US20060225335A1 - Method and apparatus for safe operation of an electronic firearm sight depending upon the detection of a selected color - Google Patents

Abstract

A weapon sight can be mounted on a weapon. According to still another aspect of the invention, the sight takes a selected action if it detects the presence of a selected color within radiation originating externally of the sight.

Description

TECHNICAL FIELD OF THE INVENTION
• This invention relates in general to a device that facilitates accurate aiming of a firearm and, more particularly, to a firearm sight that is mounted on the firearm, and through which a user observes a potential target.
BACKGROUND OF THE INVENTION
• Over the years, various techniques and devices have been developed to help a person accurately aim a firearm, such as a rifle or a target pistol. One common approach is to mount a sight or scope on the firearm's barrel. A person then uses the sight or scope to view an intended target in association with a reticle, often with a degree of magnification. Although existing firearm sights of this type have been generally adequate for their intended purposes, they have not been satisfactory in all respects.
• For example, some pre-existing sights have included the capability to record an image showing a target and/or a reticle, and to later display one or more of these recorded images. However, when these recorded images are displayed, it is possible for a safety hazard to occur. For example, if the recorded image is presented on an electronic display that is separately used to show actual targets, a user may mistake the recorded image for an actual target, and may then discharge the weapon in the belief that he or she is shooting at something in the recorded image, when the weapon is actually pointed at some other person or thing. Moreover, even if the user does not intentionally discharge the weapon while viewing recorded images, there is always a risk of accidental discharge. Consequently, if the user is distracted while viewing recorded images, or gives the weapon and sight to another person who is distracted or who is not familiar with weapon safety, the weapon may be inadvertently pointed in a direction that presents a safety hazard.
• A different consideration is that hunting regulations in most states stipulate that hunting is allowed only during the time from one-half hour before sunrise to one-half hour after sunset. The intent of these regulations is to prevent the unsafe practice of shooting in very low light levels, where the actual identity of a target may be questionable. The level of illumination at one-half hour before sunrise and at one-half hour after sunset is sometimes referred to as “civil twilight”, and falls in a luminance range of 0.1 to 1.0 foot-candles. This luminance range corresponds to a cloudless sky. Other conditions can cause the illumination level to drop below that of civil twilight at almost any time during the day, for example where there is a dense cloud cover, or where a hunter is in a dense forest. There is no easy way for hunters and game wardens to determine actual levels of illumination, and this is why states have adopted the compromise approach of defining allowable hunting conditions in terms of dusk and dawn, rather than in terms of actual levels of illumination. Existing sights provide hunters with no assistance in detecting or avoiding actual low light conditions that can present potential safety hazards.
• Still another consideration is that virtually all states have a hunting regulation that requires hunters to wear a fluorescent orange garment above the waist while hunting. This color does not occur naturally in any big game animals, or in their environment. The fluorescent orange color is thus intended to be a visual cue to a hunter that a person is present, rather than a potential animal target. Even where such a garment is present, the patch of orange color may be partly obscured by other objects in the scene, or may be very small if the hunter is a significant distance from the person wearing the garment. In either case, the presence of the orange color in the scene may be inadvertently and unintentionally overlooked by a hunter, resulting in a potentially dangerous situation for the person wearing the garment. Existing rifle sights provide hunters with no assistance in detecting fluorescent orange to avoid potentially dangerous hunting situations.
SUMMARY OF THE INVENTION
• According to one aspect of the invention, a method and apparatus relate to a weapon-mountable sight having a display and involve presenting selected information on the display only when a detector portion indicates that the sight has an orientation that meets an orientation criteria.
• According to a different aspect of the invention, a method and apparatus relate to a weapon-mountable sight and involve: using a detector portion to determine a level of ambient illumination external to the sight; and taking a selected action in response to a determination that the level of ambient illumination is less than a selected level of illumination.
• According to still another aspect of the invention, a method and apparatus relate to a weapon-mountable sight, and involve taking a selected action in response to detection of a selected color within radiation originating from externally of the sight.
BRIEF DESCRIPTION OF THE DRAWINGS
• A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which:
• FIG. 1 is a diagrammatic perspective view of an apparatus that is a digital rifle sight embodying aspects of the present invention;
• FIG. 2 is a block diagram of the digital rifle sight ofFIG. 1, and shows some internal components thereof;
• FIG. 3 is a diagrammatic view of an internal display that is a component of the rifle sight ofFIG. 1, as seen by the eye of a person using the sight;
• FIG. 4 is a diagrammatic view of a switch panel that is a component of the rifle sight ofFIG. 1, and that has a plurality of manually operable switches;
