separately or
simultaneously, and also displaying the mask image in a manner specifying
the left or right image.
In the apparatus for watching around a vehicle, a plurality of colors
including light and dark colors are provided as the display color of the
mask image, and the display color of the mask image may be switched to the
dark color when the luminous intensity outside the vehicle is decided to
be high through the light-to-dark decision signal, and to the light color
when the luminous intensity outside the vehicle is decided to be low
therethrough.
In the apparatus for watching around a vehicle, the light-to-dark decision
unit has a lamp lighting circuit mounted on the vehicle, and the
light-to-dark decision signal includes a light-on and a light-off signal
of the lamp lighting circuit, thereby to switch the display colors of the
mask image when the luminous intensity outside the vehicle is decided to
be high by the light-off signal or when the luminous intensity outside the
vehicle is decided to be low by the light-on signal.
A means of technically solving the foregoing problems by an apparatus for
watching around a vehicle using an image pick-up element to be mounted in
the vehicle to pick up images on both the left and right sides of the
surroundings of the vehicle and displaying the left and right images thus
picked up on a display unit provided within the vehicle via an image
control unit, wherein the image control unit may comprise an image pick-up
element power switch for turning on and off the operating circuit of the
image pick-up element, an image output signal switch for turning on and
off an image output circuit for subjecting an image signal picked up by
the image pick-up element to a conversion process and supplying the
converted image signal, and a switch control portion having the upper
threshold speed of vehicle speed for turning on and off the image pick-up
element power switch and a lower threshold speed of the vehicle speed for
turning on and off the image output signal switch and wherein the image
pick-up element power switch may be turned on by the switch control
portion when it is detected that the vehicle speed reaches the upper
threshold speed during the time of speed reduction and the image output
signal switch is turned on by the switch control portion when it is
detected that the vehicle speed reaches the lower threshold speed during
the time of speed reduction.
An apparatus for watching around a vehicle may be such that the image
pick-up element power switch as well as the image output signal switch is
turned off by the switch control portion when it is detected that the
vehicle speed reaches the lower threshold speed.
An apparatus for watching around a vehicle may be such that the image
control unit includes a display unit power switch for turning on and off
the operating circuit of the display unit, wherein the display unit power
switch and the image pick-up element power switch are turned on and off in
synchronization with each other by the switch control portion.
In order to technically accomplish the object above, an apparatus for
watching around a vehicle by picking up images of dead angle areas around
the vehicle to display the images within the vehicle, comprises: an image
pick-up unit for picking up images of dead angle areas around the vehicle;
a display unit for displaying the images picked up by the image pick-up
unit; a distance measuring unit for detecting the distance between the
vehicle and an obstacle so positioned as to obstruct the view of a driver
on at least one side out of both sides of the vehicle during the travel of
the vehicle; and a controller for deciding whether or not the display of
the image on the display unit will be needed on the basis of the distance
detected by the distance measuring unit and controlling the display unit
over switching the on and off states of display according to the decision
made thereby.
Preferably, the apparatus for watching around a vehicle is such that the
distance measuring unit detects the distance between the vehicle and each
of the obstacles positioned on both the left and right sides of the
vehicle during the travel of the vehicle; and the controller detects a
space between the left- and right-hand obstacles on the basis of the
distance between the vehicle and each of the left- and right-hand
obstacles detected by the distance measuring unit, regards the space as
width of a road on which the vehicle is traveling, decides whether or not
the display of the image on the display unit will be needed on the basis
of the value of the width thereof, and controls the display unit over
switching the on and off states of display according to the decision made
thereby.
Preferably, the apparatus for watching around a vehicle further comprises a
travel-condition detector for accepting at least one vehicle signal for
making reduced vehicle speed detectable out of vehicle signals indicating
travel conditions which are output from a plurality of vehicle portions,
and detecting the reduced vehicle speed according to the one vehicle
signal, wherein the controller decides whether or not the display of the
image on the display unit will be needed on the basis of the width of the
road detected by the distance measuring unit and the result detected by
the travel-condition detector, and controls the display unit over
switching the on and off states of display according to the decision made
thereby.
