Patent Publication Number: US-2013242138-A1

Title: Enhanced resolution image capture

Description:
FIELD 
     The present disclosure relates to image capture, and more particularly relates to synthesizing an image with enhanced resolution from captured image data. 
     BACKGROUND 
     In the field of image capture systems, one area of research is in improving the versatility of such systems. 
     SUMMARY 
     In an effort to improve versatility of image capture systems, the inventors herein have conducted research into reconfigurable soft optics, i.e., optics which allow reconfiguration of characteristics of image capture without significant reconfiguration of the physical capture hardware. In such systems, for example, one item of capture hardware can be reconfigured for multiple different configurations, such as multiple different optical properties controlled by application of a configuration parameter to the item of capture hardware. 
     In the course of their research into soft optics, the inventors have investigated the use of an optical element comprising a stack of microlens arrays. One example of a stack of microlens arrays is a Gabor superlens. A Gabor superlens was described a UK patent in the 1940&#39;s, namely GB541753, and was built and benchmarked in 1999. 
     In some cases, the stack of microlens arrays is itself not reconfigurable, but in such cases it can still be used in reconfigurable capture systems by combining it with other items of capture hardware which are reconfigurable. In other cases, the stack of microlens arrays is itself mechanically (or otherwise) reconfigurable. For example, the stack of microlens arrays might include one or two tunable microlens arrays comprised of liquid crystal lenslets, such that the focal length can be varied. 
     One difficulty with optical elements such as the stack of microlens arrays is that such elements can tend to have poor resolution, and may in fact have resolution that is inhomogeneous across the field of view. 
     The foregoing situation is addressed through an image capture system which combines first and second images captured using respectively different first and second optical paths to generate a synthesized image with improved image characteristics, wherein at least one path includes a stack of microlens arrays. 
     Thus, in an example embodiment described herein, first and second images of a scene are captured using respectively different first and second optical paths. The first optical path includes an optical element comprising a stack of microlens arrays. A synthesized image of the scene is generated by calculations using the first and second captured images of the scene. The synthesized image has improved image characteristics as compared to both of the first captured image and the second captured image. 
     By combining first and second images captured using first and second optical paths to generate a synthesized image, it is ordinarily possible to utilize optical elements such as the Gabor superlens while improving image characteristics such as resolution. 
     In some example embodiments, the first and second optical paths are defined by a beam splitter which splits the first and second optical paths into physically different optical paths. In other example embodiments, the first and second captured images are captured in succession by an image sensor used commonly for both of the first and second optical paths. 
     This brief summary has been provided so that the nature of this disclosure may be understood quickly. A more complete understanding can be obtained by reference to the following detailed description and to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are views depicting an external appearance of an image capture device according to an example embodiment. 
         FIGS. 2A and 2B  are detailed block diagrams for explaining the internal architecture of the image capture device shown in  FIG. 1  according to an example embodiment. 
         FIG. 3  is a view for explaining an image capture module according to one example embodiment. 
         FIG. 4  is a view for explaining image capture according to an example embodiment. 
         FIG. 5  is a view for explaining image capture according to another example embodiment. 
         FIG. 6  is a flow diagram for explaining enhanced resolution image capture according to an example embodiment. 
         FIG. 7  is a diagram depicting a cross-sectional view of a stack of microlens arrays such as a Gabor superlens. 
     
    
    
     DETAILED DESCRIPTION 
     In the following example embodiments, there is described a digital camera which may be a digital still camera or a digital video camera. It is understood, however, that the following description encompasses arbitrary arrangements which can incorporate or utilize imaging assemblies with reconfigurable soft optics, for instance, a data processing apparatus having an image sensing function (e.g., a personal computer) or a portable terminal having an image sensing function (e.g., a mobile telephone), a video camera, a microscope or an endoscope. 
