Coordinated camera pan tilt mechanism

In various embodiments, a camera may be controlled by one or more motors in a base of the camera. Cables and other components may be used to manipulate the camera lens through the side arms of the camera. Putting the motors in the base may reduce the size of the outer case of the camera and add stability. A pan motor may pan the camera while a tilt motor may move a tilt pulley relative to a lens portion of the camera (which may or may not tilt the camera depending on the panning motion of the camera). In some embodiments, images from the camera may be converted into a serialized stream and transported over a cable from the lens through a center shaft of the camera.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to cameras and, more specifically, to video camera pan tilt mechanisms.

2. Description of the Related Art

Cameras may be used in a number of video applications. For example, cameras may be used in filming movies or providing live video in video conferences. Camera types may include film and charge-coupled device (CCD) among others. Cameras often include a lens portion mounted to a stand. The lens portion may be aimed at a subject by panning or tilting the lens. The lens portion may be moved directly by a user or indirectly through a motor coupled to the lens portion. Some camera lenses may also be zoomed in or out on a subject.

SUMMARY OF THE INVENTION

In various embodiments, a camera (e.g., a High Definition (HD) pan-tilt-zoom (PTZ) camera) may have a lens portion and a base portion coupled to each other through one or more arm portions. The camera may be controlled by one or more motors in the camera's base. A tilt motor in the camera base may control the tilt of the camera, while a pan motor in the camera base may pan the camera. In some embodiments, the pan and tilt motors may work together to pan and/or tilt the camera. The tilt and pan motors may be coupled to plates in the base of the camera. The tilt motor may also be coupled to cables in an arm portion of the camera.

Putting the motors in the base may reduce the size of the outer case of the camera and add stability. In some embodiments, images from the camera may be converted into a serialized digital stream and transported over a data cable from the lens through a center shaft of the camera. This may allow the placement of several components for processing images, etc. in a base of the camera instead of in the lens portion. Other information may also be sent over the data cable (e.g., bi-directional control data and power). Other components in the lens portion and/or base portion may also be used to increase the functionality of the camera.

In various embodiments, cables and other components may be used to manipulate the camera lens through the side arms of the camera. Putting the motors in the base may reduce the size of the outer case of the camera and add stability. In some embodiments, images from the camera may be converted into a serialized stream and transported over a cable from the lens through a center shaft of the camera. Other components may also be used to increase the functionality of the camera.

In various embodiments, a camera support mechanism (CSM) may be used to couple a camera to a display. In some embodiments, the CSM may have a flat top that folds open to access a tripod mount screw that couples the camera to the CSM. After attaching the camera to the top of the CSM, the CSM may be placed on the top center of the display device. The CSM may have an adjustable front lip that aligns to the top front edge of the display device. In some embodiments, the front lip may be attached to a lower deck through a mount screw. The front lip may have two separate offsets that may cushion the contact with the display. In some embodiments, if multiple pads are used, the CSM may work with display devices that have either a concave or a convex front surface. The front lip may be adjusted to one of a number of set positions so that the CSM can accommodate even extremely thin screens that may be wall mounted.

In some embodiments, when the CSM is placed on the display, a user may tighten an adjustment knob on one side of the pivot point at the rear of the CSM. This may rotate the adjustable rear leg towards the back of the display. In some embodiments, the rear leg may rotate from flat and parallel to the top of the display to perpendicular to the top of the display. When the rear leg has rotated to the point where it makes contact with the display, further tightening of the knobs may apply additional pressure. The rear leg may be tightened to lock the rear leg firmly against the back of the display at that position. In some embodiments, the rear leg may have a foam/rubber tip for better gripping. In some embodiments, the CSM may also accommodate variable slope on the screen from front to back using the foam/rubber tip.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Incorporation by Reference

U.S. patent application titled “Speakerphone”, Ser. No. 11/251,084, which was filed Oct. 14, 2005, whose inventor is William V. Oxford is hereby incorporated by reference in its entirety as though fully and completely set forth herein.

U.S. patent application titled “Video Conferencing System Transcoder”, Ser. No. 11/252,238, which was filed Oct. 17, 2005, whose inventors are Michael L. Kenoyer and Michael V. Jenkins, is hereby incorporated by reference in its entirety as though fully and completely set forth herein.

U.S. patent application titled “Speakerphone Supporting Video and Audio Features”, Ser. No. 11/251,086, which was filed Oct. 14, 2005, whose inventors are Michael L. Kenoyer, Craig B. Malloy and Wayne E. Mock is hereby incorporated by reference in its entirety as though fully and completely set forth herein.

FIG. 1illustrates a camera mounted to a base through yoke arms, according to an embodiment. In some embodiments, the camera100(e.g., a HD PTZ camera) may be used to provide video of participants during a video conference call. In some embodiments, the camera may be a companion HiDef PTZ camera with a resolution of 1280×720 at 30 frames per second (fps). Other cameras, resolutions, and frame rates are also contemplated.

In some embodiments, the camera100may have a lens portion101coupled to a base105by one or more arm portions (e.g., camera yoke arms103). In some embodiments, the lens portion101may be panned and/or tilted by motors (i.e., a device that converts one or more forms of energy into mechanical energy) in the base105. For example, an electro-mechanical motor may be used. In some embodiments, the motor may be a step motor. Other motors are also contemplated. The lens portion101may be pointed towards a participant or another source of visual interest. In some embodiments, the lens portion101may be panned by a motor turning a base shaft107. In some embodiments, the lens portion101may be tilted by a motor turning a rod109. In some embodiments, the pan motor and the tilt motor may be in the base of the camera100. Other locations of the pan and tilt motors are also contemplated. In some embodiments, one motor may be used for panning and tilting the camera100. In some embodiments, multiple motors may be used for panning and/or tilting the camera.

In some embodiments, multiple motors in the camera base may be used together to pan and/or tilt the camera100. For example, a Field Programmable Gate Array (FPGA) (e.g., see FPGA321inFIG. 3) in the camera100may receive a serial command (e.g., from a video conferencing system codec) to move the camera100. The FPGA321may calculate a response to send to each motor in the base to move the camera to the requested position. The FPGA321may store or have access to a memory medium storing the position of the camera and/or motors. In some embodiments, the response may be a stepping wave that includes an acceleration phase, a constant move phase, and a deceleration phase. Other response patterns are also contemplated (e.g., the response may be a straight response for the motor to move at a predefined speed to a designated position). The FPGA321may receive other types of serial commands. For example, the FPGA321may be requested to move the camera to a preset position, to pan/tilt the camera at a specified speed, to move the camera to a specified position as fast as possible, to continue moving the camera until a command is received to stop, etc. The FPGA321may translate these commands into a response to send to each motor (or a subset of motors) in the camera100. In some embodiments, the FPGA321and/or other camera components may be encased in an electromagnetic interference (EMI) shield (e.g., made of sheetmetal).

FIG. 2illustrates a cutaway view of a camera100, according to an embodiment. In some embodiments, a pan motor201and/or tilt motor207may be in the base of the camera100. Putting the motors in the base may reduce the size of the outer case of the camera100and add stability. Pan motor201and tilt motor207may substantially control movement of the camera100(the main bodies of motor201and207may be located below reference plate291with the gear segment of the motor protruding through the reference plate291).

In some embodiments, pan motor201may rotate a pan plate203that may pan the camera100to the left or right. In some embodiments, the pan motor201may turn a gear with teeth that interlock with teeth on the plate203to rotate the camera100through a range of motion (e.g., 180 degrees) left to right. In some embodiments, a larger or smaller range of motion may be implemented. Other sizes of plates203may also be used. For example, a larger plate may allow a larger range of motion.

In some embodiments, a tilt motor207may turn a tilt plate209using a gear with teeth that interlock with teeth on the tilt plate209. The tilt plate209may turn a tilt pulley205that may pull cable211(e.g., flexible stainless steel cable) to the left or right (depending on which way the plate209is rotated). Other cable types are also contemplated. The cable211may rotate a tilt wheel215that may turn a rod109to tilt the camera100in the up and down direction. Offsetting connectors213with grooves for the cable211may hold the cable211away from the side of the interior of the camera100while also allowing the cable211to move back and forth along the interior of the camera yoke arm103. While two sets of offsetting connectors213are shown, other numbers of offsetting connectors213may also be used.

In some embodiments, if the pan plate203pans the yoke arm103and lens portion101, while the tilt motor207(and correspondingly the tilt plate209and tilt pulley205) remain stationary, the cable211may move inside the yoke arm103as the yoke arm103is panned relative to the tilt pulley205. The motion of the cable211may rotate the rod109as the lens portion101pans resulting in the lens portion101tilting as the lens portion101is panned. In some embodiments, the tilt motor207may be operable to rotate the tilt pulley205through the tilt plate209during a panning motion to offset relative motion of the tilt pulley205with respect to the lens portion101. The cable211may then remain stationary relative to the lens portion101and tilt pulley205resulting in no tilting of the lens portion101. Therefore, in some embodiments, the lens portion's tilt may be dependent on the relative difference in position between the pan plate203and the tilt plate209. Other configurations are also contemplated.

In some embodiments, the tilt plate209and pan plate203may be substantially coplanar. In some embodiments, the tilt plate209and pan plate203may overlap. The tilt plate209and pan plate203may be partially circular, and may extend through less than 180 degrees. Other configurations are also contemplated. As the pan plate203moves, an area for the tilt plate209to pass through may correspondingly move. In some embodiments, the tilt range provided at each panned position may be substantially similar, even though the tilt plate209may move through a different position relative to the base portion105. Specifically, in some embodiments, the tilt of the lens portion101may be relative to the difference in position between the tilt plate209and the pan plate203.

In some embodiments, to execute a pan motion with no tilting, both motors and plates may be driven substantially simultaneously so that there is no relative motion between the two plates. As another example, to execute a tilt movement, plate203may be held stationary by motor201while motor207drives plate209. If plate209were held stationary by motor207while motor201drove plate203, the result may be a diagonal motion because there is relative motion between the plates. Other motor and plate configurations are also contemplated.

In some embodiments, the motors201and207may be fixed. In some embodiments, the motors may be on moving parts within the camera100. In some embodiments, the FPGA321may determine appropriate responses for the motors based on their current positions and the effect on their positions caused by the movement of other motors being controlled by the FPGA321(e.g., the motion of a motor caused by another motor's actions).

FIG. 3illustrates a side view of the internal components of the camera100, according to an embodiment. In some embodiments, a screw hole301for a tripod mount screw may be provided. The camera100may attach to a mount through the tripod mount screw (other fasteners are also contemplated). In some embodiments, the camera100may use a wide angle lens309to capture an image of a participant even at a close angle. A data cable303may provide a link for data to and from the camera100. In some embodiments, the data cable303may curve downward without going past the back of the camera (e.g., to make the camera100easier to mount against a wall or other flat surface). FPGA321is shown in the base of the camera100. The FPGA321may be located in other areas of the base. In some embodiments, the FPGA321may be located in the lens portion of the camera100. Other placements of the FPGA321are also contemplated. In some embodiments, the signal from the camera100may be digitized before being sent down the data cable303in a high-speed serial digital stream. Other data types and conversions are also contemplated. For example, an industry standard electrical (Low Voltage Differential Signaling (LVDS)) and/or mechanical (e.g., Firewire/IEEE1394) interface may be used. In some embodiments, the data cable303may be thin and flexible. The data cable303may provide a digital interface to the camera100with, for example, six wires from the camera100to the camera base105. Other numbers of wires may also be used. In some embodiments, the data cable303may form a high-speed digital bus for carrying digitized microphone data, digital image data, bi-directional control data for controlling pan, tilt, focus, zoom motors, iris motors, and/or power to the camera100. In some embodiments, the data cable303may be up to 50 feet long. Other lengths are also contemplated. In some embodiments, the data cable303may run up one of the yoke arms103of the camera100to the central components of the lens portion101. In some embodiments, the data cable303may run up the other of the yoke arms103that does not contain the tilt cable211.

FIG. 4illustrates another view of the internal components of the camera100, according to an embodiment. In some embodiments, a detector (e.g., an opto-interrupter411comprising a light emitting diode (LED) and phototransistor which detect when a corresponding blade passes between them) on the gear plate209may be used to stop panning or tilting of the camera100if the camera100is panned or tilted past a predefined point (e.g., a blade may be placed on gear plate203or gear plate203may pass between the LED and phototransistor). Other detectors are also contemplated. In some embodiments, additional opto-interrupters may be put on the other gear plate203. In some embodiments, the opto-interrupters may be put on both sides of each gear plate to detect when the camera100was rotated or tilted past each end of a predefined point. There may be also be opto-interrupters on the reference plate291(the large, stationary, rectangular part that supports the moving elements) that define the limits of motion for plate203(and/or gear plate209), preventing the unit from trying to pan or tilt beyond an allowable range. Since tilt angle may be determined by the relative motion between plates203and209, the opto-interrupters that define the tilt limits may be mounted on one of the plates203and209and sense the position of the tilt plate209relative to the pan plate203.

In some embodiments, ball bearings may be placed between portions of the tilt plate209and pan plate203. In some embodiments, a spring401may bias the motor support plate403toward the center of the camera100. This bias may keep the motor gear201in contact with the gear plate203. In some embodiments, various parts of the camera100(e.g., casing, plates, pulleys, etc.) may be injection molded (e.g., using acetal, polycarbonate, and/or acrylonitrile butadiene styrene, etc.). Other manufacturing mechanisms and materials are also contemplated.