Preferably, the apparatus for watching around a vehicle further comprises a
travel-condition detector for detecting vehicle speed by accepting a
vehicle signal indicating vehicle speed, wherein the controller decides
that the display of the image by the display unit will be needed only in
case where the width of the road detected by the distance measuring unit
is equal to a predetermined reference distance or less and where the
vehicle speed detected by the travel-condition detector is a predetermined
reference speed or lower, and causes the image to be displayed on the
display unit.
Preferably, the apparatus for watching around a vehicle is such that the
image pick-up unit is installed in the front end portion of the vehicle
and used to pick up images in left and right directions in front of the
vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an external perspective view of an apparatus for watching around
a vehicle applied to an automobile according to a first embodiment of the
invention.
FIG. 2 is an overall block diagram descriptive of the whole apparatus for
watching around the vehicle above.
FIG. 3 is an overall block diagram descriptive of an apparatus for watching
around a vehicle according to a second embodiment of the invention.
FIG. 4 is a block diagram of an overall system embodying the invention.
FIG. 5 is a flowchart showing the operation during speed reduction.
FIG. 6 is a flowchart showing the operation during speed acceleration.
FIG. 7 is a flowchart showing the operation at the initial stage of
starting.
FIG. 8 is a block diagram showing the configuration of an apparatus for
watching around a vehicle according to a fourth embodiment of the present
invention.
FIG. 9 is a diagram showing the travel-condition of a vehicle on a road
with the apparatus for watching around a vehicle of FIG. 8.
FIG. 10 is a diagram showing the travel-condition of a vehicle on a road
with the apparatus for watching around a vehicle of FIG. 8.
FIG. 11 is a flowchart showing the principal control contents of the
control unit 211.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention will be described in detail with reference to the
accompanying drawings.
First Embodiment
A first embodiment of the present invention will be described with
reference to the drawings. As shown in FIGS. 1 and 2, an apparatus for
watching around an automobile as a vehicle, for example, comprises an
image pick-up unit 3 installed beneath a front bumper or the like, a
display unit 4 formed with an LCD (Liquid Crystal Display), a CRT or the
like provided in a position on an instrument panel or the like within the
vehicle where it is easily visible to a driver, an image signal processing
portion 5 for converting the image signal picked up by the image pick-up
unit 3 to a predetermined display signal and supplying to the display unit
4 the display signal, a mask addition processor 6 for adding (so-called
superimposing) a predetermined mask image 16 by the image signal
processing portion 5 onto the display signal and supplying the mask image
16 to the display unit 4, and a photodiode 7 as a light-to-darkness
decision unit for detecting the luminous intensity outside the vehicle.
The image pick-up unit 3 includes a rectangular case body 10 extending
along the longitudinal direction of the automobile 1, a pair of lateral
transmission windows 11 and 12 of transparent glass fitted to the
rectangular opening formed and positioned on both the respective front
side openings of the case body 10, a CCD camera 13 as a single image
pick-up portion disposed in the case body 10, and a prism body 14 for
guiding light onto the image pick-up surface of the CCD camera 13 by
reflecting the light introduced through the transmission windows 11 and
12.
As shown in FIG. 2, light entering from the left transmission window 11 is
reflected by the prism body 14 and guided to the right half of the image
puck-up surface of the CCD camera 13, whereas light entering from the
right transmission window 12 is reflected by the prism body 14 and guided
to the left half of the image pick-up surface of the CCD camera 13, so
that both the left and right scenes are simultaneously picked up by the
single CCD camera 13.
