Patent Publication Number: US-2003222990-A1

Title: Video camera for transmitting video, audio and control signals to a remote recording device

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention generally relates to the field of hand-held video cameras, and more particularly to hand-held video cameras and systems which transmit video and audio information as well as control signals over a radio frequency (RF) link to a remotely located converter box which, in turn, provides corresponding video, audio, and control signals to a recording device such as a video cassette recorder (VCR).  
       [0002] Video cameras which transmit video and audio information over a radio frequency and video camcorders (i.e., video cameras with internal recording capability) are well known in the art. These video cameras and camcorders typically include a lens which focuses light reflected from an object or scene being photographed onto a small semiconductor image sensor such as charge coupled device (CCD) or CMOS sensor. These image sensors comprise an array of thousands of tiny light-sensitive photosites. Each photosite measures the amount of light that hits a particular point, and translates this information into electrical image signals. In the case of video camcorders, these electronic image signals are subsequently processed and formatted in the video camera and recorded on a removable storage medium such as a magnetic tape. However, since video camcorders include recording components (e.g., a rotating head drum with recording heads, audio head, etc.) as well as mechanical components for advancing the tape, they are typically larger, heavier, and more expensive than a stand alone video camera.  
       [0003] Recently, video camcorders have become available which store video and audio information on a miniaturized recording media such as compact tapes or discs. While the use of compact recording media has enabled the size and weight of video camcorders to be reduced, the compact recording media for these video camcorders are typically not directly compatible with standard playback devices such as VCRs and either require an additional interfacing device to play back the video and audio information stored on the compact recording media or require the outputs of the video camcorder to be directly coupled to the playback device.  
       [0004] Alternatively, rather than store the video information on removable medium, the video information generated by a video camera can be viewed real time on a monitor remotely located from the video camera. Such systems are typically employed in security and surveillance systems. In such systems, video information generated by a video camera is transmitted over an RF link to a receiver at a remotely located monitor. For example, a product referred to as XCam2 includes a small wireless camera including a 2.4 GHz transmitter and a stand alone receiver having standard video outputs which can be connected to a television or VCR. Video information generated by the camera located, e.g., at the entrance of one&#39;s home, can be transmitted to the receiver located in the house and viewed on a monitor. Alternatively, the video outputs from the receiver can be connected to a VCR so that the video information generated by the remotely located camera can be recorded. However, in such a system, recording can only be initiated by a person at the location of the VCR, and cannot be initiated or controlled by a person at the remotely located camera.  
       [0005] Remote control devices are also well known in the art. Practically all commercial available audio or video products include remote control devices which can be used to turn the products on and off as well as control their mode of operation. These remote control devices typically transmit signals over an infrared (IR) link to an IR input port on the product, and therefore must be used in the line of sight of the product in order to work reliably. To overcome this shortcoming, prior art references disclose the use of RF remote control devices. For example, U.S. Pat. No. 4,916,532 describes a system having a video source such as a VCR which transmits video and audio information via an RF transmitter to a receiver at a remote location which converts the RF signals to baseband signals which are displayed on televison set. The system also includes an IR controller at the location of the television set which transmits control information to an IR detector. The IR control signals are subsequently converted into an electrical coded signal which is transmitted by a remote control transmitter which operates on one of the frequencies provided for the local transmission of coded information (e.g., those employed by garage door openers) to a remote control receiver at the location of the VCR. The remote control receiver outputs the received control signals to an IR repeater which, in turn, provides IR inputs to an IR detector of the VCR.  
       SUMMARY OF INVENTION  
       [0006] Accordingly, it is the object of the present invention to provide a small, lightweight, and inexpensive video camera which can be used in conjunction with a standard recording device such as a VCR to record audio and video information generated by the video camera.  
       [0007] It is also the object of the present invention to provide a video camera which transmits audio, video, and control signals over an RF-link to a remotely located base system which converts the received audio, video, and control signals into VCR compatible formats. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0008] FIGS.  1 A- 1 C are diagrams of the video camera of the preferred embodiment of the invention.  
     [0009]FIG. 2A is schematic diagram of a video camera having a RF transmitter in accordance with the preferred embodiment of the invention.  
     [0010]FIG. 2B is a schematic diagram of a base station/converter box having an RF receiver in accordance with the preferred embodiment of the invention.  