• FIG. 5 is a diagrammatic view of an external display that is a component of the rifle sight ofFIG. 1, with a recorded image displayed thereon;
• FIG. 6 is a diagrammatic view of the internal display while the rifle sight is being used to view a scene having a low level of ambient illumination; and
• FIG. 7 is a diagrammatic view of the internal display while the rifle sight is being used to view a scene that includes a person wearing a fluorescent orange garment.
DETAILED DESCRIPTION
• FIG. 1 is a diagrammatic perspective view of an apparatus that is adigital rifle sight10, and that embodies aspects of the present invention. Although thesight10 is sometimes referred to herein as a “rifle” sight, it can actually be used not only with rifles, but also with other types of firearms, such as target pistols.
• Thesight10 includes arail mount12 that can fixedly and securely mount thesight10 on the barrel of a firearm. Thesight10 has aswitch panel13, with several manually operable switches that are discussed in more detail later. Thesight10 has anexternal color display14 that, in the disclosed embodiment, is a liquid crystal display (LCD) of a type commonly found on digital cameras and video cameras for the purpose of viewing images or video clips that have been stored within these cameras. One end of thesight10 has aneyepiece section15.
• FIG. 2 is a block diagram of therifle sight10, and shows some internal components of thesight10 that are relevant to an understanding of the present invention.
• Thesight10 includes anobjective lens section16 of a known type. In the disclosed embodiment, thelens section16 has a field of view (FOV) of 5°, but it could alternatively have some other field of view. Thelens section16 optically images a remote scene or target17 onto animage detector18. In the disclosed embodiment, theimage detector18 is a charge coupled device array (CCD array) of a known type, and has 1,920,000 detector elements that each correspond to a respective pixel in each image produced by theimage detector18, and that are arranged as an array of 1600 detector elements by 1200 detector elements. However, theimage detector18 could alternatively be implemented with any other suitable device, including a device having a larger or smaller number of detector elements, or a type of device other than a CCD array, such as a Complementary Metal Oxide Semiconductor (CMOS) image sensor.
• Theimage detector18 produces a sequence of digital color images of thescene17, and this sequence of images is supplied to aprocessing section21. Although theimage detector18 of the disclosed embodiment produces color images, the images could alternatively be monochrome images, or black and white images. Theprocessing section21 includes aprocessor22 of a known type, and amemory23. Thememory23 inFIG. 2 is a diagrammatic representation of the memory provided for theprocessor22, and may include more than one type of memory. For example, thememory23 may include a read only memory (ROM) that contains a program executed by theprocessor22, as well as data that does not change during program execution. Thememory23 can also include some semiconductor memory of the type commonly known as “flash” RAM. A “flash” RAM is a type of memory that is commonly used in devices such as memory cards for digital cameras, and that maintains the information stored therein even when electrical power is turned off.
• Theprocessing section21 further includes areformatter26 of a known type. Thereformatter26 is capable of taking an image generated by theimage detector18, and reformatting the image to a lower resolution that is suitable for presentation on a display having a lower resolution than theimage detector18. Images processed by thereformatter26 are selectively supplied to twodisplay driver circuit30 and31. Thedisplay driver circuit30 drives theexternal display14, and thedisplay driver circuit31 drives aninternal color display32. Thedisplay driver circuits30 and31 can be different channels of a single display driver circuit, but are shown as separate blocks inFIG. 2 for clarity. In the disclosed embodiment, thecolor display32 is a liquid crystal display (LCD) of a known type, and has 76,800 pixel elements arranged as an array of 320 elements by 240 elements. Thedisplay32 could, however, have a larger or smaller number of pixel elements, or could be any other suitable type of display, such as an organic light emitting diode (OLED) display, a liquid crystal on silicon (LCOS) display, or a micro-electro-mechanical system (MEMS) reflective display.
• The eyepiece section15 (FIG. 1) of thesight10 includeseyepiece optics36 of a known type. Theeyepiece optics36 permit theinternal display32 to be comfortably viewed by aneye37 of a person who is using thesight10 in association with a firearm. In the disclosed embodiment, theeyepiece optics36 have an FOV of 15°, but could alternatively have some other suitable FOV. In addition, theeyepiece optics36 of the disclosed embodiment could optionally be omitted for applications that allow a person to directly view thedisplay32 with a viewing distance greater than about 8 inches, since comfortable viewing is then possible with little eye accommodation needed.
• Thesight10 includes anaccelerometer41 that has an output coupled to theprocessing section21. In the disclosed embodiment, theaccelerometer41 is a device that can be obtained commercially as part number ADXL105 from Analog Devices, Inc. of Norwood, Mass. Although the disclosed embodiment implements theaccelerometer41 with the Analog Devices-ADXL105 device, theaccelerometer41 could alternatively be implemented with any other suitable device. Theaccelerometer41 is a micro-electro-mechanical system (MEMS) device, and serves as a highly sensitive sensor that can detect the relatively small shock wave caused when a firing pin strikes a cartridge within a firearm on which thesight10 is mounted. In addition, as discussed later, theaccelerometer41 is also responsive to the force of gravity.
