Abstract:
Method and apparatus for attenuating unwanted aspects of lighting from a luminaire which is disposed to illuminate an object or objects being photographed. A light attenuating mask is disposed between the luminaire and the object or objects. The light attenuating mask may diffuse, obstruct, or otherwise modify projected light such that light intensity is diminished, unwanted reflections of the luminaire are suppressed, or other aspects of the light are altered. The mask may attach to the luminaire or may be free standing and separate therefrom.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the filing dates under 35 USC 119(e) to U.S. Provisional Application Ser. No. 61/014,884, filed Dec. 19, 2007, and U.S. Provisional Application Ser. No. 61/074,215, filed Jun. 20, 2008 the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to control of light which is being intentionally projected from a luminaire onto an object or surface for the purpose of illuminating the object or surface. More specifically, the invention relates to controlling light originating from the luminaire so that harshness of the light, and unintended lighting effects which result from the luminaire are mitigated. 
       BACKGROUND OF THE INVENTION 
       [0003]    The field of photography frequently uses supplemental intentional illumination of the subject of the photography. As employed herein, photography will be taken in its broadest context, encompassing still photography, dynamic photography (i.e., motion pictures), videography, and all forms of visual image capture. In professional settings, luminaires have been utilized to illuminate a subject to be photographed. This is done to improve the captured images. For example, a minimum level of light may be necessary to capture an image displaying optimum clarity and visibility. Also, certain optical effects may thus be realized, such as spotlighting certain parts of an object being imaged. 
         [0004]    The use of supplementary luminaires may provide the requisite level of light, but may also be subject to certain unwanted effects. One possible unwanted effect is that of too much light impinging upon the subject, especially upon one portion of an object being photographed. As an illustration, a photographer may wish to photograph a large object such as an automobile, only to find that a supplemental luminaire creates overly bright lighting which disrupt the final image. The overly bright lighting may be limited to certain portions of the object being photographed, such that portions appear too bright relative to the rest of the object. Another potential problem may occur when shiny or reflective objects are being photographed. Illustratively, an automobile having a reflective surface may possibly transmit reflections of the luminaire to the camera, thereby disrupting the desired effect of the final image in that the luminaire may be fully or partially visible in the final image. 
         [0005]    An example is seen in  FIG. 8 , wherein a bottle  2 , which represents subject matter of photography, is being illuminated by a luminaire  4 . The luminaire  4  has a stand  6  and a lighting head  8 . The lighting head  8  includes three elongated fluorescent tubes  10 ,  12 ,  14 . The bottle  2  is seen to bear a reflection  16  in which are visibly reproduced the three fluorescent tubes  10 ,  12 ,  14 . The lighting effect achieved by use of the luminaire  4  is somewhat harsh, as represented by the extreme contrast between the reflection  16  and the balance of the bottle  2 , which is seen as quite dark. Both the contrast in brightness and the reproduction of the fluorescent tubes  10 ,  12 ,  14  are objectionable. 
         [0006]    There exists a need in the prior art which enables luminaires to be used for illuminating an object being photographed, while limiting optical effects projected onto that object. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention addresses the above need by providing apparatus and method of mitigating unwanted optical effects arising from the use of supplementary luminaires used to illuminate objects being photographed. In broad terms, the novel approach is to interpose a mask between the luminaire and the subject of photography. This mask passes light yet controls optical effects such that undesirable brightness and harshness are mitigated, and unwanted reflections originating from the luminaire are effectively if not totally suppressed. 
         [0008]    The mask is generally transparent or translucent, and has light obstructing structure arranged so as to suppress light transmission progressively and increasingly with increasing distance from the center of the projected light beam. In the most preferred form of the invention, although not necessarily, progressive suppression of light is achieved so gradually that no discrete steps or zones of lighting, lighting levels, and optical effects will appear to the eye in the resulting photographic images. 
         [0009]    It is an object of the invention, therefore, to suppress unwanted optical effects from use of supplementary illumination of a scene from which images are to be captured. 
         [0010]    Another object of the invention is to avoid conspicuous or discernible transition as lighting is progressively controlled. 
         [0011]    A further object of the invention is to provide apparatus which is useable with conventional photography lighting luminaires to achieve suppression of unwanted optical effects. 
