Abstract:
The present invention includes a periscope, which has two camera objectives. The cameras are housed on top of the viewing monitor inside of a housing cell, so as to efficiently utilize the cabin space of the vehicle. One camera objective is a day camera bullet that may be used during day time or low light viewing. Another camera objective is the night board camera that may be used for night time viewing. Both cameras are electronically connected to a flat panel display, so that the optical picture may be displayed by others. In addition, the periscope of the present invention utilizes a heater sensor system that allows the day or night camera to be operated at or below temperatures of 32° Fahrenheit. The periscope of the present invention also implements an 18 mm image intensifier tube, which has the capability of detecting and amplifying low light level images during night time viewing and surveillance, under moonlight or starlight.

Description:
FIELD OF INVENTION 
     The present invention relates to an improved optical image forming apparatus and more particularly to a periscope system that allows for day and night imagery which includes a low light day system, coupled with a high resolution flat panel display. 
     BACKGROUND OF THE INVENTION 
     Periscopes are optical instruments for conducting observations from a concealed or protected position. A simple periscope consists essentially of reflecting mirrors or prisms at opposite ends of a tube with the reflecting surfaces parallel to each other, and at a 45° angle to the axis of the tube. The so-called field or tank periscope has been commonly used in trenches, behind parapets and earthworks, and in tanks to provide protected vision for the user. Periscopes are also used as viewing devices in military aircraft, in nuclear physics laboratories to observe radioactive reactions, and in particle accelerators. 
     The physics behind periscope operation, as mentioned above, is based on principles of light reflection and has been implemented for many years. Light always reflects away from a mirror at the same angle that it hits the mirror. As mentioned previously, a simple periscope consists essentially of reflecting mirrors or prisms at opposite ends of a tube with the reflecting surfaces parallel to each other, and at a 45° angle to the axis of the tube. With this periscope configuration, light hits the top mirror at a 45° angle and reflects away at the same angle, which bounces it down to the bottom mirror. That reflected light hits the second mirror at a 45° angle and reflects away at the same angle, right into your eye. One such periscope configuration is U.S. Pat. No. 3,454,222 owned by United States of America, as represented by the Secretary of the Army. In that invention the periscope utilized a catadioptric system for night periscope sight. Another such periscope, also owned by the United States of America, as represented by the Secretary of the Army, is U.S. Pat. No. 3,549,231, a lens prescription for an optical system for day and night periscope sight. In these early periscope configurations the images are observed via the reflective characteristics of the mirrors along with their positions relative to each other. However, these earlier periscope configurations had very limited image production and night time viewing capabilities. 
     With the advancement of optical technology periscopes became more and more advanced as well. Night time image viewing capabilities improved, whether of the lens switching type, side by side sensor systems type, or the aperture sharing systems type; however these refractive optical systems had their disadvantages too. The lens switching system required the use of additional manpower, or bulky expensive mechanical or electromechanical lens switching mechanisms, requiring the attention of the operator for the lens selection. The side by side sensor systems required boresighting both of them on a common elevation or azimuth or both using optics such as a head mirror or a prism. The resulting structure is large, complicated, and expensive to manufacture, repair and maintain. The aperture sharing systems have increased substantially the system diameter which complicates stabilization of the system and adds to the size and the cost of the system, especially in a panoramic periscope where 360 degrees of azimuth coverage is required and the torquers, resolvers, and slip-ring assemblies become large. One such aperture sharing system with typical lens switching for covering wide chromatic bandwidths U.S. Pat. No. 4,260,217. 
     The assignee of the present invention, Selectron, currently sells the commander periscope, model M-36, U.S. Pat. No. 5,943,163, the disclosures of which are herein incorporated by reference, which provides a dual band periscope, which provides side-by-side imaging of an optical field of view in the visible light spectral band and the 3 to 5 micron spectral band; a 35° prism was used to accomplish this. The prism has a first portion that reflects and refracts light in the visible range. This visible light region consists of a spectrum of wavelengths, which range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm; that would be 7×10 −7  m to 4×10 −7  m. The second portion of the prism reflects and refracts light in the infrared range of the light spectrum. Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. The second portion of the prism may be composed of optical grade silicon for refracting in the range of 3 microns to 5 microns. If the range of refraction desired was 8 microns to 12 microns then the second portion of the prism may be composed of optical grade germanium. A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter. Portion one and portion two abut each other and are bonded at a juncture by an adhesive. The prism in that invention was allowed to pivot inside the housing so as enable the field of view to be changed. 