The image signal picked up by the CCD camera 13 is subjected to a mirror
image inversion process in the image signal processing portion 5 and
supplied to the display unit 4. During the supply of thus processed image
signal from the image signal processing portion 5 to the display unit 4,
further, the predetermined mask image 16 is added thereto in the mask
addition processor 16 and supplied to the display unit 4. In outer
peripheral and central portions in the display portion 4a of the display
unit 4, the window frame type mask image 16 is displayed. The right-hand
side scene picked up through the transmission window 12 is displayed in
the right frame of the mask image 16, whereas the left-hand side scene
picked up through the transmission window 11 is displayed in the left
frame of the mask image 16. In this case the left and right images are
displayed on the right and left sides of the display unit 4 by the display
unit 4.
The mask addition processor 6 supports two kinds of display colors
including blue as a light display color to be added to the mask image 16
and black as a dark display color to be added thereto. These colors are so
controlled that they are switched according to a brightness signal as a
light-to-darkness decision signal from the photodiode 7.
A predetermined threshold value has been set as the brightness signal, for
example, and in a case where the brightness signal has a threshold value
or greater, the black color is added to the mask image 16. In a case where
the brightness signal has a threshold value less than the threshold value,
that is, the outside of the vehicle is dark and has not predetermined
lightness, the light blue color is added to the mask image 16.
The apparatus for watching around the automobile 1 is arranged so that the
left and right scenes may simultaneously be taken in at an intersection
offering poor lateral visibility from each of the transmission windows 11
and 12 of the image pick-up unit 3 by causing only the front bumper 2 of
the front end portion of the automobile 1 to enter the intersection. As
the scene divided into the left and right images is displayed on the
display portion 4a of the display unit 4 within the vehicle, the driver is
allowed to readily confirm the safety on both left and right sides at the
intersection by looking at the display portion 4a.
At this time, the mask image 16 is provided with a plurality of display
colors including blue and black. Then the photodiode 7 detects the
lightness whereby to have a black mask image 16 added and displayed while
the ambience is light in the daytime and to have a blue mask image 16
added and displayed while the ambience is dark at night. Consequently,
irrespective of lightness outside the vehicle, the boundary between the
picked-up left and right images and the mask image 16 is clearly
recognized and this makes it possible to specifically distinguish between
the left and right images. Thus, the visibility is improved.
Although the mask image 16 of a two-stage switching structure including two
kinds of black and blue display colors has been referred to according to
this embodiment of the invention, a system of automatically switching more
than two stages with multicolors including various light and dark colors
to be displayed on the mask image 16 depending on the outside luminous
intensity may be adopted. Further, any system of successively changing the
brightness of the mask image 16 depending on the outside luminous
intensity may also be adopted. In these cases, a display color of the dark
color system may be employed while the luminous intensity outside the
vehicle is high, whereas a display color of the light color system may be
employed while the luminous intensity outside the vehicle is low.
Although blue and black have been employed as the light color and dark
color respectively, the invention is not limited to these colors but may
be adapted to use any one of the display colors as long as the visibility
is secured depending on the lightness outside the vehicle.
Although the invention is so configured as to have the photodiode 7 as a
light-to-dark decision unit for detecting the lightness outside the
vehicle, any one of the luminous intensity detecting unit may be employed.
Second Embodiment
FIG. 3 shows a second embodiment of the invention, wherein like reference
characters designate like components in the first embodiment thereof.
The second embodiment of the invention is so configured as to utilize a
lamp lighting circuit 18 for a headlamp and a small lamp mounted on a
vehicle in place of the photodiode 7 according to the first embodiment of
the invention as the light-to-darkness decision unit for detecting the
lightness outside the vehicle. In this case, ON/OFF of the lamp in the
lamp lighting circuit 18, that is, a lamp-on or a lamp-off signal is used
as the light-to-dark decision signal. The mask image 16 having the two
kinds of blue and black display colors respectively as light and dark
colors is so controlled as to switch the lamp-on and lamp-off signals.
According to the second embodiment of the invention, the black mask image
16 is added in a case where a signal from the lamp lighting circuit 18 is
the light-off signal, that is, the outside of the vehicle has a
predetermined lightness or greater as in the daytime and the lighting of
the lamp is decided to be unnecessary. On the other hand, the light blue
mask image 16 is added in a case where a signal from the lamp lighting
circuit 18 is the light-on signal, that is, the outside of the vehicle is
dark enough not to reach the predetermined lightness at night and the
lighting of the lamp is decided to be necessary.
