Abstract:
An image input device having: an image pickup unit to photograph an object and generate an image signal; an optical axis control unit to enable an optical axis of the image pickup unit to be moved; and a control unit to interlockingly control the optical axis control unit and the image pickup unit is described. The image input device may also have signal processing means for performing predetermined processes on the image signal, such as white balancing and automatic focusing. The image input device in accordance with the present invention is particularly suited for use in a television conferencing system.

Description:
This appln. is a cont. of Ser. No. 08/123,836 filed Sep. 20, 1993 Abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an image input device having a mechanism for enabling a photographing range to be moved and a mechanism for controlling an image state of the photographed image. 
     2. Related Background Art 
     In recent years, a video camera is widely used as an image input device for a computer. 
     Particularly, as a system in which a video camera and a computer or the like (for example, personal computer or work station) are combined, an electronic mail of an image or a television (TV) conference system is being used. 
     Hitherto, as a video camera apparatus of the image input device which is used in such an application field, a video camera which has been developed for the application for monitoring, a video camera having a lens which can be controlled by a remote operation, and the like have been known. 
     In case of using such an image input device for a television conference, however, there are the following various kinds of problems to be solved. 
     In the image input device as mentioned above, since an angle of camera cannot be remotely controlled, in case of using the image input device in a TV conference or the like, in order to change a photographing range, a plurality of video camera must be prepared and switched, so that its use efficiency is bad. 
     The video camera has an auto white balance function and an auto focusing function, or the like in which a state of the photographed image is automatically adjusted. 
     The auto focusing function is a function to automatically adjust a focal point to an in-focus state. 
     The auto white balance function will now be described. 
     Even in case of the same object, under different light sources, the spectral characteristics of the light which is reflected from the object are changed by being influenced by the spectral characteristics (light source color) of the light source, so that the color tone of the image plane differs. In this case, however, according to the human feeling, the man feels such that a special color, for example, white on the image plane is sensed as a color different from white which the man himself has stored or felt, so that there is a case where he feels unpleasant. The video camera, accordingly, has an auto white balance (AWB) function adjusting the color tone in accordance with the light source, thereby automatically adjusting the color tone so that the white color can be always seen as white at a predetermined level even under the light source. 
     As a method of white balance (WB) adjusting methods, there has conventionally been known a method whereby with reference to color difference signals R-Y and B-Y which are obtained by processing a plurality of chrominance signals obtained by, for example, a CCD or the like as an image pickup element, chrominance signals of, for example, three colors of R, G, and B, a control operation to change ratios among the chrominance signals R, G, and B in a manner such that the values obtained by integrating the color difference signals for a certain period of time become mininum is executed, thereby adjusting the WB. 
     In the video camera having such a WB adjusting function, there is a video camera such that just after the power source was turned on, the WB adjusting operation is automatically executed, thereby enabling a good image of a well-balanced WB to be obtained just after the turn-on of the power source. 
     However, when the WB adjusting operation of the camera is executed during the pan operation or tilt operation for changing the photographing range, the color of the image which is obtained from the CCD is unstable and the image becomes hard to see. 
     In case of the TV conference system since information is digitally transmitted, when an amount of information of the image data which is transmitted increases, it takes a time to transmit the information. A time difference occurs between the transmission side and the reception side. Such a drawback becomes a serious problem in a TV conference system which needs to execute operations in a real-time manner. 
     SUMMARY OF THE INVENTION 
     The invention is made under such circumstances and it is an object of the invention to solve the above problems and to provide an image input device which is particularly effective when the apparatus is used in a TV conference system. 
     To accomplish the above object, according to one preferred embodiment of the invention, there is provided an image input device comprising: image pickup means for photographing an object image; signal processing means for executing a predetermined signal process to an image signal that is generated from the image pickup means; an optical axis control means for changing an optical axis of a field of view which is photographed by the image pickup means; and control means for interlockingly controlling the image pickup means and the optical axis control means. 
     The above and other objects, features, and advantages of the invention will become apparent from the following detailed description taken in conjunction with the appended claims with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic block diagram showing an embodiment of the image input device of the invention; 
     FIG. 2 shows an example of schematic timings of the remote operation according to the invention and is a timing chart showing an example in the case where an optical axis control device and a focus control as interlocked; 
     FIG. 3 shows an example of schematic timings of the remote operation according to the invention and is a timing chart showing an example in the case where the optical axis control device, a focus control, and a position detection are interlocked; 
     FIG. 4 is a schematic block diagram for explaining an example of an accumulation control according to the invention; 
     FIG. 5 is a schematic timing chart for explaining an example of the accumulation control operation according to the invention; 
     FIG. 6 is an external view of an embodiment of the invention; 
     FIG. 7 is a diagram for explaining a drive mechanism in the horizontal direction in an embodiment of the invention; 
     FIG. 8 is a diagram for explaining a drive mechanism in the vertical direction in an embodiment of the invention; 
     FIG. 9 is a schematic flowchart for explaining an embodiment of the invention; 
     FIG. 10 is a schematic flowchart for explaining another embodiment of the invention; 
     FIG. 11 is a schematic block diagram for explaining another embodiment of the invention; 
     FIG. 12 is a schematic flowchart for explaining the operation of an image input apparatus in FIG. 11; 
     FIG. 13 is a schematic flowchart for explaining the operation of the image input apparatus in FIG. 11; and 
     FIG. 14 is a schematic flowchart for explaining the operation of the image input apparatus in FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of an image input apparatus of the invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic construction of the image input device of the embodiment. 
     In FIG. 1, the light from an object (not shown) passes through a lens  1  and an iris device  2  and reaches an image pickup device  3 . 