     In accordance with the invention, U.S. Pat. No. 5,943,163, visible light entering the window of the periscope is refracted and reflected by prism portion along a path into the optical viewing members contained in housing and eyepiece to provide conventional visible light observation. Infrared emissions, such as self-emissions of personnel and equipment, pass through the window and are refracted and reflected by the prism portion along infrared optical path, through the infrared focusing lens, onto an infrared detector, such as a focal plane array. The lower housing included the electronics required for processing the detected infrared image and provided a visible display of the image elements on a cathode ray tube for observation through the eyepiece. Remote viewing could also have been provided through a cable carrying the video image signal. The processing of the infrared image and display could have been controlled through control elements on the bottom of housing. The processing could have included electronic insertion of a reticule. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide a periscope that is easy to manufacture and cost effective to produce. 
     It is an object of the present invention to provide a periscope that may be used with a variety of different types of vehicles. 
     It is another object of the present invention to provide a periscope where optical viewing may be achieved by one or many users. 
     It is still another object of the present invention to provide a periscope with a housing that is capable of containing all the advanced circuitry needed, and a housing that will not capture too much space, thus providing the viewer ample room to move. 
     It is still a further object of the present invention to transmit the images of both spectral bands to an improved high resolution flat panel display. 
     SUMMARY OF INVENTION 
     The present invention includes a periscope that allows for better day and night time viewing. In the present invention, visual imaging is dramatically improved through utilization of two specialized cameras; one particularly suited for day time viewing, the bullet camera, and one specially adapted for low light viewing, the night board camera. In addition, the periscope of the present invention utilizes an 18 mm image intensifier tube, which up until now, has never been used in periscopes. Generally, ANVIS, aviator&#39;s night vision imaging system, are primarily used in conjunction with goggles. The 18 mm image intensifier tube provides the present invention with the capability of detecting and amplifying low light level images during night time viewing and surveillance, under moonlight or starlight. In addition, for very low light levels the 18 mm image intensifier may be equipped with two or three microchannel plates to create an image by detecting single photons. Furthermore, one may implement a high speed gate with the 18 mm image intensifier tube to capture a fast event such as motion analysis of high speed moving objects and fluorescence lifetime imaging. The viewing panel of the present invention is a high resolution flat panel display, which has electronic reticles that are in focus at all ranges. The flat panel viewing screen is also fatigue free, which results in improved gunner performance. The present invention also implements cutting edge circuitry which maintains proper LCD and camera operation at temperatures at or below 32° Fahrenheit. The advanced circuitry compares on board temperatures to ambient temperatures, and when the temperature falls below a predetermined threshold temperature, small amounts of current are allowed to flow to around the optical viewing equipment. In addition, unlike previous periscopes, the present invention allows for viewing of the optical display via a state of the art flat panel screen, which as mentioned previously has electronically generated reticles always in focus. Furthermore, the optical display from the periscope may be viewed by others in real time, i.e. no time delay, via a video channel connection, which may be transmitted to others via radio transmission and or electronically, to another LCD, or other display apparatuses, such as a CRT, plasma T.V. or the like. The present invention also allows the user to take still shots from the display screen if desired. One may also implement a wide variety of overlays with the flat panel screen. The present invention also implements a state of the art laser range finder. In addition, the housing which contains most of the circuitry is smaller then prior art, thus allowing for an easier viewing environment. The decreased size of the housing is a result of more sophisticated electronic circuitry. The present invention is a necessary and much needed improvement for military personal, especially with the United States involvement overseas. 
    
    
     
       BRIEF DESCRIPTION OF INVENTION 
         FIG. 1  is a front end view of day night elbow; 
         FIG. 2  is a back end view of day night elbow; 
         FIG. 3  is a left side view of day night elbow; 
         FIG. 4  is a rear end view of day night elbow; 
         FIG. 5  is a right side view of day night elbow; 
         FIG. 6  is a top end view of day night elbow; 
         FIG. 7  is a bottom end view of day night elbow; 
         FIG. 8  is a front end view of day/night elbow with housing cell removed; 
         FIG. 9  is a top view of day/night elbow with housing cell and bottom ring removed; 
         FIG. 10  is a top view of day/night elbow with housing cell and top ring removed; 
         FIG. 11  is a front end view of day/night elbow with housing cell and day camera alignment removed; 
         FIG. 12  is an exploded view of night camera assembly of day/night elbow; 
         FIG. 13  is a stand alone view of day/night elbow&#39;s camera mount; 
         FIG. 14  is a stand alone view of day/night elbow&#39;s camera mounting plate and day camera; 
         FIG. 15  is a stand alone view of day and/night elbow&#39;s camera mounting collar; 
         FIG. 16  is a stand alone view of day/night elbow&#39;s light intensifier; 
         FIG. 17  is a stand alone inside view of day/night elbow&#39;s light intensifier; 
         FIG. 18  is a stand alone inside view of day/night elbow&#39;s objective mount; 
         FIG. 19  is a stand alone inside view of day/night elbow&#39;s nighttime camera. 
