Video camera with record shutoff mechanism

A video camera includes a viewfinder through which an operator may view an image of an object to be videoed, a rotatably supported head-carrier cylinder and a capstan for transporting a length of magnetic recording medium. This video camera also includes at least one of first and second detecting units for detecting a change in rotation of the rotary head-carrier cylinder and for detecting a change in rotation of the capstan, respectively, and a determining unit operable to determine, in reference to information supplied from at least one of the first and second detecting units, whether or not a video recording then taking place is in accordance with the will of an operator. The video camera may be provided with at least one of a camera wobbling detector and an eye sensor for detecting whether or not the operator looks through the viewfinder and, in such case, the determining unit makes the determination in reference to information supplied from one of the camera wobbling detector and the eye sensor and that from at least one of the first and second detecting units.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to a video camera operable with 
either a VHS magnetic recording tape or a 8 mm magnetic recording tape 
and, more particularly, to the video camera equipped with means for 
disabling an uncalled-for recording in the event that a video camera 
continues video recording against the will of an operator such as when the 
operator inadvertently fails to switch the video camera off. 
For the purpose of the present invention, the means for disabling an 
uncalled-for recording in the event that video camera continues video 
recording against the will of an operator will be referred to as a "record 
shutoff mechanism". 
2. Description of the Prior Art 
Video cameras equipped with a record shutoff mechanism, i.e., means for 
disabling an uncalled-for recording in the event that the video camera 
continues video recording against the will of an operator, are well known 
and prior art examples of record shutoff mechanisms are disclosed in, for 
example, the Japanese Laid-open Patent Publications No. 2-87875 and No. 
3-274969. 
The record shutoff mechanism disclosed in the Japanese Laid-open Patent 
Publication No. 2-87875 comprises a detector means for detecting a change 
of a portion or the whole of the viewed image of an object being videoed, 
a determining means operable in response to information provided by the 
detecting means to determine whether or not the viewed image has actually 
changed within the framework of a viewfinder screen and then to provide an 
output only when it has determined the viewed image having been changed, 
and a disabling means operable in response to the output from the 
determining means to disable a video recording operation of the video 
camera. 
The record shutoff mechanism disclosed in the Japanese Laid-open Patent 
Publication No. 3-274969 includes either one of a photoelectric sensor or 
a touch-sensor installed at an eyepiece area of the viewfinder. In one 
embodiment where the photoelectric sensor is employed, the photoelectric 
sensor is utilized to determine whether or not an operator of the video 
camera is viewing the image cast on the viewfinder screen with his or her 
eye close towards the eyepiece and then to provide an output necessary to 
disable the operation of the video camera when the photoelectric sensor 
determines that the operator's eye is substantially distant from the 
eyepiece of the viewfinder. In the different embodiment where the 
touch-sensor is employed, the touch-sensor is utilized to determine 
whether or not an operator of the video camera is viewing the image cast 
on the viewfinder screen with his or her eye held in contact with an 
eyepiece area of the viewfinder and then to provide an output necessary to 
disable the operation of the video camera when the touch-sensor determines 
that the operator's eye is substantially distant from the eyepiece of the 
viewfinder. 
Video cameras currently available in the market have, in addition to a 
power control switch, a REC (RECORD) button which is generally in the form 
of a toggle button capable of selectively assuming one of two different 
positions, a REC position to initiate a video recording and a STOP 
position to halt the video recording, for ease of camera handling. More 
specifically, commercially available video cameras are such that, when the 
power control switch is turned on, the video camera is held at a STAND-BY 
position in readiness for actual video recording which subsequently takes 
place upon manipulation (either slide or push) of the REC button to assume 
the REC position. In some of the video cameras, the STAND-BY position 
means that a length of magnetic recording tape is turned around a 
head-carrier cylinder so that the video recording can be quickly initiated 
immediately after manipulation of the REC button to assume the REC 
position. The video recording can be terminated when the REC button is 
again manipulated, but to assume the STOP position. 
With those types of video cameras, it is not unusual that the operator 
fails to move the REC button to the STOP position and allows the video 
camera to continue its recording operation without realizing that the REC 
button in the REC position has not yet been moved to the STOP position. 
This uncalled-for video recording results in an unnecessary take-up of a 
substantial length of magnetic recording tape with no significant image 
recorded thereon and an unnecessary waste of the very limited battery 
power and it often occurs that, next time the operator intends to make a 
video recording, the video camera will no longer work because no more tape 
is available and/or because of a shortage of battery power. 
In view of the generalities of the video cameras as discussed above, the 
record shutoff mechanism such as disclosed in the Japanese publications 
referred to above appears to be a convenient instrument. However, the 
record shutoff mechanism disclosed in the No. 2-87875 publication has been 
found having a problem in that, particularly where still-frame video 
images are being taken in succession with the video camera installed on a 
tripod, the record shutoff mechanism will work in response to the change 
of the viewed image to halt the recording operation against the will of an 
operator. Another problem associated with this known record shutoff 
mechanism is that, if the operator hailing to move the REC button to the 
STOP position walks around with the video camera hung from the shoulder, 
the video camera is correspondingly shaken to such an extent as to result 
in a considerable change of an image signal for one field or one frame, 
thereby fooling the record shutoff mechanism, that is, rendering the 
record shutoff mechanism to be ineffective to stop the video recording. 
On the other hand, even the record shutoff mechanism disclosed in the No. 
3-274969 publication has problems in that, in the event that the operator 
remove his or her eye away from the eyepiece area of the viewfinder for 
visual inspection of the object being videoed or for any other reason, the 
record shutoff mechanism immediately works to stop the video recording 
against the operator's will and in that, since the record shutoff 
mechanism works immediately after the operator removes his or her eye away 
from the viewfinder, a high-angle video recording with the video camera 
held overhead is impossible. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention has been devised to substantially 
eliminate the above discussed problems and inconveniences inherent in the 
prior art video cameras equipped with a record shutoff mechanism and is 
intended to provide a video camera equipped with an improved and reliable 
record shutoff mechanism of a type which allows the video recording to 
continue when so desired by an operator, but to halt recording when an 
uncalled-for video recording is likely to occur. 
To this end, according to one aspect of the present invention, there is 
provided a video camera which comprises a detecting means for detecting a 
change in rotation of a speed-controlled rotary element of the video 
camera, and a determining means operable in response to information 
supplied from the detecting means to determine whether or not a video 
recording then taking place is in accordance with the will of an operator. 
The speed-controlled rotary element of the video camera referred to above 
may be either a rotary head-carrier cylinder and a capstan used to 
drivingly transport a length of magnetic recording medium. 
