Abstract:
A security camera system for safeguarding a designated area includes at least one camera for encoding and transmitting streaming video of the designated area, and a video receiver for receiving, decoding and analyzing the streaming video for relevant motion, such as movement indicative of the presence of a person. Upon detecting a motion event, the video receiver triggers an alert condition, which results in storing each video steam into memory. Each camera is provided with a PIR detector circuit for measuring infrared radiation within the designated area, the video steam and IR data being transmitted to the receiver via analog communication means to reduce implementation costs. To minimize the risk of false trigger events, the receiver monitors both pixel changes in the streaming video signals as well as measured IR radiation levels within the designated area that fall within the traditional thermal energy range of human body heat.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to security camera systems and, more particularly, to security camera systems which are designed to detect the presence of relevant movement within a designated environment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Security camera systems, also referred to herein simply as security systems, are well known in the art and are widely used, in both residential and business settings, to monitor and safeguard a designated environment from intruders. One well-known type of security system includes at least one video surveillance camera that is connected to a common digital recording device, such as a digital video recorder (DVR) or network video recorder (NVR), by a cable or other conventional communication path. In use, each camera continuously compiles video of the monitored area and processes the video for transmission to the common video recording device. The common recording device, in turn, receives the encoded video signal compiled from each camera and decodes the signal into a corresponding digital video stream. 
         [0003]    The two principal types of video surveillance cameras that are traditionally utilized in security systems are analog cameras and digital cameras, which are also commonly known in the art as Internet Protocol (IP) cameras. Analog and digital cameras differ primarily in that analog cameras process the compiled video signal to be transmitted to the common recording device in analog form, whereas digital cameras process the compiled video signal to be transmitted to the common recording device in digital form. As a consequence, it has been found that the two aforementioned types of video cameras differ principally in cost, with analog cameras being generally less expensive than digital cameras. 
         [0004]    Commonly, security camera systems of the type as described above are designed to detect any relevant movement within the monitored environment, such as the presence of an individual. Upon detecting such movement within the area under surveillance, the system is designed to initiate a predefined response, such as the commencement of video recording and/or activation of an alert signal. In this manner, security camera systems serve as effective tools in safeguarding a monitored area from unauthorized intruders. 
         [0005]    Motion detection technology is often used to detect the presence of an individual within the monitored environment. The detection of motion within the designated area is commonly achieved by examining pixel changes in the compiled digital video streams. Specifically, a central controller in the common recording device is programmed to measure pixel changes in each digital video stream. Any detected pixel change that exceeds a predefined threshold is considered a motion detection event and, as such, causes the recording device to undertake the previously determined motion detection response. 
         [0006]    Although well-known and widely used in the art, security systems that rely solely on pixel changes to detect relevant movement within the monitored environment have been found to suffer a notable shortcoming with respect to accuracy. Specifically, it has been found that monitoring pixel changes in video streams frequently results in relatively inconsequential movement triggering a motion detection event. Examples of irrelevant action which may induce a motion detection event include, inter alia, (i) variances in light within the monitored environment (e.g., resulting from lights being turned on/off, sunlight changes and the like), (ii) movement of animals, insects, dust or other small elements within the monitored environment, and (iii) movement of elements in the background (e.g., rain, wind-induced movement of trees, shrubs or swings) or immediately outside of the monitored environment (e.g., a moving car or rain seen through a window within the designated area). As can be appreciated, this detection of inconsequential movement within the monitored environment often results in unnecessary recordings and alerts, which is highly undesirable. 
         [0007]    In view thereof, it has become increasingly common for security systems to monitor infrared radiation variances within the designated environment, rather than monitor pixel changes in a digital video feed, in order to detect relevant movement within the area under surveillance (e.g., the presence of a person). For instance, it is known in the art for security systems to equip a digital Internet Protocol (IP) camera with a pyroelectric infrared radial (PIR) sensor circuit. 
         [0008]    In use, the PIR sensor circuit measures infrared light that radiates from objects in its field of view (e.g., thermal energy produced from a person) in relation to the remainder of the monitored environment. The digital output signal from the PIR sensor circuit is then combined with the streaming video signal during signal processing prior to transmission to the common recording device. The recording device then analyzes the infrared radiation signal component of the mixed signal. If any thermal energy variance is detected that can be attributed to, inter alia, the standard body temperature range, the recording device initiates the predefined motion detection response. In this manner, an effective method for detecting a notable motion event within the monitored environment can be achieved. 
