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Claims  |
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What is claimed is:
1. A video camera system comprising:
picture element information forming means for forming picture element
information constructing a display plane on the basis of an imaging output
signal of an object whose image is to be taken;
standard measurement frame setting means connected to said forming means
for setting a standard measurement frame of a predetermined size at a
predetermined position on said display plane;
detection measurement frame setting means connected to said forming means
for setting a detection measurement frame of the predetermined size on
said display plane;
standard frequency characteristic data forming means receiving said
standard measurement frame and said picture element information for
forming standard frequency characteristic data of brightness levels and
hue angles on the basis of brightness information and hue information of
the image within said standard measurement frame;
detection frequency characteristic data forming means receiving said
detection measurement frame and said picture element information for
forming detection frequency characteristic data of said brightness levels
and said hue angles on the basis of said brightness information and said
hue information of the image within said detection measurement frame;
detection measurement frame determining means receiving said standard
frequency characteristic data and said detection frequency characteristic
data for determining a similarity of said standard frequency
characteristic data and said detection frequency characteristic data in
order to determine said detection measurement frame having said detection
frequency characteristic data of a large similarity; and
picture element information change control means connected to said
determining means for driving and controlling said picture element
information forming means so as to enter image information of said
determined detection measurement frame into said standard measurement
frame.
2. A video camera system of claim 1, wherein:
said detection measurement frame setting means sets a plurality of
detection measurement frames of different sizes from each other;
said detection frequency characteristic data forming means forms said
detection frequency characteristic data from said plurality of detection
measurement frames respectively;
said detection measurement frame determining means determines the detection
measurement frame having said detection frequency characteristic data of
the largest similarity in said detection frequency characteristic data of
said plurality of detection measurement frames; and
said picture element information change control means zooming-controls said
picture element information forming means in order to coincide the size of
said detection measurement frame determined by said detection measurement
frame determining means with the size of said standard measurement frame.
3. A video camera system of claim 2, wherein:
said detection measurement frame setting means sets said plurality of
detection measurement frames at predetermined positions different each
other on said display plane;
said picture element information change control means controls said picture
element information forming means so as to enter the image information of
said detection measurement frame into said detection measurement frame
determined by said detection measurement frame determining means.
4. A video camera system of claim 3, wherein;
said standard measurement frame setting means forms said standard
measurement frame at the center of said display plane.
5. A video camera system of claim 4, wherein:
said detection measurement frame determining means calculates a Euclidean
distance between said standard frequency characteristic data and said
detection, frequency characteristic data with respect to said plurality of
detection measurement frames, and determines the detection measurement
frame of said Euclidean distance as the detection measurement frame of the
large similarity.
6. A video camera system, comprising:
picture element information forming means for forming picture elements
constructing a display plane on the basis of an imaging output signal of
an object whose image is to be taken;
standard measurement frame setting means connected to said forming means
for setting a standard measurement frame of a first predetermined size at
a predetermined position on said display plane;
detection measurement frame setting means connected to said forming means
for setting a detection measurement frame of the first predetermined size
on said display plane;
main feature detection measurement frame setting means receiving said
standard measurement frame and connected to said forming means for setting
a measurement frame for main feature detection of a second predetermined
size within said standard measurement frame;
main feature data forming means receiving said measurement frame for main
feature detection and said imaging output signal for forming main feature
data being names of frequency characteristic components of brightness
levels and hue angles on the basis of brightness information and hue
information of the image within said measurement frame for said main
feature detection;
standard frequency data forming means receiving said standard measurement
frame for forming standard frequency characteristic data having standard
frequency characteristic data components being names of said frequency
characteristic components expressed by said main feature data in said
standard frequency characteristic data of said brightness levels and said
hue angles on the basis of said brightness information and said hue
information of the image within said standard measurement frame, and
determining the value of the standard frequency characteristic data
components being a name of other frequency characteristic components as a
predetermined value;
detection frequency characteristic data forming means connected to said
main feature data forming means and said standard frequency data forming
means for forming detection frequency characteristic data having detection
frequency characteristic data components being names of said frequency
characteristic components expressed by said main feature data in said
detection frequency characteristic data of said brightness levels and said
hue angles on the basis of said brightness information and said hue
information of the image within said detection measurement frame, and
determining the value of the standard frequency characteristic data
components being names of the other frequency characteristic components as
the predetermined value;
detection measurement frame determining means connected to said detection
frequency characteristic data forming means for determining a similarity
of said standard frequency characteristic data and said detection
frequency characteristic data in order to determine said detection
measurement frame having said detection frequency characteristic data of a
large similarity; and
picture element information change control means connected to said
determining means for driving and controlling said picture element
information forming means so as to enter image information of said
determined detection measurement frame into said standard measurement
frame.