According to another aspect of the present invention, there is provided a 
video camera which comprises a first detecting means for detecting a 
change in rotation of a rotary head-carrier cylinder, a second detector 
unit for detecting a change in rotation of a capstan used to drivingly 
transport a length of magnetic recording medium, and a determining means 
operable in response to information supplied from at least one of the 
first and second detecting means to determine whether or not a video 
recording then taking place is in accordance with the will of an operator. 
According to the present invention, when surge information indicative of a 
considerable change in rotation of at least one of the cylinder or the 
capstan is provided from the detecting means while the REC button is held 
at the REC position, the determining means determines that the 
uncalled-for video recording is taking place and, therefore, the 
uncalled-for video recording is immediately halted automatically. In cases 
other than such surge case in which the information is provided, the 
determining means determines that the video recording is taking place as 
intended by the operator and, in such case, the video recording is allowed 
to continue.

DETAILED DESCRIPTION OF THE EMBODIMENTS 
Referring first to FIGS. 1 and 2, a video camera shown therein comprises an 
optical system including various lens elements for directing rays of 
light, reflected from an object to be videoed, towards an imaging element 
102 which converts the incoming light into an electric signal proportional 
to the intensity of the reflected light received thereby, a viewfinder 201 
through which an operator of the video camera aims at the object to be 
videoed and a main power switch 202 capable of assuming one of ON and OFF 
positions. The video camera also comprises a REC button 108 which, when 
activated, initiates supply of an electric signal necessary to initiate a 
video recording, that is, a recording of images on a length of magnetic 
recording tape (not shown), a STOP button 109 which, when activated, 
initiates supply of an electric signal necessary to stop the video 
recording, and a shutoff disable button 110 for disabling a record shutoff 
mechanism which will be described subsequently. All of the REC button 108, 
the STOP button 109 and the disable button 110 are electrically connected 
with a system control microcomputer 111 built in the video camera for 
controlling a camera unit and a VTR (video tape recorder) unit. It is to 
be noted that, although the video camera is shown to have the separate REC 
and STOP buttons, it may have a toggle REC button capable of assuming one 
of the REC and STOP positions as discussed in connection with the prior 
art. 
As best shown in FIG. 1, the camera unit of the video camera includes, in 
addition to the optical system 101 and the imaging element 102, a camera 
signal processing circuit 103 for converting the electric signal from the 
imaging element 102 into luminance and color signals which are 
subsequently stored in a memory 104, a motion vector detector 105 as will 
be described later, and a read-out position control 106 operable to 
calculate the position from which an image stored in the memory 104 is to 
be read out in reference to a motion vector of the image viewed within the 
framework of the viewfinder 201. 
The motion vector detector 105 referred to above is operable to divide the 
luminance signal from the signal processing circuit 103 into a plurality 
of areas, to calculate a motion vector of the image in each of these 
divided areas, to determine the validity of the motion vector in each of 
these divided areas, to calculate a vector coefficient representative of 
the degree of dispersion of the motion vectors in reference to the motion 
vector and the validity thereof and finally to calculate the motion vector 
of the image based on these elements. In any event, this motion vector 
detector is well known in the art and is discussed in detail by K. Uomori 
et al. in "AUTOMATIC IMAGE STABILIZING SYSTEM BY FULL-DIGITAL SIGNAL 
PROCESSING", IEEE Transaction on Consumer Electron, Vol. 36, No. 3, August 
1990, which is herein incorporated by reference. Alternatively, a motion 
vector detector disclosed in any one of U.S. Pat. No. 5,099,323 issued to 
Morimura et al. on Mar. 24, 1992, and the Japanese Laid-open Patent 
Publication No. 3-198488 may be employed therefor, both of which are also 
herein incorporated by reference. 
It is to be noted that the motion vector detector 105 and the read-out 
position control 106 together constitute a camera wobbling detecting unit 
121. 
The VTR unit includes a plurality of, for example, two, magnetic recording 
and/or reproducing heads 112 carried by a rotary carrier cylinder 113 for 
rotation together therewith, a rotation sensor 114 in the form of a 
frequency generator for generating a frequency signal indicative of the 
frequency proportional to the number of revolutions of the head-carrier 
cylinder 113, and an angle sensor 115 in the form of a pulse generator for 
generating a switching pulse necessary to selectively switching one of the 
magnetic heads 115 into operation when each of the magnetic heads 115 
being rotated together with the head-carrier cylinder 113 is brought to a 
predetermined angular position. The VTR unit also includes a VTR signal 
processing circuit 116 operable to convert a video signal, read out from 
the memory 104 under the control of the read-out position control 106, 
into luminance and color signals to form an image signal to be 
subsequently recorded on the length of magnetic recording tape, and a 
cylinder control 117 for detecting a deviation in both speed and phase of 
the head-carrier cylinder 113 in reference to the frequency signal and the 
switching pulse supplied respectively from the frequency generator 114 and 
the pulse generator 115 and then to output control information, necessary 
to permit the head-carrier cylinder 113 to undergo the normal rotation, to 
a drive circuit 118. The drive circuit 118 is operable to drive a drive 
motor (not shown) for driving the head-carrier cylinder 113 at the 
prescribed speed in reference to the control information supplied from the 
cylinder control 117. 
The record shutoff mechanism includes an error determining circuit 119 
operable in reference to information supplied from the cylinder control 
117 and indicative of the deviation in speed of rotation of the 
head-carrier cylinder 113 to determine whether or not a video recording 
then taking place is called for by an operator of the video camera, and a 
warning means 120 operable to provide the operator with an indication of 
an erroneous video recording taking place. 
The video camera further comprises a sound recording and reproducing system 
of any known circuit configuration which is herein neither discussed nor 
shown for the sake of brevity since it does not constitute subject matter 
of the present invention. 
Hereinafter, the operation of each of the camera unit, the VTR unit and the 
system control microcomputer 111 will be described. 
Camera Unit 
Rays of light carrying an image of the object to be videoed and having 
passed through the optical system 101 are converted by the imaging element 
102 into an electric signal which is subsequently converted by the camera 
signal processing circuit 103 into luminance and color signals. The 
luminance and color signals outputted from the signal processing circuit 
103 are stored in the memory 104 for each field or frame. The luminance 
signal outputted from the signal processing circuit 103 is also supplied 
to the motion vector detector 105. In this motion vector detector 105, the 
luminance signal from the signal processing circuit 103 is divided into a 
plurality of areas; a motion vector of the image in each of these divided 
areas is calculated for each field or frame; the validity of the motion 
vector in each of these divided areas is then determined; a vector 
coefficient representative of the degree of dispersion of the motion 
vectors is calculated in reference to the motion vector and the validity 
thereof; and the motion vector of the image based on these elements is 
finally calculated. 
