Abstract:
A camera ( 10 ) with an automatic daytime/nighttime feature includes a lens ( 16 ) for focusing an image, an image capture element ( 14 ) for capturing a digital representation of the image focused by the lens, the image capture element ( 14 ) operable to capture images in both the visible light and infrared portions of the electromagnetic spectrum, and a filter ( 18 ) for preventing passage of substantially all electromagnetic waves within the infrared portion of the electromagnetic spectrum. An actuator ( 20 ) moves the filter ( 18 ) between a first position wherein the filter ( 18 ) is at least partially interposed between the lens ( 16 ) and the image capture element ( 14 ), and a second position wherein the filter ( 18 ) is not interposed between the lens ( 16 ) and the image capture element ( 14 ). A controller ( 44 ) automatically causes the filter ( 18 ) to be moved between the first position and the second position at times of day indicated by instructions received via an interface ( 46 ).

Description:
RELATED APPLICATION 
       [0001]    The present application is a nonprovisional patent application and claims priority benefit, with regard to all common subject matter, of earlier-filed U.S. provisional patent application titled “TRAIL CAMERA WITH AUTOMATIC DAYTIME/NIGHTTIME FEATURE”, Ser. No. 60/804,876, filed Jun. 15, 2006, incorporated by reference into the present document. 
     
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present technology relates to camera devices. More particularly, embodiments of the technology involve a camera operable to capture images in the presence or absence of ambient light using a single image capture element. 
         [0004]    2. Description of Related Art 
         [0005]    It is often desirable to capture images in the absence of visible ambient light, such as at night or in enclosed, unlit locations. To capture images in the absence of visible light, “night vision” cameras have been developed that use infrared light emitting diodes to illuminate a field of view with infrared light and use an infrared image capture element to capture images of the field of view based on the infrared light. Dual-mode cameras have been developed that capture images based on ambient visible light (i.e., “daytime” mode) and images based on infrared light (i.e., “night vision” mode). Such cameras may include a single image capture element capable of capturing both visible light images and infrared light images. To enhance the infrared light images, such cameras often include infrared light emitters (“flashes”) that are invisible to humans and animals. 
         [0006]    Conventional dual-mode cameras must be placed in either the daytime mode or the night vision mode when used or installed in the field. Due to the inconvenience of manually switching the camera, operators typically leave such cameras in one of the two modes for long periods of time. Use of the infrared light emitter results in daytime images that are black and white with an occasional undesirable pink hue and nighttime images that are black and white. 
         [0007]    Accordingly, there is a need for an improved camera operable to capture images in the presence and absence of visible light that does not suffer from the limitations of conventional cameras. 
       SUMMARY OF THE INVENTION 
       [0008]    The present teachings provide an improved camera for capturing images in the presence or absence of ambient light that does not suffer from the problems and limitations of the prior art. Particularly, embodiments of the present teachings provide a camera comprising an image source, an image capture element, a filter, and an actuator. 
         [0009]    The image capture element may be operable to detect both visible and infrared light. The filter prevents passage of light defined by a first portion of the electromagnetic spectrum, such as infrared light, and allows passage of light defined by a second portion of the electromagnetic spectrum, such as visible light. The actuator moves the filter between a first position wherein the filter is at least partially interposed between the image source and the image capture element, and a second position wherein the filter is not interposed between the image source and the image capture element. 
         [0010]    If the filter is operable to block infrared light, the filter may be interposed between the image source and the image capture element in the presence of ambient light to prevent image deterioration due to infrared light, and may be removed in the absence of ambient light to allow infrared light to reach the image capture element. 
         [0011]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Preferred implementations of the present technology are described in detail below with reference to the attached drawing figures, wherein: 
           [0013]      FIG. 1  is a front elevation view of a camera constructed according to principles of the present teachings and including a lens and filter assembly, the camera illustrated in broken lines; 
           [0014]      FIG. 2  is a generally front and side perspective view of the camera of  FIG. 1  with a face of the camera fragmented to illustrated the lens and filter assembly encased in the camera, the camera shown with a cover in an open position exposing a user interface and a plurality of battery receptacles; 
           [0015]      FIG. 3  is a generally front perspective view of the lens and filter assembly of  FIGS. 1 and 2 ; 
           [0016]      FIG. 4  is a generally rear perspective view of the lens and filter assembly of  FIG. 3 ; 
           [0017]      FIG. 5  is a generally front exploded view of the lens and filter assembly of  FIGS. 3 and 4 ; 
           [0018]      FIG. 6  is a generally rear exploded view of the lens and filter assembly of  FIGS. 3 and 4 ; 
           [0019]      FIG. 7   a  is a rear elevation view of the lens and filter assembly of  FIGS. 3-6  illustrating a filter component in a first position; 
           [0020]      FIG. 7   b  is a rear elevation view of the lens and filter assembly of  FIGS. 3-6  illustrating the filter component in a second position; and 
           [0021]      FIG. 8  is a schematic diagram of various components of the camera of  FIGS. 1 and 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    A camera embodying principles of the present teachings is illustrated in  FIGS. 1 and 2  and designated generally by the reference numeral  10 . The camera  10  includes a lens and filter assembly  12  operable to direct light toward an image capture element  14  and selectively filter the light directed toward the image capture element  14 . The lens and filter assembly  12  may be encased within the camera  10 , as illustrated, and interposed between a camera lens and an image capture element, as explained below. Referring also to  FIGS. 3-6 , the lens and filter assembly  12  generally comprises a lens  16 , a filter component  18 , and an actuator  20 . 
         [0023]    As used herein, “light” includes electromagnetic radiation that is detected by the image capture element  14 , and includes visible light as well as one or more portions of the electromagnetic spectrum in addition to visible light. Particularly, “light” includes electromagnetic radiation in the visible (wavelengths within the range of about 380 nm to about 750 nm) and infrared (wavelengths within the range of about 750 nm to about 1 mm) portions of the electromagnetic spectrum. 
         [0024]    The lens  16  may be a conventional glass or plastic lens for focusing or otherwise directing light onto the image capture element  14 . The lens  16  is but one example of an image source that may be used in the lens and filter assembly  12 . An alternative image source may include, for example, a simple aperture that does not focus or otherwise direct light passing through the aperture. 
         [0025]    The filter component  18  selectively filters a portion of the light passing from the lens  16  to the image capture element  14 . The illustrated filter component  18  includes a first window  22  and a second window  24 , wherein the first window  22 , the second window  24 , or both, include a filter to remove or block at least a portion of the light passing through the lens  16 . The filter component  18  is selectively positioned such that either the first window  22  or the second window  24  is interposed between the lens  16  and the image capture element  14 . One or both of the windows  22 ,  24  may include an insert, such as the insert  26 , with the filter characteristics described above. 
         [0026]    The first window  22  and the second window  24  may pass overlapping portions of the electromagnetic spectrum. For example, the first window  22  may include an infrared filter to pass substantially all light except for infrared light, while the second window  24  may pass substantially all light, including infrared light. In this example, the filter component  18  may be used to switch between a night mode wherein all light is passed, and a daytime mode wherein infrared light is blocked to prevent degradation of the image detected by the image capture element  14 . 
         [0027]    The actuator  20  selectively moves the filter component  18  between a first filter position wherein the first window  22  is interposed between the lens  16  and the image capture element  14 , and a second filter position wherein the second window  24  is interposed between the lens  16  and the image capture element  14 . Stated another way, the actuator  20  moves a filter between a first position wherein the filter at least partially intercepts light from the image source (lens  16 ), and a second position wherein the filter does not intercept light from the image source. Thus, the lens and filter assembly  12  selectively filters light passing from the lens  16  to the image capture element  14  by interposing different filter elements between the lens  16  and the image capture element  14 . Because, the lens and filter assembly  12  physically moves one or more filter elements into a position interposed between an image source and an image capture element to filter light reaching the image capture element, a single image capture element  14  may be used to capture both visible light images and infrared images without image degradation caused by the influence of infrared light in visible light images. 
         [0028]    The illustrated actuator  20  includes an electromagnet  28  that moves an arm  30  between a first arm position and a second arm position according to a polarity of the magnetic field generated by the electromagnet  28 . Thus, the arm  30  may include a magnetic element, such as a permanent magnetic, that is responsive to a magnetic field. Movement of the arm  30  between the first arm position and the second arm position causes the filter component  18  to move between the first filter position and the second filter position. The filter component  18  is illustrated in the first position in  FIG. 7   a  and in the second position in  FIG. 7   b.    
         [0029]    As illustrated in  FIGS. 4 and 6 , the lens and filter assembly  12  includes a chamber for encasing or receiving the image capture element  14 . In particular, a plurality of walls extend generally rearwardly from the assembly  12  and substantially circumscribe a path of light originating from the lens  16 . The walls define a substantially planar rim such that when the assembly  12  is secured to an external object with a planar surface, such as a printed circuit board, the walls of the chamber surround the image capture element  14  and contact the planar surface to prevent light from reaching the image capture element  14  from any source other than the lens  16 . The assembly  12  may further include a plurality of attachment components including, for example, one or more internally-threaded, screw-receiving recesses. 
         [0030]    It will be appreciated that these features of the lens and filter assembly  12  facilitate adaptation of the assembly  12  to various types of cameras by substantially modularizing the assembly  12 . For example, the lens and filter assembly  12  can be physically attached to a camera by placing the assembly  12  on a printed circuit board supporting the image capture element  14  and securing the assembly  12  to the printed circuit board using the plurality of attachment components. 