         FIG. 20  is a functional block diagram of the present invention. 
         FIG. 21  is a schematic of the DC-DC converter of the present invention. 
         FIG. 22  is a schematic of the SPDT switches of the present invention. 
         FIG. 23  is a schematic of the main power circuitry of the present invention. 
         FIG. 24  is a schematic of the microcontroller circuitry of the present invention. 
         FIG. 25  is a schematic of the camera select circuitry of the present invention. 
         FIG. 26  is a schematic of the video select/amp circuitry of the present invention. 
         FIG. 27  is a schematic of the voltage regulator circuitry of the present invention. 
         FIG. 28  is a schematic of another voltage regulator circuit of the present invention. 
         FIG. 29  is a schematic of the temperature sensor and heater control circuitry of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Referring to  FIG. 1  is housing  20  for the electronics that is required for the processing of the detected images and providing a visible display of the image elements on a monitor  21 , any suitable monitor known in the art but not limited to a Cathode Ray Tube, Liquid Crystal Display, etc. In the present embodiment a high resolution color flat panel display was implemented. The shape of the housing  20  is constructed so as to house the electronics required to process the detected images, any suitable construction known in the art but not limited to a cubical, rectangular, etc may be used. In the present embodiment a cubical construction was implemented, as seen in  FIG. 2 . The cubical housing  20  has right, left, rear, and front walls  23 ,  24 ,  25 ,  26  respectively, and top and bottom surfaces,  27 , and  28  respectively, as seen in  FIGS. 1 ,  2 ,  3 ,  4 ,  5 ,  6 , and  7 . On the bottom side there may be a knob  29 , a knob of any suitable construction known in the art may be used; in the present embodiment a fluted knob was implemented. On housing  20  there exist two covers,  30  and  31 , located on sides  24  and  25  respectively, as seen in  FIGS. 2 ,  3 ,  4 . In addition, there exists a door  32 , located on side  23 . This specific configuration of covers and doors, is not based on necessity, it could have been constructed in a plethora of ways. Door  32  allows the user accessibility into housing  20 , for repair, maintenance, etc. 
     “One of the key features of the present invention is the display monitor. As mentioned above one may implement any suitable display monitor known in the art including, but not limited to a Liquid Crystal Display (LCD), a plasma T.V., a Cathode Ray Tube, or the like. The display monitor allows imagery taken from the periscope  120 , via the day or night camera, to be viewed. In addition, one may implement more than one monitor; this will depend on user requirements. For example, in one embodiment one may have more than one monitor on board, or in another embodiment one may have a monitor located in at a different location, i.e. a different vehicle or aircraft. With the latter embodiment the display seen on the monitor on board may be transmitted via radio signals to a different location where the other monitor is located. High a resolution color flat panel display monitor  21  is connected to front wall  26  of housing  20 , any suitable connection method known in the art but not limited to a bolt, screw, clamp, weld, rivet etc. may be used. In the present embodiment a mounting bracket and bolts were implemented, not shown. Switches  33  may be used to control the periscope&#39;s  120  electronic equipment; any suitable switches known in the art but not limited to toggle switches, push button, etc. may be used. In the present embodiment toggle switches were implemented. Switches  33  may be placed on the flat panel display  21  or switches  33  may be placed in any location suitable for the users needs. In the present embodiment switches  33  were placed below screen  34  of flat panel display  21 .” 
     On top surface  27  of housing  20  is a hollow cell  35  used to house day camera assembly,  36  and night camera assembly  37 , as seen in  FIG. 8 . The hollow cell  35  used to house camera assemblies  36  and  37 , may be of any suitable shape including but not limited to cylindrical, rectangular, etc. In the present embodiment a cylindrical cell was implemented. Cylindrical cell  35  is mounted on top portion  27 , any suitable mounting method known in the art may be used including but not limited to bolting, welding, etc. In the present embodiment cell  35  was bolted to top portion  27  of housing  20 , as seen in  FIGS. 2 and 6 . Hollow cell  35  has a flanged bottom portion  38 . Flanged bottom portion  38  has three apertures  39  that are aligned with three apertures  40  on top plate  27 ; this is to facilitate the mounting of hollow cell housing  35  to housing  20 , as seen in  FIGS. 2 and 6 . 