7. A video camera system of claim 6, wherein:
said detection measurement frame setting means sets a plurality of
detection measurement frames of different sizes each other;
said detection frequency characteristic data forming means forms said
detection frequency characteristic data from said plurality of detection
measurement frames respectively;
said detection measurement frame determining means determines the detection
measurement frame having said detection frequency characteristic data of
the largest similarity in said detection frequency characteristic data of
said plurality of detection measurement frames; and
said picture element information change control means zooming-controls said
picture element information forming means in order to coincide a size of
said detection measurement frame determined by said detection measurement
frame determining means with a size of said standard measurement frame.
8. A video camera system of claim 7, wherein:
said detection measurement frame setting means sets said plurality of
detection measurement frames at predetermined positions different each
other on said display plane;
said picture element information change control means controls said picture
element information forming means so as to enter the image information of
said detection measurement frame into said detection measurement frame
determined by said detection measurement frame determining means.
9. A video camera system of claim 8, wherein;
said standard measurement frame setting means forms said standard
measurement frame at the center of said display plane.
10. A video camera system of claim 9, wherein:
said detection measurement frame determining means calculates a Euclidean
distance between said standard frequency characteristic data and said
detection frequency characteristic data with respect to said plurality of
detection measurement frames, and determines the detection measurement
frame of said Euclidean distance as the detection measurement frame of the
large similarity.
11. A video camera apparatus, comprising:
a lens for focusing light from an object whose image is to be taken;
an imaging element for converting the light from said lens into an electric
signal;
picture element information forming means for forming picture element
information constructing a display plane on the basis of an output signal
from said imaging element;
standard measurement frame setting means connected to said forming means
for setting a standard
detection measurement setting means connected to said forming means for
setting a detection measurement frame of the predetermined size on said
display plane;
standard frequency characteristic data forming means receiving said
standard measurement frame and said picture element information for
forming standard frequency characteristic data of brightness levels and
hue angles on the basis of brightness information and hue information of
the image within said standard measurement frame;
detection frequency characteristic data forming means receiving said
detection measurement frame and said picture element information for
forming detection frequency characteristic data of said brightness levels
and said hue angles on the basis of said brightness information and said
hue information of the image within said detection measurement frame;
detection measurement frame determining means receiving said standard
frequency characteristic data and said detection frequency characteristic
data for determining a similarity of said standard frequency
characteristic data and said detection frequency characteristic data in
order to determine said detection measurement frame having said detection
frequency characteristic data of a large similarity; and
picture element information change control means connected to said
determining means for driving and controlling said picture element
information forming means so as to enter the picture element information
of said determined detection measurement frame into said standard
measurement frame.
12. A video camera apparatus of claim 11, wherein:
said detection measurement frame setting means sets a plurality of
detection measurement frames of different sizes each other;
said detection frequency characteristic data forming means forms said
detection frequency. characteristic data from said plurality of detection
measurement frames respectively;
said detection measurement frame determining means determines the detection
measurement frame having said detection frequency characteristic data of
the largest similarity in said detection frequency characteristic data of
said plurality of detection measurement frames; and
said picture element information change control means zooming-controls said
picture element information forming means in order to coincide a size of
said detection measurement frame determined by said detection measurement
frame determining means with a size of said standard measurement frame.