     The image pickup device  3  photoelectrically converts the light from the object and generates an electric signal and sends to a signal processing circuit  4 . The signal processing circuit  4  executes necessary signal processes to the inputted electric signal and produces a video signal and generates to the outside. For example, a WB control circuit  4   a  to control the white balance (WB) is included in the signal processing circuit  4 . The video signal produced as mentioned above is connected to a codec in, for example, a television (TV) conference system. 
     On the other hand, the video signal is sent from the signal processing circuit  4  to a camera control circuit  5 . The camera control circuit  5  is constructed by, for example, a small electronic computer and controls an iris drive circuit  6  in accordance with the level of the inputted video signal. Due to this, the iris device  2  is driven and is controlled so as to keep the video signal level constant. A drive amount by the iris drive circuit  6  can be adjusted by the camera control circuit  5  in accordance with information which is given from an I/F control circuit  9 . 
     The camera control circuit  5  generates control signals to a focus control circuit  7  and a zoom control circuit  8  and controls them, thereby controlling a focus amount and a zoom amount of the lens. Such zoom and focus controls can be performed in accordance with the information from the I/F control circuit  9 . 
     On the other hand, the camera control circuit extracts, for example, a high frequency component of the inputted video signal and can also drive the focus control circuit  7  so that the high frequency component amount becomes maximum. Namely, the camera control circuit  5  can also execute what is called an auto focus operation. The camera control circuit  5  can also control processing parameters which are necessary in the signal processing circuit  4  and image pickup device  3 . 
     The camera control circuit  5  executes the transmission and reception (communication) with the I/F control circuit  9 . The I/F control circuit  9  is connected to an external apparatus (for example, personal computer or work station) and can communicate therewith (for example, serial communication). 
     The I/F control circuit  9  can change the photographing direction by controlling a horizontal direction drive device  10  and a vertical direction drive device  11  which construct an optical axis control device  18 . In the horizontal and vertical movable portions of the drive devices  10  and  11 , a horizontal position detecting device  10   a  and a vertical position detecting device  11   a  are provided in order to detect the position information. The position information detected by the detecting devices  10   a  and  11   a  are sent to the I/F control circuit  9 . 
     By concentratedly managing the optical axis control system, camera control system, lens control system, and communication system with the outside by one control circuit  5  as mentioned above, a more proper control can be performed and a good image quality can be obtained. 
     The above point will now be specifically explained. In case of using the digital image transmission at the TV conference or the like hitherto, image information is compressed in order to reduce an amount of information which is transmitted. For example, there is a block coding method of the CCITT Recommendation (H.61) as a method which is well known as a compressing method of image information. In case of an image which vigorously moves, however, a compression ratio decreases and an amount of information to be transmitted is insufficient, so that there is a problem such that a reconstructed image becomes hard to see. Particularly, in case of changing a photographing range (in case of moving it in the horizontal and vertical directions), a whole image plane changes, so that a block distortion occurs in the whole image plane of the reconstructed image and the reconstructed image is extremely hard to see. 
     To avoid such problems, according to the embodiment, for instance, by deviating a focus of the lens before the optical axis control device is driven, the information amount of the image is reduced. After that, the optical axis control device is driven. The focus of the lens is adjusted after the optical axis control device was stopped. 
     The image input device of the embodiment has a WB control function. The WB control operation will now be described hereinbelow. 
     After the power supply of the image input device was turned on and predetermined initialization operations were finished (which will be explained hereinlater), the operation of the WB control circuit  4   a  is started. The WB control operation is stopped at a time point of the end of the WB adjustment. A WB control method is substantially the same as the method described in the foregoing conventional technique. At this time point, it is not always necessary to stop the WB control operation and no problem occurs even when the operation is continued. 
     In the case where the operation of the optical axis control device  18  is started by a control signal from the outside for a period of time during which the WB control operation is continued by the WB control circuit  4   a , the operation of the WB control circuit  4   a  is stopped by the camera control circuit  5 . During the operation of an optical axis control device  18 , all of instruction signals such as to start the operation of the WB control circuit  4   a  are ignored. 
     When the operation of the optical axis control device  18  is finished by a control signal from the outside, the camera control circuit  5  receives a signal indicative of the end of the operation of the optical axis control device  18  from the I/F control circuit  9  and starts the WB control operation by the WB control circuit  4   a . When the white balance is obtained, the WB control operation is finished or can be also continued as it is. 
     In a state in which the WB control operation by the WB control circuit  4   a  is stopped, the operation of the optical axis control apparatus  18  is started by the control signal from the outside. During the operation of the optical axis control device  18 , all of the instruction signals so as to start the operation of the WB control circuit  4   a  by the camera control circuit  5  are ignored. 
     When the operation of the optical axis control device  18  is finished by the control signal from the outside, the camera control circuit  5  receives the signal indicative of the completion of the operation of the optical axis control device  18  from the I/F control circuit  9  and starts the WB control operation by the WB control circuit  4   a . When the WB is obtained, the WB control operation is finished or can be also continued as it is. 
     That is, in the embodiment, as mentioned above, when the I/F control circuit  9  receives the signal to control the operation of the optical axis control device  18 , the horizontal direction drive device  10  and the vertical direction drive device  11  are driven and the camera control circuit  5  is controlled so as to deviate the focus. By this method, since a defocusing state is obtained for a period of time during which the whole image plane is moving, the high frequency component of the image decreases. Therefore, since an image information amount decreases, a block distortion is also reduced and a good image is derived. 