     Inside of cell housing  35 , post  41  extends upward and parallel to the inside of cell  35 , and is used in multiple locations. The bottom portion  44  of post  41  is set in top surface  27  of housing  20 . The post  41  may be of any suitable shape known in the art. In the present embodiment cylindrical posts were implemented, as seen in  FIG. 8 . The top portion  47  of post  41  is set in bottom surface  51  of bottom ring  50 . Bottom ring  50  is defined by bottom surface  51 , upper surface  55 , inside wall  53  and outside wall,  54 , as seen in  FIG. 9  and  FIG. 11 . Extending up from top surface  55  of bottom ring  50  is post  56 , which may have the same cross-section as post  41 . The top portion  59  of post  56  is set into bottom surface  62  of top ring  63 ; top ring  63  may have the same circumference as bottom ring  50 . Top ring  63  has two apertures,  64  and  65 . Aperture  64  has inner wall  66 , and a diameter large enough to secure day camera assembly  36 . Aperture  65  has inner wall  67 , and a diameter large enough to secure night camera assembly  37 , as seen in  FIG. 10 . 
     Bottom ring  50  and top ring  63  have borings so as to house day and night camera assemblies. Bottom ring  50  has boring  68  located on top surface  55 , as seen in  FIG. 9 . Boring  68  is of such dimension so as to house day camera alignment  69  of day camera  36 , as seen in  FIG. 8 . Day camera alignment  69  houses day camera body  70 , as seen in  FIG. 8  and  FIG. 11 . Day camera alignment  69  has a top circular surface  71 , with an aperture  72 , located in its center to house day camera body  70 . Day camera body  70  is a cylindrical tube with a protrusion  73  at it&#39;s bottom, as seen in  FIG. 11 . Protrusion  73  is of such dimension so as to fit into an aperture in top circular surface  71  of day camera alignment  69 . Day camera body  70  is of such dimension so as to be able to house day camera objective  74 . Day camera objective  74  rests in day camera body  70  and is set into aperture  64  of top ring  63 , as seen in  FIGS. 10 and 11  Aperture  64  of top ring  63  has a diameter capable of securing camera objective  74 . Top surface  71  of camera objective  74  may be flush with top surface  64  of top ring  63 . 
     Night camera assembly  37 , as seen in  FIG. 12 , has a camera mount  75 , as seen in  FIG. 13 , any suitable type of camera mount known in the art may be used. In the present embodiment a cylindrical mount was implemented. Camera mount  75  can best be described as having a circular bottom portion  76  and a circular top portion  77 . Bottom portion  76  has inner and outer walls  78  and  79  respectively, and has top and bottom surfaces  80  and  81  respectively. Top portion  77  also has inner and outer walls,  82  and  83  respectively, and top and bottom surfaces  84  and  85  respectively. Top portion  77  may have an inner diameter equal to the inner diameter of bottom portion  76 . Top portion  77  has an outer diameter less then the outer diameter of bottom portion  76 , which will leave top surface  80  partially exposed. Night camera  37  has a camera mounting plate  86 , as seen in  FIGS. 12 and 14 , any suitable type of camera mounting plate known in the art may be used, in the present embodiment the camera mounting plate is a circular plate with aperture  87  in its center. It has inner and outer walls  88  and  89  respectively, and top and bottom surfaces  90  and  91  respectively. The diameter of camera mounting plate  86  is the same as top portion  77  of camera mount  75 . In addition, camera mounting plate  86  has 4 linear grooves  92  located on bottom surface  91 , which are perpendicular to each other, thus forming a grooved square on bottom surface  91 . Night camera  93 , as seen in  FIGS. 12 and 14 , may be any suitable camera known in the art, in the present embodiment the night camera  93  has a platform  94  on its lower body. Platform  94  of night camera  93  fits into grooves  92  located on bottom surface  91 . Night camera assembly  37  has a camera mount collar  95 , as seen in  FIGS. 12 and 15 ; any suitable known collar in the art may be used. In the present embodiment the camera mount collar  95  has a circular bottom portion  96  and a circular top portion  97 . In addition camera mount collar  95  has threads  98  on it&#39;s upper inside wall surface. In the present embodiment the camera mount collar  95  is designed to fit over camera mount plate  86 , and rest on the exposed area of top surface  80  of camera mount  75  so as to hold platform  94  of night camera  93  in place. 