With the second embodiment of the invention thus arranged, the system of
automatically switching the display colors of the mask image 16 according
to whether the light-or light-off signal sent from the lamp lighting
circuit 18 is like this. The black mask image 16 is added and displayed in
the daytime when the lighting of the lamp is unnecessary, whereas the
light blue display color is added and displayed at night when the lighting
of the lamp is necessary. Thus, irrespective of lightness outside the
vehicle, the boundary between the picked-up left and right images and the
mask image 16 is clearly recognized and this contributes to improving the
visibility.
The second embodiment of the invention is advantageous in that the lamp
lighting circuit 18 installed in the vehicle is utilized without specially
providing any photodiode 7, thus making the structure of the apparatus for
watching around the vehicle can be simplified.
Incidentally, though the image pick-up unit 3 is installed in the front
portion of the vehicle, it may be installed in the rear of the vehicle.
Although the mask area of the mask image 16 has been formed like a window
frame, it may be so configure as to provide left and right partitioned
areas existing in the at least central portion even though any mask area
does not exit along the outer periphery of each of the left and right
images.
Further, though each of the embodiments of the invention teaches a
structure wherein a so-called window frame type mask area to be
synthesized into and displayed on the display unit 4 as the superimposed
mask image 16, the picked-up left and right images may be displayed
separately. At this time, the superimposed image 16 may be displayed with
discriminating characters of (L) and (R) respectively designating left and
right for specifying the left and right sides. Even in this case, the
image individually displayed can be recognized as the right-side image or
left-side one.
Moreover, though the single CCD camera 13 has been used to pick up images
on both the left and right sides of the vehicle, pick-up unit for
separately picking up left and right scenes may be provided.
Third Embodiment
A third embodiment of the present invention will be described with
reference to the drawings. As shown in FIGS. 1 and 4, an apparatus for
watching around an automobile as a vehicle, for example, comprises a
camera unit 103 as an image pick-up unit installed beneath a front bumper
or the like, a display unit 104 formed with an LCD, a CRT or the like
provided in a position on an instrument panel or the like with the vehicle
where it is easily visible to a driver, and an image control unit 105 for
subjecting the image pick-up signal in the camera unit 103 to a conversion
process and supplying the converted signal to the display unit 104.
The camera unit 103 includes a rectangular case body 110 extending along
the longitudinal direction of the automobile 101, a pair of lateral
transmission windows 111 and 112 of transparent glass fitted to the
rectangular opening formed and positioned on both the respective front
side openings of the case body 110, a CCD camera 111 as a single image
pick-up element disposed in the case body 110, and a prism body 112 for
guiding light onto the image pick-up surface of the CCD camera 111 by
reflecting the light introduced through the transmission windows 111 and
112.
As shown in FIG. 4, light entering from the left transmission window 11 is
reflected by the prism body 112 and guided to the right half of the image
puck-up surface of the CCD camera 111, whereas light entering from the
right transmission window 112 is reflected by the prism body 112 and
guided to the left half of the image pick-up surface of the CCD camera
111, so that both the left and right scenes are simultaneously picked up
by the single CCD camera 111.
The imagepick-up signal from the CCD camera 111 is subjected to a mirror
image inversion process in the image control unit 105 and supplied to the
display unit 104. The right-hand side scene picked up through the right
transmission window is displayed in the right half portion of the display
unit 104 as a right image, whereas the left-hand side scene picked up
through the left transmission window is displayed in the left half portion
thereof.
The image control unit 105 includes a camera power switch 114 as the image
pick-up element power switch for turning on and off the actuating circuit
of the CCD camera 111, a video signal switch 115 as the image output
signal switch for subjecting the image pick-up signal to a predetermined
converting process and supplying the converted signal to the display unit
104 as video signal, a display unit power switch 116 for turning on and
off the actuating circuit of the display unit 104, and a switch control
portion 117 for controlling the on and off of the camera power switch 114,
and the video signal switch 115 and the display unit power switch 116.
In the switch control portion 117, there are set an upper threshold speed
Va of the vehicle speed for controlling the on and off in synchronization
with the on and off of the camera power switch 114, and a lower threshold
speed Vb of the vehicle speed for controlling the on and off of the video
signal switch 115; in this case, Va>Vb. The upper and lower threshold
values Va and Vb may be set at 20 km/h and 10 km/h, respectively, on the
assumption that while it takes one second or greater to reduce the vehicle
speed from 20 km/h up to 10 km/h during traveling in an urban area, the
operation of starting the CCD camera 111 as well as the display unit 104
is sufficiently stably performable within that time.
The switch control portion 117 also functions as what decides whether the
vehicle speed will be increased or decreased by detecting a pulse signal
corresponding to the vehicle speed via a vehicle speed sensor 119 of the
vehicle and calculating the vehicle speed from the period of the signal.
A description will be given of the operation of the switch control portion
117 when the vehicle speed is reduced as it is coming near to the
intersection with reference to a flowchart of FIG. 5.
First, it is decided whether or not the present vehicle speed will be
higher than the upper threshold speed Va (Step S1). In case where the
former is higher than the latter, Step S2 is followed. Then the camera
power switch 114, the video signal switch 115 and the display unit power
switch 116 are held OFF.
The vehicle speed is reduced further and when vehicle speed V reaches the
upper threshold speed Va or lower, Step S3 is followed and an ON control
signal is applied from the switch control portion 117 to each of the
camera power switch 114 and the display unit power switch 116. The camera
power switch 114 and the display unit power switch 116 are controlled so
that both may be turned on in synchronization with each other. At this
time the video signals witch 115 are held OFF. Consequently, the video
signals of the left and right images picked up by the CCD camera 111 are
not applied to the display unit 104 at this time, whereupon no images are
displayed on the display unit 104.
Then Step S4 is followed and whether or not the vehicle speed V will be
higher than the lower threshold speed Vb is decided and in case where the
former is higher than the latter, Step S3 is followed again.
In case where the vehicle speed V is reduced further to the lower threshold
speed Vb or lower, Step S5 is followed and while the camera power switch
114 and the display unit power switch 116 are both held ON, the ON control
signal is applied from the switch control portion 117 to the video signal
switch 115, whereby the video signal switch 115 is turned on. In this
case, the video signals of the left and right images are applied to the
display unit 104 and the left and right images are simultaneously display
on the display unit 104. As the driver is allowed to confirm safety on the
left and right sides within the intersection zone all at once by looking
at the display portion of the display unit 104; thus, safety is easily
confirmable.
The operation of the switch control portion 117 will be described with
reference to a flowchart of FIG. 6 in case where a normal travel condition
is restored by acceleration after the vehicle in the reduced speed
condition passes through the intersection zone.
First, it is decided whether or not the present vehicle speed will be lower
than the lower threshold speed Vb (Step S11). In case where the former is
lower than the latter, Step S12 is followed. At step S12, the camera power
switch 114, the video signal switch 115 and the display unit power switch
116 are held ON, so that the left and right images are being displayed.
The vehicle speed is increased further and when vehicle speed V reaches the
upper threshold speed Va or higher, Step S13 is followed and an OFF
control signal is applied from the switch control portion 117 to each of
the display unit power switch 116 and the video signal switch 115. The
camera power switch 114, the display unit power switch 116, and the video
signal switch 115 are controlled so that they may be turned off in
synchronization with one another. Then the display of the left and right
images on the display unit 104 is stopped.
As described above, according to this embodiment of the invention, the
vehicle speed is reduced from the normal travel condition to the upper
threshold speed Va or lower, the power is supplied to turn on the CCD
camera 111 and the display unit 104. After the passage of the
predetermined time until the operation of the CCD camera 111 as well as
the display unit 104 is stabilized, the video signal switch 115 is then
turned on in this system. A noise image disturbance at the initial stage
of the rise of the CCD camera 111 is effectively prevented from being
displayed and display quality is made improvable.
When the display unit 104 is not needed to make display after the normal
travel condition is restored by acceleration, the supply of power to the
CCD camera 111 and the display unit 104 is totally stopped, whereby the
power is supplied to the CCD camera 111 and the display unit 104 only
during the time watching around the vehicle is needed. It is thus possible
to implement power saving effectively.
FIG. 7 is a flowchart showing the rise of the peripheral watching unit when
the engine of the automobile 101 is started, for example, in case where it
is started from a garage. The vehicle power supply is turned on by
pivoting an engine key from an OFF position to an ACC position (or the ON
position) (Step S21) for shifting to Step S22. The ON control signal is
applied from the switch control portion 117 to the camera power switch 114
and the display unit power switch 116 first. Then the camera power switch
114 and the display unit power switch 116 are controlled so that both are
turn on in synchronization with each other. At this time, the video signal
switch 115 is held OFF. Therefore, the video signals of the left and right
images picked up by the CCD camera 111 are not applied to the display unit
104 and no images are displayed on the display unit 104.
Further, it is decided whether or not a preset fixed time (ex., about one
second) necessary for stabilizing the operation of the CCD camera 111 and
the display unit 104 is passed (Step S23). Upon the passage of the
predetermined time, Step S24 is followed and after the camera power switch
114 and the display unit power switch are both turned on, the ON control
signal is applied from the switch control portion 117 to the video signal
switch 115 so as to hold ON the video signal switch 115. Then the video
signals of the left and right signals picked up by the CCD camera 111 are
applied to the display unit 104, so that the left and right images are
simultaneously displayed on the display unit 104.
During acceleration and deacceleration, the apparatus for watching around
the vehicle is operated in accordance with the flowcharts shown in FIGS. 5
and 6.
Although a system of taking in the left and right images by the single
camera unit has been shown according to this embodiment of the invention,
a CCD camera 111 for taking in the left and right scenes of images may be
so arranged as to be disposed on both left and right sides separately.
The upper and lower threshold speeds Va and Vb may properly be set in order
to secure a time necessary for stabilizing the operation of the CCD camera
111 as well as the display unit 104.
Although an arrangement of turning on and off the CCD camera 111 and the
display unit 104 is in synchronization with each other, the display unit
104 may be turned on and off independently. In this case, it is only
needed to hold ON the display unit 104 beforehand. The rest of the
operations may be performed as shown in FIGS. 5 and 6.
Fourth Embodiment
FIG. 8 is a block diagram showing the configuration of an apparatus for
watching around a vehicle according to a fourth embodiment of the present
invention. FIGS. 9 and 10 are diagrams each showing the travel-condition
of a vehicle on a road with the apparatus for watching around a vehicle of
FIG. 8.
As shown in FIG. 8, the apparatus for watching around a vehicle comprises a
camera (an image pick-up unit) 201, a display (a display unit) 203, a
distance measuring sensor (a distance measuring unit) 205, a
travel-condition detecting portion (a travel-condition detector) 207, a
power switch 209, and a control unit (a controller) 211.
As shown in FIG. 10, the camera 201 is installed in the front end portion
of the vehicle and used to pick up images in image pick-up areas (dead
angle areas) 213 and 215 on the left and right sides in front of the
vehicle. The display 203 is installed in a position visible to a driver in
the vehicle and used to display the image picked up by the camera 201 or a
car navigation image in case where the vehicle is equipped with a car
navigation unit. The power switch 209 is a switch for turning on and off
the apparatus for watching around a vehicle.
As shown in FIG. 9, the distance measuring sensor 205 is installed on both
the left and right sides of the front end portion of the vehicle and used
to detect not only the presence or absence of obstacles on both the left
and right sides of a road 221 during the travel of the vehicle but also
distances up to the respective obstac | | |