         [0031]    The lens and filter assembly  12  illustrated in the drawings and described above is an exemplary embodiment of various principles of the present teachings. It is noted that equivalents may be employed and substitutions made to the lens and filter assembly  12  without departing from the ambit of the present teachings. By way of example, a linear solenoid, electric motor, or other actuator may be used in place of the electromagnet  28  illustrated and described herein. Furthermore, the filter component  18  may include a single window, wherein the single window includes a filter such that interposing the single window between the image source and the image capture element  14  filters a portion of the light striking the image capture element  14 . 
         [0032]    An exemplary application of the lens and filter assembly  12  is illustrated in  FIGS. 1 and 2 , wherein the assembly  12  is mounted in the camera  10  used for discretely capturing images in the presence or absence of visible light. Such cameras are commonly used, for example, by hunters who wish to scout animal activity. The camera  10  has other uses as well, including, for example, security surveillance. 
         [0033]    In addition to the lens and filter assembly  12  and the image capture element  14 , the camera  10  may include, among other things, a passive infrared sensor  32  for detecting the presence of a person or animal; an infrared emitter  34  such as the illustrated array of infrared light emitting diodes; a visible light emitter  36 ; an outer camera lens  38 ; a memory receptacle  40 ; a control panel  42  including one or more user interface elements; and a controller  44  ( FIG. 8 ) for generally controlling operation of the camera  10 . 
         [0034]    The passive infrared sensor  32  senses motion in a conventional manner, and may require infrared energy (heat) in addition to motion to trip the sensor  32 . The infrared emitter  34  generates infrared light for the capture of images in the absence of visible light, such as at nighttime or in an unlit room. In order to capture images in the absence of visible light, the image capture element  14  senses visible light as well as infrared light. The visible light emitter  36  may be a standard flash, such as a xenon flash tube or other flash device, and may be used to capture images with little or no ambient light. The visible light emitter  36  may be used instead of the infrared emitter  34  where, for example, the user prefers visible light images. 
         [0035]    Light enters the camera  10  through the outer camera lens  38  and strikes the lens  16 . The memory receptacle  40  receives a memory element, such as a memory card or other data storage device, and enables communication between the memory element and the controller  44 . The control panel  42  includes one or more user interface elements, such as buttons, switches, and a display. The control panel  42  thus enables users to interact with the controller  44  to configure operation of the camera  10 , as explained below in greater detail. 
         [0036]    A schematic diagram of various electric components of the camera  10  is illustrated in  FIG. 8 . The controller  44  generally controls operation of the electrical components of the camera  10 , and is preferably a digital integrated circuit such as a general use, commercial off-the-shelf computer processor. Alternatively, the controller  44  may be a programmable logic device configured for operation with the camera  1   0 ,or may be an application specific integrated circuit (ASIC) especially manufactured for use in the camera  10 . 
         [0037]    While illustrated as a single component of the block diagram, the controller  44  may include two or more separate integrated circuits working in cooperation to control operation of the camera  10 , and may include one or more analog elements operating in concert with or in addition to the digital circuit or circuits. The controller  44  may even comprise a plurality of discrete components. The controller  44  may operate in conjunction with a memory element (not shown) that stores data, instructions, or both used by the controller  44 . The memory element may be internal or external to the controller  44 . 
         [0038]    In addition to the controller  44 , the diagram illustrated in  FIG. 8  illustrates an interface  46 ; the image capture element  14 ; the actuator  20 ; and a plurality of additional electrical components  48 , 50  that may correspond to one or more of the passive infrared sensor  32 , infrared emitter  34 , visible light emitter  36 , or the memory receptacle  40  of the camera  10 . 
         [0039]    The interface  46  may be a user interface, a wireless interface, or both. Thus, the interface  46  may correspond, at least in part, to one or more elements of the control panel  42 . Via the interface  46 , a user may configure the controller  44  to automatically drive the filter component  18  to the first filter position at a first time of day and drive the filter component  18  to the second filter position at a second time of day via the actuator  20 . 
         [0040]    By way of example, a user may wish to filter out infrared light during the day to prevent image quality deterioration, but may wish to allow infrared light to reach the image capture element  14  at night to capture infrared images enhanced by the infrared emitter  34 . Thus, the control panel  42  may include interface elements that enable a user to select a first time of day for switching to night mode and a second time of day for switching to day mode, wherein the controller  44  causes an infrared filter to be interposed between the lens  16  and the image capture element  14  in the day mode, and causes the infrared filter to be moved to a location not interposed between the lens  16  and the image capture element  14  in the night mode. 
         [0041]    Although the present technology has been described with reference to the preferred embodiments illustrated in the attached drawings, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims. It will be appreciated, for example, that the lens and filter assembly  12  may be used with a hand-held camera.