     Night camera assembly  37  has a light intensifier tube  99 , as seen in  FIGS. 12 and 16 ; any suitable light intensifier known in the art may be used. In the present embodiment a tubular light intensifier was implemented. Light intensifier  99  is configured with dimensions similar to an open top end drum, which allows for it to fit inside night camera mount collar  95  and surround night camera  93 . Light intensifier  99  has inner and outer walls,  100  and  101  respectively, a circular bottom plate with bottom and top surfaces,  102 ( a ) and  102 ( b ) respectively, with aperture  103  in its center. One may implement any suitable known light intensifier in the art including, but not limited to 18 mm, 25 mm and the like. In a preferred embodiment one implemented a 18 mm image intensifier tube, with microchannel plate capability. Inner wall  100  has a circular inner lip  104 , as seen in  FIG. 17  that extends around the inner circumference of light intensifier  99 , located near the middle of inner wall  100 . The upper and lower portions of light intensifier&#39;s  99  outer wall  101  also have external threads  105 . Light intensifier  99  acts like a couple between night camera mount collar  95  and night camera objective mount  106 , as seen in  FIGS. 12 and 18 , any suitable night camera objective mount known in the art may be used. In the present embodiment night camera objective mount  106  has a circular bottom portion  107  with inner and outer walls,  108  and  109  respectively, and top and bottom surfaces  110  and  111  respectively. Circular inner wall  108  is also partially threaded. The threads of collar  95 , light intensifier  99  and objective mount  106  will interlock when they are joined. Night camera objective mount  106  has a circular top portion  112  with inner and outer walls  113  and  114  respectively, and top surface  115 . 
     Bottom ring  50  has aperture  53 , where aperture  53  is of such dimension so as to allow night camera objective mount  106  to fit through bottom ring  50 . Both, top surfaces  110  of circular bottom portion  107  and top surface  115  of circular top portion  112  of night camera objective  107  lie above the top surface  55  of bottom ring  50 . 
     Night camera objective  117  of night camera assembly  37  may be any suitable night camera objective known in the art. In the present embodiment the night camera objective  117  was able to fit inside night camera objective mount  106 . The base  119  of night camera objective  117  rests on the inner lip portion  104  of inner wall  100  of light intensifier  99 . 
     “In normal operation the user will power up the LCD display via power switch  33 . The user may then view the outside perimeter with the periscope  120  of the present invention. The user, in day time viewing, may choose the day bullet camera via switch  33 . Conversely, for night time viewing the user may choose the night board camera via switch  33 . The user may then utilize some of the key functions of the present invention, by communicating with the internal electric circuitry by means of the Power/Video-CB2  100  supply hub.” 
     The functionality of the key features of the present invention will now be discussed with reference to the CB2 functional block diagram, as seen in  FIG. 20 , along with reference to the electronic circuit diagrams shown in  FIGS. 21-29 . 
     As seen in  FIG. 20 , is the Power/Video-CB2  700  supply hub. Power/video-CB2 supplies power, and inputs/outputs to a different components of the present invention. For example, power/video-CB2 provides a steady power supply to the LCD display. This is accomplished by connecting the leads from the transient suppression module  701  to power/video CB-2, as seen in  FIG. 20 . A detailed description of this connection may be seen in  FIG. 23 . Pins 1 and 2 of transient suppression module  701  are connected to the main power supply, and pins 3 and 4 are connected to ground. From transient suppression module  701  the regulated power is sent to the power and signal connector to the internal circuitry of the LCD display, as seen in  FIG. 20 . 
     The present invention utilizes many different circuits and as such needs many different voltages. In the present invention one implemented 3 voltage regulators, as seen in  FIGS. 27 and 28 .  FIG. 27  is an example of one of the voltage regulators that was implemented; it is a precision 1 amp regulator that allows output voltages of up to 24 volts. Pin 1 of voltage regulator  400 , VR 1 , will generally have an input voltage less then the main power supply. The voltage at pin 1 may be adjusted by implementing a variety of different circuit configurations, depending on how much regulated voltage is desired at pin 3 of voltage regulator  400 . One such configuration may be seen in  FIG. 27 . A Zener diode, ZR 1 , with a rating of 10V and 5 W was placed in series with the 24 VDC power supply. In addition, a 3.3 μF capacitor was placed in parallel with the voltage regulator. In the present invention the Zener diode will allow current to flow only after a certain voltage drop is obtained across the diode. The output at pin 3 will be approximately 12 VDC, which will be used to power the day and night camera. In another embodiment one may implement an Astrodyne DC-DC converter. 
     The 12 VDC at pin 3 of voltage regulator  400  will also be routed to pin 3 of another voltage regulator  401 , VR 2 , this voltage regulator operates similarly as the previously discussed voltage regulator and for purposes of brevity a detailed discussion will not be introduced. The output of VR 2 , will be approximately 5 VDC, and felt at pin 1 of VR 3   402 . The output of VR 3  will be approximately 3 VDC, and felt at pin 5 of VR 3 , and used to power the ISQ Device at leads 1 and 3, as seen in  FIGS. 20 and 28 . Leads 3 and 4 of the ISQ Device are connected to ground. 
     Also connected to the power/video-CB2 is the LTC3780 regulator board  702 . The LTC 3780 regulator board serves as a high performance switching regulator controller that operates from input voltages above, below, or equal to the output voltage. The connection may be seen in more detail in  FIG. 23 . Pins 1 and 2 are connected to the 24 VDC SW power supply; pins 3 and 4 are connected to the 5 amp 24 VDC power supply, and the remaining pins 5-8 are connected to ground. 