     When the I/F control circuit  9  stops the horizontal direction drive device  10  and the vertical direction drive device  11 , the camera control circuit  5  is also controlled so as to simultaneously make the auto focusing control and the WB control operative. Due to this, simultaneously with the stop of the drive devices  10  and  11 , the focus and WB can be correctly adjusted and a good image is derived. It is more preferably to start the WB adjustment after completion of the focusing adjustment. An outline of such a state is shown in a timing chart of FIG.  2 . 
     In FIG. 2, an axis or abscissa denotes a time base and oblique arrows C, D, and c in the diagram show the transfer of information. The arrows C and D indicate signals for control which are sent from a remote operation unit to the image input device. The arrow c indicates an image signal which is sent from the image input device to the remote operation unit. 
     In FIG. 2, the case where the driving of the optical axis control device  18  is stopped while looking at the image sent to the external operation unit side has been described. 
     As shown in the following example, however, by constructing in a manner such that a control signal indicating “in which direction (α) by which amount (β)” the optical axis control device  18  should be driven is sent from the remote operation unit side, an overoperation as shown in F-G in FIG. 2 is eliminated and the good operation can be executed. 
     A schematic timing chart of FIG. 3 shows an example in which such an operation is allowed to be executed. 
     In FIG. 3, suffixes added to the control signal C denote a code (α) indicative of the direction and a code (β) indicative of a drive amount. 
     As will be obviously understood from FIG. 3, when the control signal is sent from the remote control side to the image input device side, the optical axis is operated in the a direction by the optical axis control device  18  and, at the same time, the camera control unit  5  is controlled so as to obtain an out-of-focus state. When a fact that the optical axis was driven by only β is known from the information of the position detecting device ( 10   a  or  11   a ), the I/F control circuit  9  stops the motion of the optical axis control device  18  and, at the same time, makes the AF mechanism and WB control operative, thereby allowing a good image to be obtained. 
     An embodiment of the image input device according to the invention will now be described. As an embodiment, in case of using a solid state photographing device as a photographing device, there is a method whereby when the optical axis control device is driven, by setting an accumulation time of the image pickup element to be longer than that in the ordinary photographing mode (field accumulation or frame accumulation) in place of deviating the focus, a space frequency of the image is reduced. In this case, since the operations are substantially the same as those in the schematic timing chart in the embodiment mentioned above except the switching step of the accumulating mode, only switching means of the accumulating mode will now be described. 
     FIG. 4 is a schematic block diagram showing a construction of an embodiment of the portion regarding the switching of the accumulating mode. In FIG. 4, the same portions as those in FIG. 1 to explain the foregoing embodiment are designated by the same reference numerals. 
     In FIG. 4, the light from an object (not shown) is photoelectrically converted by a solid state image pickup element  3 - 1 . For example, the solid state image pickup element  3 - 1  is constructed by a CCD image pickup device of the interline type and time-sequentially generates a video signal and sends to a process circuit  4 - 1  at the post stage. 
     The process circuit  4 - 1  executes necessary processes (for example, gamma process, white balance process, color difference matrix process, and the like) as a video image signal. After completion of the necessary signal proceses as mentioned above, the signal generated from the process circuit  4 - 1  is supplied to one end of a change-over switch  4 - 6  and is also sent to a memory unit  4 - 3 . 
     A signal which is generated from the memory unit  4 - 3  is given to the other end of the change-over switch  4 - 6  to which the output signal from the process circuit  4 - 1  is given. A neutral point of the switch  4 - 6  is connected to an encoder circuit  4 - 2 . The signal selected by the switch  4 - 6  is supplied to the encoder circuit  4 - 2 . The encoder circuit  4 - 2  converts the input signal into the video signal and generates the video signal. 
     On the other hand, the image pickup element  3 - 1  is driven through a buffer circuit  3 - 2  by a group of pulses (a pulse Ø H  for H transfer, a pulse Ø V  for V transfer, a reset pulse Ø R , a transfer gate pulse Ø T , etc.) generated by a drive pulse generation circuit  3 - 3 . The transfer gate pulse Ø T  is supplied to the buffer circuit  3 - 2  through a gate circuit  3 - 4 . 
     A signal from a synchronism (sync) signal generation circuit  4 - 4  is supplied to the drive pulse generation circuit  3 - 3 , thereby matching the timing with sync signals (H and V field pulses) of the video. 
     The sync signal from the sync signal generation circuit  4 - 4  is also supplied to an accumulation signal generation circuit  4 - 5  to generate a signal for control of an accumulation time and to the memory unit  4 - 3 . A control signal is also supplied to the accumulation signal generation circuit  4 - 5  from the camera control circuit  5  (or I/F control circuit  9 ). When the control signal is supplied to the accumulation signal generation circuit  4 - 5 , the signal for the accumulation time control is generated on a vertical period V unit basis. 
     One of two output signals of the accumulation signal generation circuit  4 - 5  is supplied to a switching terminal of the change-over switch  4 - 6  and to the memory unit  4 - 3 . When the signal is read out from the image pickup element  3 - 1 , the change-over switch  4 - 6  is connected to the process circuit  4 - 1  side, thereby allowing a signal of the real time to be generated. 
     While the signal is being accumulated in the image pickup element  3 - 1 , the switch  4 - 6  is connected to the memory unit  4 - 3  side, thereby outputting the image from the memory unit and interpolating. 
     The output of the accumulation signal generation circuit  4 - 5  is also supplied to the gate circuit  3 - 4  and a transfer gate pulse Ø T  is controlled by a signal for the accumulating time control. The transfer gate pulse Ø T  is a signal to read out the charges accumulated in a photoelectric converting section (for example, photodiode) in a CCD solid image pickup element and to transfer the charges to a CCD shift register for transfer (CCD shift register in the V direction). 