• When a firing pin strikes a cartridge, it triggers combustion of the gunpowder or other propellant within the cartridge, so as to expel a bullet or other projectile from the cartridge and firearm. Consequently, a relatively small shock wave is produced when the firing pin strikes the cartridge, and this small shock wave is promptly followed by a significantly larger shock wave or recoil that is produced by the combustion of the gunpowder and the expulsion of the bullet. The latter shock wave is several orders of magnitude larger than the shock wave produced when the firing pin strikes the cartridge. Theaccelerometer41 has the sensitivity and bandwidth needed to detect the relatively small shock wave produced when the firing pin strikes the cartridge, but also has the durability needed to withstand the much larger shock wave produced by the ensuing combustion within the cartridge.
• The output signal from theaccelerometer41 has a frequency spectrum for the small shock wave that is significantly different from the frequency spectrum for the ensuing large shock wave. Consequently, theprocessing section21 can distinguish a shock wave that represents the firing pin striking a cartridge from a shock wave that represents some other type of event, such as combustion within a cartridge. For example, in order to identify the small shock wave, theprocessing section21 could apply a fast Fourier transform (FFT) to the output of theaccelerometer41, filter out frequency components that are outside a frequency band of approximately 5 KHz to 10 KHz, and then look for a pulse in the energy between 5 KHz and 10 KHz.
• Thesight10 includes agyroscope43, with an output that is coupled to theprocessing section21. The gyroscope is referred to herein as a rate gyro. In the disclosed embodiment, therate gyro43 is implemented with a MEMS device that is available commercially as part number ADXRS150 from Analog Devices, Inc. Although the disclosed embodiment uses the Analog Devices ADXRS150 device, it would alternatively be possible to implement therate gyro43 with any other suitable device.
• Therate gyro43 is capable of detecting angular movement of thesight10 about a not-illustrated vertical axis that is spaced from therate gyro43. Thus, therate gyro43 is a highly sensitive device that is effectively capable of detecting movement of thesight10 in directions transverse to a not-illustrated center line of theobjective lens section16.
• Thesight10 includes aremovable memory card46 that, when present within thesight10, is operatively coupled to theprocessing section21. In the disclosed embodiment, thememory card46 is a memory card of the type commonly used in digital cameras. However, it would alternatively be possible to use any other suitable device for theremovable memory card46.
• Thesight10 includes abattery51 that, in the disclosed embodiment, is a replaceable battery of a known type. However, thebattery51 could alternatively be a rechargeable battery. Thesight10 also includes anexternal power connector52 that can be coupled to an external source of power, such as a converter that converts alternating current (AC) to direct current (DC).
• As mentioned above in association withFIG. 1, thesight10 has aswitch panel13 with a plurality of manually operable switches. These switches include apower switch57, and also include several other switches58-65 that are each coupled to theprocessing section21, and that are discussed in more detail below. Thebattery51 and theexternal power connector52 are each coupled to inputs of thepower switch57. When thepower switch57 is respectively actuated and deactuated, it respectively permits and interrupts a flow of current from thebattery51 and/or theconnector52 to circuitry71 that is disposed within thesight10, and that requires electrical power in order to operate. The circuitry71 includes theimage detector18, theprocessing section21, thedisplay drivers30 and31, theexternal display14, theinternal display32, theaccelerometer41, therate gyro43, and thememory card46.
• Thesight10 has aconnector81 that is coupled to theprocessing section21. Theconnector81 can be used to upload image data or video data from thesight10 to a not-illustrated computer, as discussed later. In addition, theconnector81 can be used to download an electronic reticle from a computer to thesight10, as also discussed later. In the disclosed embodiment, the physical configuration of theconnector81, as well the protocol for transferring information through it, conform to an industry standard that is commonly known as the Universal Serial Bus (USB) standard. However, it would alternatively be possible to use any other suitable type of connector and communication protocol, such as a standard serial connector and communication protocol, or a standard parallel connector and communication protocol.
• Thesight10 includes afurther connector82, through which video information can be transferred from thesight10 to an external device, in a manner conforming to an industry video standard that is commonly known as the National Television Standards Committee/Phase Alternating Line (NTSC/PAL) standard. In the disclosed embodiment, theconnector82 is a standard component of the type commonly known as an RCA jack. However, it could alternatively be any other suitable type of connector, and information could be transferred through it according to any other suitable protocol.
• FIG. 3 is a diagrammatic view of theinternal display32, as seen by theeye37 of a person looking into thesight10 through theeyepiece optics36. In a normal operational mode, thedisplay32 presents a view of thescene17, as captured by theimage detector18 through theobjective lens section16. Thescene17 is shown diagrammatically inFIG. 2 by broken lines.
