BACKGROUND 
       [0001]    Field of the Disclosure 
         [0002]    The present disclosure relates to variable apertures, and more specifically, to time-varying and transparency-varying apertures. 
         [0003]    Background 
         [0004]    Typically, an iris in a lens forms an aperture that closes down to change the amount of light going through the imaging system. The iris can sometimes be completely closed to act as a shutter. 
         [0005]      FIG. 1  is a diagram of a conventional lens system  100  including various lens or optical elements  110 ,  112 ,  114 ,  116  and an iris  120 . In  FIG. 1 , the light rays  140  incident on the lens elements  110 ,  112  pass through the iris  120  and the lens elements  114 ,  116  and falls on an image sensor  142 . 
         [0006]    The blades  122  of the iris  120  form an opening or aperture  130 . The shape of the iris opening (or the aperture) also affects the image rendition. Term “aperture” may be used interchangeably with “iris”. In  FIG. 1 , the shape of the aperture may have pointed edges  124 . For example, having an aperture that has pointed edges (typical of most lenses) may result in star patterns for strong light sources, or out-of-focus areas being nervously-detailed rather than having smooth bokeh. This may be undesirable for certain purposes. Thus, a round aperture, which may result in relatively round out-of-focus discs in a more pleasingly-rendered bokeh, may be desirable. Towards that goal, the lens designers often increase the number of blades to improve on the circular shape of the aperture formed by the blades. However, adding blades adds complexity to the lens system and may cause unanticipated operational problems. 
         [0007]    Further, the bokeh is often not just a function of the aperture shape, but also of the optics. Thus, even if the aperture shape is substantially circular, the lens design itself may result in a bad bokeh. For example, a harsh bokeh is often generated when out-of-focus rings have more noticeable outer rims or rings inside the disc. To counter this problem, some lenses may include an apodisation filter near the aperture to soften the edges of the disc. An apodisation filter is similar to a neutral density filter configured to attenuate more light in areas that are farther away from the center of the aperture. However, such a filter is normally designed for one aperture size. Therefore, the filter would need to be changed as other parameters change, such as changing the aperture size, the focal length (in a zoom lens) or the focusing distance of the imaging system. 
       SUMMARY 
       [0008]    The present disclosure provides for controlling variation of light attenuation by an aperture module. 
         [0009]    In one implementation, a system is disclosed. The system includes: a plurality of lens elements; and an aperture module coupled to the plurality of lens elements and including an array of pixels, wherein the aperture module is configured to be variable in transparency for each pixel. 
         [0010]    In another implementation, an apparatus is disclosed. The apparatus includes: a plurality of optical elements to receive incident light rays; and an array of pixels coupled to the plurality of optical elements, wherein the array pixels is configured to be variable in transparency to process the light rays. 
         [0011]    In one implementation, a method of controlling variation in transparency of an aperture module is disclosed. The method includes: varying the effective shape and transparency of the aperture module by controlling an array of pixels; determining desired variation of the effective shape and transparencies over a fixed period of time; controlling the array of pixels to keep the shape and transparency fixed over the fixed period of time if it is determined that the desired transparencies is fixed; and controlling the array of pixels to vary the shape and transparency over the fixed period of time if it is determined that the desired transparencies are variable. 
         [0012]    Other features and advantages of the present disclosure should be apparent from the present description which illustrates, by way of example, aspects of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The details of the present disclosure, both as to its structure and operation, may be gleaned in part by study of the appended drawings, in which like reference numerals refer to like parts, and in which: 
           [0014]      FIG. 1  is a diagram of a conventional lens system including various lens elements and an iris; 
           [0015]      FIG. 2  is a diagram of a lens system in accordance with one implementation of the present disclosure; 
           [0016]      FIG. 3  is a diagram of a lens system in accordance with another implementation of the present disclosure; 
           [0017]      FIG. 4  is a diagram of an aperture module in accordance with one implementation of the present disclosure; 
           [0018]      FIG. 5  is a diagram of an aperture module in accordance with another implementation of the present disclosure; 
           [0019]      FIG. 6  shows an aperture module with pixel elements arranged like concentric rings and designed to have a large aperture; 
           [0020]      FIG. 7  shows an aperture module with pixel elements arranged like concentric rings and designed to have a medium-sized aperture; 
           [0021]      FIG. 8  shows an aperture module designed into an arbitrary star shape; and 
           [0022]      FIG. 9  is a flow diagram illustrating a process for controlling variation of the shape and transparency of the aperture module in accordance with one implementation of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    As described above, increasing the number of aperture blades to improve on the shape of the aperture can add complexity to the lens system and may cause unanticipated operational problems. Further, adding an apodisation filter to counter a harsh bokeh problem may only address issues for one aperture size. Accordingly, there is a need for a filter that can provide a variable modification for the light throughput. 