       FIGS. 1A and 1B  are views showing an example of an external appearance of an image capture device  100  according to an example embodiment. Note that in these figures, some components are omitted for conciseness. A user operates buttons and switches  310  to  319  for turning ON/OFF the power of the digital camera  100 , for setting, changing or confirming the shooting parameters, for confirming the status of the camera, and for confirming shot images. 
     Optical finder  104  is a viewfinder, through which a user can view a scene to be captured. In this embodiment optical finder  104  is separate from image display unit  28 , but in some embodiments image display unit  28  may also function as a viewfinder. 
     Flash (flash emission device)  48  is for emitting auxiliary light to illuminate a scene to be captured, if necessary. 
     Reconfigurable soft optics  150  are optics which allow reconfiguration of characteristics of image capture without significant reconfiguration of the physical capture hardware. In such systems, for example, one item of capture hardware can be reconfigured for multiple different configurations, such as multiple different optical properties controlled by application of a configuration parameter to the item of capture hardware. Put another way, reconfigurable soft optics  150  provide one generic piece (or system) of hardware for image capture, which can be reconfigured for different applications such as resolution, frame rules, or light-field data. Furthermore, the existing hardware can be reconfigured in a way that facilitates or enables software to perform functions which were previously performed by lens hardware only. 
     In one example, reconfigurable soft optics  150  might include an optical element comprising a stack of microlens arrays (e.g., stacks of arrays of tiny lenses). In that regard, a microlens array may comprise closely packed lens structures arranged in a particular geometry (rectangular, honeycomb, quincunx, etc.), where the lens size is small in comparison to the thickness of the supporting substrate. Stacks of microlens arrays are ordinarily useful because of their small size and ability to capture a relatively larger amount of image data than a standard lens. 
     One example of a stack of microlens arrays is a Gabor superlens, in which two microlens arrays act as a camera array. A Gabor superlens was described a UK patent in the 1940&#39;s, namely GB541753, and was built and benchmarked in 1999. The Gabor superlens generally has a useful form factor, as it provides a substantially flat zoom lens in addition to a substantially flat lens. Moreover, the Gabor superlens can capture different views of the image at different points, leading to additional data and/or perspectives such as various zooms and depths for image processing. Additionally, the Gabor superlens can be advantageously combined with a spatial light modulator to achieve certain lens effects. However, as mentioned above, the Gabor superlens can tend to have poor resolution, and may in fact have resolution that is inhomogeneous across the field of view, in addition to other aberrations. Accordingly, the present disclosure describes generating a synthesized image has improved image characteristics, as discussed more fully below. 
     It should be understood that the Gabor superlens is only one example of a stack of microlens arrays, and that other arrangements are possible. For example, while the Gabor superlens or other stacks of microlens arrays generally include two microlens arrays, it might be possible to include three or more microlens arrays, for example to correct lens abberations from the first two stacks. 
     In some cases, the stack of microlens arrays itself might not be not reconfigurable, but in such cases it can still be used in reconfigurable soft optics  150  by combining it with other items of capture hardware which are reconfigurable. In other cases, the stack of microlens arrays is itself reconfigurable. 
     Reconfigurable soft optics  150  includes other hardware for image capture, and such other hardware might itself be reconfigurable or might not be reconfigurable. Examples of such other hardware include a visible light lens or lenses, which may include a zoom lens, a shutter having an aperture function, and one or more image sensors. Other examples of such hardware include a flip mirror and a half-silvered mirror, for creating two different optical paths, as explained in greater detail below. 
     The power button  311  is provided to start or stop the digital camera  100 , or to turn ON/OFF the main power of the digital camera  100 . The menu button  313  is provided to display the setting menu such as shooting parameters and operation modes of the digital camera  100 , and to display the status of the digital camera  100 . The menu includes selectable items or items whose values are variable. 
     A delete button  315  is pressed for deleting an image displayed on a playback mode or a shot-image confirmation screen. In the present embodiment, the shot-image confirmation screen (a so-called quick review screen) is provided to display a shot image on the image display unit  28  immediately after shooting for confirming the shot result. Furthermore, the present embodiment is constructed in a way that the shot-image confirmation screen is displayed as long as a user keeps pressing the shutter button  310  after the user instructs shooting by shutter button depression. 