         [0009]    As can be appreciated, the use of PIR sensors in security camera systems to detect relevant movement within a monitored environment has been found to suffer from a couple notable shortcomings. 
         [0010]    As a first shortcoming, PIR sensors are traditionally used with digital camera systems due to the processing capabilities of the signal processor responsible for combining and conditioning the digital PIR output signal with the digital video stream. However, as referenced briefly above, digital cameras have been found to be relatively expensive in nature, largely due to the cost associated with the advanced signal processor as well as the signal communication channels commonly used in conjunction therewith (e.g. Ethernet cables). 
         [0011]    As a second shortcoming, security camera systems which rely solely upon the detection of infrared radiation within a defined thermal energy range to initiate a trigger event have been found to be experience reliability issues. Specifically, it has been found that unforeseen variances in infrared radiation within the monitored environment can often be attributed to conditions other than relevant movement (e.g., the presence of people) and, as such, can induce false trigger events. Examples of non-human action which may induce a variance in infrared radiation within the designated temperature range include, inter alia, (i) rapid changes in sunlight radiation within the field of view, (ii) intense thermal energy changes caused by equipment within the monitored environment (e.g., a burner), and (iii) sun, lightning or other bright light reflecting off highly reflective surfaces (e.g., glass or a pool) toward the PIR sensor. 
       SUMMARY OF THE INVENTION 
       [0012]    It is an object of the invention to provide a new and improved security camera system for monitoring a designated environment. 
         [0013]    It is another object of the present invention to provide a security camera system as described above that monitors the designated environment using one or more continuous video streams. 
         [0014]    It is yet another object of the present invention to provide a security camera system as described above that records the one or more continuous video streams upon detecting relevant movement within the designated environment. 
         [0015]    It is still another object of the present invention to provide a security camera system as described above that detects relevant movement within the designated environment with reliable accuracy. 
         [0016]    It is yet still another object of the present invention to provide a security camera system as described above that is simple to use, readily scalable in size, and inexpensive to implement. 
         [0017]    Accordingly, as one feature of the present invention, there is provided a security camera system for monitoring a designated area for relevant movement, the security system comprising (a) an analog video transmitter, comprising, (i) an image capture device for producing a streaming digital video signal of the designated area, (ii) a PIR detector circuit for measuring infrared radiation within the designated area, the PIR detector circuit producing a digital infrared radiation signal that indicates relevant movement within the designated area based on measured infrared radiation, and (iii) a signal processor for processing the digital video and infrared radiation signals together to yield a mixed analog signal, the signal processor transmitting the mixed analog signal, and (b) a video receiver adapted to receive and decode the mixed analog signal transmitted from the analog video transmitter into a corresponding decoded digital signal, the video receiver analyzing the decoded digital signal and triggering an alert condition when the decoded digital signal indicates relevant movement within the designated area. 
         [0018]    As another feature of the present invention, there is provided a security camera system for monitoring a designated area for relevant movement, the security system comprising (a) a video transmitter, comprising, (i) an image capture device for producing a streaming digital video signal of the designated area, (ii) a PIR detector circuit for measuring infrared radiation within the designated area, the PIR detector circuit producing a digital infrared radiation signal that indicates relevant movement within the designated area based on measured infrared radiation, and (iii) a signal processor for processing the digital video and infrared radiation signals together to yield a mixed signal, the signal processor transmitting the mixed signal, and (b) a video receiver adapted to receive and decode the mixed signal transmitted from the video transmitter into a corresponding decoded digital signal with multiple image frames, each image frame comprising a plurality of pixels, the video receiver detecting a number of pixel changes between successive image frames in the decoded digital signal, (c) wherein the video receiver analyzes the decoded digital signal and triggers an alert condition only when both the amount of measured infrared radiation and the number of detected pixel changes in the decoded digital signal indicates relevant movement within the designated area. 