13. A video camera apparatus of claim 12, wherein:
said detection measurement frame setting means sets said plurality of
detection measurement frames at predetermined positions different each
other on said display plane;
said picture element information change control means controls said picture
element information forming means so as to enter the image information of
said detection measurement frame into said detection measurement frame
determined by said detection measurement frame determining means.
14. A video camera apparatus of claim 13, wherein;
said standard measurement frame setting means forms said standard
measurement frame at the center of said display plane.
15. A video camera apparatus of claim 14, wherein:
said detection measurement frame determining means calculates a Euclidean
distance between said standard frequency characteristic data and said
detection frequency characteristic data with respect to said plurality of
detection measurement frames, and determines the detection measurement
frame of said Euclidean distance as the detection measurement frame of the
large similarity.
16. A video camera apparatus, comprising;
a lens for focusing a light from an object whose image is to be taken;
an imaging element for converting the light from said lens into an electric
signal;
picture element information forming means for forming picture element
information constructing a display plane on the basis of an output signal
from said imaging element;
standard measurement frame setting means connected to said forming means
for setting a standard measurement frame of a first predetermined size at
a predetermined position on said display plane;
detection measurement frame setting means connected to said forming means
for setting a detection measurement frame of the first predetermined size
on said display plane;
main feature detection measurement frame setting means receiving said
standard measurement frame and connected to said forming means for setting
a measurement frame for main feature detection of a second predetermined
size within said standard measurement frame;
main feature data forming means receiving said measurement frame for main
feature detection and said picture element information for forming main
feature data being names of frequency characteristic components of
brightness levels and hue information of the image within said measurement
frame for said main feature detection;
standard frequency data forming means receiving said standard measurement
frame for forming standard frequency characteristic data having standard
frequency characteristic data components being names of said frequency
characteristic components expressed by said main feature data in said
standard frequency characteristic data of said brightness levels and said
hue angle on the basis of said brightness information and said hue
information of the image within said standard measurement frame, and
determining a value of the standard frequency characteristic data
components being names of other frequency characteristic components as a
predetermined value;
detection frequency characteristic data forming means connected to said
main feature data forming means and said standard frequency data forming
means for forming said detection frequency characteristic data having
detection frequency characteristic data components being name of said
frequency characteristic components expressed by said main feature data in
said detection frequency characteristic data of said brightness levels and
said hue angles on the basis of said brightness information and said hue
information of the image within said detection measurement frame, and
determining the value of the standard frequency characteristic data
components being names of the other frequency characteristic components as
the predetermined value;
detection measurement frame determining means receiving said standard
frequency characteristic data and said detection frequency. characteristic
data for determining the similarity of said standard frequency
characteristic data and said detection frequency characteristic data in
order to determine said detection measurement frame having said detection
frequency characteristic data of a large similarity; and
picture element information change control means connected to said
determining means for driving and controlling said picture element
information forming means so as to enter image information of said
determined detection measurement frame into said standard measurement
frame.
17. A video camera apparatus of claim 16, wherein:
said detection measurement frame setting means sets a plurality of
detection measurement frames of different sizes each other;
said detection frequency characteristic data forming means forms said
detection frequency characteristic data from said plurality of detection
measurement frames respectively;
said detection measurement frame determining means determines the detection
measurement frame having said detection frequency characteristic data of
the largest similarity in said detection frequency characteristic data of
said plurality of detection measurement frames; and
said picture element information change control means zooming-controls said
picture element information forming means in order to coincide a size of
said detection measurement frame determined by said detection measurement
frame determining means with a size of said standard measurement frame.
18. A video camera apparatus of claim 17, wherein: said said detection
measurement frame setting means set a plurality of detection measurement
frames at predetermined positions different each other on said display
plane;
said picture element information change control means controls said picture
element information forming means so as to enter the image information of
said detection measurement frame into said detection measurement frame
determined by said detection measurement frame determining means.
19. A video camera apparatus of claim 18, wherein;
said standard measurement frame setting means forms said standard
measurement frame at the center of said display plane.