As hereinbefore indicated, the motion vector detector 105 may be the one 
disclosed in the Japanese Laid-open Patent Publication No. 3-198488 to 
which, in the case where a portion of the viewed image of the object being 
videoed undergoes a motion and an error would likely occur in detecting 
the motion vector, an erroneous detection can be suppressed by controlling 
the magnitude of the motion vector outputted therefrom. 
VTR Unit 
Assuming that the signal processing circuit 116, the cylinder control 117 
and the drive circuit 118 are started in response to the information 
generated from the system control microcomputer 111, the drive circuit 118 
supply an electric signal to the head-carrier cylinder 113 to drive the 
latter. While the headcarrier cylinder 113 is so driven in one direction 
in any known manner, the frequency generator 114 and the pulse generator 
115 output the frequency signal and the switching pulse, respectively. In 
this way, the frequency signal and the switching pulse altogether provide 
the drive circuit 118 and the error determining circuit 119 with 
information representative of a change in rotation of the head-carrier 
cylinder 113, which information is hereinafter referred to as "cylinder 
surge information". While the cylinder control 117 is so structured as 
shown in FIG. 3 and will be described later, the drive circuit 118, in 
response to the head surge information controls the head-carrier cylinder 
113 to compensate for a change in rotation, thereby eliminating the change 
in rotation of the head-carrier cylinder 113. 
On the other hand, the video signal outputted from the memory 104 is 
supplied to the VTR signal processing circuit 116 by which the video 
signal is separated into luminance and color signals which are 
subsequently supplied to the magnetic heads 112 to record them on the 
length of magnetic recording tape. Although the magnetic heads 112 are 
generally employed not only for information recording purpose, but also 
for information reproducing purpose as is well known to those skilled in 
the art and, therefore, the video camera is also provided with a signal 
processing system associated with the information reproduction, it will 
not be described herein since the information reproduction system is 
irrelevant to the subject matter of the present invention. 
Referring to FIGS. 1 and 3 for discussion of the cylinder control 117, the 
cylinder control 117 includes a speed detecting circuit 301 for detecting 
the speed of rotation (the number of revolutions) of the head-carrier 
cylinder 113 in reference to the frequency signal supplied from the 
frequency generator or rotation sensor 114; a speed control circuit 302 
operable in response to an output from the speed detecting circuit 301 to 
provide a speed control signal necessary to drive the head-carrier 
cylinder 113 at the prescribed speed; a phase detecting circuit 303 for 
detecting the phase of rotation of the head-carrier cylinder 113 in 
reference to the switching pulse supplied from the pulse generator or 
angle sensor 115; a phase control circuit 305 adapted to receive a phase 
signal from the phase detecting circuit 303 and a reference signal which 
consists of a servo signal and a sync signal defining reference for the 
video signal and to output a phase control signal necessary to drive the 
head-carrier cylinder 113 at a predetermined phase; and an adder circuit 
306 for weighing both of the speed control signal from the speed control 
circuit 302 and the phase control signal from the phase control circuit 
305 and summing the weighed speed and phase control signals together to 
provide the drive circuit 118 with the cylinder surge information. 
During rotation of the head-carrier cylinder 113, the speed detecting 
circuit 301 analyzes the frequency signal from the frequency generator 114 
to detect the speed of the head-carrier cylinder 113 and then outputs the 
speed signal to the speed control circuit 302. In response to the speed 
signal from the speed detecting circuit 301, the speed control circuit 302 
outputs to the adder circuit 306 the speed control signal necessary to 
drive the head-carrier cylinder 113 at the predetermined speed. On the 
other hand, the phase detecting circuit 303 analyzes the switching pulse 
from the pulse generator 115 to detect the phase of rotation of the 
head-carrier cylinder 113 and then outputs the phase signal to the phase 
control circuit 305. Upon receipt of the phase signal from the phase 
detecting circuit 303 and the reference signal, the phase control circuit 
305 outputs to the adder circuit 306 the phase control signal necessary to 
drive the head-carrier cylinder 113 at the predetermined phase. The adder 
circuit 306 performs a weighing of both of the speed control signal from 
the speed control circuit 302 and the phase control signal from the phase 
control circuit 305 and summing of the weighed speed and phase control 
signals together to provide a result of calculation performed thereby, 
that is, the cylinder surge information, which is then supplied to the 
drive circuit 118. 
It is to be noted that the sync signal included in the reference signal is 
supplied to various circuit components of the video camera as is well 
known to those skilled in the art and, therefore, the supply of the sync 
signal to the various circuit components of the video camera will not be 
described in detail for the sake of brevity as it is irrelevant to the 
subject matter of the present invention. 
System control microcomputer 111 
The system control microcomputer 111 receives information representative of 
switching states of the REC button 108, the STOP button 109, the disable 
button 110 and other buttons and is, based on those pieces of information, 
operable to supply those pieces of information to the error determining 
circuit 119 for each field or frame and also to control the camera unit, 
the VTR unit and other mechanisms. 
Error determining circuit 119 
The operation of the error determining circuit 119 may be implemented by a 
software program executed by a microcomputer and, therefore, reference 
will be made to the flowchart shown in FIG. 4. 
FIG. 4 illustrates the sequence of operation of the error determining 
circuit 119 executed by a microcomputer. Subsequent to start of the 
program flow, and at step 1A, query is made to the system control 
microcomputer 111 if the various buttons including the REC button 108 and 
so on are switched on. At subsequent step 2A, the microcomputer receives 
from the system control microcomputer 111 the information indicative of 
the respective switching states of the various buttons and stores the 
information in a memory, followed by step 3A at which a decision is made 
to determine the status of the REC button 108. Where step 3A determines 
that the REC button 108 has been switched off, the program flow goes back 
to step 1A, but where the step 3A determines that the REC button 108 has 
been switched on, the program flow goes to step 4A at which a determining 
counter which is a variable provided in the memory of the microcomputer is 
reset. The determining counter represents a variable indicative of how 
many fields or frames a video recording takes place. At step 5A subsequent 
to the resetting of the determining counter, a decision is made to 
determine the status of the disable button 110. Should step 5A determine 
that the disable button 110 has been switched on, indicating that the 
operator of the video camera has no intention to utilize the record 
shutoff mechanism, the program flow goes back to step 1A, but it goes to 
subsequent step 6A if the disable button 110 is found having been switched 
off. 
At step 6A, a decision is made to determine the status of the STOP button 
109. If the STOP button 109 is found having been switched on, indicating 
that the video recording is interrupted according to the will of the 
operator, the program flow goes back to step 1A. However, if the STOP 
button 109 is found having been switched off, the program flow goes to 
step 7A at which the microcomputer acquires the cylinder surge information 
from the cylinder control 117 and stores it in the memory. At subsequent 
step 8A, a decision is made to determine if the cylinder surge, that is, 
change in rotation of the head-carrier cylinder 113, is considerable. In 
the event that a result of decision at step 8A indicates NO indicating 
that the cylinder surge is not considerable, the program flow goes back to 
step 1A, but in the event of the contrary (YES indicating that the 
cylinder surge is considerable), the program flow goes to subsequent step 
9A at which the determining counter is incremented by 1 (one) and then to 
step 10A at which a decision is made to determine whether the count of the 
determining counter is greater than a predetermined value N. 