     Therefore, when the transfer gate pulse Ø T  is not supplied, the charges which were photoelectrically converted into the electric signal are not read out but are held in a state in which they are accumulated in the photodiode, so that the accumulating time is long. In this instance, when there is a motion in the photographed image, its electric signal is averaged by the accumulating time, so that the high frequency component of the image decreases. 
     FIG. 5 shows an example of a schematic timing chart among the transfer gate pulse Ø T  when the accumulating time is long, the output signal of the image pickup element  3 - 1 , and the interpolation signal by the memory unit  4 - 3 . As for the output signal of the image pickup element  3 - 1 , the timing in the case where a sensor which operates in the field accumulating mode was used is shown. 
     In FIG. 5, a waveform shown at the top stage indicates a vertical sync pulse VD and a waveform shown at the second stage indicates a field pulse. The pulse waveform Ø T  at the third stage indicates a pulse after it was gated by the gate circuit  3 - 4  and a pulse is generated every two other fields. Although the gate pulse Ø T  is generated at every field in the ordinary operation, it is intermittently generated because the accumulating time control is executed in this case. 
     The field in which the gate pulse Ø T  was generated is outputted as a video signal from the image pickup element  3 - 1  because the charges of the photodiode are sent to a CCD transfer line. Such a state is diagrammatically shown at the fourth stage. In the diagram, reference mark O denotes a signal of the ODD field and E denotes a signal of the EVEN field. Each of the reference numerals shown as suffixes indicates the order of the signal shown in the diagram. 
     In two fields after the ODD field signal O 1  was generated as mentioned above, since there is no gate pulse Ø T , no signal is outputted. Therefore, a signal corresponding to those two fields is interpolated by the signals stored in the memory unit  4 - 3 . Such a state is shown at the fifth stage. 
     In the diagram, O i  denotes an interpolation signal for the ODD field and E i  denotes an interpolation signal for the EVEN field. Each of the reference numerals as suffixes  1 ,  2 , - - - written in the right lower positions indicates a memory output of the signal (signal which has previously been stored in the memory unit  4 - 3 ) of the same kind of field at the fourth stage in the diagram to which the same suffix was added. 
     By interpolating the signals as shown in FIG. 5, the accumulating time can be increased. Therefore, when an image plane moves for a long accumulating time, the images are averaged and an information amount can be reduced. 
     As another embodiment, there is also a method whereby the movement of the photographing position by the optical axis control device  18  is interlocked with the focusing and zoom states. 
     In case of the TV conference, for instance, when considering the case of photographing a few persons, the photographing position, focusing stage, and zoom state are determined for each person. Therefore, at the beginning of the conference, the focusing state and zoom state have previously been set into the I/F control circuit  9  by the remote operation in the initial setting in correspondence to each of the photographing positions. 
     In the subsequent operation, by presetting the I/F control circuit  9  so as to control the focusing and zoom states interlocking with the photographing position, only the information regarding the photographing position exists as control information from the outside and the focusing and zoom states are automatically properly adjusted, so that the photographing operation can be preferably executed. 
     A mechanism of the image input device, particularly, the optical axis control device of the embodiment will now be described with reference to FIGS. 6 to  8 . 
     FIG. 6 shows a schematic external view of the image input device of an embodiment of the invention. In FIG. 6, reference numeral  17  denotes a camera head having the image pickup device and the signal processing device. Reference numeral  18  indicates the optical axis control device which is constructed integratedly with the camera head  17  and is used to move the camera head  17  in the pan direction (horizontal direction) or in the tilt direction (vertical direction). 
     FIG. 7 shows an example of the optical axis control device  18  and, particularly, shows an outline of a mechanism to move the camera head  17  in the pan direction. FIG. 8 shows another example of the optical axis control device  18  and, particularly, shows an outline of a mechanism to move the camera head  17  in the tilt direction. 
     In FIG. 7, reference numeral  22  denotes a motor;  23  a worm gear inserted into a rotary shaft (not shown) of the motor  22  with a pressure;  24  a helical gear which is come into engagement with the worm gear  23 ;  25  a worm gear which rotates integratedly with the helical gear  24 ; and  26  a rotary shaft which rotates integratedly with the helical gear  24  and the worm gear  25 . 
     The rotary shaft  26  is axially rotatably supported by two bearings  27 . Reference numeral  28  denotes a disk which rotates integratedly with the shaft  26  and has a number of slits  29 . Reference numeral  30  denotes a transmission type photointerrupter. In association with the rotation of the disk  28 , the slit  29  allows the transmission light of the photointerrupter  30  to pass or shuts off the transmission light, thereby detecting its signal. A detection signal is sent to a counter (not shown). 
     Reference numeral  31  denotes a shaft which is rotatably axially supported by a base plate  19 ; and  32  indicates a helical gear which is come into engagement with the worm gear  25  and is constructed integratedly with the shaft  31 . Two microswitches  33  are provided as shown in the diagram. When the helical gear  32  rotates in the pan direction as will be explained hereinlater, a cam pin (not shown) projected under the lower surface of the helical gear  32  makes the two microswitches  33  operative. Thus, the operation limit position in the pan direction of the camera head  17  (not shown) is detected. The initial position can be also set by the two microswitches  33 . 
     In the above construction, when the motor  22  is driven in accordance with the control signal from the I/F control circuit  9  (refer to FIG.  1 ), the rotational force of the motor is sequentially transferred to the worm gear  23 , helical gear  24 , worm gear  25 , and helical gear  32 . Thus, the helical gear  32  is rotated integratedly with the shaft  31  axially supported by the base plate  19 . 