20. A video camera apparatus of claim 19, wherein:
said detection measurement frame determining means calculates a Euclidean
distance between said standard frequency characteristic data and said
detection frequency characteristic data with respect to said plurality of
detection measurement frames, and determines the detection measurement
frame of said Euclidean distance as the detection measurement frame of the
large similarity.
21. A tracking method for forming a brightness feature pattern and hue
feature pattern on the basis of a brightness signal Y and a hue signal HUE
of respective picture elements taken into a picture memory in a brightness
histogram generating apparatus and a hue histogram generating apparatus so
as to control a zooming-motion of a lens block in optimum condition,
comprising:
first step for initializing a field number FN to FN=O, and then waiting to
release a recording pause button RECPAUSE by a user and to start
recording;
second step for memorizing a frequency characteristic of the brightness
signal Y and the hue signal HUE within a standard measurement frame at a
central position of a display plane as a standard feature pattern, when
starting the recording;
third step for incrementing the field number FN to FN+i, taking a
brightness frequency characteristic YStd (i) and a hue frequency
characteristic HueStd (i) with respect to respective measurement frames
FMX1, FMX2, and FMX3 while sequentially switching a measurement frame
(FMX) to a plurality of measurement frames of different sizes from each
other FMX1, FMX2, and FMX3, selecting there measurement frames, composed
of a small measurement frame FMX1 being a small area having an unit area
AR, a middle measurement frame FMX2 being a middle area having a plurality
of unit areas, and a large measurement frame FMX3 being a large area
having a plurality of unit areas the number of which is larger than said
middle area, and taking in data of said respective measurement frame FMX1,
FMX2, and FMX3 as Small, Middle, and Large detection feature patterns,
respectively;
fourth step for determining a Euclidean distance between the standard
feature pattern and the detection feature pattern with respect to
brightness and hue, and setting the sum of those as Jsmall, Jmiddle, and
Jlarge;
fifth step for determining a size of the measurement frame of a smallest
evaluation value to the size of new object to be taken an image;
sixth step for controlling a zooming-motor so that the size of a new
measurement frame becomes the size of a middle; and
seventh step of renewing standard frequency characteristic data of the
brightness signal and the hue signal within the new measurement frame as
the standard feature pattern. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a video camera system, and more particularly to
an improvement of a video camera system adapted to automatically follow
changes of the object seen in the visual field of the video camera in
order to provide a suitable image.
2. Description of the Related Art
Nowadays, a single-lens reflex camera having an automatic zooming function
has been used. Such camera has a CCD (charge coupled device) line sensor
determining a correct distance between the object and the camera and a
zoom motor for the automatic zooming function.
According to the automatic zooming camera system of the conventional
single-lens reflex camera, it is adapted to restrict the object to be shot
to adult persons, the camera user previously selects one of the face-up
shot, bust shot, and full body shot by pushing buttons, and the zoom motor
is driven according to the position of the zoom lens after the particular
position of the zoom lens corresponding to the distance between the lens
position and the object, which distance being previously programmed
according to the particular kind of the shot, is determined.
Because such single-lens reflex camera provides a CCD line sensor for
automatic focusing, and the CCD line sensor can judge whether it is out of
focus before or behind and correctly determine the distance to the object,
it is possible to obtain or structure an auto-zooming system relatively
easily.
In addition, there have been automatic tracking apparatus which are adapted
to automatically track or follow the change of the object or the moving
object in the visual field of the video camera. According first proposed
conventional object tracking apparatus of a video camera, it memorizes a
peak value of high-frequency part of a brightness signal in the
measurement frame and recognizes motion of the object as the peak value
changes.
According to second proposal of such automatic object tracking apparatus of
a video camera, it takes a matching of representative points of luminance
signals in before and after fields within the measurement frame in order
to form a motion vector, and supposes the motion vector in the measurement
frame as a motion of the object.
The conventional automatic zooming systems of the single-lens reflex camera
fail to be employed in the video camera having an automatic focusing
system of the so-called mountain-climbing control type, since the
conventional automatic zooming systems can not correctly measure the
distance to the object.