         [0019]    Various other features and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings which form a part thereof, and in which is shown by way of illustration, an embodiment for practicing the invention. The embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    In the drawings wherein like reference numerals represent like parts: 
           [0021]      FIG. 1  is a simplified block representation of a security camera system constructed according to the teachings of the present invention, the system being shown with a simplified representation of person present within a monitored environment; 
           [0022]      FIG. 2  is a sample signal waveform of the mixed analog signal transmitted by the camera shown in  FIG. 1 ; 
           [0023]      FIGS. 3( a ) and 3( b )  are front perspective and partially exploded side views, respectively, of one implementation of the camera shown in  FIG. 1 ; and 
           [0024]      FIGS. 4( a )-( c )  are a series of sample frames of the analog video stream produced by the camera shown in  FIG. 1 , the sample video frames being useful in illustrating how security camera system detects and determines a relevant motion event, wherein a portion of each sample frame in  FIGS. 4( b ) and 4( c )  is shown enlarged and exploded therefrom as an inset. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Security Camera System  11   
       [0025]    Referring now to  FIG. 1 , there is shown a security camera system constructed in accordance with the teachings of the present invention, the security camera system being identified generally by reference numeral  11 . As will be explained further in detail below, security camera system  11  is designed to provide video surveillance of a particular environment. As a primary feature of the present invention, system  11  is able to detect relevant movement within the monitored environment (e.g., the presence of an individual) with great accuracy and at minimal cost to implement. 
         [0026]    Security camera system  11  comprises at least one video transmitter, or camera,  13  that is connected to a common video receiver, or recorder,  15  by an appropriate communication channel  17 . For simplicity purposes only, system  11  is represented herein as comprising a single camera  13 . However, it is to be understood that a plurality of cameras  13  could be connected to common receiver  15  via corresponding communication channels  17  without departing from the spirit of the present invention. In this capacity, surveillance could be achieved over a larger environment and/or with greater overall effectiveness. 
         [0027]    In use, each camera  13  is designed to continuously compile video of the monitored environment. The video signal is then transmitted via channel  17  to video receiver  15  for analysis. If receiver  15  determines that a relevant motion event has taken place within the monitored environment, receiver  15  initiates a predefined alert response, such as commencing recording of the video feed into a data storage device and/or activating an alert signal. 
         [0028]    As will be explained in greater detail below, system  11  is provided with two novel design features, each of which offers notable advantages over conventional security camera systems. Specifically, system  11  is designed to (i) utilize both infrared (IR) radiation-based motion detection technology and pixel-based motion detection technology to determine relevant movement within the monitored environment, thereby minimizing the frequency of false alert triggers and improving overall accuracy, and (ii) operate as an analog system, with the temperature detection signal and the video signal compiled by camera  13  being processed into a mixed analog signal that is transmitted to receiver  15  via analog-based communication channel  17 , thereby offering considerable cost savings to implement. 
         [0029]    As seen in  FIG. 1 , each camera  13  comprises an optical system, or image capture device,  19  that produces a digital video signal Sy, a PIR detector circuit  21  that produces a digital IR radiation signal S IR , and an image signal processor, or ISP,  23  that processes the digital video signal S V  and digital IR radiation signal S IR  together to yield a combined, or mixed, analog signal S A . As referenced briefly above, incorporating IR radiation detection technology into an analog security camera system serves to ensure detection accuracy while minimizing implementation costs, which is highly desirable. 
         [0030]    Optical system  19  preferably includes an optical lens  25 , which captures visible light in its field of view within the monitored environment, and an image sensor  27  that converts the visible light captured by lens  25  into a corresponding digital video signal S V . As seen, image sensor  27  is in electrical communication with ISP  23 . As a result, digital video signal S V  produced from optical system  19  is streamed to ISP  23  for subsequent processing. 
         [0031]    PIR detector circuit  21  preferably includes a Fresnel lens  29 , which refracts all light in its field of view within the monitored environment, a PIR sensor  31 , which converts any infrared (IR) radiation from the refracted light into a corresponding voltage, and a signal conditioning circuit  33  that converts the voltage produced by PIR sensor  31  into a corresponding digital IR radiation signal S IR . As can be seen, signal conditioning circuit  33  is in electrical communication with ISP  23 . As a result, digital IR radiation signal S IR  produced from circuit  33  is delivered to ISP  23  for processing. 