     A tilt direction working table, which will be explained hereinlater, is fixed to the other edge of the shaft  31 . In this instance, when the two microswitches  33  are made operative by a cam pin (not shown), the initial position and the operation limit position of the camera head  17  (not shown) can be known. Further, a rotational angle in the pan direction of the camera head  17  (not shown) can be known by the signal which is generated from the photointerrupter  30 , so that the rotational angle in the pan direction of the camera head  17  (not shown) can be also controlled by such information. 
     The operation in the tilt direction will now be described with reference to FIG.  8 . In FIG. 8, reference numeral  21  denotes a tilt direction working table coupled with the shaft  31  shown in FIG. 7;  46  a camera head fixing plate which is constructed integratedly with the camera head  17  (not shown);  34  a motor;  35  a spur gear inserted into a rotary shaft (not shown) of the motor  34 ;  36  a spur gear which is in engagement with the spur gear  35 ; and  37  a worm gear which rotates integratedly with the spur gear  36 . Both edges of the worm gear  37  are rotatably axially supported by two bearing portions  48  provided over the tilt direction working table  21 . 
     Reference numeral  38  denotes a helical gear which is come into engagement with the worm gear  37 ;  39  a bevel gear which rotates integratedly with the helical gear  38 ; and  40  a bevel gear which is come into engagement with the bevel gear  39 . A cam pin  49  is projected on one side of the bevel gear  40 . In association with the rotation of the bevel gear  40 , the cam pin  49  makes two microswitches  50  arranged on both of the right and left sides of the front surface of the bevel gear  40  operative. Due to this, the initial position and the operation limit position of the operations in the tilt direction of the camera head  17  (not shown) can be known. 
     Reference numeral  41  denotes a shaft which rotates integratedly with the bevel gear  40 ;  42  a pair of bearings provided on the working table  21  in order to rotatably axially support the shaft  41 ;  43  a disk which rotates integratedly with the shaft  41  and has a number of slits  44 ; and  51  a transmission type photointerrupter. In association with the rotation of the disk  43 , the slit  44  allows the transmission light of the photointerrupter  51  to pass or shuts off the transmission light, thereby detecting its signal. The detection signal is sent to a counter (not shown). 
     Reference numeral  45  denotes cams each having a long hole shape fixed to both edges of the shaft  41 . The cam  45  is in engagement with a cam groove  47  formed on the camera head fixing plate  46 . The camera head fixing plate  46  is rotatably axially supported by two shafts  52 . 
     In the above construction, when the motor  34  is driven in accordance with a control signal from the I/F control circuit  9  (refer to FIG.  1 ), its rotational force is sequentially transferred to the spur gear  35 , spur gear  36 , worm gear  37 , helical gear  38 , bevel gear  39 , bevel gear  40 , shaft  41 , and long hole shaped cam  45 . 
     On the other hand, since the cam  45  is in engagement with the cam groove  47 , the camera head fixing plate  46  moves in the tilt direction around the shaft portion  52  as a center together with the camera head  17  (not shown) by the rotating operation of the cam  45 . 
     The initial position and the operation limit position of the camera head fixing plate  46 , namely, the camera head  17  (not shown) can be known by two microswitches  50 . Further, since the rotational angle in the tilt direction of the camera head  17  (not shown) by the signal generated from the photointerrupter  51 , the rotational angle can be also controlled on the basis of such information. 
     By providing the foregoing optical axis control device  18  integratedly with the camera head  17 , the camera head  17  can freely operate in the pan or tilt direction. 
     Although the mechanism of the embodiment has been described with respect to the camera head as a portion which is driven by the optical axis control device, the invention is not limited to such a case. For example, it is also possible to drive the lens and the image pickup device and to fix the signal processing circuit. 
     When there is no need to largely change the photographing range (position), the lens and the image pickup device can be also driven in consideration of the relative positional relation between them. Or, the optical axis of the incident light can be also changed. Specifically speaking, it is also possible to provide a variable apex angle prism to a position in front of the lens and to change the apex angle. Further, it is also possible to provide a parallel flat plate glass onto the optical path and to change an angle for the optical axis. 
     An initialization of the image input device of the embodiment will now be described hereinbelow. 
     The initialization of the camera system and the lens control system will be first described. FIG. 9 shows a schematic flow chart in this case. 
     In the diagram, processes shown in steps S 2  to S 7  relate to an example of the initialization step newly added. 
     When a power supply is turned on, in step S 1 , the I/F control circuit  9  is initialized and the function as a control circuit can operate. In step S 2 , a signal to move the zoom to the wide side is transmitted from the I/F control circuit  9  to the camera control circuit  5  and controls the zoom control circuit  8  from the camera control circuit  5 , so that the zoom starts to move toward the wide side. At the same time, a signal indicative of the zoom position information is sent from the zoom control circuit  8  to the I/F control circuit  9  through the camera control circuit  5 . 
     The I/F control circuit  9  receives such a signal (step S 3 ) and evaluates (step S 4 ). In the evaluation in step S 4 , when the zoom is not located at the zoom end, the processing routine is returned to step S 2 . When the zoom is located at the wide end, step S 5  follows and a signal to stop the zoom operation is generated. A state setting of the zoom is finished. 
     Subsequently, in step S 6 , a signal to start the auto focusing operation is supplied from the I/F control circuit  9  to the camera control circuit  5 , thereby starting the auto focusing mode. In step S 7 , a signal to start the auto white balance adjusting operation is similarly sent to the camera control circuit  5 , thereby starting the auto white balance mode. The auto white balance mode is, for example, a well-known auto tracking auto white balance mode. 