         [0024]    After reading these descriptions, it will become apparent how to implement the disclosure in various implementations and applications. However, although various implementations of the present disclosure will be described herein, it is understood that these implementations are presented by way of example only, and not limitation. As such, this detailed description of various implementations should not be construed to limit the scope or breadth of the present disclosure. 
         [0025]    In one implementation, an aperture module disposed in place of or in addition to an existing iris/aperture is configured in a system. In one implementation, the system is a lens system. In another implementation, the system is an imaging system. In a further implementation, the system is any system that includes an aperture. In one implementation, the aperture module can be varied in time and transparency for each local element, which could effectively have the result of changing the shape of the aperture (hereafter referred to as “shape”). Thus, it should be noted that term “changes in shape of the aperture” is referring to modulating the light that goes through the aperture layer by varying the transparency of sensels so that the aperture layer forms a “pattern” or “shape”. 
         [0026]      FIG. 2  is a diagram of a lens system  200  in accordance with one implementation of the present disclosure. In the illustrated implementation of  FIG. 2 , the lens system  200  includes an iris  120  and an aperture module  210 . The lens system  200  also includes various lens elements  110 ,  112 ,  114 ,  116 . In one implementation, the lens system  200  further includes a controller  220  configured to control the variation of the shape and/or transparency of the aperture module  210 . In one implementation, the shape and/or transparency of the aperture module  210  is fixed over a fixed period of time. In another implementation, the shape and/or transparency of the aperture module  210  is varied over time. 
         [0027]    In  FIG. 2 , the light rays  140  incident on the lens elements  110 ,  112  pass through the iris  120 , the aperture module  210 , the lens elements  114 ,  116  and falls on an image sensor  240 . In one implementation, the aperture module  210  includes an array of pixel elements configured to be variable in transparency to process the light rays. 
         [0028]      FIG. 3  is a diagram of a lens system  300  in accordance with another implementation of the present disclosure. The lens system  300  may include an aperture module  310  in place of the iris  120  shown in  FIGS. 1 and 2 . In the illustrated implementation of  FIG. 3 , the aperture module  310  includes a variable aperture  312  which is substantially circular compared to the aperture  124  of the conventional iris  120  of  FIG. 1 . The lens system  300  also includes various lens elements  110 ,  112 ,  114 ,  116 . 
         [0029]    In one implementation, the aperture module  210 ,  310  of  FIG. 2  or  FIG. 3  is configured as a liquid crystal display (LCD) array of pixel elements arranged in a row-column configuration. In another implementation, the aperture module  210  is configured as an LCD array of pixel elements arranged in concentric rings. The LCD array of pixel elements can be controlled such that the aperture module  210 ,  310  is varied in time, shape, and transparency. In one implementation, the pixel elements are independently varied in transparency to turn on or off the aperture at different locations in module  210 ,  310  at different times. In another implementation, the transparency of some of the pixel elements is varied to change the light attenuation of the aperture module at different locations in module  210 ,  310  at different times. 
         [0030]    In one implementation shown in  FIG. 4 , the LCD pixel elements  410  are programmed to generate more pleasant bokeh by designing the aperture module  400  as an apodisation filter.  FIG. 5  shows the aperture module  500  with the pixel elements arranged like concentric rings. Since the pattern and transparency can be varied, the aperture module  400 ,  500  can be designed as an apodisation filter for any aperture size. 
         [0031]      FIG. 6  shows the aperture module  600  with pixel elements arranged like concentric rings and designed to have a large aperture.  FIG. 7  shows the aperture module  700  with pixel elements arranged like concentric rings and designed to have a medium-sized aperture. 