The former or first object automatic tracking apparatus has a merit of
simple structure of the whole mechanism. However, it has a problem of
failing to track an object of a man if, for example, there are trees in
the background within the measurement frame as well as the man. The reason
of such problem resides in that the high frequency component of the tree
becomes the largest peak.
The latter or second automatic tracking method uses basically signals
outputted when the peak is occurred, so that the method is sensitive to
noise resulting in malfunction of the automatic tracking apparatus in a
taking image environment with low brightness. Theoretically, because the
second conventional automatic tracking method picks up the high frequency
component, it is apprehensive that the tracking apparatus fails to
automatically track the objects with low contrast.
Furthermore, the second tracking method can not or only with difficulty
judge whether the calculated motion vector is owing to shaking of hands of
a user holding the video camera or motion of the object, resulting in
erroneous operation of the video camera or the tracking apparatus therein.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a video
camera system enabling to stably and effectively pick up a quantity of
features of the object in the visual field, thereby automatically tracking
the motion of the object simply and surely.
The foregoing object and other objects of this invention have been achieved
by the provision of a video camera system comprising:a picture element
information forming means 1, 5, 6 and 7 for forming picture elements
structuring display plane PIC on the basis of imaging output signal of the
object to be taken an image; standard measurement frame setting means 16,
17, 15 and SP3 for setting standard measurement frame FMXR of a
predetermined size at a predetermined position on the display plane PIC;
detection measurement frame setting means 16, 17, 15 and SP3 for setting a
detection measurement frames FMX1 to FMX3 and FMXD of a predetermined size
on the display plane PIC; a standard frequency characteristic data forming
means 19, 20 and 16 for forming standard frequency characteristic data
YStd (i), Hue Std (i) of hue angle and/or brightness level on the basis of
brightness information and/or hue information of the image within the
standard measurement frame FMXR; detection frequency characteristic data
forming means 19, 20 and 16 for forming detection frequency characteristic
data YSmall (i), Hue Small (i), Y (x, y), (i), Hue (x, y) (i) of
brightness and/or hue angle on the basis of brightness information and/or
hue information of the image within the detection measurement frame FMX1
to FMX3 and FMXD; detection measurement frame determining means 16, SP5
and SP15 for determining a similarity of the standard frequency
characteristic data and/or detection frequency characteristic data in
order to determine the detection measurement frame having detection
frequency characteristic data of a large similarity; and picture element
information change control means 16, SP6 and SP16 for driving and
controlling the picture element information forming means 1, 5, 6 and 7 so
as to enter image information of the determined detection measurement
frame into the standard measurement frame.
In the operation of the video camera system of this invention, the picture
element information within the standard measurement frame FMXR of the
picture element information of the object is changed to the standard
frequency characteristic data YStd (i), Hue Std (i) concerning brightness
level and/or hue angle by means of the standard frequency characteristic
data forming means 19, 20 and 16, and the picture element information
within the detection measurement frames FMX1 to FMX3 and FMXD is changed
to the detection frequency characteristic data YSmall (i), Hue Small (i),
Y (x, y) (i), Hue (x, y) (i) concerning the brightness level or hue angle
by means of the detection frequency characteristic data forming means 19,
20 and 16. The detection frequency characteristic data having large
similarity concerning the standard frequency characteristic data are
determined by the detection measurement frame determining means 16, SP5
and SP15 and the picture element information forming means 1, 5, 6 and 7
are driven and controlled by the picture element information changing
controlling means 16, SP6 and SP16 so as to enter the picture element
information within the determined detection measurement frame.
As described above, the video camera system of this invention can
automatically track and control the object so as to enter in the standard
frame of the display plane, by of using frequency characteristic data and
expressing the feature of the image. Consequently, the video camera system
can be formed without difficulty.
According to the present invention, a position of the detection measurement
frame having a large similarity on the basis of the frequency
characteristic data concerning the brightness information and hue
information in the predetermined measurement frame is measured in order to
control the image taking condition of the video camera on the object.
Consequently, it is easy to provide a video camera system enabling surely
and adaptively to operate and match any change of the object relative to
the video camera.