It is to be noted that the fact that the microcomputer has proceeded from 
the start to step 9A means that an erroneous recording or an uncalled-for 
video recording takes place at that field or frame and, therefore, at step 
9A the determining counter is incremented by 1 as described above. 
At decision step 10A, if the count of the determining counter is found to 
be smaller than the predetermined value N as indicated by YES, the program 
flow goes back to step 5A so that decision can be made to determine 
whether or not the erroneous recording takes place during the subsequent 
field or frame. 0n the other hand, if the count of the determining counter 
is found to be greater than the predetermined value N as indicated by NO, 
it means that the erroneous recording is taking place and, therefore, the 
program flow goes to step 11A at which information necessary to activate 
the warning means 120 is supplied to the system control microcomputer 111. 
Activation of the warning means 120 is represented by blinking of a light 
emitting diode (not shown) and/or display of a warning symbol within the 
framework of the viewfinder 201. 
At step 12A, a warning timer which is a variable stored in the memory of 
the microcomputer is reset. The warning timer is a variable indicative of 
whether or not no response is made by the operator during a period 
corresponding to some fields or frames subsequent to activation of the 
warning means 120. At subsequent step 13A, query is made to the system 
control microcomputer 111 if the various buttons including the REC button 
108 and so on are switched on. Then, at step 14A, the microcomputer 
receives from the system control microcomputer 111 the information 
indicative of the respective switching states of the various buttons and 
stores the information in a memory, followed by step 15A at which a 
decision is made to determine the status of the disable button 110. Where 
step 15A determines that the disable button 110 been switched on, 
indicating that the operator has no intention to utilize the record 
shutoff mechanism, the program flow goes back to step 1A, but where the 
step 15A determines that the disable button 110 has been switched off, the 
program flow goes to step 16A at which decision is made to determine the 
status of the STOP button 109. 
If at step 16A the STOP button 109 is found having been switched on, 
indicating that the operator has intentionally interrupted the video 
recording, the program flow goes back to step 1A, but if the STOP button 
109 is found having been switched off, the program flow goes to step 17A. 
It is to be noted that the fact that the microcomputer has proceeded from 
the start to step 17A means that no response was available from the 
operator of the video camera at that field or frame, and therefore, the 
count of the warning timer is incremented by 1 at step 17A. 
At subsequent step 18A, a decision is made to determine whether or not the 
count of the warning timer is smaller than a predetermined value T. If the 
count of the warning timer is found to be greater than the predetermined 
value T as indicated by NO, indicating that the erroneous or uncalled-for 
recording is taking place, the program flow goes to step 19A, but if the 
count of the warning timer is found to be smaller than the predetermined 
value T as indicated by YES, the program flow goes back to sep 13A so that 
warning can be made after lapse of a time corresponding to the next 
succeeding field or frame period. 
The fact that the microcomputer has proceeded to step 19A means that it has 
been determined that the erroneous or uncalled for video recording has 
taken place, and accordingly, at step 19A, information necessary to switch 
the REC button 108 off is supplied to the system control microcomputer 111 
so that the video recording can be automatically shut off. Thereafter, the 
program flow returns to step 1A. 
According to the program flow shown in and described with reference to FIG. 
4, the occurrence of a condition in which rotation of the head-carrier 
cylinder 113 fluctuates for a substantial length of time represents the 
erroneous or uncalled-for video recording taking place. In general, a 
camera wobbling would little occur so long as the video recording takes 
place in accordance with the will of the operator and change in rotation 
of the head-carrier cylinder 113 is substantially little. On the other 
hand, if the operator walks around with the video camera hung from the 
shoulder while he or she has failed or forgot to switch the REC button 108 
off, or under a condition in which the video camera is caused to undergo a 
considerable motion without the REC button 108 switched off, change in 
rotation of the head-carrier cylinder 113 is correspondingly considerable. 
Accordingly, by utilizing the cylinder surge information, it is possible 
to avoid the possibility of the erroneous or uncalled-for video recording 
taking place. 
FIG. 5 illustrates the video camera according to a second preferred 
embodiment of the present invention. In FIG. 5, component parts of FIG. 5 
similar to those shown in FIG. 1 are designated by like reference numerals 
and only the difference between the video camera of FIG. 1 and that of 
FIG. 5 will be discussed. In this embodiment of FIG. 5, briefly speaking, 
the motion vector detector 105 and the error determining circuit 119 both 
shown in FIG. 1 are substituted by a motion vector detector 105B and an 
error determining circuit 119B, respectively. 
The motion vector detector 105B shown in FIG. 5 is operable to calculate a 
motion vector of the image in each of the divided areas for each field or 
frame period, to determine the validity of the motion vector in each of 
these divided areas, to calculate the degree of dispersion of the motion 
vectors in reference to the validities and finally to calculate the motion 
vector of the image based on these elements. Information indicative of the 
validities of the respective motion vectors in the divided areas and the 
vector coefficient representative of the degree of dispersion are 
outputted from the motion vector detector 105B to the error determining 
circuit 119B. This error determining circuit 119B shown in FIG. 5 is 
operable to determine whether or not the video recording then taking place 
is intentionally carried out by the operator, in reference to the cylinder 
surge information supplied from the cylinder control 117 and also to image 
wobbling information supplied from the motion vector detector 105B. While 
the motion vector detector 105B employed in the present invention may be 
of a structure disclosed in the Japanese Laid-open Patent Publication No. 
3-198488 referred to hereinbefore, it is noted that the motion vector 
detector disclosed in the No. 3-198488 publication is used to determine 
the motion vector for the purpose of minimizing any possible influence 
brought on the videoed image by a camera wobbling whereas the motion 
vector detector 105B employed in the practice of the present invention 
makes use of "information indicative of whether or not the motion vector 
in each of the divided areas is valid (validity determining information)" 
and the "motion vector coefficient", both calculated in the motion vector 
detector of the No. 3-198488 publication, for the purpose of avoiding the 
erroneous or uncalled-for video recording. 