         [0012]    It is an object of the invention to provide improved elements and arrangements thereof by apparatus for the purposes described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes. 
         [0013]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0015]      FIG. 1  is a perspective view of a bottle illuminated by a luminaire the optical effects of which are attenuated according to at least one aspect of the invention. 
           [0016]      FIG. 2  is a plan view of an exemplary pattern of masking elements which progressively increasingly obstruct light with increasing distance from a central point of the pattern. 
           [0017]      FIG. 3  is an exploded detail view of part of a luminaire provided with optical effects which are attenuated according to at least one aspect of the invention. 
           [0018]      FIG. 4  is a perspective view of a mask for attenuating light from a luminaire, according to a further aspect of the invention. 
           [0019]      FIG. 5  is a perspective view of another mask for attenuating light from a luminaire on which the mask is mounted, according to still another aspect of the invention. 
           [0020]      FIG. 6  is a perspective view of a luminaire, an automobile being illuminated for photographing, and a stand-alone mask for attenuating light from the luminaire, according to still a further aspect of the invention. 
           [0021]      FIG. 7  is a block diagram of summarized steps of a method according to still another aspect of the invention, and is read starting at the upper left. 
           [0022]      FIG. 8  is a perspective view of a bottle illuminated in conventional fashion by a luminaire. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIG. 1  of the drawings shows a combination of a luminaire  100  for illuminating subject matter  10  of photography, and a mask  102  disposed to mitigate undesired optical effects visited upon the subject matter, which undesired optical effects arise from the luminaire  100 . The undesirable effects may include the reflection shown in  FIG. 8  and discussed prior. 
         [0024]    The luminaire  100  may comprise a lighting head  104  bearing at least one light source disposed to project light therefrom along a projection area having a central axis  106  and an adjacent zone surrounding the central axis  106 . The adjacent zone is represented by an arrow  108 , but will be understood to extend in two orthogonal dimensions rather than merely in one direction as visually suggested by the arrow  108 . Illustratively, the light source may comprise three fluorescent tubes  110 ,  112 ,  114  arrayed parallel to one another as is frequently done with conventional luminaires such as the luminaire  4  of  FIG. 1 . Such an array would be generally rectangular, with the field of light or projection area being commensurately rectangular, although integrity of the rectangular configuration of the resultant light beam may diminish with distance from the light source or light sources. The central axis  106  represents the centerline of the rectangular of the projection area of the luminaire  100 . 
         [0025]    The mask  102  may alter characteristics of light projected from the luminaire  100  in one or both of two ways. First, the mask  102  may suppress optical intensity of the light projected from the luminaire  100  onto the bottle, which may be for example the bottle  2  of  FIG. 8 . Intensity may be suppressed in any suitable way, such as for example obstructing some of the light, by filtering one or more frequencies, or by diffusing the light. Obstruction may be achieved by translucence of the constituent material of a stratum (not separately shown) of the mask  102 , by imposing a pattern of opaque or translucent material onto the mask  102  such that some light is obstructed and some not obstructed, or by a combination of techniques described herein. For purposes of attenuating intensity of light, degree of translucence may be varied to suit. 
         [0026]    In a second way, intensity of light projected from the luminaire  100  may be selectively reduced with increasing distance from the axis  106 . For example, where a pattern of lines, circles, or other recurring geometric elements are printed onto the constituent stratum of the mask  102 , spacing separating one geometric element from the adjacent geometric element may decrease with increasing distance from the axis  106 . An exemplary arrangement is shown in  FIG. 2 , where the axis  106  is surrounded by opaque circles or dots  116  which are increasingly closely spaced with increasing distance from the axis  106 . Spacing may be progressively reduced to the point of generating a solid field (not shown) displaying total opacity if desired. Any one or any combination of elements which alter light characteristics will be referred to herein as light attenuating elements. 