     In step S 8  and subsequent steps, the conventional functions of the I/F control circuit  9  are executed. That is, a check is made in step S 8  to see if a control signal (command) has been inputted from the outside or not. The apparatus waits for the input of a command. When a control signal is supplied from the outside, the process according to the control signal is executed in step S 9 . After that, the apparatus again waits for the input of a command. 
     By constructing the initializing procedure as mentioned above, after the turn-on of the power source, the zoom lens is set to the wide end and a just in-focus state is obtained by the auto focusing operation. Further, a good color balance state is obtained by the auto white operation. Therefore, a whole region of the photographed image can be grasped at a glance and the operator can subsequently extremely easily operate the apparatus. 
     A state setting to initialize only the optical axis control system will now be described. According to the foregoing initialization procedure of the camera system and the lens control system, by enabling the photographed image to be easily seen, the following operation can be easily executed. Particularly, such a procedure is useful means for the operator (for example, operator in a personal TV conference or the like; not a communication partner). 
     In case of remote controlling the image input device on the partner side under a state in which the circumferential environment of the communication partner of a personal TV conference or the like is unknown, there occurs a situation such that even when the whole portion of the photographed image is seen, so long as the operator doesn&#39;t recognize the partner with whom the operator is communicating at present, a position at which the optical axis of the field of view of the image pickup operation should be located is unknown. Therefore, it is troublesome to match the optical axis of the field of view to that of the communication partner, so that the apparatus is difficult to use. 
     Therefore, by automatically setting the optical axis control system into a predetermined direction (ordinarily, front position at which a probability such that the communication partner is located is high) by the initialization, for example, it is possible to immediately recognize that a person who was photographed at the front position of the field of view is a communication partner. FIG. 10 shows a schematic flowchart of an embodiment for initialization of the optical axis control system in this case. As shown in FIG. 10, when the power source is turned on, the I/F control circuit  9  is initialized in step S 11  and the function as an I/F control circuit  9  can operate. 
     Subsequently, a procedure to obtain the current position information in the horizontal direction of the optical axis control device  18  in step S 12  is executed. A procedure to set the position (for instance, the center of the movable range) in the horizontal direction to be set is executed in step S 13 . After that, the drive device in the horizontal direction is moved toward a predetermined position in step S 14 . Further, information regarding the position at that time is obtained in step S 15 . A check is made to see if the horizontal direction drive device has reached the predetermined position or not in step S 16 . If NO in step S 16 , the processing routine is again returned to step S 14 . 
     When the drive device has reached the predetermined position in step S 16 , the horizontal direction drive device is stopped in step S 17 . The initialization in the horizontal direction of the optical axis control device  18  is finished. In steps S 18  to S 23 , the initialization in the vertical direction of the optical axis control device  18  is similarly finished, the initialization in both of the horizontal and vertical directions is finished, and the initialization of the optical axis control device  18  is finished. After that, the processing routine advances to the conventional processing steps S 24  to S 25 . Since the processes in steps S 24  and S 25  are similar to those in steps S 8  and S 9  already described in FIG. 9, their descriptions are omitted. 
     By the initialization of the optical axis control device  18  as mentioned above, after the turn-on of the power source, the positions in the horizontal and vertical directions of the optical axis control device  18  are automatically set to predetermined positions (for example, the center positions of the movable ranges in the horizontal and vertical directions). Therefore, after completion of the above initialization, since the direction of the optical axis is clear, the next operator can fairly easily operate the apparatus and such means is very useful. 
     Although the contents of the initialization in FIGS. 9 and 10 have been described as if they were different, it will be understood that those initialization processes can be also set to the initialization by a series of procedures. For example, the zoom position is set to the wide end by the series of procedures in steps S 1  to S 7  in FIG. 9, the auto focusing operation is started, and the auto white balance operation is started. Subsequently, the optical axis control device  18  is set to a predetermined position by the procedures in steps S 12  to S 23  in FIG.  10 . Or, the optical axis control apparatus  18  is set to a predetermined position by the series of procedures in steps S 11  to S 23  in FIG.  10 . Subsequently, the zoom position is set to the wide end and the auto focusing operation and auto white balance operations are set by the series of procedures in steps S 2  to S 7  in FIG.  9 . 
     After completion of the initialization by the series of procedures as mentioned above, the whole portion of the image which was picked up can be seen at a glance and the optical axis of the field of view of the image picked up is directed toward a predetermined direction (for example, front side). Therefore, it is very useful for the operator and a large effect is derived. 
     In case of the above example, each of the devices to be controlled has been initialized after the turn-on of the power source. However, it is not always necessary to initialize them after the power-on. For example, it is also possible to construct in a manner such that the series of initialization processes of the devices to be controlled as mentioned above have been preset so that they can be executed by one control command and by inputting the control command from the control signal from the outside to the I/F control circuit  9 , the device to be controlled is initialized at an arbitrary time. In this case, by merely inputting the above one control command from the outside just after the power-on, an effect similar to that mentioned above can be obtained without sending all of the control commands to various devices to be controlled. 
     There is another advantage such that during the operation of the image input device of the embodiment, an operating state can immediately be set into a predetermined state irrespective of any state of the image input device, so that a remarkably large effect is derived. The set states mentioned above are not fixed states. For example, the set state in the initialization for the optical axis control device is not limited to, for example, only the center of the movable range. Namely, since the image input device has a small construction, when it is used as an image input device for a computer, there is a case where it is put on a monitor. 