In various embodiments, an array of microphones405may be used to point the camera100in the direction of a speaking participant. The signals from the microphones405may be beamformed to determine the direction of arrival. The camera100may then be aimed at a participant or another source of audio. In some embodiments, eight low noise microphones405may be integrated into the camera100. Other numbers of microphones and other microphone array orientations may be used. In some embodiments, the camera100may not have microphones (e.g., it may be steered by a user). Digitized microphone data may be sent down the data cable303.

In some embodiments, the location or angle of a participant relative to the camera100may be determined by beamforming data from the microphones405. The microphone positions relative to the camera100, along with the angle and zoom of the camera100may be known. The microphone positions, camera angle, and camera zoom may then be used in conjunction with the data from the microphones405to determine the angle of the participant relative to the true visual field of the camera100. In some embodiments, the spatial positioning of the participant relative to the visual field may be determined and the camera100may be steered/aimed to center on the participant (or may be steered to another predetermined angle and zoom relative to the participant).

In some embodiments, a remote control sensor407may be provided. In some embodiments, multiple remote control sensors may be provided to make it easier for the camera100to receive signals from a remote control. In some embodiments, the camera100may receive signals through the remote control sensor407from an integrated unit and/or codec managing a video conference call. Additional connectors may also be provided. For example, light-pipe409may be provided (e.g., for a light emitting diode (LED) on a circuit board behind the light-pipe409). The LED may be used to indicate when a signal is received from the remote control or may be illuminated when the camera100is powered. Other uses for the LED are also contemplated.

Camera Support Mechanism

As seen inFIGS. 5 and 6, in various embodiments, a camera support mechanism (CSM)501may be used to mount a camera on top of a television (TV) or display device. The CSM501and camera may be installed on top of a monitor very quickly (e.g., in less than 1 minute). Other installation times are also contemplated. The CSM501may work for a video conferencing pan-tilt-zoom camera, or may be used for mounting any object on top of another object with a variable shape and thickness. This could be adapted for example to place a Digital Versatile Disc (DVD) player and/or a satellite receiver on top of the TV.

In various embodiments, the CSM501may have an upper deck503(which may be flat) that folds open to access a tripod mount screw515that couples the camera to the CSM501. Other fasteners may also be used to couple the camera to the CSM501. In some embodiments, the CSM501may not have a flat top that folds open. After attaching the camera to the top of the CSM501, the CSM501may be placed on the top center of the display device. The CSM501may have an adjustable front lip505(adjustable in an approximate range of plus or minus 5 degrees) that aligns to the top front edge of the display device. Other adjustment ranges are also contemplated. This may compensate for any “droop” of the lower deck when the CSM501is mounted to a display. (The camera lens may pan tilt in a range of approximately +/−25 degrees. Other camera tilt ranges are also contemplated.) In some embodiments, the front lip505may be attached to a lower deck519through a mount screw603. Other fasteners between the front lip505and the lower deck519are also contemplated. The front lip505may have two separate offsets (e.g., foam rubber pads507) that may cushion the contact with the display. Other numbers, shapes, and materials for the offsets are also contemplated. In some embodiments, if multiple pads507are used, the CSM501may work with display devices that have either a concave or a convex front surface. In some embodiments, the CSM501may work with display devices that have either a concave or a convex surface if a single pad is used. The front lip505may be adjusted to one of a number of set positions so that the CSM501can accommodate even extremely thin screens that may be wall mounted. For thin display devices mounted to a wall, the CSM501and camera may actually extend a couple of inches in front of the display in order for the back of the CSM501to not hit the wall.

In some embodiments, when the CSM501is placed on the display, a user may tighten adjustment knob509on one side of the pivot point at the rear of the CSM501. In some embodiments, the adjustment knob509may be a large knurled plastic knob. Other materials and shapes are also contemplated. This may rotate the adjustable rear leg511towards the back of the display. In some embodiments, the rear leg511may rotate from flat and parallel to the top of the display to perpendicular to the top of the display. In some embodiments, the rear leg511may accommodate different monitors or TVs (e.g., monitor based displays, rear-projection displays LCD displays, and plasma screens). When the rear leg511has rotated to the point where it makes contact with the display, further tightening of the knobs509may apply additional pressure. The rear leg511may be tightened to lock the rear leg511firmly against the back of the display at that position. In some embodiments, the lower deck face gear609and leg face gear611may be used to move and/or tighten the rear leg511. In some embodiments, the two face gears609,611may disengage to allow the rear leg511to swing against the back of the display. Then the face gears609,611may engage to lock the rear leg511in one position. In some embodiments, conical mating surfaces may be used in place of face gears609,611. For example, conical mating surfaces (similar to a conical clutch) may be used to allow continuous stopping positions for the rear leg511. In some embodiments, discrete stopping distances may be used. In some embodiments, the rear leg511may have a foam/rubber tip517for better gripping. In some embodiments, the CSM501may also accommodate variable slope on the screen from front to back using the foam/rubber tip517.