• Theprocessing section21 superimposes a reticle101-105 on the image of thescene17. In the disclosed embodiment, the reticle includes asmall center circle101, and four lines102-105 that each extend radially with respect to thecircle101, and that are offset by intervals of 90°. The reticle101-105 is a digital image that is downloaded into thesight10 through theUSB connector81, and that is stored by theprocessing section21 in a non-volatile portion of thememory23. The reticle can have almost any configuration desired by a user. In particular, a reticle with virtually any desired configuration can be created by a user in a separate computer, or obtained by the user from the sight manufacturer or a third party through a network such as the Internet. The new reticle can then be downloaded electronically in digital form through theconnector81, and is stored in thememory23 of theprocessing section21.
• Theprocessing section21 takes the reticle that is currently stored in thememory23, and digitally superimposes the reticle on images that will be sent to thedisplay32. InFIG. 3, the reticle101-105 has been superimposed on the image in a manner so that the reticle is centered on thedisplay32. However, the position where the reticle appears on thedisplay32, and thus the position of the reticle relative to the image of thescene17, can be adjusted in a manner that is described later.
• Theprocessing section21 can also superimpose some additional information on the image of thescene17. In this regard, the lower left corner of thedisplay32 includes a windage orazimuth adjustment value111. As mentioned earlier, the position of the reticle101-105 on thedisplay32 can be adjusted, in a manner that is discussed in more detail later. Thewindage adjustment value111 is a positive or negative number that indicates the offset by which the reticle101-105 has been adjusted either leftwardly or rightwardly from the centered position shown inFIG. 3.
• The upper right corner of thedisplay32 has abattery charge indicator113 that is divided into three segments, and that is used to indicate the state of thebattery51. In particular, when the battery is fully charged, all three segments of thebattery charge indicator113 are displayed. Then, as thebattery51 becomes progressively discharged, there will be a progressive decrease in the number of displayed segments of thebattery charge indicator113.
• The upper left corner of thedisplay14 presents animage count value114, and thiscount value114 relates to the fact that theprocessing section21 can store images in theremovable memory card46, as discussed later. Theimage count value114 is an indication of how many additional images can be stored in the unused space that remains within thememory card46.
• The top center portion of thedisplay32 has acapture mode indicator115, and a firingpin detection indicator116. Thecapture mode indicator115 shows which of two capture modes is currently in effect, as discussed later. The firingpin detection indicator116 indicates whether or not the sight is currently enabled to detect the firing pin striking a cartridge, as discussed later.
• The bottom central portion of thedisplay32 includes anautoboresight alignment indicator117, for a purpose that is not related to the present invention, and that is therefore not described here in detail. Anangular error indicator120 appears in the central portion of thedisplay32. Theindicator120 is a circle that is larger than and concentric to thecircle101 at the center of the reticle101-105. The diameter of theindicator120 is increased and decreased in response to variation of a particular operational criteria, as discussed later. Depending on the current mode of operation of thesight10, the reticle101-105 and the various indicators111-120 may all be visible, or only some may be visible.
• FIG. 4 is a diagrammatic view of theswitch panel13, and shows each of the manually operable switches57-65 of theswitch panel13. The types of switches and their arrangement on thepanel13 is exemplary, and it would alternatively be possible to use other types of switches, and/or to arrange the switches in a different configuration. Thepower switch57 has already been discussed above, and therefore is not discussed again here.
• Theswitch58 is a detect switch. As mentioned earlier, the accelerometer41 (FIG. 2) is capable of detecting a shock wave that occurs when the firing pin of the firearm strikes a cartridge. Successive manual actuations of the detectswitch58 alternately instruct theprocessing section21 to enable and disable this detection feature. When this feature is respectively enabled and disabled, thedetection indicator116 is respectively visible on and omitted from thedisplay32.
• Theswitch59 is a mode switch. In one operational mode, theprocessing section21 of thesight10 can take a single image generated by theimage detector18, and store this image in theremovable memory card46. In a different operational mode, theprocessing section21 can take several successive images generated by theimage detector18, which collectively form a video clip, and store these images in thememory card46. Successive actuations of themode switch59 cause theprocessing section21 to toggle between these two operational modes. When the mode for storing video clips is respectively enabled and disabled, thedetection indicator115 is respectively visible on and omitted from thedisplay32. There are two types of events that will cause theprocessing section21 to save an image or a video clip.
• First, if the detectswitch58 has been used to enable detection of the firing pin striking a cartridge, theprocessing section21 will respond to each detection of this event by saving either a single image or a video clip in thememory card46, depending on whether the capture mode that has been selected using themode switch59 is the image capture mode or the video capture mode. It will be recognized that, since a video clip is a series of several images, saving a video clip in thememory card46 will take up several times the storage space that would be required to save a single image. After saving an image or a video clip, theprocessing section21 adjusts theimage count indicator114 presented on thedisplay32. In particular, if a single image is stored, then thecount value114 will simply be decremented. On the other hand, if a video clip is saved, the value of theindicator114 will be reduced by an amount that corresponds to the number of images in the video clip.