         [0032]    As can be appreciated, signal conditioning circuit  33  preferably includes a microcontroller that is specifically tuned to monitor a particular IR radiation range within the field of view (namely, the corresponding thermal energy range which is indicative of the presence of a person). Based on the voltage produced by PIR sensor  31 , circuit  33  produces a series of intermittent yes/no-type temperature signals S IR , with a “yes” signal denoting that a trigger condition has been met (e.g., a thermal energy variance within the field of view which is indicative of the presence of a person) and a “no” signal denoting that a trigger condition has not been met. 
         [0033]    Preferably, signal conditioning circuit  33  compares two sensor readings (e.g., by analyzing the outputs of a pair of separate PIR sensors  31 ) to obtain IR radiation differentials within the field of view. Using this technique, the average, or natural, temperature within the field of view is effectively normalized. Among other things, this technique further enables circuit  33  to compensate for (ii) broader changes throughout the entire field of view that may be attributable to lighting and/or temperature changes within the monitored environment and (ii) common-mode interference that may be attributable to nearby electric fields. 
         [0034]    Although separate complementary pairs of lenses and sensors are used to produce corresponding video and temperature signals, it is to be understood that the same lens and/or sensor could be used in conjunction with the production of both video signal S V  and IR radiation signal S IR . By eliminating such components, camera  13  may be effectively reduced in both size and cost of manufacture. 
         [0035]    As referenced briefly above, image signal processor, or controller,  23  is disposed in electronic communication with optical system  19  and PIR detector circuit  21 . Processor  23  is specifically programmed to condition and mix digital video signal Sy and digital IR radiation signal S IR  to yield combined analog signal S A . In turn, encoded analog signal S A  is transmitted to video receiver  15  via communication channel  17  for subsequent decoding and analysis, which will be explained further below. 
         [0036]    It should be noted that utilizing an analog signal format to transmit signals from each camera  13  to receiver  15  provides system  11  with a couple notable advantages. 
         [0037]    As a first advantage, because analog signal transmission protocols are rather limited in complexity, controller  23  requires minimal processing capabilities. Consequently, a relatively inexpensive controller  23  could be utilized in each camera  13 , thereby significantly reducing the overall cost to manufacture system  11 . 
         [0038]    As a second advantage, analog signal transmission allows for the use of analog communication channels  17 , which are often already configured in certain environments. As can be appreciated, analog communication mediums, such as coaxial cables, are both generally inexpensive in nature and can be relatively long in length without experiencing signal degradation. 
         [0039]    ISP  23  utilizes a novel method of conditioning and mixing digital video signal S V  and digital IR radiation signal S IR  together to yield combined analog signal S A . As will be explained further in detail below, signal mixing is achieved by taking advantage of inherent constructs of certain analog video transmission protocols. 
         [0040]    Specifically, certain analog signal transmission protocols (e.g., National Television System Committee (NTSC) and Phase Altering Line (PAL) transmission protocols) transmit video in a frame-by-frame manner. In the present invention, ISP  23  is able to combine streaming digital video signal S V  with PIR sensor signal S IR  by inserting the IR radiation data in the space between successive frames of the video during conversion into analog form. 
         [0041]    To illustrate the signal mixing concept set forth in detail above, a sample signal waveform is shown in  FIG. 2 , the waveform being identified generally by reference numeral  111 . As can be seen, sample waveform  111  includes a first set, or frame, of active lines of video  113  and a second set, or frame, of active lines of video  115  that are separated by a vertical blanking interval (VBI)  117 . A limited portion of interval  117  includes certain non-visible data used for video synchronization and equalization purposes. For instance, in waveform  111 , a portion of interval  117  includes vertical synchronization pulses  119 , which are used to indicate when the next successive frame of video is to commence, and color synchronization carriers  121 . 
         [0042]    As can be seen, PIR signal data, or component,  123  is embedded into waveform  111  within interval  117 . As previously referenced, PIR signal component  123  is preferably of the yes/no variety, generating one or more pulses of a first amplitude upon detecting a “yes” condition and one or more pulses of a second amplitude upon detecting a “no” condition. In this manner, video receiver  15  is easily able to discern when a IR radiation alert condition has occurred, as will be explained further below. 
         [0043]    Referring now to  FIGS. 3( a ) and 3( b ) , there are shown front perspective and side views, respectively, of one implementation of camera  13 . However, it is to be understood that the implementation of camera  13  shown in  FIGS. 3( a ) and 3( b )  is provided for illustrative purposes only and that the overall design and configuration of camera  13  could be modified without departing from the spirit of the present invention. 