In some embodiments, with the CSM501firmly attached to the display, the camera may be relatively flat but may not be perfectly lined up with the top of the display device resulting in a tilt offset. By turning the lifter knob601(as seen inFIG. 6) on the CSM501, the angle of the camera can be adjusted up or down approximately in a range of plus or minus 10 degrees (other ranges are also contemplated). In some embodiments, the lifter knob601may be made of knurled plastic. Other materials and shapes are also contemplated. In some embodiments, the lifter cam605may adjust the angle of the camera as the lifter knob601is turned to raise lift607. The back of the CSM501may have a slot701(as seen inFIG. 7) in front of the adjustment knobs that may be used to route the camera cable without increasing the overall depth. Other locations for the slot701are also contemplated. In some embodiments, the electronics from the camera in the video conferencing system may be split in order to use a smaller mount for fitting the camera on top of the display device. In some embodiments, a cam follower arm609may be used to tilt the upper deck503approximately in a range of plus or minus 5 degrees (other ranges are also contemplated).

FIG. 8illustrates a method of positioning a camera100, according to an embodiment. It is noted that in various embodiments one or more of the method elements may be performed concurrently, in a different order, or be omitted. Additional elements may be performed as desired.

At801, a first signal to pan the camera100may be received.

At803, a first motor (e.g., pan motor201) may be activated to pan the camera100. In some embodiments, the first motor may pan the camera100through rotation of a pan plate203coupled to the camera100.

At805, a second signal to tilt the camera100may be received.

At807, a second motor (e.g., tilt motor207) may be activated to tilt the camera100. In some embodiments, the second motor may tilt the camera100through rotation of a tilt plate209coupled to the camera100through cables in an arm of the camera100.

At809, if the pan plate203or the tilt plate209moves past a predefined point (as detected by an opto-interrupter), the opto-interrupter411may signal the first motor or the second motor, respectively, to stop. In some embodiments, the signal may be received by the FPGA that may signal the first motor or second motor to stop.

At811, data to and from the camera100may be transmitted as a high-speed serial digital stream through a thin cable coupled to the camera100.

FIG. 9illustrates a method of panning a camera100, according to an embodiment. It is noted that in various embodiments one or more of the method elements may be performed concurrently, in a different order, or be omitted. Additional elements may be performed as desired.

At901, a first signal to pan the camera100may be received.

At903, a first motor (e.g., pan motor201) may be activated to pan the camera100. In some embodiments, the first motor may pan the camera100through rotation of a pan plate203coupled to the camera100.

At905, a second signal may be sent to the tilt motor207.

At907, a second motor (e.g., tilt motor207) may be activated to move a tilt pulley such that there is no relative motion between the tilt pulley and the panning camera.

At909, motion of at least the pan plate or the tilt plate past a predefined point may be detected.

At911, if the opto-interrupter detects motion past the predefined point, the opto-interrupter may send a signal to stop the first motor or the second motor.

At913, a high-speed serial digital stream may be transmitted through a thin cable coupled to the camera.

Embodiments of these methods may be implemented by program instructions stored in a memory medium or carrier medium. A memory medium may include any of various types of memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device; a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; or a non-volatile memory such as a magnetic media, e.g., a hard drive, or optical storage. The memory medium may comprise other types of memory as well, or combinations thereof. In addition, the memory medium may be located in a first computer in which the programs are executed, or may be located in a second different computer that connects to the first computer over a network, such as the Internet. In the latter instance, the second computer may provide program instructions to the first computer for execution. The term “memory medium” may include two or more memory mediums that may reside in different locations, e.g., in different computers that are connected over a network.

In some embodiments, the computer system may include a memory medium(s) on which one or more computer programs or software components according to one embodiment of the present invention may be stored. For example, the memory medium may store one or more programs that are executable to perform the methods described herein. The memory medium may also store operating system software, as well as other software for operation of the computer system.