The nature, principle and utility of the invention will become more
apparent from the following detailed description when read in conjunction
with the accompanying drawings in which like parts are designated by like
reference numerals or characters.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a block diagram of the first embodiment of the video camera
system according to the present invention;
FIG. 2 is a schematic diagram explaining HLS color coordinates expressing
sight stimulus;
FIG. 3 is a schematic diagram explaining the standard measurement frame
FMR;
FIG. 4 is a characteristic curve diagram depicting standard hue frequency
characteristic obtained from the standard measurement frame FMXR;
FIG. 5 is a characteristic curve diagram depicting standard brightness
frequency characteristic obtained from the standard measurement frame
FMXR;
FIG. 6 is a flow chart showing an automatic tracking process procedure
according to the first embodiment;
FIG. 7 is a schematic diagram depicting a detection measurement frame;
FIG. 8 is a characteristic curve diagram depicting a detection hue
frequency characteristic;
FIG. 9 is a characteristic curve diagram depicting a detection brightness
frequency characteristic;
FIG. 10 is a block diagram showing the second embodiment of the video
camera system according to the present invention;
FIG. 11 is a flow chart showing the automatic tracking processing procedure
of the second embodiment;
FIG. 12 is a schematic diagram showing the detection measurement frame of
the second embodiment;
FIG. 13 is a characteristic curve diagram showing a detection hue frequency
characteristic obtained from the detection measurement frame shown in FIG.
12;
FIG. 14 is a characteristic curve diagram depicting a detection brightness
frequency characteristic obtained from the detection measurement frame of
FIG. 12;
FIG. 15 is a flow chart of the automatic tracking processing procedure of
the third embodiment of the video camera system according to the present
invention;
FIG. 16 is a schematic diagram showing a main feature detection measurement
frame set in the step SP12A shown in FIG. 15;
FIG. 17 is a characteristic curve diagram depicting a hue frequency
characteristic obtained from the main feature detecting measurement frame
FMXF of FIG. 16;
FIG. 18 is a characteristic curve diagram depicting a brightness frequency
characteristic obtained from the main feature detecting measurement frame
FMXF shown in FIG. 16;
FIG. 19 is a schematic diagram explaining a setting of the main feature
detecting measurement frame FMXF of, in particular the object part to be
tracked, displayed in the picture plane PIC;
FIG. 20 is a characteristic curve diagram showing the hue frequency
characteristic obtained from the standard measurement frame FMXR shown in
FIG. 16;
FIG. 21 is a characteristic curve diagram showing the brightness frequency
characteristic obtained from the standard measurement frame FMXR of FIG.
16;
FIG. 22 is a characteristic curve diagram showing the hue frequency
characteristic obtained when the display plane PIC is scanned by the
detection measurement frame FMXD (FIG. 17);
FIG. 23 is a characteristic curve diagram showing the brightness frequency
characteristic obtained when the display plane PIC is scanned by the
detection measurement frame FMXD (FIG. 12); and
FIG. 24 is a schematic diagram explaining an automatic tracking of the
particular object part.
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of this invention will be described with reference to
the accompanying drawings:
(1) First Embodiment
In FIG. 1, VCS denotes generally a construction of a video camera system in
which an imaging light LA from the object whose image is to be taken is
received by a solid-state image taking element 4 consisting of, for
example, a CCD (charge coupled device) after passing through a lens 2 and
an iris 3 in a lens block section 1, and imaging output signal S1
expressing the image of the object is given to a signal
separation/automatic gain control circuit section 5.
The signal separation/automatic gain control circuit section 5 samples and
holds the imaging output signal S1 and controls the control signal from an
automatic iris AE (not shown) so as to make the imaging output signal S1
have a predetermined gain. The thus obtained imaging output signal S2 is
supplied from the section 5 to a digital camera processing circuit 7
through an analog/digital conversion circuit section 6.
