Abstract:
A two-axis or three-axis digitally controlled microprocessor for remotely controlling an existing manually operated geared head uses digital technology to provide full precise control of the geared head from a remote distance. Additionally, by utilizing the system&#39;s electronics, the system operator has ten gear ratios instead of the three gear ratios that typically exist in the prior art manual geared head. Another feature permits the camera operator to set four predetermined soft stop positions. The system has the capability of being able to record the X/Y/Z position precisely and to precisely duplicate the same camera motion repeatedly. The system is very simple and ergonomically advantageous to operate. One single umbilical cable between the controller and the geared head provides the most necessary communication between the controller and the geared head and supplies power to the camera.

Description:
This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional Application Ser. No. 60/213,365, filed on Jun. 23, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to the fields of motion picture and video production, and more particularly to apparatus and methods for motorizing and remotely controlling, using a digitally controlled microprocessor, existing manually operated geared heads for positioning motion picture and electronic medium (such as video) cameras. 
     Prior art geared heads for positioning motion picture and electronic medium cameras are usually operated manually. When the cameraman needs to move the camera right to left (known in the art as “panning” the camera) or up and down (known in the art as “tilting” the camera), the operator will rotate two hand wheels, each controlling an axis. For example, if the cameraman needs to make a 180 degree pan, he has to physically travel 180 degrees behind the camera in an arc with the camera to view the shot through the viewing system. 
     Referring now to FIG. 1, there is shown therein a typical prior art geared head system  11 . The illustrated geared head system  11  is sold under the trademark ARRIHEAD  2 , available from Arri, Inc. However, it is merely representative, and any similar type of geared head assembly could alternatively be referenced. The geared head system  11  includes a camera platform  13 , which is capable of adjustment in at least two axes, namely pan and tilt. A tilt handwheel  15  and a pan handwheel  17  are provided for use by the camera operator when it is desired to pan and/or tilt the camera (not shown) mounted on the platform  13 . The camera platform  13  is disposed on a gearhead housing  19 , within which reside a plurality of interengaged gears for selectively driving the camera platform, and thus the camera mounted thereon, through a predetermined range of motion in the pan and tilt axes. The gearhead housing  19  is supported by a plurality of legs  21 . 
     Thus, in operation, the camera operator is stationed behind the gearhead housing  19 , in position to actuate the two hand wheels  15  and  17 , and to view the scene through the viewfinder of the camera (not shown). To pan or tilt the camera, the hand wheels  15  and  17  are selectively rotated. Since the hand wheels  15  and  17  are drivingly connected to the interengaged gears via a manual tilt gear drive interface and a manual pan gear drive interface, respectively, rotation of the hand wheels  15  and  17  functions to drive the gears within the gearhead housing  19 , which in turn are drivingly engaged with the camera platform  13 . In other words, the hand wheels  15  and  17  are mechanically linked to the platform  13  so that a ratio of turns will be converted into movement, through the gearhead, in the tilt axis and the pan axis, respectively. In some embodiments (not shown), a third hand wheel or motor is provided which rotates the camera on a roll axis. There is no ability to provide predetermined fixed stops in pan, and in tilt, only the end of the permitted travel arc provides a hard stop. No intermediate stops may be selected. 
     Most existing geared heads have three mechanical gear ratios which enable the camera operator to choose the rate at which he would like to move the photographic device. Unfortunately, this limited selection of travel speeds can be very restrictive during a shoot. 
     With a conventional geared head, it is very difficult to move the camera rapidly and stop on a precise mark. Generally, since the operator cannot see beyond the viewing system when the final mark will be approaching, it is possible to either go beyond the final mark or to fail to reach the final mark. Geared heads for motion picture and electronic medium cameras were designed to assist the camera operator&#39;s ability to pan or tilt the camera from point A to point B with a greater degree of accuracy than was previously possible, in order to accommodate the ever more complex shots required in an increasingly sophisticated and demanding industry, but their present limitations continue to frustrate both camera operators and directors. 
     Presently available geared heads have virtually infinite panning ability, but are generally restricted to +/− approximately 30 degrees in tilt. It is possible, therefore, for the operator to reach a hard mechanical stop on the tilt axis during photography, which is unacceptable in most cases. 
     Additionally, because present motion picture geared heads are operated manually, it is possible to move the camera the same way multiple times, but never to replicate a previous camera move exactly. 
     Still another problem with existing geared head assemblies is the necessity for the camera operator to be positioned directly behind the assembly. Often, the camera must be placed in a relatively hazardous orientation in order to obtain an acceptable shot, and this entails danger and inconvenience to the operator. Although remote controlled cameras are presently available for such occasions, they are generally very expensive and relatively complex, and are not adaptable to typical geared head assemblies, thereby entailing a time consuming and complex “change-out” operation, or a separate camera assembly for those unique shots. 
     Various prior art systems have been developed for providing remotely controlled camera systems, particularly for ensuring repeatable shots and for permitting hazardous shoots without placing a camera operator in harm&#39;s way. For example, U.S. Pat. No. 4,673,268 discloses a remote camera operation system comprising pan and tilt tables which are each actuatable by respective stepper motors. These tables may be computer controlled for repeatable shot sequences. However, this system is not adaptable for use with existing gear heads. 
     U.S. Pat. No. 4,720,805 discloses a computer-controlled camera system for controlling pan and tilt motors remotely using a digitizing tablet. However, again, this system is not adaptable for use with existing gear heads. 
     U.S. Pat. No. 4,847,543 discloses a remote-controlled camera system which uses control handles similar to those used in certain manual systems to actuate pressure transducers, which convert the movements of the handles initiated by the camera operator to voltage signals for actuating pan and tilt motors at the camera. The purpose of this arrangement is to facilitate repeatability of camera operation. This is not a remote system, but rather requires the operator to be located at the camera location. 
     U.S. Pat. No. 5,220,848 discloses a remote camera operation system wherein handwheels are used to operate a prior art cine head, which has a video monitor instead of a camera mounted thereon. Sensors transmit signals to a central control unit, based upon movements initiated by the camera operator on the handwheels, thereby actuating step or stepless actuator head motors. This system is disadvantageous, however, in that it is a complex customized approach not readily adaptable for quick change-out and use with existing gear heads. 
     Therefore, it would be highly desirable to have a geared head assembly which is directly adaptable to existing geared heads, is simple and quick to change out, affords a substantially greater number of mechanical gear ratios to select from, in order to provide the camera operator with an increased range of pan and tilt speeds, is programmable to provide selectable soft stops in both the pan and tilt axes, and is capable of recording a complex move so that it can be repeated precisely as many times as desired. 
     SUMMARY OF THE INVENTION 
     The present invention solves the aforementioned problems by providing a two-axis or three-axis digitally controlled microprocessor for remotely controlling an existing manually operated geared head. Because of the digital technology, the camera operator has full precise control of the geared head from a remote distance, as if he or she were physically behind the geared head personally. 
     Additionally, by utilizing the inventive system&#39;s electronics, the operator has, in one preferred embodiment, ten gear ratios instead of the three gear ratios that typically exist in the prior art manual geared head. Also, three out of the ten speeds are matched with the standard geared head to emulate standard gearing on conventional geared heads. The additional seven gear ratios give the camera operator the ability to control the geared head speed by increasing or decreasing the speed from conventional choices. 
     Another advantage of the present invention permits the camera operator to set four predetermined soft stop positions, in one preferred embodiment. With the ability to set soft stop positions, the camera operator is guaranteed that he will never exceed the final position on either axis. For example, if a stunt person jumps from a platform into a stunt safety bag, the camera operator will take the camera, find the final position, and mark that position before photographing it. During photography, the electronics remember precisely where the mark is, and ensure that the camera will stop at that predetermined mark. The aforementioned stops are “soft stops” because, regardless of how fast the operator moves the camera, the device ensures that the camera comes to a very soft and gentle stop. 
     Still another important feature of the present invention is that, because a standard motion picture geared head is utilized, with its limited tilt capability, the mechanical limits positions on the tilt axis are calibrated and recorded. As a result, the tilt axis may be feathered and stopped before the geared head reaches its mechanical limits in the up and down position, thus creating a soft stop for the tilt axis. 
     The inventive system has the capability of being able to record the X/Y/Z position precisely and to precisely duplicate the same camera motion repeatedly. The system is very simple and ergonomically advantageous to operate. One single umbilical cable between the controller and the geared head provides the most necessary communication between the controller and the geared head and supplies power to the camera. 
     More particularly, in one aspect of the invention there is provided a system for remotely controlling geared heads for motion picture and electronic medium cameras. Advantageously, the system comprises an electronic interface for attachment to an existing geared head for a motion picture or electronic medium camera. The system additionally comprises a tilt motor assembly mechanically attachable to the geared head and electronically attachable to the electronic interface, and a pan motor assembly which is also mechanically attachable to the geared head and electronically attachable to the electronic interface. A control console is electronically attachable to the electronic interface, which control console comprises a tilt motor input control and a pan motor input control. 
     In order to provide the remote operational capabilities of the inventive system, the control console is physically spaced from the geared head when the system is in an operating configuration. 
     In a preferred embodiment of the invention, the system further comprises a record/playback module, as well as a video monitor for use with the control console. The tilt motor input control and the pan motor input control each comprise a handwheel, preferably the handwheels which were originally attached to the geared head. This is advantageous in order to minimize any adaptations necessary on the part of the camera operator. The tilt motor assembly comprises a shaft for engagement with the tilt drive gear mechanism of the existing geared head, while the pan motor assembly comprises a shaft for engagement with the pan drive gear mechanism of the existing geared head. 
     In another aspect of the invention, there is provided an apparatus for electronically controlling geared heads for motion picture and electronic medium cameras, which comprises a tilt motor assembly attached to the geared head and a pan motor assembly attached to the geared head. Additionally, the apparatus comprises a system for establishing soft stops for limiting the pan and tilt travel of the geared head, which comprises software and a plurality of control inputs for actuation by an operator. A plurality of control inputs are disposed on a control panel and each of the control inputs operates to establish a soft stop for the geared head in one direction of travel. The soft stops are established by first moving the geared head to desired travel limits so that the computer software learns those limits. 
     In yet another aspect of the invention, there is provided a system for controlling geared heads for motion picture and electronic medium cameras, which comprises a geared head for controlling the movement of a camera attached thereto in the pan and tilt directions. A tilt motor assembly and a pan motor assembly are each attached to the geared head. Additionally, a control console is attached to the tilt motor assembly and the pan motor assembly. The control console is physically spaced and separate from the geared head and comprises a tilt motor input control and a pan motor input control. 
     In another aspect of the invention, there is disclosed a method of converting an existing manual geared head for a motion picture or electronic medium camera to a remotely controlled motorized gear head. The method comprises steps of replacing manual control inputs for pan and tilt gear mechanisms in the existing geared head with motorized control inputs, and a further step of attaching a control console to the motorized control inputs. 
     In still another aspect of the invention, there is disclosed a method of setting soft stops for limiting the range of motion of geared heads for motion picture and electronic medium cameras in the pan and/or tilt directions. The inventive method comprises a step of moving the geared head to its desired final position in any direction while depressing a soft stop control switch corresponding to that direction, and a further step of memorizing the desired final position using software adapted for such a purpose. 
    
    
     The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of a prior art geared head assembly for use with motion picture and electronic medium cameras; 
     FIG. 2 is a perspective view of the control console and video monitor which form a part of a preferred embodiment of the inventive system; 
     FIG. 3 is an elevational enlarged view of the control panel shown in FIG. 2 for the inventive system, which is disposed on the control console; and 
     FIG. 4 is a perspective exploded view of a prior art geared head which has been modified to include the inventive system. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Now with particular reference to FIGS. 2 through 4, a preferred embodiment of the inventive system for remotely controlling a motion picture geared head, such as the geared head system  11  shown in FIG. 1, will be described. Those elements which are equivalent to elements shown in FIG. 1 are designated by like reference numerals, preceded by the numeral  1 . 
     Thus, as illustrated in FIG. 4, a first portion  111   a  of a geared head system is constructed in accordance with the principles of the present invention and includes a camera platform  113 , upon which a camera (not shown) may be mounted. In the preferred embodiment, the camera platform is from a system such as system  11  shown in FIG. 1, available under the trademark ARRIHEAD, from Arri, Inc. Other existing geared head systems may alternatively be adapted to result in inventive system  111 , however, such as, for example, the system available under the trademark PANAHEAD, from Panavision, Inc. The camera platform  113  is disposed on a gearhead housing  119 , which is preferably from the existing system  11  as well. 
     To modify the prior art system  11  into the inventive system  111 , an electronic interface or signal split box  123  is provided which is attachable to the gearhead housing  119  using a signal split box bracket  125  and a signal split box receiving bracket  127 , or other suitable means. The signal split box  123  includes thereon a calibrate switch  129  and a camera remote and power output jack  131  on a top surface  133  thereof. On a rear surface  135  of the signal split box  123  are disposed a tilt motor output connector  137 , a pan motor output connector  139 , and an umbilical signal input  141 . A tilt motor assembly  143  comprises a tilt motor  145 . Attached to the tilt motor  145  is a tilt motor cable  147  and output connector  149 . 
     Also provided as a part of the system  111  is a pan motor assembly  151 , which includes a pan motor  153 . Attached to the pan motor  153  is a pan motor cable  155  and output connector  157 . 
     The tilt motor  145  is attached to the gearhead housing  119  by means of attachment screws  159 . Initially, the tilt hand wheel  15  (FIG. 1) is removed (disengaged) from the hub  161  (and specifically the manual tilt gear drive interface) and set to the side for the moment. Then, the tilt motor drive shaft (not shown) is engaged with the manual tilt gear drive interface associated with the hub  161 , in the same manner as the tilt hand wheel shaft was previously engaged, so that the tilt motor can rotate the tilt drive gear mechanism within the housing  119 , thereby permitting the operator to control the movement of the camera on the tilt axis. Then the screws  159  are inserted into the provided registered mounting holes and tightened to secure the tilt motor  145  on the housing. 
     Both the pan and tilt motors, in the preferred embodiment, are servo motors available from Pittman, Inc. 
     In the preferred embodiment, both the pan motor drive shaft  163  and the tilt motor drive shaft do not directly engage the pan or tilt drive gear mechanisms, respectively, within the housing  119 . The preferred drive system is illustrated with respect to the pan motor, and it will be understood that this system, though not illustrated in the drawing, is preferred for, the tilt motor as well. In particular, a timing belt  165  is supplied which is connected between the drive shaft  163  and a timing pulley  166  which is associated with a gearhead coupling  167 . Initially, the pan hand wheel  17  (FIG. 1) is removed (disengaged) from the hub  169  (and specifically the manual pan gear drive interface) and set to the side for the moment. Then, the gearhead coupling  167  is engaged with the manual pan gear drive interface associated with the hub  169 , in the same manner as the pan hand wheel shaft was previously engaged, so that the pan motor can rotate the pan drive gear mechanism within the housing  119 , thereby permitting the operator to control the movement of the camera on the pan axis. Then, the screws  171  are inserted into the provided registered mounting holes and tightened to secure the pan motor  153  on the housing. A cover for the timing belt and gearhead coupling arrangement is preferably provided, for appearance as well as protection of the drive mechanism components. 
     An umbilical cable  175  is coupled to the umbilical signal input, and a camera power and remote cable  177  is coupled to the camera power and remote output jack  131  for reasons that will become clear hereinbelow. 
     Now referring particularly to FIG. 2, the remainder  111   b  of the inventive geared head system is illustrated. A control console  179  is provided, which may advantageously be placed at a selected location spaced from the location of the camera and gearhead housing  119 , so that the operator need not be placed at safety risk or in an uncomfortable situation. The control console  179  includes a tilt input/receiver  181  and a pan input/receiver  183 . The tilt hand wheel  15  from the original prior art system  11 , which was previously set aside, is installed onto the tilt input/receiver  181  using a hand wheel attachment screw  184 . Similarly, the pan hand wheel  17  is installed onto the pan input/receiver  183  using a second hand wheel attachment screw  184 . A control panel  185 , which will be discussed in greater detail in connection with FIG. 3, is disposed on a front face  187  of the control console  179 . Atop the control console  179  is disposed a video monitor  189 , though, since it is a separate element, it may be placed in any desired location, including locations remote from the control console  179 . The system  111  also includes a record/playback module  191 . 
     A power cable  193  is connected to the control console  179  for providing electrical power to the system  111 . The umbilical cable  175  is connected to the console  179  via a jack  195 , for providing a control signal from the control console  179  to the signal split box  123  (FIG.  4 ). A video monitor cable  197  is connected between a 12 volt output  199  on the control console  179  and the video monitor  189 . The record/playback module  191  is attached to the control console  179  at jack  201  via cable  203 . A bloop light  205  may be attached to the record/playback module  191  via a cable  207 . 
     The control console  179  further preferably includes a PC output jack  209  and handwheel reversing switches  211 , and a camera power input  213 , to which are attached the distal ends  213 ,  215  of the camera power and remote cable  177  (FIG.  4 ). The record/playback module  191  includes thereon a record switch  217 , a playback and first position switch  219 , a stop switch  221 , a record indicator  223 , a playback indicator  225 , a memory occupied indicator  227 , and a first position indicator  229 . 
     Now with particular reference to FIG. 3, an enlarged version of the control panel  185  of FIG. 2 is illustrated. On the panel  185  are disposed a power switch and circuit breaker  231 , a tilt on/off switch  233 , a pan on/off switch  235 , a voltage monitor  237 , a tilt gear speed selector  239 , a pan gear speed selector  241 , an upper soft stop switch  243 , a left soft stop switch  245 , a lower soft stop switch  247 , a right soft stop switch  249 , a camera on/off switch  251 , and LED status indicators  253 . 