     An enter button  314  is pressed for selecting a mode or an item. When the enter button  314  is pressed, the system controller  50  in  FIG. 2A  sets the mode or item selected at this time. The display ON/OFF button  66  is used for selecting displaying or non-displaying of photograph information regarding the shot image, and for switching the image display unit  28  to be functioned as an electronic view finder. 
     A left button  316 , a right button  318 , an up button  317 , and a down button  319  may be used for the following purposes, for instance, changing an option (e.g., items, images) selected from plural options, changing an index position that specifies a selected option, and increasing or decreasing numeric values (e.g., correction value, date and time). 
     Half-stroke of the shutter button  310  instructs the system controller  50  to start, for instance, AF processing, AE processing, AWB processing, EF processing or the like. Full-stroke of the shutter button  310  instructs the system controller  50  to perform shooting. 
     The zoom operation unit  65  is operated by a user for changing the angle of view (zooming magnification or shooting magnification). 
     A recording/playback selection switch  312  is used for switching a recording mode to a playback mode, or switching a playback mode to a recording mode. Note, in place of the above-described operation system, a dial switch may be adopted or other operation systems may be adopted. 
       FIG. 2A  is a block diagram showing an example of the arrangement of the digital camera  100  as an image capture device according to this embodiment. Referring to  FIG. 2 , reference numeral  16  denotes an A/D converter which converts an analog signal from one or more image sensors into a digital signal. The A/D converter  16  is used when an analog signal output from the image sensor(s) is converted into a digital signal and when an analog signal output from an audio controller  11  is converted into a digital signal. 
     As discussed above, reconfigurable soft optics  150  are optics which allow reconfiguration of characteristics of image capture without significant reconfiguration of the physical capture hardware. As indicated above, reconfigurable soft optics  150  will, in many embodiments, include a microlens array, a visible light lens or lenses which might include a zoom lens, and an image sensor or sensors. In addition, as indicated above, reconfigurable soft optics  150  will, in many embodiments, include a flip mirror assembly and/or a half-silvered mirror, or other optics for creating two or more different optical paths. Various hardware elements of reconfigurable soft optics  150  are and are not reconfigurable under control of system controller  50 , in accordance with configuration information stored in memory such as non-volatile memory  56 , as explained in greater detail below. 
     A light beam (light beam incident upon the angle of view of the lens) from an object in a scene impinges on reconfigurable soft optics  150  and two or more images of the object are captured by the image sensor(s) through respective ones of two or more different optical paths. The image sensor(s) convert the optical image to analog image signals and outputs the signals to an A/D converter  16 . The A/D converter  16  converts the analog image signals to digital image signals (image data). The image sensor(s) and the A/D converter  16  are controlled by clock signals and control signals provided by a timing generator  18 . The timing generator  18  is controlled by a memory controller  22  and a system controller  50 . 
     Reference numeral  18  denotes a timing generator, which supplies clock signals and control signals to the image sensor(s), the audio controller  11 , the A/D converter  16 , and a D/A converter  26 . The timing generator  18  is controlled by a memory controller  22  and system controller  50 . Reference numeral  20  denotes an image processor, which applies resize processing such as predetermined interpolation and reduction, and color conversion processing to data from the A/D converter  16  or that from the memory controller  22 . The image processor  20  executes predetermined arithmetic processing using the captured image data, and the system controller  50  executes exposure control and ranging control based on the obtained arithmetic result. 
     As a result, TTL (through-the-lens) AF (auto focus) processing, AE (auto exposure) processing, and EF (flash pre-emission) processing are executed. The image processor  20  further executes predetermined arithmetic processing using the captured image data, and also executes TTL AWB (auto white balance) processing based on the obtained arithmetic result. It is understood that in other embodiments, optical finder  104  may be used in combination with the TTL arrangement or in substitution therefor. 