     In this instance, it is necessary that the optical axis of the field of view in the vertical direction is slightly downwardly directed and is not located at the center. Particularly, in case of setting the optical axis into a state other than the “center” as in the above example, such a state can be easily realized by providing a “memory unit” into the I/F control circuit  9 . 
     The more detailed contents of the above initialization will now be described hereinbelow. 
     The following description relates to an embodiment of the initialization of the optical axis control device. Particularly, it relates to one specific example regarding the case where a series of initialization processes can be executed by one control command. A case of using stepping motors as power sources for driving the horizontal and vertical direction control devices in the optical axis control device will now be described. 
     In the image input device of the embodiment of the invention, upon initialization after the power-on, a predetermined fixed absolute position is detected and the optical axis direction is recognized, thereby enabling the direction of the optical axis at the time of turn-on of the power source to be recognized. During the operation, the position information of the optical axis control device is stored into a position memory and the contents in the position memory are rewritten every operation, thereby always recognizing the current position. When a fixed point in a certain movable range is detected, by correcting the position information, the more accurate position control of the optical axis can be executed. 
     Another embodiment of the image input device of the invention will now be described hereinbelow with reference to FIGS. 11 to  14 . 
     FIG. 11 is a schematic block diagram of the image input device according to another embodiment. In FIG. 11, the portions corresponding to those in FIG. 1 are designated by the same reference numerals and their descriptions are omitted here. 
     The I/F control circuit  9  is constructed by a control unit  101 , an external interface unit  102 , and a memory unit  103 . 
     In FIG. 11, the control unit  101  controls the camera control circuit  5 , thereby controlling the lens  1 , iris device  2 , image pickup device  3 , signal processing circuit  4 , and optical axis control device  18 . The external interface unit  102  receives commands from an external control device. In the embodiment, the external interface unit  102  receives all of the commands from an external host computer by a serial communication. 
     The memory unit  103  is used to temporarily store various kinds of data such as position information in the horizontal and vertical directions, operating frequency information in the optical axis control device  18 , and the like. The optical axis control device  18  is constructed by a mechanical mechanism for changing the optical axis and stepping motors (refer to FIGS. 7 and 8) for mainly executing the operations in the horizontal and vertical directions. All of the driving, stop, management of the operating frequencies, and the like of the stepping motors are executed by the control unit  101 . 
     The device includes a switching mechanism to detect the operation limits in the horizontal and vertical directions. Switching information by the switch can be monitored by the control unit  101 . The control of the focus, zoom, iris device  2 , and image pickup device  3  included in the lens unit  1  is performed by controlling the camera control circuit  5  by the control unit  101 . 
     An operation flow of the image input device of FIG. 11 will now be described. 
     FIG. 12 is a flowchart of an embodiment according to the image input device of FIG.  11 . FIGS. 13 and 14 are flowcharts for the initialization process in FIG.  12 . 
     In FIG. 12, a control command is sent from a computer to the image input device in step S 201  through an interface such as RS232C or the like. In step S 202 , a check is made to see if the control command has been received or not. When the command is received, step S 203  follows. In step S 203 , a check is made to see if the received command is an optical axis control command or not. If YES, step S 204  follows and a check is made to see if the received command is a command to initialize the optical axis control device or not. When the received command is not the optical axis control command in step S 203 , step S 205  follows. In the embodiment, the control operation of the camera is executed in step S 205 . Practically speaking, the zooming, focusing, white balance, iris, and the like are adjusted. In step S 204 , in case of the initialization command, step S 206  follows and the initialization process is executed as will be explained hereinlater. When the received command is not the initialization command, step S 207  follows and the following operation control of the optical axis is executed. 
     In step S 207 , the designated absolute angle is converted into the position information. In step S 208 , the position information of the designated angle is stored into a designated position memory in the memory unit  103 . In step S 209 , the number of pulses indicative of the position information stored in the designated position memory and the number of pulses indicative of the current position information stored in the position memory are compared. When they are equal, it is regarded that the current position has reached the designated position, and the operation of the optical axis (operation of the stepping motor) is stopped (step S 213 ). The processing routine is returned to step S 202 . 
     When the current position is not the designated position in step S 209 , step S 210  follows, thereby making the stepping motor operative. In step S 211 , a check is made to see if the optical axis has reached the operation limit point or not. If YES, the data of the current position is corrected to the position indicative of the limit point (step S 212 ). If NO, in step S 214 , the number of pulses indicative of the current position stored in the position information memory is increased or decreased in accordance with the operation amount. In step S 215 , the position information is stored into the position memory. The processing routine is returned to step S 209 . 
     The initialization process in step S 206  shown in FIG. 12 will now be specifically explained with reference to FIG.  13 . 
     The initialization will be first performed in the horizontal direction. In step S 301 , the stepping motor is made operative so that the optical axis control device rotates in an arbitrary A direction. In step S 302 , the operation in step S 301  is continued until the operation limit point is detected. When the operation limit point is detected, the operation of the stepping motor is stopped (step S 303 ). After that, in step S 304 , arbitrary position information (for example, information corresponding to the center of the variable range) is supplied into the horizontal direction designated position memory in the memory unit  103 . In step S 305 , the position information corresponding to the operation limit point is set into the horizontal direction position memory. After that, in step S 306 , the optical axis control device is made operative in the direction opposite to the above A direction. In step S 307 , the value in the horizontal position memory is decreased in accordance with the operation amount of the stepping motor. 
     In step S 308 , at a time point when the value in the horizontal position memory is equal to the value stored in the horizontal direction designated position memory, the operation in the horizontal direction is stopped (step S 309 ). The initialization process in the vertical direction is executed. When they are different in step S 308 , the processing routine is returned to step S 306  and the operation to move the optical axis control device in the direction opposite to the A direction is continued. 