     [0011] FIGS.  3 A- 3 B are diagrams of the base station/converter box of the preferred embodiment of the invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0012] A detailed diagram of the video camera system of the preferred embodiment of the present invention is shown in FIGS.  1 A- 1 C. As shown, video camera  1  includes a lens  2  through which light reflected from an object or scene being recorded is focused on an optical pick-up device  10  (FIG. 2A) such as a CCD or CMOS sensor which translates the detected image into a NTSC or PAL signal. Eyepiece  3  enables the user to accurately point the camera at the object being recorded. Video camera  1  also includes an integral microphone  4  for detecting and recording audio information as well as external jack  5  by which an external microphone (not shown) can be coupled to the video camera. The video camera also includes a mode selection switch  6  which enables the user to place the video camera into standby and off modes. Also included are a number of user selectable keys or buttons  7   a - 7   f  corresponding to standard VCR functions such as record, pause, stop, fast forward, rewind, and play. The video camera also includes an input jack  8  by which a remote control device (not shown) also having a plurality of user selectable keys or buttons corresponding to standard VCR functions can be coupled to the camera.  
     [0013] As shown in the schematic diagram FIG. 2A, video camera  1  also includes a 2.4 GHz RF transmitter  11  and associated antenna  9 . RF transmitter  11  may be any one of a variety of commercially available integrated circuit (IC) transmitter chips or may be constructed from discrete components. The video information from the optical pick-up device  10  and audio information from microphone  4  are both provided as inputs to RF transmitter  11 . Likewise, VCR control signals generated from user selectable keys  7   a - 7   f  are also provided via switch coding circuitry  12  as inputs to RF transmitter  11  which combines the audio, video, and control signals into a composite signal which is modulated at a 2.4 GHz carrier frequency and transmitted via antenna  9  to remotely located base station/converter box  20 .  
     [0014] A diagram of the base station/converter box  20  is shown in FIGS.  3 A- 3 B. As shown, base station/converter box  20  includes a rotatable antenna  21 , on/off switch  22 , and channel selection switch  23 . As shown in the schematic diagram FIG. 2B, base station/converter box  20  also includes an RF receiver  24  coupled to antenna  21  for receiving, and demodulating the audio, video, and control signals transmitted by the video camera. Here again, RF receiver  24  may be any one of a variety of commercially available IC receiver chips or may be constructed from discrete components. As shown in FIG. 3B, the composite video and audio outputs from RF receiver  24  are provided to standard RCA jacks  25  which can be coupled to the standard video and audio inputs of a VCR. Base station/converter box  20  also includes a microprocessor or controller  27  for decoding received control signals and an IR light emitting diode (LED)  26  for generating IR signals corresponding to the control signals transmitted by the video camera compatible with the standard IR inputs included on commercially available VCRs. In one embodiment IR LED  26  is included in a housing  27  that can be physically coupled to the IR input of the VCR using, e.g., self adhesive velcro  30 . Housing  27  includes an opening  28  allowing control signals from other remote control devices to also be received and processed by the VCR. Alternatively, IR LED  26  can be included in base station/converter box  20  with the control signals being transmitted to the VCR in the same manner as a commercially available remote control device.  
     [0015] The microprocessor  27  in base station/converter  20  may also include universal remote control programming and circuitry which is well known in the art and programming that can be activated by the user during initial system installation to interrogate and establish communications with the VCR.  
     [0016] In operation, a user of video camera  1  using the viewfinder/eyepiece  3  can point the lens  2  at the object or scene to be recorded. When the “record” key  7   a  is selected, the video camera transmits a corresponding control signal via the 2.4 GHz RF link to the remotely located base station/converter box  20 . The base station/converter box  20  generates a corresponding “record” command signal at its IR output which is received by the VCR  40  at its IR input port. The VCR is placed into “record” mode and records the video and audio signals transmitted from the video camera over the 2.4 GHz RF link. If the user wants to interrupt recording, the “pause” key  7   b  can be selected and a “pause” command signal is transmitted over the RF link to the base station/converter box  20 , converted into the appropriate IR signal, and output to the VCR placing the VCR in the “pause” mode. Recording can be resumed by re-selecting the “pause” button. When the user has finished recording, the “stop” button  7   c  is selected causing a “stop” command to be transmitted over the RF-link to the base station/converter box  20  which outputs a corresponding IR “stop” signal to the VCR  40  which responds accordingly.  
     [0017] Various additional modifications and improvements thereon will become readily apparent to those skilled in the art. For example, the RF-link between the video camera and base station/converter box need not utilize a carrier frequency of 2.4 GHz, but may be utilize a 900 MHz carrier frequency or other radio frequency. Additionally, the audio and video outputs from the base station/converter box need not be output as composite signals but may be formatted in any other well known video formats such as RGB and S-video, and be provided on any number of types of connectors such as a standard coaxial cable, etc. Further, the invention is not limited to use with VCRs, but may be used with any type of recording device, e.g., CD or DVD recorders. Accordingly, the spirit and scope of the present invention is to be construed broadly and limited only by the appended claims, and not by the foregoing specification.