         [0027]    Again referring to  FIG. 1 , the optical effect of the mask  102  may include sufficient diffusion of light so as to eliminate the effect of  FIG. 8 , wherein each fluorescent tube  10 ,  12  or  14  produces a corresponding discrete visible element in the reflection  16 . Rather, as seen in  FIG. 1 , a single bright spot  118  may be seen. The single bright spot  118  does not reproduce either any one of the individual fluorescent tubes  110 ,  112 ,  114 , nor does it reproduce the housing  120  which partially envelops the fluorescent tubes  110 ,  112 ,  114 . The image of the bottle  2  is also softened from that of  FIG. 8  in that the extreme contrast between brightness of the reflection  16  and the rest of the bottle  2  as seen in  FIG. 8  is reduced since more light strikes and is reflected that portion of the bottle  2  which lies outside the reflection  118  in  FIG. 2 . This is represented by cross hatching of that portion of the bottle  2  outside the reflection  118 . 
         [0028]    The luminaire  100  may comprise at least one light source, where “light source” signifies a lamp such as the fluorescent tubes  110 ,  112 ,  114 . Of course, the light source may take any other form, such as incandescent lamps, light emitting diodes, electroluminescent elements, and others. The luminaire  100  may comprise a plurality of light sources in any combination of variety, size, light output, hue, and other optical characteristics, or may comprise a single light source. 
         [0029]    Turning momentarily to  FIG. 3 , the mask  102  may comprise two separate light transmissive strata  122 ,  124  to achieve the two optical effects described above, namely, diffusion and progressive obstruction. In  FIG. 3 , the light transmissive stratum  122  may include a roughened surface or internally embedded light scattering particles or any other apparatus (none shown) which would randomly diffuse light from what would otherwise be a relatively coherent beam emanating from the light source or light sources. In  FIG. 3 , the light transmissive strata  122 ,  124  cover or encircle or partially encircle both the light sources (i.e., the fluorescent tubes  110 ,  112 ,  114 ) and also the housing  120 . Of course, it is only critical to the invention to cover or substantially cover the light sources. Engagement of the housing  120  may be practiced as a convenience in attaching the strata  122 ,  124  to the lighting head  104 , but is not necessary to attenuate lighting characteristics. 
         [0030]    The light transmissive stratum  124  may have a pattern of translucent or opaque nature imprinted thereon so as to have a property of suppressing optical intensity of light projected from the luminaire  100  onto the subject matter such that relatively greatest light transmission occurs along the central axis  106  and relatively decreasing light transmission occurs with increasing distance from the central axis  106 . Alternatively stated, the light transmissive stratum  124  may be regarded as a separate graduating stratum, whereas by contrast, the light transmissive stratum  122  serves as a diffusing stratum which uniformly diminishes light intensity throughout its full extent. 
         [0031]    The light transmissive stratum  124  may have a relatively unobscured zone  126  and a relatively obscuring zone  128 . Also, where even more effectively light suppressing zones are provided within the light transmissive stratum  124 , the light attenuating elements will be selected to display relatively decreased light emission including plural levels of light projection, and wherein the light attenuating elements enable transition of light projected from one level of light projection to another level of light projection which is not readily discernible to the unaided eye. The latter condition comes into play where there are obscuring zones (not shown) which are comparable to and which would surround the obscuring zone  128 , but which would display a still greater degree of light suppression than that of the obscuring zone  128 . 
         [0032]      FIG. 3  also shows another aspect of the invention, wherein the mask  102  is attached to and supported on the housing  120 . To this end, the light transmissive strata  122  and  124  comprise flexible mounting tabs  130   a ,  130   b ,  130   c ,  130   d ,  130   e ,  130   f ,  130   g  which engage or encircle the housing  120 , and which bear fastening elements (not separately shown) which may be disposed to engage the luminaire  100  and to secure the mask  102  in a selected mounting position on the luminaire  100 . The fastening elements may comprise adhesive for direct engagement of the luminaire  100 , and which adhesive will be understood to include hook and loop fastening arrangements for example. Of course, attachment may utilize encirclement and latching such as by hook and eye, snaps, buttons, resilient constriction, and any other known fastening method. 
         [0033]      FIG. 4  shows a graduating stratum  132  which may have a separate obscuring or light attenuating panel  134  including a relatively unobscured zone  136  and a surrounding obscuring zone  138 . The graduating stratum  132  may be functionally similar to the light transmissive stratum  124  except that it may comprise a supporting frame  140  to which the panel  134  may be removably secured for example with cords  142   a ,  142   b ,  142   c . The graduating stratum  132  may be removably connected to an associated luminaire, such as the luminaire  100 , by flexible tabs  144   a ,  144   b ,  144   c  bearing hook and loop patches. Corresponding hook and loop patches (not shown) may be adhered to the associated luminaire. 