         [0044]    As represented herein, camera  13  comprises a common protective housing  211  into which all the principal electronic components of camera  13  are disposed in order to create a unitary item. Specifically, housing  211  includes a generally cylindrical member, or canister,  213  that is appropriately dimensioned to retain optical system  19 , detector circuit  21  and signal processor  23 . 
         [0045]    A stem  215  extends orthogonally out from the rear of canister  213  and is pivotally coupled to a dome-shaped base  217 , which is designed to be fixedly mounted onto a wall or other similar surface. As such, the orientation of canister  213  can be adjusted, as needed, relative to base  217  to modify the field of view for camera  13 . 
         [0046]    In the present embodiment, both optical system  19  and PIR detector circuit  21  are shown retained within canister  213 . To facilitate assembly of camera  13 , canister  213  is designed with a narrow extension, or bump-out,  219  to receive PIR detector circuit  21  without interfering with the larger components of camera  13 . 
         [0047]    Referring back to  FIG. 1 , video receiver  15  represents any device capable of receiving, analyzing and selectively recording video, such as a DVR or NVR. As can be seen, receiver  15  preferably includes a decoder  35  for, inter alia, decoding analog signal S A  back into digital form, a main chipset, or microcontroller unit (MCU),  37  for, inter alia, determining when thermal-based and pixel-based motion detection exceeds a defined threshold, and a data storage device  39  for saving digital video signal S D  when MCU  37  determines a motion detection event. 
         [0048]    Decoder  35  represents any device capable of receiving and decoding an analog signal into digital form. As can be appreciated, decoder  35  receives the analog video signal from each camera  13  and, in turn, is responsible for both (i) decoding the video component of processed analog signal S A  back into a corresponding digital video signal S D  and (ii) generating a digital PIR flag signal S PIR  which indicates the yes/no status of the embedded PIR signal component in analog signal S A . 
         [0049]    MCU  37  is in electrical communication with decoder  35  and is adapted to receive both digital video signal S D  and digital PIR flag signal S PIR . Using the aforementioned digital signals, MCU engages in three principal processes, namely, (i) analyzing pixel changes in digital video signal S D  to determine whether a pixel-based motion detection event has occurred, (ii) analyzing the status of digital PIR flag signal S PIR  to determine whether a thermal-based motion detection event has occurred, and (iii) if both thermal-based and pixel-based motion detection is determined, initiating the predefined alert response (e.g. commence storing of video signal S D  into memory). 
         [0050]    Preferably, pixel detection is achieved by programming MCU  37  to analyze frames of digital video signal S D , wherein each video frame is an image which contains a matrix of pixels. Because each pixel is assigned a value which determines its color, a motion detection algorithm can be applied by MCU  37  that compares the value of each pixel on a frame-by-frame basis to detect change. If pixel change is detected which exceeds a predefined threshold (e.g., amongst a certain minimum-sized pixel cluster), a pixel-based motion detection event is assessed. 
         [0051]    Storage device  39  is electrically connected to MCU  37  and is adapted to receive and store video signal S D  into memory. Accordingly, storage device  39  represents any device capable of storing video, such as a local hard disk drive (HDD). Although storage device  39  is represented herein as being an internal component of receiver  15 , it is to be understood that storage device  39  could be remotely located (e.g., a cloud-based data storage solution) without departing from the spirit of the present invention. 
         [0052]    As referenced above, communication channel  17  represents any conventional communication medium that is capable of transmitting an analog signal. For instance, channel  17  may be in the form of a length of relatively inexpensive, analog coaxial cable that directly connects each camera  13  to common receiver  15 . Alternatively, channel  17  may be in the form of a wireless communication path, thereby facilitating the installation of cameras  13 . 
       Operation of Security Camera System  11   
       [0053]    Security camera system  11  is designed to operate in the following manner. As referenced above, each camera  13  is designed to compile a continuous stream of digital video S V  for the monitored environment. Additionally, each camera  13  measures IR light within the monitored environment, thereby allowing for the detection of any change in IR radiation within the environment that is indicative of relevant movement, such as a change in thermal energy attributable to body heat. 
         [0054]    Signal processor  23  then mixes digital video signal Sy and digital IR radiation signal S IR  together to yield a combined analog signal S A . As a feature of the invention, ISP  23  can process each of the aforementioned digital signals using different analog transmission protocols. Accordingly, it is to be understood that the principles of the present invention could be applied or retrofitted across a broad spectrum of digital and analog security camera systems, which is highly desirable. 
         [0055]    Mixed analog signal S A  from each camera  13  is then transmitted in analog form to common receiver  15  via analog communication medium  15 . As can be appreciated, the use of analog signal transmission technology substantially reduces the manufacturing cost associated with system  11 , which is highly desirable. 
         [0056]    Upon receipt of combined analog signal S A , receiver  15  decodes the video steam back into digital form and engages in an analysis to determine whether both IR radiation-based and pixel-based motion detection has occurred within the monitored environment. For ease in understanding how video receiver  15  engages in its motion detection analysis, a series of illustrative screen displays are shown in  FIGS. 4( a )-( c ) . 
         [0057]    In  FIG. 4( a ) , there is shown a sample screen display, or video frame,  211  of a digital video stream S D  compiled and analyzed by video receiver  15 . As can be seen, frame  211  of video stream S D  is shown at a moment in time in which there is no motion detected within the monitored environment, which is represented herein as an office. 
         [0058]    By contrast, in  FIG. 4( b ) , there is shown a second sample screen display, or video frame,  221  of a digital video stream S D  compiled and analyzed by video receiver  15 . As can be seen, a plurality of cables  223  has fallen into the field of view. Because receiver  15  monitors pixel changes in the video feed, the pixel changes attributed to the movement of cables  223  triggers a pixel-based motion detection motion event. Upon detecting the pixel-based motion detection event, MCU marks video stream S D  with a corresponding tag  225 , represented herein simply as the letter “M.” 
         [0059]    It should be noted that the presence of cables  223  does not similarly induce a thermal energy-based motion detection event because no notable change in infrared radiation is detected within the field of view (e.g., thermal energy falling within the typical range of human body heat). Because no relevant, thermal-based movement is detected within the field of view, the pixel-based detection event motion is considered inconsequential (e.g., not a human intrusion) and, as such, no alert response is undertaken. 
         [0060]    However, in  FIG. 4( c ) , there is shown a third sample screen display, or video frame,  231  of a digital video stream S D  compiled and analyzed by video receiver  15 . As can be seen, a hand  233  is present within the field of view. The thermal radiation produced from hand  233  is detected by PIR detector circuit  21  and, in turn, yields an indicative digital PIR signal S IR . Receiver  15  ultimately identifies that a IR radiation-based motion detection event has occurred and marks video stream S D  with a corresponding tag  235 , represented herein simply as “PIR.” 
         [0061]    Additionally, by monitoring pixel changes in the video feed, the initial movement of hand  233  within the field of view triggers a pixel-based motion detection event. Upon detecting the pixel-based motion detection event, MCU marks video stream S D  with a corresponding tag  237 , represented herein simply as the letter “M.” 
         [0062]    It should be noted that if both IR radiation-based and pixel-based motion detection events are detected, video receiver  15  engages in an appropriate alert response, such as commencing storage of the video feed S D  into data storage device  39 . However, it is to be understood that the triggering of an alert response is only undertaken when both types of events are detected, thereby eliminating frequent false trigger events that generally occur when only one of the two events is detected. 
       Features and Advantages of the Present Invention 
       [0063]    As can be appreciated, the construction and operation of security camera system  11  yields a number of notable advantages over traditional security camera systems. 
         [0064]    As a first advantage, security camera system  11  incorporates IR radiation-based motion detection capabilities into an analog-based security camera system. Due to certain inherent positive characteristics associated with analog-based signal transmission systems (e.g., lower costs, longer signal transmission capabilities), a highly advantageous security camera system can be achieved. 
         [0065]    As a second advantage, security camera system  11  utilizes IR radiation-based and pixel-based motion detection, in tandem, to increase the accuracy in sensing relevant movement, such as the presence of a person within a monitored environment. In fact, testing indicates that the use of the two aforementioned motion detection techniques can diminish the occurrence of false trigger events by as much as 90%. 
         [0066]    The embodiment shown above is intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.