• The other event that will cause theprocessing section21 to save one image or a video clip is manual operation of theswitch64, which is a capture switch. Whether theprocessing section21 saves a single image or a video clip is dependent on the capture mode that has been selected using themode switch59. When thecapture switch64 is manually operated, theprocessing section21 selects either a single image or a video clip from the current output of theimage detector18, and then saves this image or video clip in thememory card46. As mentioned earlier, a separate and not-illustrated computer can be coupled to theconnector81, and theprocessing section21 can upload to that computer the images or video clips that are stored in thememory card46.
• Theswitch63 is a rocker switch that serves as a zoom control switch. Pressing one end of theswitch63 increases the zoom factor, and pressing the other end decreases the zoom factor. In the disclosed embodiment, the zoom is continuous and can range from 1× to 4×. When the disclosed system is operating at a zoom factor of 4×, a center portion is extracted from each image produced by theimage detector18, where the center portion has a size of 320 by 240 pixels. This center portion is then displayed on thecolor display32, with each pixel from the center portion being mapped directly on a one-to-one basis to a respective pixel of thedisplay32.
• When the zoom factor is at 1×, thereformatter26 essentially takes an entire image from theimage detector18, divides the pixels of that image into mutually exclusive groups that each have 16 pixels arranged in a 4 by 4 format, averages or interpolates the 16 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of thedisplay32. Similarly, when the zoom factor is at 3×, thereformatter26 essentially takes an image from theimage detector18, extracts a center portion having a size of about 960 pixels by 720 pixels, divides the pixels of this center portion into mutually exclusive groups that each have 9 pixels arranged in a 3 by 3 format, averages or interpolates the 9 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of thedisplay32. As still another example, when the zoom factor is at 2×, thereformatter26 essentially takes an image from theimage detector18, extracts a center portion having a size of about 640 pixels by 480 pixels, divides the pixels of this center portion into mutually exclusive groups that each have 4 pixels arranged in a 2 by 2 format, averages or interpolates the 4 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of thedisplay32.
• As mentioned above, the zoom from 1× to 4× is continuous in the disclosed embodiment. When the zoom factor is between 1× and 2×, between 2× and 3×, or between 3× and 4×, thereformatter26 takes an appropriate portion of an image, and then groups, interpolates and maps the pixels of this portion into the pixels of thedisplay32, in a manner analogous to that discussed above. Although the zoom in the disclosed embodiment is continuous, it would alternatively be possible for the zoom factor to be moved between discrete zoom levels, such as the four discrete zoom levels of 1×, 2×, 3× and 4×. In addition, although the zoom range in the disclosed embodiment is 1× to 4×, it would alternatively be possible to use some other zoom range.
• With reference toFIG. 4, theswitch65 is a four-way reticle switch. Any one of the upper, lower, left or right sides of this switch (as viewed inFIG. 4) can be manually operated in order to respectively indicate a selection of up, down, left or right. Each time the upper side of theswitch65 is actuated, the position of the reticle101-105 is adjusted upwardly with respect to thedisplay32, and thus with respect to the image of thescene17 that is presented on thedisplay32. Each such actuation of theswitch65 causes the reticle101-105 to be moved upwardly by a predetermined number of pixels, and theelevation value112 in the lower right corner of thedisplay32 is incremented in response to each such adjustment. Similarly, if the lower side of theswitch65 is actuated, the reticle101-105 is adjusted downwardly on thedisplay32 by the predetermined number of pixels, and theelevation value112 is decremented. Similarly, actuation of the left or right side of theswitch65 causes the reticle101-105 to be adjusted leftwardly or rightwardly by a predetermined number of pixels on thedisplay32, and causes thewindage value111 in the lower left corner of thedisplay32 to be either incremented or decremented.
• As mentioned above, thesight10 is capable of capturing and storing either single images or short video clips. In order to view these stored images or clips, the user presses theview switch62, thereby causing theprocessing section21 to use theexternal display14 to present either the first still image from thememory card46, or the first video clip from thememory card46.FIG. 5 is a diagrammatic view of thedisplay14 with a recorded image displayed thereon. It will be noted that the recorded image includes not only the scene, but also the reticle101-105, so that the user can see where the reticle was positioned with respect to the scene when the trigger of the rifle was pulled.