The digital camera processing circuit 7 forms brightness signal Y and
chroma signal C on the basis of the imaging output signal S2 and sends out
the brightness signal Y and chroma signal C as video signals S3 through a
digital/analog conversion circuit
In addition, the digital camera processing circuit 7 supplies brightness
signal Y and color difference signals R-Y and B-Y of object tracking
detection signal S4 to a tracking control circuit section 11. The tracking
control circuit section 11 outputs tracking control signals S5 to a
zooming drive motor 12A and tilting drive motor 128 used for the lens
block portion 1 on the basis of the object tracking detection signal S4.
The tracking control circuit section 11 gives color difference signals R-Y
and B-Y to a saturation level/hue detection circuit 14 to form a hue
signal HUE and a saturation signal SAT and memorizes the signals HUE and
SAT together with brightness signal Y in an image memory 15 consisting of,
for example, a field memory at a unit of picture element.
The saturation level/hue detection circuit 14 converts color difference
signals R-Y and B-Y from orthogonal coordinates to curvilinear coordinates
to form the hue signal HUE and the saturation level signal SAT, thereby
recognizing the object on the basis of sight stimulation for making the
man perceive the object by means of brightness signal Y, hue signal HUE,
and saturation level signal SAT.
By the way, in general, the sight stimulation which the man perceives can
be shown in FIG. 2 and expressed by color coordinates system provided with
L axis and SH plane perpendicular to the L axis forming the so-called HLS
system.
L axis depicts a lightness corresponding to the brightness signal Y. The SH
plane is expressed by curvilinear coordinates perpendicular to the L axis.
On the SH plane, S shows a saturation and is expressed by the distance
from the L axis. H shows a hue and is expressed by an angle measured from
the direction of color difference signal R-Y of 0 degree.
All colors of the solid body shown by the HLS system become white when the
light source becomes bright, or the SH plane or color coordinates rises
along the L axis. During such rising of the color coordinates, saturation
level S lessens. On the contrary, when the light source diminishes in its
lightness, the color coordinates or SH plane lowers along the L axis and
all colors become black, together with the saturation level S decreased.
According to the features of such HLS color coordinates, the saturation
level S and brightness Y are easily influenced by lightness of the light
source, so that it is difficult to say that these saturation level and
brightness are good parameters expressing a quantity of feature of the
object. On the contrary, it is apparent that a hue H expressing the
quantity of a feature particular to the object is difficult to be
influenced by the light source.
However, when the color of the object resides near the L axis or the color
is white, black or gray, the hue signal H fails to have a meaningful of
information and, at the worst case of the image having a bad S/N ratio,
the white color appeared on the image may have vectors of various hues H.
In order to solve the problem, the tracking control circuit section 11 of
the present invention uses the features of such HLS color coordinates. The
tracking control circuit section 11 picks up the features of the object
and drives the zooming drive motor 12A and the tilting drive motor 12B so
as to track the changing object when its feature changes resulting in an
obtaining of video signals S3 zooming-processed, thereby suitably tracking
the moving object.
That is, the picture element information constructing the object tracking
detection signal S4 memorized in the image memory 15 is divided by means
of an address signal S7 supplied from an address generation circuit 17
which generates the address signal S7 based on a block designating signal
S6 sent from a tracking signal processing circuit 16 having a micro
processor, so as to divide, as shown in FIG. 3, the display plane PIC
formed substantially within the image memory 15 into the block consisting
of the predetermined sized unit regions AR on the basis of the XY
rectangular coordinates (x, y).
As described above, data of each picture element consisting of the display
plane PIC of the image memory 15 are read out at every unit region and
processed as one block of image information at every unit region AR.
According to this embodiment of the video camera system, the display plane
or picture window PIC is divided respectively into sixteen unit regions AR
both along x direction and y direction. Consequently, designating the
coordinates x=i, y=j (for example, the coordinates at the upper left
corner) of the rectangular coordinates (x, y) concerning the unit region
AR of 16.times.16 (=256) pieces, the image information I (x=i, y=j) of the
designated unit region AR can be respectively read out.
As described above, the hue signal HUE component of the image information I
(x=i, y=j) read out for every the unit region AR from the image memory 15
is given to a hue histogram generation circuit 19 through a gate circuit
18. On the contrary, the brightness signal Y component is directly given
to a brightness histogram generation circuit 20.