     Located on the outside of the housing of the LCD may be 4 switches  33 , as mentioned previously. A switch panel  703  may be located inside of housing  20 . The switches that were implemented in the present embodiment were a power switch, a switch for choosing the day or night camera, a zoom, in or out switch, and a dim, up or down switch. For a more detailed description of the wiring diagram, see  FIG. 22 . The power switch may be configured so that the “on” setting is connected to pin 1 of power/video-CB2  700 , and the “off” setting is connected to pin 2 of power/video-CB2  700 , as seen in  FIG. 23 . In addition pin 3 may be connected to the day setting and pin 4 may be connected to the night setting of power/video-CB2. Also, pin 5 may be connected to zoom select and pins 6 and 7 may be connected to dim, up and down, respectively. In normal operation when the user desires to turn on the LCD monitor, the user will place the “on/off” switch to the on position. In addition the user may place camera switch, into either day or night mode. Also, the user may choose zoom, or dim, up or down, if desired. 
     When the switches are placed into the desired position, pulses will be transmitted to the microcontroller  704 , located inside of power/video-CB2  700 , as seen in  FIG. 24 . Microcontroller  704  may include a PIC 12C508A-04/P chip  120 . Chip  120  comes from a family of low-cost high performance, 8-bit, fully static, EEPROM/EPROM/ROM-based CMOS microcontrollers. Chip  120  employs RISC architecture with only 33 single word/single cycle instructions. Chip  120  has 8 pins. Pin 1 has a 5 VDC positive supply, referenced VDD, for logic and I/O pins. Pin 8 is connected to ground and is referenced by VSS. In between pins 1 and 8 may be a 0.1 μF capacitor. Pins 2, 3, and 4 receive input signals from the day, power, and night switches respectively. Pins 2, 3, and 4 may be connected to the 5 VDC power supply. In addition pins 2, 3, and 4 may be connected to resistors R58, R57, and R56 respectively. Resistors R56, R57, and R58 may have different or the same resistances. In the present embodiment all the resistors in microcontroller  704  had the same resistance, 1000 Ωs. In the present embodiment pin 4 of chip  120  may not have a voltage drop greater then VDD, i.e. 5V, because this would cause chip  120  to enter a programming mode. Pins 5, 6, and 7, are generally Bi-directional I/O ports. Pin 5 may be also configured as a TOCKL. Pins 5, 6, and 7 were implemented in the present invention as output ports. 
     Pin 6 was implemented to send an output, LOGIC POWER ENABLE, and pins 5 and 7 were implemented to send signals to a MOCD 207M dual channel phototransistor  121 . The output of pin 7 of chip  120  is sent to pin 1 of dual phototransistor  121 . Pin 1 of dual phototransistor  121  is connected to the anode of LED  122 , light emitting diode, and pin 2 is connected to ground. In addition, a resistor, R8, may be located in series with anode of light emitting diode  122 . The output of pin 5 is sent to pin 3 of dual phototransistor  121 . Pin 3 is connected to the anode of LED  123 , light emitting diode, and pin 4 is connected to ground. A light emitting diode is a semiconductor device that emits incoherent narrow-spectrum of light. In addition, there may also be a resistor, R9, which may be located in series with anode of light emitting diode  123 . Both R8 and R9 may have resistances of 1000Ω each. Pin 8 of dual phototransistor  121  is connected to the collector of one of the phototransistor, and pin 7 is connected to the emitter. The output at pin 8 is designated for DAY ENABLE, and pin 7 is a ground. Pin 6 of dual phototransistor  121  is connected to the collector  125  of the other phototransistor  125 , and pin 5 is connected to the emitter. The output of pin 6 is designated for NIGHT ENABLE, and pin 5 is connected to ground. In normal operation when the LED is electrically biased in the forward direction a narrow spectrum of light will be created, which will reach the base-collector junction of the phototransistor. The end result will be either a DAY ENABLE or a NIGHT ENABLE, depending on the switch that was selected. 
     In normal operation the output from pin 6 of chip  120  will be transmitted to different parts of the power/video-CB2. In addition, the outputs from pins 8 and 6, of dual phototransistor  121 , will also be transmitted to different parts of the power/video-CB2. For example, as seen in  FIG. 20  Day Bullet Camera block and Night Board Camera block are connected to power/video-CB2, via J10 and J12, respectively; these blocks include camera selection circuitry. 