The operation of the video camera shown in FIG. 5 will now be described 
with reference to the flowcharts of FIGS. 6 and 7. Subsequent to start of 
the program flow, and at step 1B, query is made to the system control 
microcomputer 111 if the various buttons including the REC button 108 and 
so on are switched on. At subsequent step 2B, the microcomputer receives 
from the system control microcomputer 111 the information indicative of 
the respective switching states of the various buttons and stores the 
information in a memory, followed by step 3B at which a decision is made 
to determine the status of the REC button 108. Where step 3B determines 
that the REC button 108 has been switched off, the program flow goes back 
to step 1B, but where the step 3B determines that the REC button 108 has 
been switched on, the program flow goes to step 4B at which a determining 
counter which is a variable provided in the memory of the microcomputer is 
reset. The determining counter represents a variable indicative of how 
many fields or frames a video recording takes place. At step 5B subsequent 
to the resetting of the determining counter, a decision is made to 
determine the status of the disable button 110. Should step 5B determine 
that the disable button 110 has been switched on, indicating that the 
operator of the video camera has no intention to utilize the record 
shutoff mechanism, the program flow goes back to step 1B, but it goes to 
subsequent step 6B if the disable button 110 is found having been switched 
off. 
At step 6B, a decision is made to determine the status of the STOP button 
109. If the STOP button 109 is found having been switched on, indicating 
that the video recording is interrupted according to the will of the 
operator, the program flow goes back to step 1B. However, if the STOP 
button 109 is found having been switched off, the program flow goes to 
step 7B at which the microcomputer acquires the cylinder surge information 
from the cylinder control 117 and stores it in the memory. At subsequent 
step 8B, a decision is made to determine if the cylinder surge, that is, 
change in rotation of the head-carrier cylinder 113, is considerable. In 
the event that a result of decision at step 8B indicates NO indicating 
that the cylinder surge is not considerable, the program flow goes back to 
step 1B, but in the event of the contrary (YES indicating that the 
cylinder surge is considerable), the program flow goes to subsequent step 
9B at which the microcomputer acquires the information on the motion 
vector validity information and the information on the degree of 
dispersion both supplied from the motion vector detector 105B and store 
them in the memory. 
At subsequent step 10B, a decision is made, based on the vector validity 
information, to determine if the motion vectors for all areas are not 
valid. In the event that the decision at step 10B indicates that the 
motion vector for at least portion of the areas is valid as indicated by 
NO, the program flow goes to subsequent decision step 11B, but in the 
event that the decision at step 10B indicates that the motion vector for 
all of the areas is not valid as indicated by YES, the program flow skips 
step 11B onto step 12B. 
In general, little camera wobbling would occur so long as the video 
recording takes place in accordance with the will of the operator and 
change in rotation of the head-carrier cylinder 113 is substantially 
small. Under this condition, a vector detecting range is exceeded and, 
therefore, no valid motion vector is available. Because of this, the 
decision at step 10B corresponds to a determination of the magnitude of 
wobbling of the video camera. At step 11B, a decision is made to determine 
if the motion vector coefficient representative of the degree of 
dispersion is smaller than a predetermined value. If the decision at step 
11B indicates that the motion vector coefficient is smaller than the 
predetermined value, the program flow goes back to step 1A as indicated by 
YES, but if it indicates that the motion vector coefficient is greater 
than the predetermined value as indicated by NO, the program flow goes to 
subsequent step 12B. 
In general, little camera wobbling would occur so long as the video 
recording takes place in accordance with the will of the operator and 
change in rotation of the head-carrier cylinder 113 is substantially 
small. On the other hand, if the operator walks around with the video 
camera hung from the shoulder while he or she has failed or forgot to 
switch the REC button 108 off, the video camera is not only wobbled left 
and right or up and down, but also twisted. In such case, the motion 
vector coefficient increases to a value enough to make the determination 
at step 11B possible to execute. The fact that the microcomputer has 
proceeded from the start to step 12B means that the erroneous or 
uncalled-for video recording takes place at that field or frame, and 
therefore, the determining counter is incremented by 1 (one) at step 12B, 
followed by step 13B. 
Then at step 13B, a decision is made to determine if the count of the 
determining counter is smaller than the predetermined value N. If the 
count of the determining counter is found to be smaller than the 
predetermined value N as indicated by YES, the program flow goes back to 
step 5B so that decision can be made to determine whether or not the 
erroneous recording takes place during the subsequent field or frame. On 
the other hand, if the count of the determining counter is found to be 
greater than the predetermined value N as indicated by NO, it means that 
the erroneous recording is taking place and, therefore, a warning 
subroutine shown in FIG. 7 is executed. 
Referring now to FIG. 7, at step 14B, the information necessary to activate 
the warning means 120 is supplied to the system control microcomputer 111. 
Activation of the warning means 120 is represented by blinking of a light 
emitting diode (not shown) and/or display of a warning symbol within the 
framework of the viewfinder 201. Then at step 15B, a warning timer which 
is a variable stored in the memory of the microcomputer is reset. The 
warning timer is a variable indicative of whether or not no response is 
made by the operator during a period corresponding to some fields or 
frames subsequent to activation of the warning means 120. At subsequent 
step 16B, query is made to the system control microcomputer 111 if the 
various buttons including the REC button 108 and so on are switched on. 
Then, at step 17B, the microcomputer receives from the system control 
microcomputer 111 the information indicative of the respective switching 
states of the various buttons and stores the information in a memory, 
followed by step 18B at which a decision is made to determine the status 
of the disable button 110. Where step 18B determines that the disable 
button 110 been switched on, indicating that the operator has no intention 
to utilize the record shutoff mechanism, the program flow goes back to 
step 1B, but where the step 18B determines that the disable button 110 has 
been switched off, the program flow goes to step 19B at which decision is 
made to determine the status of the STOP button 109. 
If at step 19B the STOP button 109 is found having been switched on, 
indicating that the operator has intentionally interrupted the video 
recording, the program flow goes back to step 1B, but if the STOP button 
109 is found having been switched off, the program flow goes to step 20B. 
It is to be noted that the fact that the microcomputer has proceeded from 
the start to step 20B means that no response was available from the 
operator of the video camera at that field or frame, and therefore, the 
count of the warning timer is incremented by 1 at step 20B. 
At subsequent step 21B, a decision is made to determine whether or not the 
count of the warning timer is smaller than a predetermined value T. If the 
count of the warning timer is found to be greater than the predetermined 
value T as indicated by NO, indicating that the erroneous or uncalled-for 
recording is taking place, the program flow goes to step 22B, but if the 
count of the warning timer is found to be smaller than the predetermined 
value T as indicated by YES, the program flow goes back to sep 16B so that 
warning can be made after lapse of a time corresponding to the next 
succeeding field or frame period. 
The fact that the microcomputer has proceeded to step 22B means that it has 
been determined that the erroneous or uncalled-for video recording has 
taken place, and accordingly, at step 22B, information necessary to switch 
the REC button 108 off is supplied to the system control microcomputer 111 
so that the video recording can be automatically shut off. Thereafter, the 
program flow returns to step 1B. 