• If thememory card46 contains more than one image or video clip, then anarrow142 will be visible to indicate that the user can move forward through the images or video clips. The user presses the right side of thereticle switch65 in order to move to the next successive image or video clip. Except when the user is viewing the first image or video clip, anarrow141 will be visible to indicate that the user can move backward through the images or video clips. The user presses the left side of thereticle switch65 in order to move backward through the images or video clips. Theview indicator142 will be visible except when the user is viewing the last image or video clip, and theview indicator141 will be visible except when the user is viewing the first image or video clip. The view mode is terminated by pressing the switch62 a second time, in order to turn off theexternal display14 and thereby conserve battery power.
• As is well known to persons who use rifles and similar weapons, care must always be used to avoid pointing the rifle at anyone or anything that the user does not intend to shoot, in case there is an accidental discharge of the rifle. Thesight10 is designed to reduce the likelihood that the rifle may be inadvertently pointed in a direction that presents a safety hazard. In particular, thesight10 includes theexternal display14, in order to avoid displaying any recorded images from the memory on theinternal display32. This avoids a situation in which a hunter might mistake a recorded image on theinternal display32 for an actual view of the target, and then discharge the firearm in the belief that he or she was shooting at something in the recorded image, when in fact the rifle was actually aimed at something or someone else.
• A further consideration is that, even with the presence of theexternal display14, there could still be a potential safety hazard if a user became distracted while viewing recorded images on thedisplay14, and inadvertently pointed the rifle in a direction that presented a safety hazard. A similar scenario is that the user might inadvertently point the rifle in an unsafe direction while trying to orient thesight10 so that another person can see the images on thedisplay14. Or the user might hand the rifle with thesight10 to that other person, in order to allow the person to have a good view of images presented on theexternal display14. That other person might then point the rifle in an unsafe manner, either because the person was distracted by the displayed images, and/or because the person simply was not suitably familiar with the basic principles of safe weapon handling.
• Thesight10 is designed to also avoid this latter type of hazard. More specifically, as mentioned above, theaccelerometer41 is very sensitive and can detect the force of gravity. Consequently, as thesight10 is progressively moved from a position where the rifle barrel is horizontal to a position where the rifle barrel is pointing vertically upwardly, the output signal of theaccelerometer41 will have a force component due to gravity that progressively increases. Based on that force component, theprocessor22 of thesight10 does not present any images on theexternal display14, unless an optical centerline of the sight10 (which extends generally parallel to the barrel of the attached rifle) is within 10° to 20° of a vertical reference. Consequently, the rifle barrel will be pointing almost directly upwardly wherever theexternal display14 is actuated and showing any recorded image information.
• Although thesight10 uses theaccelerometer41 to determine its orientation, it would alternatively be possible to use any other suitable sensor arrangement to detect orientation. As one example, it would be possible to use a group of conventional mercury switches having different orientations.
• Theswitch61 serves as an angle rate switch that can be operated to enable and disable the display of an angular error rate, as sensed by therate gyro43. In particular, successive manual actuations of theswitch61 will alternately enable and disable this function. When this function is respectively enabled and disabled, theangular error indicator120 is respectively visible on and omitted from thedisplay32. When this function is enabled, theprocessing section21 monitors the output of therate gyro43. Typically, a user will be aiming the firearm and attempting to keep thereticle center101 accurately centered on a portion of thescene17 that is considered to be a target.
• If the user happens to be holding the firearm very steady, then therate gyro43 will detect little or no angular motion of thesight10 and the firearm, or in other words little or no transverse movement thereof. Consequently, theprocessing section21 will present theindicator120 as a circle of relatively small diameter, in order to indicate to the user that the firearm is being relatively accurately held on the selected target. On the other hand, if the user is having difficulty holding the firearm steady, then therate gyro43 will detect the greater degree of angular movement of the firearm and thesight10. Consequently, theprocessing section21 will display theindicator120 with a larger diameter, thereby indicating that thereticle center101 is not being held on the target as accurately as would be desirable.
• In the disclosed embodiment, the change in the diameter of theindicator120 is continuous. In other words, a progressive increase in the amount of angular movement of the firearm and thesight10 results in a progressive increase in the diameter of theindicator120. Conversely, a progressive decrease in the amount of angular movement of the firearm and sight results in a progressive decrease in the diameter of theindicator120. The user will therefore endeavor to squeeze the trigger of the firearm at a point in time when thereticle center101 is centered on the target, and when theindicator120 has a relatively small diameter that indicates the firearm is currently being held very steady.
• The remainingswitch60 on the switch panel55 is a boresight switch, and is used to enable and disable an autoboresight alignment mode. When this mode is respectively enabled and disabled, theautoboresight alignment indicator117 is respectively visible on and omitted from thedismay32. As indicated earlier, the autoboresight alignment function is not related to the present invention, and therefore is not described here in detail.