         [0032]    The patterns can be dynamically varied or pre-programmed with different shapes and stored in a storage unit. Different patterns for the aperture module creates different look and feel for the bokeh. For example, to get a certain look, different zoom lengths or focusing parameters may require variations on the pattern. Further, the shape of the aperture module can be designed like cookie cutters to make out-of-focus discs appear in that shape (e.g., hearts, stars, or dinosaurs).  FIG. 8  shows the aperture module  800  designed into an arbitrary star shape. 
         [0033]    In some implementations, the aperture module can be patterned so that all pixel elements are designed to be opaque and used as a shutter. Since the duration of the aperture opening/closing can be changed electronically, the performance of the aperture module as a shutter would surpass the limitations imposed by the physical shutter. Further, since the electronic shutter configured with the aperture module is very quiet, the absence of vibration provides substantial reduction in image degradation or noise. 
         [0034]    In some implementations, the aperture module can be patterned so that all pixel elements are similarly semi-transparent so as to be used as a neutral density filter. 
         [0035]    In other implementations, the pattern (including transparencies) of the pixel elements of the aperture module is varied over time. This could enable fade-in or fade-out exposures. For example, by controlling the variation of the transparency over time, lights of a car at night can be shown as either getting brighter tailing the car or going ahead of the movement of the car. For example, the pattern can be changed so the light is a star at the end, but is a round disc at all other times. In another implementation, the size of the aperture changes so that if the camera zooms during its exposure, the out-of-focus areas change from smaller to larger or vice versa. In yet another implementation, the aperture module is used to fade in and out in a wave pattern. In a further implementation, multi-exposure shots can be taken by using the aperture module as a shutter that is open at certain times. 
         [0036]      FIG. 9  is a flow diagram illustrating a process  900  for controlling variation of the shape and transparency of the aperture module in accordance with one implementation of the present disclosure. In the process  900 , the transparency of the aperture module is varied, at block  910 , by controlling the array of pixels. In one implementation, the array of pixels is arranged in concentric circles. The array of pixels arranged in the concentric circles can be used to form an apodisation filter. A determination is made, at block  920 , whether the variation of the transparency should be fixed over a fixed period of time. If it is determined, at block  920 , that the variation of the transparency should be fixed over a fixed period of time, then the transparency of the aperture module is fixed over a fixed period of time, at block  930 . Otherwise, if it is determined, at block  920 , that the variation of the transparency should be variable over a fixed period of time, then the transparency of the aperture module is varied over the fixed period of time, at block  940 . 
         [0037]    The foregoing methods and apparatus are susceptible to many variations. For example, although the specification describes an aperture module or apparatus within the context of a lens or imaging system, the aperture module can be used in any system that includes an aperture. Additionally, for clear and brief description, many descriptions of the methods and apparatus have been simplified. Many descriptions use terminology and structures of specific standards. However, the disclosed methods and apparatus are more broadly applicable. 
         [0038]    Those of skill in the art will appreciate that the various illustrative logical blocks, modules, units, and algorithm steps described in connection with the implementations disclosed herein can often be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular constraints imposed on the overall system. Skilled persons can implement the described functionality in varying ways for each particular system, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure. In addition, the grouping of functions within a unit, module, block, or step is for ease of description. Specific functions or steps can be moved from one unit, module, or block without departing from the disclosure. 
         [0039]    The above description of the disclosed implementations is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to these implementations will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other implementations without departing from the spirit or scope of the disclosure. Accordingly, the techniques are not limited to the specific examples described above. Thus, it is to be understood that the description and drawings presented herein represent a presently possible implementation of the disclosure and are therefore representative of the subject matter that is broadly contemplated by the present disclosure. It is further understood that the scope of the present disclosure fully encompasses other implementations that may become obvious to those skilled in the art and that the scope of the present disclosure is accordingly limited by nothing other than the appended claims.
System and apparatus including: a plurality of lens elements; and an aperture module coupled to the plurality of lens elements and including an array of pixels, wherein the aperture module is configured to be variable in pattern and transparency. Key words include variable aperture and pixels.