     A more detailed description of the camera selection circuitry may be seen in  FIG. 25 . The camera selection circuitry includes another dual MOCD 207M dual channel phototransistor  200 . The LOGIC POWER ENABLE is transmitted to pin 1 of dual phototransistor  200 . In addition, there may be a resistor connected in series with pin 1 of dual phototransistor  200 . Pin 1 is also connected to the anode of the LED  201 . Pin 2 of LED  201  of dual phototransistor  200  is connected to ground. Pin 8 of dual phototransistor  200  is connected to the collector  202 . Pin 7 is also connected to ground and pin 8 is part of the POWER ENABLE circuitry. In addition, pin 3 of dual phototransistor  200  may be connected in series with a 1000Ω resistor, R 21 , and a 12 VDC potential, as seen in  FIG. 25 . Pin 3 is also connected to the anode of LED  203  of dual phototransistor  200  and pin 4 is part of the DAY ENABLE circuitry. Pins 6 and 5 are connected to the collector  204  and emitter respectively; pin 5 is also connected to ground. Pin 6 may also be connected in parallel with a double transistor Q 4 ,  206 , as seen in  FIG. 25 . In addition, a 5 VDC potential with a 1000Ω resistor, R 21 , connected in series, may be implemented to supply power to the collector  204 , and to pin 5 of double transistor Q 4 ,  206 , as seen in  FIG. 25 . Pin 5 is connected to base  1  of double transistor Q 4 . Pin 4 is connected to the emitter of double transistor Q 4 , and to ground. Pin 3 is connected to a 1000Ω resistor R 4 , and a 5 VDC potential. Pins 1 and 2 are connected to collectors 1 and 2 respectively. In addition, the output of pin 1 is connected to the NIGHT/DAY circuitry, and the output of pin 2 is connected to the ZOOM circuitry. 
     The Power/Video-CB2 communicates with the above digital circuitry via J10 and J12, as seen in  FIG. 20 . J10 routes input and output signals via leads 1, 2, 3, and 4 for the day camera, and J12 routes inputs and outputs for the night camera via leads 1, 2, 3, 4, and 5. An IRF 7342 MOSFET  207  may be connected to leads, 1 of night camera block and 1 of day camera block. Lead 1 of the day camera block may be connected to the drain  1  of the MOSFET  207 , located at pins 7 and 8. Lead 1 of the night camera block may be connected to the drain  2  of the MOSFET  207 , located at pins 5 and 6. In addition, pins 1 and 2 of the MOSFET  207  will be connected to source 1 and gate 1 respectively, and pins 3 and 4 of the MOSFET  207  will be connected to source 2 and gate 2 respectively. Power to the day and night camera selection will be supplied via a 12 VDC potential. In normal operation, depending on the camera selection, the output of either the day or night camera will be transmitted, via leads 3 of, J10 or J12 respectively, to the LCD of the present invention, as seen in  FIG. 20 . 
     Power/Video-CB2 communicates with the LCD via leads 1, 2, and 3, of junction, J2, as seen in  FIG. 20 . A more detailed description of the digital and analog circuitry may be seen in  FIG. 26 . The main circuitry may include a video amp, which implements a 2 channel multiplexer (hereinafter mux), as an input to the non-inverting leg of the amp. In the present embodiment one implemented a MAX 4313ESA chip  300 . Chip  300  is a high speed, low-power, single-supply multichannel, video multiplexer-amplifier. One chose chip  300 , because of its excellent harmonic distortion and differential gain/phase performance. Lead 3 of J10 from day camera may be connected to pin 4 of chip  300 . One may also connect lead 3 from J12 from night camera to pin 5 of chip  300 . The output of chip  300  may be connected to the non-inverting input of the amplifier of chip  300 . Other pin connections may be as follows, pin 6 may be connected to a −5 VDC, represented by V EE  and pin 3 may be connected to a 5 VDC, represented by V CC . In addition, pin 7 may be connected to ground, and pin 1 may be an input selector, designated A 0 . Furthermore, all parts feature a low-power shutdown mode that is activated by driving the SHDN input low, located at pin 2. The output video of chip  300 , located at pin 8, is connected to lead 1 of J2. Chip  300  operates like most typical muxs, that is, a device that has multiple input streams and only one output stream. It forwards one of the input streams to the output stream based on the values of one or more of the “selection inputs”. For example, a two input multiplexer, like the one in the present invention, is a simple connection of logic gates whose output Y is either input A or input B depending on the value of a third input S which selects the input. In normal operation of the present invention chip  300  will have an input either at pin 4 or 5 depending on which camera is selected. Pin 1 will select the appropriate input, based upon the signal from pin 5 of Q 4  of the camera selection block. The input will then be transmitted to the non-inverting leg of the amplifier, where it will be amplified and transmitted to the LCD, as video for display. One may also implement a variety of different bypass capacitors and resistors to obtain the desired gain, one type of configuration may be seen in  FIG. 26 . Lead 3 from J2 of the LCD is connected to ground and lead 2 from J2 of the LCD is the video return lead which transmits the video back lead 4 of J10 or J12, depending on which camera is selected. 