• Hunting regulations in most states stipulate that hunting is allowed during the time from one-half hour before sunrise to one-half hour after sunset. The intent of these regulations is to prevent the unsafe practice of shooting in very low light levels, where the actual identity of a target may be questionable. The level of illumination at one-half hour before sunrise and at one-half hour after sunset is sometimes referred to as “civil twilight”, and falls in a luminance range of 0.1 to 1.0 foot-candles. This luminance range corresponds to a cloudless sky. Other conditions can reduce ambient illumination to a level below that of civil twilight at almost any time during the day, for example where there is a dense cloud cover, or where a hunter is in a dense forest. There is no easy way for hunters and game wardens to determine actual levels of illumination, and this is why states have adopted the compromise approach of defining allowable hunting conditions in terms of dusk and dawn, rather than in terms of actual levels of illumination.
• Theimage detector18, based on its sensitivity and integration time, can give a direct measure of the actual levels of illumination present in scenes viewed through thesight10. Consequently, theprocessing section21 analyzes the images received from theimage detector18, in order to determine the ambient level of illumination within the detected scene. In the disclosed embodiment, theprocessing section21 averages the brightness of all of the pixels in a given image, and then compares the calculated average to a predetermined threshold that corresponds to civil twilight. Alternatively, however, any other suitable technique may be used to make this analysis. If theprocessing section21 determines that the calculated average brightness is above the predetermined threshold, indicating that the level of ambient illumination is greater than civil twilight, then thesight10 is operated in a normal manner. On the other hand, if theprocessing section21 determines that the calculated average brightness is below the threshold, then the processing section displays a warning.
• More specifically,FIG. 6 is a diagrammatic view of theinternal display32 while thesight10 is being used to view a scene having a low level of ambient illumination. After calculating the average level of brightness for the displayed image, and determining that the calculated average is below the predetermined threshold, theprocessing section21 displays the image with the addition of awarning201. In the disclosed embodiment, the warning201 is the alphanumeric phrase “LOW LIGHT LEVEL”. In order to attract the attention of the user, this warning can be displayed in a color such as red, and/or can be made to blink. This warning notifies the user that light levels are low, thereby reminding the user that target recognition may be questionable and that hunting conditions may be unsafe. A responsible hunter will not want to shoot in these conditions.
• Although thewarning201 in the disclosed embodiment is the alphanumeric phrase “LOW LIGHT LEVEL”, it could alternatively be some other alphanumeric phrase, a symbol such as a circle with a slash through it, or a combination of a symbol and an alphanumeric phrase. In addition, as discussed above, the disclosed embodiment responds to detected low light levels by displaying the warning201 in association with the detected image. Alternatively, however, it would be possible for theprocessing section21 to respond to the detection of a low light level by inhibiting the display of any image of any scene. In that case, the processing section could display the warning201 (without any image), or could simply disable the presentation of any information on thedisplay32.
• Virtually all states have a hunting regulation that requires hunters to wear a fluorescent orange garment above the waist while hunting. This color does not naturally occur in any big game animals or their environment, and is intended to be a visual cue to a hunter that a person is present, rather than a potential animal target. Even where such a garment is present, the patch of orange color may be partly obscured by other objects in the scene, or may be very small if the hunter is a significant distance from the person wearing the garment. In either case, the presence of the orange color in the scene may be inadvertently and unintentionally overlooked by a hunter, resulting in a potentially dangerous situation for the person wearing the garment.
• As a safety measure, the processing section of thesight10 monitors images received from theimage detector18 for any pixels therein that represent a fluorescent orange color in the scene. If this color is detected, then theprocessing section21 superimposes a warning on the image. In this regard,FIG. 7 is a diagrammatic view of theinternal display32 while thesight10 is being used to view a scene that includes a person wearing a fluorescent orange garment. In response to detection of the fluorescent orange color, theprocessing section21 superimposes awarning221 over the portion of the image where the fluorescent orange color was detected. In the disclosed embodiment, the warning221 is a circle with a slash. In order to attract the attention of the user to thewarning221, the warning can be presented in a color such as red, and/or can be made to blink.
• As discussed above, the warning221 in the disclosed embodiment is a symbol in the form of a circle with a slash. Alternatively, however, the warning221 could be some other symbol, an alphanumeric phrase, or a combination of a symbol and an alphanumeric phrase.
• Although one embodiment has been illustrated and described in detail, it will be understood that various substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the following claims.