The hue histogram generation circuit 19 determines, as shown in FIG. 4, hue
frequency characteristic Hue Std (i) expressing the number of the picture
elements having respective hue angles 0.degree. to 359.degree. concerning
the hue of the picture elements within the measurement frame FMX set on
the display plane or picture window PIC, and sends the hue frequency
characteristic Hue Std (i) to the tracking signal processing circuit 16 as
hue histogram signal S11.
In other words, the hue histogram generation circuit 19 converts the
features of hue of the image in the measurement frame FMX into the hue
feature pattern expressed by the hue frequency characteristic Hue Std (i).
Similarly, the brightness histogram generation circuit 20 determines, as
shown in FIG. 5, brightness frequency characteristic YStd (i) expressing
the number of the picture elements having respective brightness levels 0
to 255 on the basis of the brightness signal Y concerning the picture
elements within the measurement frame FMX set on the display plane PIC,
and supplies the brightness frequency characteristic YStd (i) to the
tracking signal processing circuit 16 as the brightness histogram signal
S12.
As a result, the brightness histogram generation circuit 20 converts the
feature of the brightness of the image within the measurement frame FMX to
the brightness feature pattern expressed by the brightness frequency
characteristic YStd (i) and supplies the pattern to the tracking signal
processing circuit 16.
According to this embodiment of the video camera system, it has a hue noise
gate signal generation circuit 25 having a comparator for a gate circuit
18 in order to compare a saturation signal SAT read out every picture
element from the image memory 15 with a noise judge signal S14 given by
the tracking signal processing circuit 16. When the saturation signal SAT
is less than the predetermined level, a gate signal S15 for closing the
gate circuit 18 is given to the same, thereby preventing the hue signal
HUE for the particular picture element from inputting to the hue histogram
generation circuit 19.
As a reason for this, when the saturation signal SAT detected in the
saturation/hue detection circuit 14 resides near the L axis (FIG. 2), the
hue signal HUE of the saturation signal SAT may have a little saturation
being hidden in or buried in noise failing to have meaningful information,
so such hue signal HUE is removed from the gate circuit 18.
In the structure of the video camera system described above, the tracking
signal processing circuit 16 operates corresponding to the manipulation of
the user and carries out an automatic tracking processing procedure RT1
shown in FIG. 6. As a result, the brightness feature pattern and the hue
feature pattern are formed in the brightness histogram generation circuit
20 and the hue histogram generation circuit 19 on the basis of the
brightness signal Y and hue signal HUE of respective picture elements
taken in the image memory 15, so that the zooming operation of the lens
block 1 is controlled at the most effective condition.
When the tracking signal process circuit 16 enters into the automatic
tracking process procedure RT1 shown in FIG. 6, a field number FN is
initially set to FN=0 in a step SP1, the user of the video camera releases
a record pause button RECPAUSE waiting for a start of the recording
operation.
Then, when the user enables to start the record, the tracking signal
processing circuit 16 proceeds to a step SP2, in which frequency
characteristic (or histogram) of the brightness signal Y and hue signal
HUE or brightness frequency characteristic YSsd (i) (FIG. 5) and hue
frequency characteristic Hue Std (i) (FIG. 4) within the standard
measurement frame FMXR (in this embodiment, this is selected to unit
regions of 4.times.4 pieces) set at the central position of the display as
shown in FIG. 3 are taken from the brightness histogram generation circuit
20 and hue histogram generation circuit 19 as respectively a standard
brightness frequency characteristic and standard hue frequency
characteristics. These characteristic above are memorized as "standard
feature pattern".
Then, the tracking signal processing circuit 16 proceeds to a step SP3 and
the field number FN is incremented to FN+1, then the measurement frame FMX
sequentially is changed to a plurality of measurement frames FMX1, FMX2
and FMX3, respectively having different sizes, as well as the brightness
frequency characteristic YStd (i) and hue frequency characteristic Hue Std
(i) concerning respective measurement frames FMX1, FMX2 and FMX3 are taken
from the brightness histogram generation circuit 20 and hue histogram
generation circuit 19 | | |