     The power/video-CB-2 also communicates with the Bullet Camera Heater &amp; Sensor, and the Night Camera Heater &amp; Sensor, as seen in the functional block diagram,  FIG. 20 . A more detailed description of the heater sensor may be seen in  FIG. 29 . 
     This circuitry compares the onboard temperature to the outside temperature. The main power supply is routed to both the day and night camera heater and sensor circuitry, as seen in  FIG. 29 . Both circuitries may be identical and for the purposes of brevity, only the day camera circuitry will be discussed. The main power is connected in parallel to a P-channel enhancement transistor Q 2   503 , and a 10K resistor, R 31 . R 31  may be connected to the gate of Q 2   503 , and to another 10K resistor, R 37 , a seen in  FIG. 29 . In between the drain of Q 2   503  and leads 1 and 2 of J9 may be a 3 amp fuse. J9 also may have leads 3, 4, and 6 connected to ground and lead 5 may be connected to regulated 5 VDC power source. In addition lead 7 may transmit the DAY TEMP signal. As mentioned above R 31  may be connected to the drain of Q 2   503  and to another resistor, R 37 . R 37  may also be connected to one collector, pin 8, of a dual phototransistor  500 . Dual phototransistor  500  operates similarly to the previously mentioned dual phototransistor  200 , and for the purposes of brevity will not be discussed. 
     The day camera heater and sensor circuitry also has an on board temperature sensor  501 . In the present embodiment a TMP36 low voltage temperature sensor was implemented. The TMP36 is a low voltage, precision, centigrade temperature sensor. It provides a low output that is linearly proportional to the Celsius temperature. The low output impedance of the TMP36 and its linear output and precise calibration simplify interfacing to temperature control circuitry and A/D converters. Pin 8 is connected to the 5 VDC power supply. One may also have a 0.1 μF capacitor located at the input near pin 8. Generally, this capacitor should be a ceramic type, have very short leads (surface-mount is preferable), and be located as close as possible in physical proximity to the temperature sensor supply pin. Pins 6 and 7 are generally not connected, and pin 5 is the SHTDN pin. Generally, a logic low, or zero-volt condition on the SHTDN pin is required to turn off the output stage. During shutdown, the output of the temperature sensors becomes a high impedance state where the potential of the output pin would then be determined by external circuitry. In addition, TMP36 has pins 1, 2, 3, and 4. Generally pin 4 is connected to ground and pins 2 and 3 are not connected. Pin 1 is the output pin and is referenced by VOUT, as seen in  FIG. 29 . 
     The output at pin 1 of temperature sensor  501  is transmitted to a voltage comparator  502 . In the present embodiment a TS339CPT chip was implemented to perform the needed comparison. The TS339 is a micropower CMOS quad voltage comparator with extremely low consumption of 9 μA typ/comparator. One may also implement a quad micropower comparator TS3704 with a push-pull CMOS output. Pins 1, 2, 14, and 13 are output pins, and pins 4-11 are input pins. Pin 3 is the input voltage, referenced VCC, and pin 12 is ground, referenced GND. All the input pins operate in similar fashion, i.e. they compare voltages and transmit an output to a corresponding pin. Pin 7 is also connected to a 5 VDC potential. Pins 5, 6, and 9 receive the onboard temperature signal, and pins 4 and 8 receive the DAY TEMP sense signals and NIGHT TIME TEMP signals respectively. Thus, one may connect pins 6 and 7 to compare the onboard temperature, and transmit an output on pin 1. The output on pin 1 may then be transmitted to one of two separate circuits. These circuits may be identical, which may include resistors, and capacitors. The resistors may have fixed values or the resistors may vary, i.e. potentiometers. The resistors and capacitors may have a range of values; this will depend on the desired need and output of the user. 
     In normal operation the user will turn the power switch to the on position and select a camera, either the day or night. For example, if the day camera is selected; the user will place the camera select switch  33  to the day camera position. The signal from lead 3 of J5 will then be transmitted to pin 2 of chip  704  of the microcontroller block. The output signal will then be transmitted to LED  122  of dual phototransistor  121 . The light emitted from LED  121  will cause phototransistor  124  to allow current to flow, thus allowing the DAY ENABLE signal to reach different circuits of the invention. For example, a signal will be sent to chip  300  of the video select/amp, via J10. In addition, the temperature sensor and heater controls will be activated by the power enable signal, thus allowing the onboard temperature and the ambient temperature to be compared, via chips  501  and  502 . 
     As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. In the view above it will be seen that several objects of the invention are achieved and other advantageous results attained.