         [0034]      FIG. 5  shows a mask  160  comprising a light attenuating panel  162  mounted on a generally rigid housing or frame  164 , which in turn may be mounted to a luminaire  166 . The light attenuating panel  162  may have a relatively unobscured zone  168  and a surrounding obscuring zone  170 , or may be of the diffusing type, such as the light transmissive stratum  122 , or may have both characteristics. The mask  160  may be attached to the luminaire  166  by wing nuts  172   a ,  172   b.    
         [0035]      FIG. 6  shows an arrangement wherein a mask  180  is a stand-alone device. That is, it is maintained at a selected position relative to, spaced apart from, and unconnected to an associated luminaire  182 . The luminaire  182  may be conventional in nature. This is accomplished by providing a stand comprising two legs such as the leg  184  to which a light attenuating panel  186  is affixed for example by a wing nut  188 . The leg  184  represents any of many possible environmental surface engaging members (no others shown) which may be disposed to engage an environmental surface and to maintain the mask  180  at the selected position relative to the luminaire  182 . This selected position will ordinarily imply that the mask  180  is positioned between the luminaire  180  and the subject of photography which is being illuminated by the luminaire  182 . In this example, the subject of photography is an automobile  190 . The light attenuating panel  186  may have any of the optical effects and mounting arrangements described herein. 
         [0036]    The invention may be regarded, in one aspect, as a method  200  of arranging lighting on subject matter of photography. Referring to  FIG. 7 , the method  200  may comprise a step  202  of providing a luminaire for illuminating the subject matter of photography, wherein the luminaire comprises at least one light source disposed to project light therefrom along a projection area having a central axis and an adjacent zone surrounding the central axis. The luminaire may be for example the luminaire  100  of  FIG. 1 . 
         [0037]    The method  200  may comprise a step  204  of providing a mask disposed to mitigate undesired optical effects visited upon the subject matter, which undesired optical effects arise from the luminaire, wherein the mask comprises at least one light transmissive stratum which is operable to suppress optical intensity of light projected from the luminaire onto the subject matter such that relatively greatest light transmission occurs along the central axis and relatively decreasing light transmission occurs with increasing distance from the central axis. The mask may be for example the mask  102  of  FIG. 1 . 
         [0038]    The method  200  may comprise a step  206  of interposing the mask between the luminaire and the subject matter of photography such that the mask attenuates light projected onto the subject of photography from the luminaire such that light is projected onto the subject matter at relatively greatest intensity along the central axis and at relatively decreasing intensity with increasing distance from the central axis such that transition from the greatest light transmission to the relatively decreasing light transmission is not readily discernible to the unaided eye. The subject matter of the step  206  may be as described hereinabove and as shown in  FIGS. 1 through 6 . 
         [0039]    The method  200  may comprise a further step  208  of photographing the subject matter of photography; and a step  210  of producing images which are devoid of reflections of the luminaire. The photography process and images which are produced may be conventional. 
         [0040]    The present invention is susceptible to modifications and variations which may be introduced thereto without departing from the inventive concepts. For example, it is important to note that elements of the inventive environment which are described in the singular will be understood to also encompass the plural. For example, while reference is made to a single object of photography, it will be appreciated that images may comprise plural objects, either similar in nature or different. Illustratively, imagery of one automobile among many, of one statue among other objects, or of one human subject beside other objects may enjoy the benefits of the invention. The novel optical effects described herein may apply to one degree or another to all objects to be photographed or otherwise subjected to image capture, as well as to solitary objects. Similarly, reference to a single luminaire may encompass usage of more than one luminaire. Reference to a single source of light such as a lamp within any one luminaire may encompass plural lamps used in one luminaire or used in plural luminaires. Reference to a single mask will be understood to encompass potential use of plural masks. Plural masks may be arranged serially, laterally adjacent, in full or partial overlapping manner, or in any combination of these arrangements. Reference to an image will be understood to encompass plural images, such as a series of images for generating a motion picture, or a series of redundant still images, or a series of complementing still or dynamic images. 
         [0041]    While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is to be understood that the present invention is not to be limited to the disclosed arrangements, but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible.