Television – Camera – system and detail – Solid-state image sensor
Reexamination Certificate
1998-02-09
2003-08-05
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Solid-state image sensor
C348S314000, C348S322000
Reexamination Certificate
active
06603512
ABSTRACT:
TECHNICAL FIELD
This invention relates to an imaging apparatus for Factory Automation (FA) suitable for carrying out imaging operation of, e.g., object moving at high speed, and a control device therefor.
BACKGROUND ART
The applicant of this application has proposed, in the Japanese Patent Application Laid Open No. 119776/1992, an imaging apparatus having electronic shutter function, which is adapted for controlling charge storage time of a solid-state image pick-up device (CCD image sensor) of the IT (Interline Transfer) type to thereby carry out exposure time adjustment without use of mechanical iris. In this imaging apparatus, the shutter speed can be changed in dependency upon movement of object by using the electronic shutter function. This imaging apparatus is advantageous particularly in taking thereinto picture image in high speed moving body.
In such an imaging apparatus, e.g., used mainly for FA and adapted for carrying out image pick-up operation of moving object, e.g., a configuration as shown in
FIG. 1
is employed. When an object
201
moving on a movement path
200
has moved to the front portion of an image pick-up section
202
, a position detecting section
203
detects this to deliver, to a shutter signal generating circuit
204
, a trigger signal which falls to low level at time t
11
of FIG.
2
(
a
).
The shutter signal generating circuit
204
is operative so that when the trigger signal is delivered thereto, it delivers, to a CCD control circuit
205
, a shutter signal which rises at time t
11
of FIG.
2
(
b
). The CCD control circuit
205
is operative so that when the shutter signal is delivered thereto, it stops supply of a shutter control signal for sweeping out electric charges (hereinafter simply referred to as charges) stored at the photo-electric converting section of the CCD image sensor
206
into the overflow drain. Thus, effective charges begin to be stored into respective pixels of the photo-electric converting section of the CCD image sensor
206
.
The CCD control circuit
205
is supplied with a vertical synchronizing signal which falls at time t
11
and rises at time t
12
of FIG.
2
(
c
) and a horizontal synchronizing signal shown in FIG.
2
(
d
) from a synchronizing signal generating circuit
207
. The CCD control circuit
205
is operative so that when the shutter control signal is delivered thereto, it carries out nine (9) count operations of pulses (i.e. counts nine (9) pulses) of the horizontal synchronizing signal shown in FIG.
2
(
d
) from the time t
11
at which the vertical synchronizing signal shown in FIG.
2
(
c
) falls thereafter to carry out several hundred count operations of clock pulses thereafter to deliver a read-out signal to the CCD image sensor
206
at time t
13
shown in FIG.
2
(
e
).
Thus, for a time period from the time when the shutter control signal is delivered to the CCD image sensor
206
at time t
11
of FIG.
2
(
b
) until the read-out signal is delivered to the CCD image sensor
206
at time t
13
of FIG.
2
(
e
), charges corresponding to image pick-up light irradiated through an imaging (image pick-up) lens
208
are stored in the CCD image sensor
206
. The time period from the time t
11
to the time t
13
is charge storage time.
In this case, FIG.
2
(
f
) indicates vertical blanking period VBLK.
The charges which have been read out from the CCD image sensor
206
are delivered to a signal processing circuit
209
as an image pick-up signal. The signal processing circuit
209
implements, to the image pick-up signal, a signal processing to add synchronizing signal, etc. to output it as a video signal through an output terminal
210
. The video signal outputted through the output terminal
210
is delivered to, e.g., monitor. Thus, it is possible to analyze the state of the object
201
in the case where the object
201
is caused to be moved.
Since such an imaging apparatus for carrying out image pick-up operation of moving object is mainly used for FA, there are instances where the object
201
shown in
FIG. 1
is caused to be moved at high speed and imaging is desired to be carried out by high speed shutter, e.g., 1/10000 sec. etc.
However, in the above-mentioned imaging apparatus, nine count operations of pulses of the horizontal synchronizing signal are carried out from, e.g., falling of the vertical synchronizing signal thereafter to deliver a read-out signal to the CCD image sensor at the timing when several hundreds of clock pulses have been counted. Namely, the output timing of the read-out signal is fixedly set in advance on the basis of the pixel arrangement of the CCD image sensor.
Accordingly, the charge storage time of the imaging apparatus could not be shortened down to a value required from the falling time of the vertical synchronizing signal to the time when the read-out signal is outputted. For this reason, the conventional imaging apparatus did not carry out image pick-up operation by high speed shutter such as 1/1000 sec., etc.
The imaging apparatus starts storage of effective charges in dependency upon trigger signal delivered from the position detecting section
203
as described above. Namely, the imaging apparatus becomes operative in dependency upon the timing of the trigger signal delivered from the position detecting section
203
. When a trigger signal is delivered at an arbitrary timing as shown in FIG.
3
(
a
), for example, the imaging apparatus delivers a read-out signal shown in FIG.
3
(
b
) to the CCD image sensor after a predetermined charge storage time, i.e., exposure time to read out the charges stored in respective pixels of the photoelectric converting section to the vertical transfer section and to generate, at the same time, a vertical synchronizing signal V-SYNC to output the charges which have been read out to the vertical transfer section as an image pick-up signal through a horizontal transfer section in the state synchronized with the vertical synchronizing signal V-SYNC thus generated.
Moreover, the applicant of this application has proposed, in the Japanese Patent Application Laid Open No. 1525502/1994, an imaging system adapted to generate a modulated synchronizing signal on the basis of a trigger signal generated at an arbitrary timing, thereby making it possible to carry out image pick-up operation by high speed shutter such as 1/1000 sec., etc in the state synchronized with the synchronizing signal of random period.
Meanwhile, in the conventional imaging system as described above, image pick-up operation by high speed shutter can be carried out, but the exposure time period cannot be adjustably set in succession over a broad range.
Thus, an object of this invention is to provide an imaging apparatus which is capable of carrying out image pick-up operation in synchronism with synchronizing signal of random period, and which permits continuous adjustable control of the exposure time period over a broad range, and a control device therefor.
DISCLOSURE OF THE INVENTION
An imaging apparatus according to this invention comprises: a solid-state image pick-up device including light receiving means adapted for producing charges corresponding to quantity of light incident thereto, vertical transfer means to which charges produced at the light receiving means are transferred, horizontal transfer means for outputting the charges transferred through the vertical transfer means, and a charge sweep-out section for sweeping out the charges stored at the light receiving means in accordance with a shutter control signal; trigger signal generating means for generating a trigger signal; pulse width adjustable setting means for generating, on the basis of input timing of the trigger signal, a trigger pulse signal of which pulse width can be adjustably set; signal generating means for outputting a shutter control signal in which the leading edge of the trigger pulse signal is caused to be timing of reference and a synchronizing signal in which the trailing edge of the trigger pulse signal is caused to be timing of reference; drive signal generating means for ou
Frommer William S.
Frommer & Lawrence & Haug LLP
Garber Wendy R.
Ye Lin
LandOfFree
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