Claims (18)

1. An apparatus comprising a weapon sight that includes:

structure configured to support said sight on a weapon;

a detector portion that can detect radiation originating externally of said sight; and

a control portion coupled to said detector portion, and responsive to the presence of a selected color within the visible spectrum in radiation detected by said detector portion for taking a selected action.

2. An apparatus according toclaim 1, wherein said selected color is a fluorescent orange.

3. An apparatus comprising a weapon sight that includes;

structure configured to support said sight on a weapon;

a detector portion that can detect radiation originating externally of said sight; and

a control portion coupled to said detector portion, and responsive to the presence of a selected color in radiation detected by said detector portion for taking a selected action;

wherein said sight includes a display coupled to said control portion for displaying information that relates to aiming a weapon, said selected action including preventing the presentation on said display of the information that relates to aiming a weapon.

4. An apparatus according toclaim 1, wherein said weapon sight includes a warning indicator coupled to said control portion, said selected action including actuating said warning indicator.

5. An apparatus according toclaim 4,

wherein said sight has a field of view that relates to aiming a weapon; and

wherein said warning indicator is a visible indicator that is disposed within said field of view.

6. An apparatus comprising a weapon sight that includes;

structure configured to support said sight on a weapon;

a detector portion that can detect radiation originating externally of said sight;

a control portion coupled to said detector portion, and responsive to the presence of a selected color in radiation detected by said detector portion for taking a selected action;

a warning indicator coupled to said control portion, said selected action including actuating said warning indicator;

an image detector coupled to said control portion and responsive to radiation originating externally of said sight, said image detector serving as said detector portion; and

a display coupled to said control portion for displaying information that relates to aiming a weapon, including images detected by said image detector, said warning indicator being a visible indicator in the form of information presented on said display by said control portion.

7. A method of operating a weapon-mountable sight having a detector portion that can detect radiation originating externally of said sight, comprising:

taking a selected action in response to the presence of a selected color within the visible spectrum in radiation detected by said detector portion.

8. A method according toclaim 7, including selecting a fluorescent orange to be said selected color.

9. A method according toclaim 7,

including configuring said sight to have a display for displaying information that relates to aiming a weapon; and

wherein said taking of said selected action includes preventing the presentation on said display of the information that relates to aiming a weapon.

10. A method according toclaim 7,

including configuring said weapon sight to have a warning indicator; and

wherein said taking of said selected action includes actuating said warning indicator.

11. A method according toclaim 10,

wherein said sight has a field of view that relates to aiming a weapon; and

including configuring said sight so that said warning indicator is a visible indicator within said field of view.

12. A method according toclaim 10, including:

configuring said sight to have an image detector responsive to radiation originating external to said sight, said image detector serving as said detector portion;

configuring said sight to have a display for displaying information that relates to aiming a weapon, including images detected by said image detector;

configuring said warning indicator to be a visible indicator; and

carrying out said actuating of said warning indicator in a manner that includes presenting information on said display.

13. An apparatus comprising a weapon sight that includes:

means for supporting said sight on a weapon;

detector means for detecting radiation originating externally of said sight; and

control means for taking a selected action in response to the presence of a selected color within the visible spectrum in radiation detected by said detector portion.

14. An apparatus according toclaim 13, wherein said selected color is a fluorescent orange.

15. An apparatus comprising a weapon sight that includes:

means for supporting said sight on a weapon;

detector means for detecting radiation originating externally of said sight;

control means for taking a selected action in response to the presence of a selected color in radiation detected by said detector portion; and

display means coupled to said control means for displaying information that relates to aiming a weapon; and

wherein said control means carries out said taking of said selected action in a manner that includes preventing the presentation on said display means of the information that relates to aiming a weapon.

16. An apparatus according toclaim 13,

wherein said weapon sight includes warning means coupled to said control portion for selectively presenting a warning; and

wherein said control means carries out said taking of said selected action in a manner that includes actuating said warning means.

17. An apparatus according toclaim 16,

wherein said sight has a field of view that relates to aiming a weapon; and

wherein said warning means includes a visible indicator disposed within said field of view.

18. An apparatus comprising a weapon sight that includes:

means for supporting said sight on a weapon;

detector means for detecting radiation originating externally of said sight;

control means for taking a selected action in response to the presence of a selected color in radiation detected by said detector portion;

warning means coupled to said control portion for selectively presenting a warning;

image detecting means coupled to said control means and responsive to radiation originating external to said sight, said image detecting means serving as said detector means; and

display means coupled to said control means for displaying information that relates to aiming a weapon, including images detected by said image detecting means, said warning means including a visible indicator in the form of information presented on said display by said control means;

wherein said control means carries out said taking of said selected action in a manner that includes actuating said warning means.

Images