Thus, according to the second preferred embodiment of the present 
invention, by the utilization of the information on the validity of the 
motion vectors and the motion vector coefficient representative of the 
degree of dispersion, in addition to the cylinder surge information, it is 
possible to accurately detect whether or the video camera is wobbled. 
FIG. 8 illustrates the video camera according to a third preferred 
embodiment of the present invention. In FIG. 8, component parts of FIG. 8 
similar to those shown in FIG. 1 are designated by like reference numerals 
and only the difference between the video camera of FIG. 1 and that of 
FIG. 8 will be discussed. In this embodiment of FIG. 8, briefly speaking, 
the video camera is additionally provided with an eye sensor 107 operable 
to detect whether or not the operator views through the viewfinder 201 and 
the error determining circuit 119 employed in the first embodiment of the 
present invention is replaced with an error determining circuit 119 of a 
type which utilizes an output signal from the eye sensor 107 and the 
cylinder surge information from the cylinder control 117 to determine if 
the video recording then taking place is intentionally carried out by the 
operator. 
The operation of the video camera shown in FIG. 8 will now be described 
with reference to the flowcharts of FIGS. 9 and 10. 
As shown in FIG. 9, subsequent to start of the program flow, and at step 
1C, query is made to the system control microcomputer 111 if the various 
buttons including the REC button 108 and so on are switched on. At 
subsequent step 2C, the microcomputer receives from the system control 
microcomputer 111 the information indicative of the respective switching 
states of the various buttons and stores the information in a memory, 
followed by step 3C at which a decision is made to determine the status of 
the REC button 108. Where step 3C determines that the REC button 108 has 
been switched off, the program flow goes back to step 1C, but where the 
step 3C determines that the REC button 108 has been switched on, the 
program flow goes to step 4C at which a determining counter which is a 
variable provided in the memory of the microcomputer is reset. The 
determining counter represents a variable indicative of how many fields or 
frames a video recording takes place. At step 5C subsequent to the 
resetting of the determining counter, a decision is made to determine the 
status of the disable button 110. Should step 5C determine that the 
disable button 110 has been switched on, indicating that the operator of 
the video camera has no intention to utilize the record shutoff mechanism, 
the program flow goes back to step 1C, but it goes to subsequent step 6C 
if the disable button 110 is found having been switched off. 
At step 6C, a decision is made to determine the status of the STOP button 
109. If the STOP button 109 is found having been switched on, indicating 
that the video recording is interrupted according to the will of the 
operator, the program flow goes back to step 1C. However, if the STOP 
button 109 is found having been switched off, the program flow goes to 
step 7C at which the microcomputer acquires from the eye sensor 107, and 
then stores, eye sensor information indicative of whether the operator 
views through the viewfinder 201. 
A decision of whether or not the operator views through the viewfinder 201 
is made at subsequent step 8C. If the result of decision at step 8C 
indicates that the operator is looking at the image through the viewfinder 
201 as indicated YES, this means that the operator wishes to continue the 
video recording and, therefore, the program flow goes back to step 1C. On 
the other hand if it indicates that the operator is not looking at the 
image through the viewfinder 201 as indicated by NO, the program flow goes 
to subsequent step 9C at which the microcomputer acquires the cylinder 
surge information from the cylinder control 117 and stores it in the 
memory. Then at step 10C, a decision is made to determine if the cylinder 
surge, that is, change in rotation of the head-carrier cylinder 113, is 
considerable. In the event that a result of decision at step 10C indicates 
NO indicating that the cylinder surge is not considerable, the program 
flow goes back to step 1C, but in the event of the contrary (YES 
indicating that the cylinder surge is considerable), the program flow goes 
to subsequent step 11C. 
The fact that the microcomputer has proceeded from the start to step 11C 
means that the erroneous or uncalled-for video recording takes place at 
that field or frame, and therefore, the determining counter is incremented 
by 1 (one) at step 11C, followed by step 11C. 
Then at step 12C, a decision is made to determine if the count of the 
determining counter is smaller than the predetermined value N. If the 
count of the determining counter is found to be smaller than the 
predetermined value N as indicated by YES, the program flow goes back to 
step 5C so that decision can be made to determine whether or not the 
erroneous recording takes place during the subsequent field or frame. On 
the other hand, if the count of the determining counter is found to be 
greater than the predetermined value N as indicated by NO, it means that 
the erroneous recording is taking place and, therefore, a warning 
subroutine shown in FIG. 10 is executed. 
Referring now to FIG. 10, at step 13C, the information necessary to 
activate the warning means 120 is supplied to the system control 
microcomputer 111. Activation of the warning means 120 may include 
blinking of a light emitting diode (not shown) and/or display of a warning 
symbol within the framework of the viewfinder 201. Then at step 14C, a 
warning timer which is a variable stored in the memory of the 
microcomputer is reset. The warning timer is a variable indicative of 
whether or not no response is made by the operator during a period 
corresponding to some fields or frames subsequent to activation of the 
warning mens 120. At subsequent step 15C, query is made to the system 
control microcomputer 111 if the various buttons including the REC button 
108 and so on are switched on. Then, at step 16C, the microcomputer 
receives from the system control microcomputer 111 the information 
indicative of the respective switching states of the various buttons and 
stores the information in a memory, followed by step 17C at which a 
decision is made to determine the status of the disable button 110. Where 
step 17C determines that the disable button 110 has been switched on, 
indicating that the operator has no intention to utilize the record 
shutoff mechanism, the program flow goes back to step 1C, but where the 
step 17C determines that the disable button 110 has been switched off, the 
program flow goes to step 18C at which decision is made to determine the 
status of the STOP button 109. 
If at step 18C the STOP button 109 is found having been switched on, 
indicating that the operator has intentionally interrupted the video 
recording, the program flow goes back to step 1C, but if the STOP button 
109 is found having been switched off, the program flow goes to step 19C 
at which the microcomputer acquires and stores the eye sensor information 
from the eye sensor 107. Then at step 20C a decision is made to determine 
whether or not the operator views through the viewfinder 201. If the 
result of decision at step 20C indicates that the operator is looking at 
the image through the viewfinder 201 as indicated YES, this means that the 
operator wishes to continue the video recording and, therefore, the 
program flow goes back to step 1C. On the other hand if it indicates that 
the operator is not looking at the image through the viewfinder 201 as 
indicated by NO, the program flow goes to subsequent step 21C at which the 
warning timer is incremented by 1. 
It is to be noted that the fact that the microcomputer has proceeded from 
the start to step 21C means that no response was available from the 
operator of the video camera at that field or frame, and therefore, the 
count of the warning timer is incremented by 1 at step 21C as described 
above. 