     Output data from the A/D converter  16  is written in a memory  30  via the image processor  20  and memory controller  22  or directly via the memory controller  22 . The memory  30  stores image data captured and converted into digital data by the A/D converter  16 , and image data to be displayed on an image display unit  28 . The image display unit  28  may be a liquid crystal screen. Note that the memory  30  is also used to store audio data recorded via a microphone  13 , still images, movies, and file headers upon forming image files. Therefore, the memory  30  has a storage capacity large enough to store a predetermined number of still image data, and movie data and audio data for a predetermined period of time. 
     A compression/decompression unit  32  compresses or decompresses image data by adaptive discrete cosine transform (ADCT) or the like. The compression/decompression unit  32  loads captured image data stored in the memory  30  in response to pressing of the shutter  310  as a trigger, executes the compression processing, and writes the processed data in the memory  30 . Also, the compression/decompression unit  32  applies decompression processing to compressed image data loaded from a detachable recording unit  202  or  212 , as described below, and writes the processed data in the memory  30 . Likewise, image data written in the memory  30  by the compression/decompression unit  32  is converted into a file by the system controller  50 , and that file is recorded in nonvolatile memory  56  and/or the recording unit  202  or  212 , as also described below. 
     The memory  30  also serves as an image display memory (video memory). Reference numeral  26  denotes a D/A converter, which converts image display data stored in the memory  30  into an analog signal, and supplies that analog signal to the image display unit  28 . Reference numeral  28  denotes an image display unit, which makes display according to the analog signal from the D/A converter  26  on the liquid crystal screen  28  of an LCD display. In this manner, image data to be displayed written in the memory  30  is displayed by the image display unit  28  via the D/A converter  26 . 
     The exposure controller  40  controls an unshown shutter (within reconfigurable soft optics  150 ) having a diaphragm function based on the data supplied from the system controller  50 . The exposure controller  40  may also have a flash exposure compensation function by linking up with flash (flash emission device)  48 . The flash  48  has an AF auxiliary light projection function and a flash exposure compensation function. 
     The distance measurement controller  42  controls an unshown visible light lens of reconfigurable soft optics  150  based on the data supplied from the system controller  50 . A zoom controller  44  controls zooming of an unshown zoom lens of reconfigurable soft optics  150 . A shield controller  46  controls the operation of an unshown shield (barrier) of reconfigurable soft optics  150  to protect it. 
     Reference numeral  13  denotes a microphone. An audio signal output from the microphone  13  is supplied to the A/D converter  16  via the audio controller  11  which includes an amplifier and the like, is converted into a digital signal by the A/D converter  16 , and is then stored in the memory  30  by the memory controller  22 . On the other hand, audio data is loaded from the memory  30 , and is converted into an analog signal by the D/A converter  26 . The audio controller  11  drives a speaker  15  according to this analog signal, thus outputting a sound. 
     A nonvolatile memory  56  is an electrically erasable and recordable memory, and uses, for example, an EEPROM. The nonvolatile memory  56  stores constants, computer-executable programs, and the like for operation of system controller  50 . Note that the programs include those for execution of various flowcharts. 
     In particular, as shown in  FIG. 2B , non-volatile memory  56  is an example of a non-transitory computer-readable memory medium, having retrievably stored thereon image capture module  300  as described herein. According to this example embodiment, the image capture module  300  includes at least a capture module  301  for capturing first and second images of a scene using respectively different first and second optical paths. The first optical path may include an optical element comprising a stack of microlens arrays, such as in reconfigurable soft optics  150 . Image capture module  300  may further include a generation module  302  for generating a synthesized image of the scene by calculations using the first and second captured images of the scene, such that the synthesized image has improved image characteristics as compared to both of the first captured image and the second captured image. These modules will be discussed in more detail below with respect to  FIG. 3 . 