     In operation, once all of the system components have been attached, as described supra, the system is activated by turning on the power switch and circuit breaker  231  on the control panel  185  (FIG.  3 ). The voltage monitor  237  will indicate the condition of voltage to the system. This will supply power to the entire system and will show four blinking status lights  253 . The hand wheels  15 ,  17  are disabled for safety at this juncture until a crewman installs the camera (not shown) on the geared head platform  113  and presses and holds the calibrate switch  129 . The calibration function causes the control system to turn on the tilt motor  145  and to tilt the camera platform  113 , and thus the camera, down at a fractional percent of its power to reach the mechanical stop on the down position. Then, after reaching the stop, corresponding to the end position, the tilt motor reverses direction at the same power setting to the extreme tilt up position. At this point, using software provided in the control console  179 , the control system has learned the physical limitations of the tilt axis of the geared head. Now, the camera operator lets go of the calibration switch  129 . Once the calibration process is completed, the power to the servo motors is returned to full power. 
     The function of the calibration switch is twofold. First, as described supra, it serves to permit the control system to learn the physical tilt limitation of the actual tilt access of the particular system being utilized, which varies from geared head to geared head. Secondly, it serves as a “dead man&#39;s switch”. To amplify, because the geared system  111  is transformed into a remote system by virtue of the inventive system, there is a safety issue regarding the possibility of the controller potentially being out of the visual range of the actual geared head during initial set-up and during some shoots. During set-up, the technician “camera assistant” is able to attach the camera and accessory to the geared head without the danger of the system moving without his or her knowledge. After the technician has completed his or her duties by installing the camera and accessories, he or she can then press the “calibrate” button which will enable the controller to start to calibrate the tilt axis and to allow the operator to control the geared head from a remote distance. The possibility exists that one operator may be turning the wheels while another technician is trying to connect the camera to the geared head. This necessitates the aforementioned “dead man&#39;s switch”. 
     By selecting desired settings of the tilt gear speed selector  239  and the pan gear speed selector  241 , the operator is able to select his desired gear ratios between the hand wheels and the geared head. The camera can be turned on or off using the camera on/off switch. 
     If soft stops, as discussed supra, are desired in either axis, before photographing, the camera operator will move the camera to its desired final position by pressing the appropriate button or switch  243 ,  245 ,  247 , or  249  until the camera has achieved the desired final position in that direction. The controller software will learn that limit. Then, subsequently, during photography, if the camera operator turns the corresponding hand wheel  15 ,  17  beyond the desired stop position, the controller will take over and ease to a complete stop at the preset soft stop limit regardless of the hand wheel position. This feature ensures that the camera never travels beyond the marked position and also avoids an unacceptable hard stop by feathering the camera to a soft stop. 
     To utilize the record/playback function of the invention, the camera operator moves the camera to its starting position by moving the hand wheels  15 ,  17  as appropriate. By pressing the record switch  217 , the record indicator  223  is activated, and the recording of the memory begins. When the camera is moved to the end position using the hand wheels  15 ,  17 , the stop switch  221  is pressed, which stores the move in the volatile memory of the controller. The memory occupied indicator  227  lights to indicate that a move has been stored in the memory. Another move cannot be recorded until the memory has been erased, by pushing the stop switch  221  and the record switch  217  simultaneously. To play back the memory, the playback switch  219  is depressed. The controller then automatically moves the camera to its beginning position and the first position indicator light  229  comes on. At this point, the controller stands by for the camera operator to press the playback switch  219  a second time to repeat the move. By pressing the playback switch, the playback indicator light  225  is activated, and the controller plays back the move in its entirety. 
     In one presently preferred embodiment, the inventive system is approximately 18 inches by 10.5 inches by 5 inches and weighs approximately eight pounds. The maximum current draw is about 4 amps, and the power requirement is 24 to 36 VDC. 
     Although in the foregoing description, the focus has been on modification of existing geared heads to permit remote operation thereof in two axes, pan and tilt, the principles of this invention extend easily to remote operation in a third axis, namely, the roll axis. The modification methods discussed herein in connection with the pan and tilt axes apply as well with respect to the roll axis, in that the general procedure is to remove the existing means for actuating the camera in the roll axis, through the geared head, and to replace that means, which may be either a handwheel or a motor, with a roll motor assembly similar to both of the pan motor and tilt motor assemblies, and to connect the roll motor assembly electronically to the control console through the signal split box. 
     Accordingly, although an exemplary embodiment of the invention has been shown and described, it is to be understood that all the terms used herein are descriptive rather than limiting, and that many changes, modifications, and substitutions may be made by one having ordinary skill in the art without departing from the spirit and scope of the invention.