At subsequent step 22C, a decision is made to determine whether or not the 
count of the warning timer is smaller than a predetermined value T. If the 
count of the warning timer is found to be greater than the predetermined 
value T as indicated by NO, indicating that the erroneous or uncalled-for 
recording is taking place, the program flow goes to step 23C, but if the 
count of the warning timer is found to be smaller than the predetermined 
value T as indicated by YES, the program flow goes back to sep 15C so that 
warning can be made after lapse of a time corresponding to the next 
succeeding field or frame period. 
The fact that the microcomputer has proceeded to step 23C means that it has 
been determined that the erroneous or uncalled-for video recording has 
taken place, and accordingly, at step 23C, information necessary to switch 
the REC button 108 off is supplied to the system control microcomputer 111 
so that the video recording can be automatically shut off. Thereafter, the 
program flow returns to step 1C. 
Thus, according to the third embodiment of the present invention shown in 
and described with reference to FIGS. 8 to 10, both of the eye sensor 
information and the cylinder surge information are utilized to determine 
the occurrence of the erroneous or uncalled-for video recording taking 
place. Accordingly, the video camera according to this third embodiment of 
the present invention is effective to eliminate the inconveniences 
encountered with the video camera equipped with the record shutoff 
mechanism disclosed in the Japanese Laid-open Patent Publication No. 
3-274965 discussed hereinbefore. In other words, the video camera 
according to the third embodiment of the present invention is effective to 
eliminate the problem associated with the incapability of the video camera 
to make a high-angle video recording with the camera held overhead. 
The video camera according to a fourth preferred embodiment of the present 
invention will now be described with particular reference to FIGS. 11 to 
13. 
Referring first to FIG. 11, it is to be noted that component parts of FIG. 
11 similar to those shown in FIG. 5 are designated by like reference 
numerals and only the difference between the video camera of FIG. 5 and 
that of FIG. 11 will be discussed. In this embodiment of FIG. 11, briefly 
speaking, not only is the video camera additionally provided with an eye 
sensor circuit 107, as is the case with the third embodiment of the 
present invention, for detecting whether or not the operator looks at the 
image through the viewfinder 201, but also the error determining circuit 
119 employed in FIG. 5 is substituted by an error determining circuit 119D 
which utilizes the cylinder surge information supplied from the cylinder 
control 117, the camera wobbling information supplied from the motion 
vector detector 105B, and the eye sensor information supplied from the eye 
sensor 107 to determine whether or not the video recording then taking 
place is intentionally carried out by the operator. 
The video camera according to the fourth embodiment of the present 
invention operates in a manner as shown in FIGS. 12 and 13, reference to 
which will now be made. 
Subsequent to start of the program flow, and at step 1D, query is made to 
the system control microcomputer 111 if the various buttons including the 
REC button 108 and so on are switched on. At subsequent step 2D, the 
microcomputer receives from the system control microcomputer 111 the 
information indicative of the respective switching states of the various 
buttons and stores the information in a memory, followed by step 3D at 
which a decision is made to determine the status of the REC button 108. 
Where step 3D determines that the REC button 108 has been switched off, 
the program flow goes back to step 1D, but where the step 3D determines 
that the REC button 108 has been switched on, the program flow goes to 
step 4D at which a determining counter which is a variable provided in the 
memory of the microcomputer is reset. The determining counter represents a 
variable indicative of how many fields or frames a video recording takes 
place. At step 5D subsequent to the resetting of the determining counter, 
a decision is made to determine the status of the disable button 110. 
Should step 5D determine that the disable button 110 has been switched on, 
indicating that the operator of the video camera has no intention to 
utilize the record shutoff mechanism, the program flow goes back to step 
1D, but it goes to subsequent step 6D if the disable button 110 is found 
having been switched off. 
At step 6D, a decision is made to determine the status of the STOP button 
109. If the STOP button 109 is found having been switched on, indicating 
that the video recording is interrupted according to the will of the 
operator, the program flow goes back to step 1D. However, if the STOP 
button 109 is found having been switched off, the program flow goes to 
step 7D at which the microcomputer acquires from the eye sensor 107, and 
then stores, eye sensor information indicative of whether the operator 
views through the viewfinder 201. 
A decision of whether or not the operator views through the viewfinder 201 
is made at subsequent step 8D. If the result of decision at step 8D 
indicates that the operator is looking at the image through the viewfinder 
201 as indicated YES, this means that the operator wishes to continue the 
video recording and, therefore, the program flow goes back to step 1D. On 
the other hand if it indicates that the operator is not looking at the 
image through the viewfinder 201 as indicated by NO, the program flow goes 
to subsequent step 9D at which the microcomputer acquires the cylinder 
surge information from the cylinder control 117 and stores it in the 
memory. 
Then at step 10D, a decision is made to determine if the cylinder surge, 
that is, change in rotation of the head-carrier cylinder 113, is 
considerable. In the event that a result of decision at step 10D indicates 
NO indicating that the cylinder surge is not considerable, the program 
flow goes back to step 1C, but in the event of the contrary (YES 
indicating that the cylinder surge is considerable), the program flow goes 
to subsequent step 11D at which the microcomputer acquires, and stores in 
the memory, both of the validity information and the dispersion 
information from the motion vector detector 105B. 
Thereafter, at step 12D, a decision is made, based on the vector validity 
information, to determine if the motion vectors for all areas are not 
valid. In the event that the decision at step 12D indicates that the 
motion vector for at least portion of the areas is valid as indicated by 
NO, the program flow goes to subsequent decision step 13D, but in the 
event that the decision at step 12D indicates that the motion vector for 
all of the areas is not valid as indicated by YES, the program flow skips 
step 13D onto step 14D. If the decision at step 13D indicated that the 
motion vector coefficient is greater than the predetermined value, the 
program flow goes to step 14D, but if it indicates that the motion vector 
coefficient is smaller than the predetermined value, the program flow goes 
back to step 1D. 
The fact that the microcomputer has proceeded from the start to step 14D 
means that the erroneous or uncalled-for video recording takes place at 
that field or frame, and therefore, the determining counter is incremented 
by 1 (one) at step 14D, followed by step 15D at which a decision is made 
to determine if the count of the determining counter is smaller than the 
predetermined value N. If the count of the determining counter is found to 
be smaller than the predetermined value N as indicated by YES, the program 
flow goes back to step 5D so that decision can be made to determine 
whether or not the erroneous recording takes place during the subsequent 
field or frame. On the other hand, if the count of the determining counter 
is found to be greater than the predetermined value N as indicated by NO, 
it means that the erroneous recording is taking place and, therefore, a 
warning subroutine shown in FIG. 13 is executed. 
Referring now to FIG. 13, at step 16D, the information necessary to 
activate the warning means 120 is supplied to the system control 
microcomputer 111. Activation of the warning means 120 is represented by 
blinking of a light emitting diode (not shown) and/or display of a warning 
symbol within the framework of the viewfinder 201. Then at step 17D, a 
warning timer which is a variable stored in the memory of the 
microcomputer is reset. The warning timer is a variable indicative of 
whether or not no response is made by the operator during a period 
corresponding to some fields or frames subsequent to activation of the 
warning mens 120. At subsequent step 18D, query is made to the system 
control microcomputer 111 if the various buttons including the REC button 
108 and so on are switched on. Then, at step 19D, the microcomputer 
receives from the system control microcomputer 111 the information 
indicative of the respective switching states of the various buttons and 
stores the information in a memory, followed by step 20D at which a 
decision is made to determine the status of the disable button 110. 
Where step 20D determines that the disable button 110 been switched on, 
indicating that the operator has no intention to utilize the record 
shutoff mechanism, the program flow goes back to step 1D, but where the 
step 20D determines that the disable button 110 has been switched off, the 
program flow goes to step 21D at which decision is made to determine the 
status of the STOP button 109. If at step 21D the STOP button 109 is found 
having been switched on, indicating that the operator has intentionally 
interrupted the video recording, the program flow goes back to step 1D, 
but if the STOP button 109 is found having been switched off, the program 
flow goes to step 22D at which the microcomputer acquires from the eye 
sensor 107, and then stores, eye sensor information indicative of whether 
the operator views through the viewfinder 201. 
A decision of whether or not the operator views through the viewfinder 201 
is made at subsequent step 23D. If the result of decision at step 23D 
indicates that the operator is looking at the image through the viewfinder 
201 as indicated YES, this means that the operator wishes to continue the 
video recording and, therefore, the program flow goes back to step 1D. On 
the other hand if it indicates that the operator is not looking at the 
image through the viewfinder 201 as indicated by NO, the program flow goes 
to subsequent step 24D at which the warning timer is incremented by 1. 
It is to be noted that the fact that the microcomputer has proceeded from 
the start to step 24D means that no response was available from the 
operator of the video camera at that field or frame, and therefore, the 
count of the warning timer is incremented by 1 at step 24D as described 
above. 
At subsequent step 25D, a decision is made to determine whether or not the 
count of the warning timer is smaller than a predetermined value T. If the 
count of the warning timer is found to be greater than the predetermined 
value T as indicated by NO, indicating that the erroneous or uncalled-for 
recording is taking place, the program flow goes to step 26D, but if the 
count of the warning timer is found to be smaller than the predetermined 
value T as indicated by YES, the program flow goes back to sep 18D so that 
warning can be made after lapse of a time corresponding to the next 
succeeding field or frame period. 
The fact that the microcomputer has proceeded to step 26D means that it has 
been determined that the erroneous or uncalled-for video recording has 
taken place, and accordingly, at step 26D, information necessary to switch 
the REC button 108 off is supplied to the system control microcomputer 111 
so that the video recording can be automatically shut off. Thereafter, the 
program flow returns to step 1D. 
Thus, according to the fourth preferred embodiment of the present 
invention, the video camera is very convenient to handle because the 
nature of the video recording then taking place, that is, whether or not 
the video recording taking place is carried out as desired by the 
operator, is determined by the utilization of not only the eye sensor 
information furnished by the eye sensor 107, but also both of the cylinder 
surge information and the information on the validity of the motion 
vectors and the motion vector coefficient representative of the degree of 
dispersion. 
Although the present invention has been described in connection with the 
preferred embodiments thereof with reference to the accompanying drawings, 
it is to be noted that various changes and modifications are apparent to 
those skilled in the art. For example, although in FIG. 3 the cylinder 
surge information provided by the error determining means 119, 119B, 119C 
or 119D has been employed in the form of the output from the adder circuit 
306, the cylinder surge information may be represented by either one of 
the output from the speed control circuit 302 and the phase control 
circuit 305, or any other electric signal provided that the latter is 
indicative of change in rotation of the head-carrier cylinder 113. 
Also, although reference has been made to the utilization of the cylinder 
surge information, information indicative of change in rotation of a 
capstan used in the video camera to transport the length of magnetic 
recording tape past the head-carrier cylinder may be equally employed. In 
such case, a capstan control may be of a circuit design similar to that of 
the cylinder control 117 best shown in FIG. 3, provided that the frequency 
and pulse generator 114 and 115 and the drive circuit 118 are modified to 
be operatively associated with the capstan. 
Each of the error determining circuits 119, 119B, 119C and 119D employed in 
the various embodiments of the present invention can be implemented by the 
software program and may therefore be implemented by the system control 
microcomputer 111. 
In describing the operation of the error determining circuit 119B or 119D 
employed in each of the second and fourth embodiments of the present 
invention, it has been described that determination based on the cylinder 
surge information is followed by determination based on the motion vector 
information as shown in FIG. 6 or 12. However, the sequence of 
determination done by the error determining circuit 119B or 119D may be 
reversed with respect to that shown in FIG. 6 or 12. 
Also in describing the operation of the video camera according to the 
second embodiment of the present invention shown in FIG. 6, it has been 
described that if the decision at step 8B indicates that the change in 
rotation of the head-carrier cylinder 113 is considerable and not 
considerable, the program flow goes to step 9B and step 1B, respectively. 
However, it may be modified so that if the decision at step 8B indicates 
that the change in rotation of the head-carrier cylinder 113 is 
considerable and not considerable, the program flow goes to step 12B and 
step 9B, respectively. 
So far as the third embodiment of the present invention is concerned, the 
error determining circuit 119C has been shown as operable on a logic AND 
condition in which determination based on the eye sensor is followed by 
determination based on the cylinder surge information. However, it may be 
modified to operate on a logic OR condition in which no priority is given 
to the sequence of determination based on the eye sensor and that on the 
cylinder surge information. 
Similarly, although in the practice of the third embodiment of the present 
invention, the error determining circuit 119D has been shown as operable 
on a logic AND condition in which determination based on the eye sensor is 
followed by determination based on the cylinder surge information which is 
in turn followed by determination based on the motion vector information, 
it may be modified to operate in such a manner that, after the sequence of 
determination based on the cylinder surge information followed by that on 
the motion vector information, determination based on the eye sensor 
information is carried our depending on a logic OR condition between a 
result of either the determination based on the cylinder surge information 
or that on the motion vector information. 
Finally, the use of the camera wobbling detecting unit 121 in any one of 
the first and third embodiments of the present invention is not always 
essential and may therefore be dispensed with if desired. 
Accordingly, such changes and modifications are to be understood as 
included within the scope of the present invention as defined by the 
appended claims, unless they depart therefrom.