Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INyENTION
Field of the In~ention
The present invention relates generally to an object
inspection systems, and more particularly to a new object in-
spection system of the type that takes the photo image of an
object to be inspected by a photo image sensing device.
Description of the Prior Art
Inspection systems for very small objects that are
transferred by such means as belt conveyers under the prior
art normally conduct insPection by microscopic magnification
cf the inspected object.When the inspected object is very
small, it is difficult to accurately detect whether or not the
inspected object is transferred to a predetermined detecting
position with high precision. Under the prior art, the
arrival of the object to the predetermined detecting position
is detected by a photo switch, proximity swltch, etc. ~hen the
inspected object is very small, there are various points of
; ~ inconvenience.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic diagram showlng an object
recognition system under the prior art;
~ Fig. 2 is a block diagram showing an example of the
`~ object recognition system according to the present invention;
Figs. 3A, 3B and 3C are schematic diagrams used to
explain the present inyention; and
Figs. 4A and 4B, Figs. 5A and SB and Pigs. 6A and 6B
are waveform diagrams used to explain the present invention.
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In order to o~ercome such inconveniences, object position
detection systems are proposed where photo sensors are in-
stalled on the monitor screen on which inspected objects are
projected. Such systems will be now explained in reference to
Fig. 1. In the system under the prior art shown on Fig. 1, 1
is a belt on which an object 2 to be inspected is transferred
in the direction indicated by an arrow 3. At a predetermined
position in connection with belt 1, a photo image sensing
equipment such as a television camera or the like 4 is in-
stalled which photo magnifies the inspected object 2. 5 is a
monitor screen of the photo image sensing system 4 on which,
at a predetermined position, a photo sensor 6 is installed in
order to detect the positioning of the inspected object 2.
In Figure 1, the hatched block is an image 7 of the inspected
object 2 on the belt 1 that is projected on the black back-
ground of monitor screen 5. Object 2 moves on the monitor
screen 5 in the direction indicated by an arrow 8 towards
sensor 6. When image 7, for instance, overlaps sensor 6, ; ~ -
sensor 6 generates a start signal which is supplied to an
object inspection or recognition system 9 such as a computer
or the like to conduct the specified inspection of the object
2. However, according to the shape and dimensions of the
inspected object 2 or the position thereof on belt 1, for
instance, when the image 7 of the inspected~object 2 as shown
on Fig. 1, is in the position shown by brokén like block 10
and moves in the arrow direction 8 on monitor screen 5, image
10 does not~ovexlap sensor 6. Therefore, the inspection
system 9 does not start its inspection operation and hence
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inspection of the object 2 is not conducted. This type of
problem can occur even though the sensor 6 is installed with
due considerations to the scan direction of the television
camera 4 and the transfer direction of the inspected object 2.
Further, from the functional standpoint of television
camera 4, since the position detection of the inspected object
2 is at intervals of 16.7 milliseconds, the positioning detec-
tion shall inevitably vary or scatter within 16.7 milliseconds.
It is further noted that non action may also be caused
by trouble in the monitor television receiver, or upon a de-
crease of brightness thereof. In addition, the monitor tele-
vision receiver is constantly in motion so that its life may
be shortened.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, an objective of the present invention is
to provide a novel object recognition system, whi~ch avoids the
above mentioned defects of systems under the prior art.
~` Another object of the invention is~to provlde an object
recognition system which can positively inspect an object in
a short time. ~
; More particularly there is provided an object inspection
system comprising:
a) a photo image sensing device picking up an object to
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be inspected and delivering a complex video signal having at
least a horizontal synchronizing signal, a vertical synchroniz~
ing signal and a video signal;
b) means for separating said horizontal and vertical
synchronizing signals and sald video signal from said complex
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video signal;
c) means for producing a comparative control signal
based upon the horizontal and vertical synchronizing signals;
d) means for generating a reference signal which is
responsive to a characteristlc of said video signal;
e) means for comparing the video signal with the
reference signal only within a period determined by the com-
parative control signal and for producing an inspection start
signal; and
f) means for inspecting said object when the inspection
start signal is supplied thereto.
. There is also provided:
An object inspection system for inspecting an object
comprising: .
means for producing a complex video signal of said
object and its background, said complex vldeo signal including
at least a horizontal and a vertical synchronizing signal and
a video signal;
means responsive to said horizontal and vertical
synchroni7.ing signals to produce a comparison start signal;
~ means responsive to said background for producing
::~ a reference signal;
means for comparing said video signal and said
-: reference signal in response to said comparison start signal
to detect a presence of said object in said video signal,
operative to produce an inspection start signal in response
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to said comparison; and
means for inspecting said object in response to
said inspection start signal.
The other objects, features and advantages of the
present invention will become apparent from the following
description taken in conjunction with the accompanying drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will hereinafter be explained in
reference with Figs. 2 through 6.
Fig. 2 is a block diagram showing an example of the
object recognition system according tothe present invention.
On Fig. 2, 11 designates a synchronizing signal separator cir-
cuit, which separates the complex video signal input from the
television camera or the like of the photo image sensing
system 4 which photographs an object to be inspected (not
shown on the Fig. 2), into a hori~ontal synchronizing signal
h, a vertical synchronizing signaI v and a video signal s,
respectiYely. The yertical synchronizing signal Y that is
separated by the synchronlzing signal separator circuit 11 is
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supplied to a timing control circuit 12~ A strobe signal stv
is produced by the timing control circuit 12 based upon the
vertical synchronizing signal v. This strobe signal stv which
specifies the vertical position of the detection area on the
monitor screen of a monitor tele~ision receiver as later
explained, is supplied to a strobe circuit 14.
The horizontal synchronizing signal h is supplied to a
timing control circuit 13. The timing control~circuit 13
produces a strobe signal sth based upon the horizontal syn-
chronizing signal h. Strobe signal sth specifies the hori-
zontal position of the detection area on the monitor screen
as later described. Strobe signal sth is supplied to the
strobe circuit 14. Strobe circuit 14, combines strobe
signals stv and sth respectively to produce a composite strobe
signal or a comparative control signal cst which specifies the
hori~ontal as well as the vertical position of the detection
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~; area on the monitor screen. Comparative control signal cst
is supplied to a comparator 16. At the time defined as
specified by the composite strobe signal~cst, m other words,
only at the specified position on the monitor screen, the
video signal s is compared with a reference signal which is
representative of the brightness level on the monitor screen
provlded from a level control or reference signal generator
15. The output of comparator 16 is supplied to a monostable
multivibrator circuit 17 which includes a retriggerable mono~
stable multivibrator having a time width of, for instance, 63
microseconds minimum. In~response to an input, the monostable
; multivibrator circuit 17~generates an inspection start signal
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sta. Inspection start signal sta is supplied to an inspection
system 18 for inspecting the object such as a computer as well
known, although it is not sho~n on Fig. 2, inspection of the
object is conducted. This inspection of the object can be
monitored on a monitor screen 19 of a monitor television
receiver which receives the output video signal from the tele-
vision camera 4.
According to the above described construction of the
object recognition or inspection system according to the
present invention the following inspection of the object is
carried out. If, it is assumed that the monitor screen 19 has
a black background, for instance, and an object 21 to be in-
spected is white as shown on Fig. 3A. When an object 21 to be
inspected arrives at a detection area 20 whose position is
specified on the monitor screen 19 by the comparative control
signal cst, the comparator 16 outputs a compared output by
which the monostable multivibrator circuit 17 generates the
start signal sta, and the inspection of the object 21 to be
inspected is conducted by the inspection system 18.
Furtner, in order to establish the detection area 20
as indicated on Fig. 3A, it is sufficient that the timing con-
trol circuit 12 so functions that the output signal stv from
the timing control circuit 12 by the vertical synchronizing
signal v shall be arranged as indicated on Fig. 4A and the
timing control circuit 13 so functions that the output signal
sth from the timing control circuit 13 by the horizontal
synchronizing signal h shall be arranged as indicated on Fig.
4B. By the present invention as above described, it is not
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necessary to provide a special photo optical sensor on the
monitor screen 19 as in the case with the prior art, and since
the detection area 20 is specified as a free determination
based upon the horizontal as well as vertical synchronizing
signals h and v from the photo image sensing system, the moni-
tor television receiver is not directly necessary for the
detection action. However, the monitor is only necessary in
order to confirm the position of the object to be inspected
and so on at the inspection starting time. Accordingly,
inspection can not only be conducted without such influence
of the monitor screen becoming difficult to observe, or the
brightness drop of the monitor screen, or further monitor
trouble, but since it does not have to be constantly operated,
the life of the monitor television receiver can be preserved
for longer periods. In other words, the conventional defects
as above mentioned can be almost entirely avoided by this
invention. ~ -
Further, as shown on Fig. 3B as an example, when theobject 21 moves in the direction indicated by an arrow 22 to
the left on the monitor screen 19, as indicated on the drawing, ~
by setting the detection area 20 narrow and long in the ver- ~;
tical direction on the~monitor screen 19, the object 21 can
be surely detected in spite of its position being high or low,
and the blank period for detection can be greatly reduced.
In order to establish the detection area 20 as
illustrated on Fig. 3B, the timing control circuit 12 so
fu~ctions such that the output signal stv from the timing
control circuit 12 by the vertical synchronizing signal v
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shall be as shown on Fig. 5A, and the timing control circuit
13 functions such that the output signal sth from the timing
control circuit 13 produced by the horizontal synchronizing
signal h shall be established as per Fig. 5B. Thus a short
horizontal segment of a large nu~ber of vertical llnes is
defined by the signal cst.
Also as illustrated on Fig. 3C, when the object 21 moves
vertically up and down on the monitor screen 19 as indicated
by an arrow 23, by establishing the detection area 20 narrow
and long in horizontal direction on monitor screen 19 as shown
on the drawing,in spite of the object 21 being mispositioned
to the right or left, it can be surely detected. In order
to establish the detection area 20 as shown on Fig. 3C, it is
sufficient that the timing control clrcuit 12 functions such
that the output signal stv from the timing control circuit 12
by the vertical synchronizing signal shall be set as shown on
Fig. 6A and the timing control circuit 13~functions such that
the output signal sth fxom the timing control circuit 13 by
the horizontal synchronizing signal h shall be set as shown on
Fig. 6B.
It is further noted that only a single preferred
example of the present invention has been explained in refer-
ence to the furnished drawings, but without losing the spirit
of the present invention, variations and changes are
obviously possible by any one skilled in the art.
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