     The initialization process in the vertical direction will now be executed in a manner similar to the case in the horizontal direction. That is, the optical axis control device is operated in the vertical direction and the operation is continued until the operation limit point is detected and the device stops. When the operation limit signal is detected, arbitrary position information (for example, information corresponding to the center of the movable range) is supplied to the vertical direction designated position memory. The position information corresponding to the operation limit point is stored and the optical axis control device is operated in the opposite direction. 
     The value in the vertical direction position memory is decreased in accordance with the operation amount of the stepping motor. At a time point when the value of the vertical direction position memory is equal to the value in the vertical direction designated position memory, the operation to move the optical axis control device in the vertical direction is stopped. Due to this, the initialization process is finished. By the initialization process, the absolute position of the optical axis control device can be recognized and the optical axis direction can be set to an arbitrary direction (for example, center of the movable range). 
     An example of another initialization process will now be described with reference to a flowchart shown in FIG.  14 . 
     The initialization is first executed in the horizontal direction. In step S 401 , the stepping motor is operated so that the optical axis control device rotates in an arbitrary A direction. At the same time, the number of pulses according to the operation amount is added in step S 402 . Until the operation limit point is detected in step S 403 , the operations in steps S 401  and S 402  are continued. When the operation limit point is detected, the operation of the stepping motor is stopped (step S 404 ). After that, in step S 405 , the position information corresponding to the operation limit point is set into the horizontal direction position memory in the memory unit  103 . In step S 406 , the optical axis control device is operated in the direction opposite to the A direction. In step S 407 , the value of the number of pulses is decreased each time the stepping motor operates by one step. 
     In step S 408 , a check is made to see if the number of pulses is equal to zero or not. When it is equal to zero, the operation is stopped (step S 409 ). The initialization process in the vertical direction is executed. When the number of pulses is not equal to  0 , the processing routine is returned to step S 406  and the operation is continued in the direction opposite to the A direction. The initialization process in the vertical direction is also executed in a manner similar to the initialization process in the horizontal direction. By the initialization processes, the optical axis direction can be set in the direction before initialization. 
     In the control of the optical axis control device after completion of the initialization, whenever the operation of the optical axis control device is executed, the position information indicative of the current position stored in the position memory is calculated in the position information adding/subtracting step S 214 , and the absolute position of the optical axis is independently stored into the horizontal direction position memory and vertical direction position memory. When the operator executes the position designating control, the position information of the designated position is supplied into the designated position memory. The value in the horizontal or vertical direction position memory is compared with the value in the designated position memory in a position information comparing step S 308 . The operation in the horizontal direction and the operation in the vertical direction are executed until the position information in the position memory and the designated position information are equal. 
     When the operation limit point is detected during each of the operations, the position memory to correct the position information is reset into the horizontal direction position memory or vertical direction position memory in step S 212  and the position information indicative of the absolute position of the limit point is written into the position memory, thereby preventing that the error due to the calculations or the like increases. 
     Although the above embodiment has been shown and described with respect to the example in which the switching mechanism is attached to the operation limit point, the switching mechanism can be applied to any of the contact type and the contactless type. Further, even when the switching mechanism of the number which is less than or larger than that shown in the diagram are provided, the control method of the invention can be applied. 
     In the above embodiment, the initialization has been performed by the command. However, the above initialization can be also automatically executed when the power source is turned on. The position (optical axis direction) of the optical axis control device after completion of the initialization can be also freely set to an arbitrary position in the movable range. Even in case of performing the subsequent designated position control as well, by merely designating the absolute position in the movable range, the control can be executed. The order of the initialization processes in the horizontal and vertical directions can be also reversed. 
     Although the above embodiment has been shown and described with respect to the example in which the stepping motors have been used to drive the optical axis control device, it will be obviously understood that even when another drive device is used, an apparatus such that clear points of the absolute position or relative position are detected and the position is recognized can be also applied to the invention. 
     According to the embodiment as mentioned above, even when the optical axis position is unknown at the time of turn-on of the power source, the position of the optical axis control device can be recognized (optical axis direction is recognized). There is also an effect such that the more accurate position control can be executed by correcting the position during the operation. 
     According to the above embodiment, the number of systems to input the control signal from the outside can be set to one and the operation is simplified. By interlocking the control of the optical axis control device with another control, an information amount of the image can be reduced as necessary and a good image can be obtained by using the TV conference or the like. 
     Further, by integrating the optical axis control device and the lens and camera unit, a whole construction can be formed in a compact size, so that the apparatus can be put on a work station or personal computer. Due to this, for example, a personal TV conference system can be simply constructed. 
     According to another feature of the embodiment, since other devices in the image input device have been initialized by the I/F control circuit, the whole initialization can be concentratedly executed at the time of turn-on of the power source or by one control command from the outside. The use efficiency can be improved. Particularly, upon initialization, the zoom is set to the wide end, the focus is set into the auto focusing operating mode, the white balance is set into the auto white balance state, and the optical axis control device is set to the center position in the movable range, so that the use efficiency can be remarkably improved. 
     The invention can be embodied by other various forms without departing from the spirit and essential features of the invention. 
     In other words, the foregoing description of the embodiments has been given for illustrative purposes only and not to be construed as imposing any limitation in every respect. 
     The scope of the invention is, therefore, to be determined solely by the following claims and not limited by the text of the specification and alterations made within a scope equivalent to the scope of the claims fallen within the true spirit and scope of the invention.