     Additionally, as shown in  FIG. 2B , non-volatile memory  56  also includes image data  251  from a first optical path, and image data  252  from a second optical path different from the first path (although both paths ordinarily capture the same scene). Soft optics configuration information  253  stores control information for configuring reconfigurable soft optics  150  so as to capture different image characteristics. Each of these elements will be described more fully below. 
     Reference numeral  50  denotes a system controller, which controls the entire digital camera  100 . The system controller  50  executes programs recorded in the aforementioned nonvolatile memory  56  to implement respective processes to be described later of this embodiment. Reference numeral  52  denotes a system memory which comprises a RAM. On the system memory  52 , constants and variables required to operate system controller  50 , programs read out from the nonvolatile memory  56 , and the like are mapped. 
     A mode selection switch  60 , shutter switch  310 , and operation unit  70  form operation means used to input various operation instructions to the system controller  50 . 
     The mode selection switch  60  includes the imaging/playback selection switch, and is used to switch the operation mode of the system controller  50  to one of a still image recording mode, movie recording mode, playback mode, and the like. 
     The shutter switch  62  is turned on in the middle of operation (half stroke) of the shutter button  310  arranged on the digital camera  100 , and generates a first shutter switch signal SW 1 . Also, the shutter switch  64  is turned on upon completion of operation (full stroke) of the shutter button  310 , and generates a second shutter switch signal SW 2 . The system controller  50  starts the operations of the AF (auto focus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, EF (flash pre-emission) processing, and the like in response to the first shutter switch signal SW 1 . Also, in response to the second shutter switch signal SW 2 , the system controller  50  starts a series of processing (shooting) including the following: processing to read image signals from the image sensor(s) of reconfigurable soft optics  150 , convert the image signals into image data by the A/D converter  16 , process the image data by the image processor  20 , and write the data in the memory  30  through the memory controller  22 ; and processing to read the image data from the memory  30 , compress the image data by the compression/decompression circuit  32 , and write the compressed image data in non-volatile memory  56 , and/or in recording medium  200  or  210 . 
     A zoom operation unit  65  is an operation unit operated by a user for changing the angle of view (zooming magnification or shooting magnification). The operation unit  65  can be configured with, e.g., a slide-type or lever-type operation member, and a switch or a sensor for detecting the operation of the member. 
     The image display ON/OFF switch  66  sets ON/OFF of the image display unit  28 . In shooting an image with the optical finder  104 , the display of the image display unit  28  configured with a TFT, an LCD or the like may be turned off to cut the power supply for the purpose of power saving. 
     The flash setting button  68  sets and changes the flash operation mode. In this embodiment, the settable modes include: auto, flash-on, red-eye reduction auto, and flash-on (red-eye reduction). In the auto mode, flash is automatically emitted in accordance with the lightness of an object. In the flash-on mode, flash is always emitted whenever shooting is performed. In the red-eye reduction auto mode, flash is automatically emitted in accordance with lightness of an object, and in case of flash emission the red-eye reduction lamp is always emitted whenever shooting is performed. In the flash-on (red-eye reduction) mode, the red-eye reduction lamp and flash are always emitted. 
     The operation unit  70  comprises various buttons, touch panels and so on. More specifically, the operation unit  70  includes a menu button, a set button, a macro selection button, a multi-image reproduction/repaging button, a single-shot/serial shot/self-timer selection button, a forward (+) menu selection button, a backward (−) menu selection button, and the like. Furthermore, the operation unit  70  may include a forward (+) reproduction image search button, a backward (−) reproduction image search button, an image shooting quality selection button, an exposure compensation button, a date/time set button, a compression mode switch and the like. 
     The compression mode switch is provided for setting or selecting a compression rate in JPEG (Joint Photographic Expert Group) compression, recording in a RAW mode and the like. In the RAW mode, analog image signals outputted by the image sensing device are digitalized (RAW data) as is and recorded. 
     Note in the present embodiment, RAW data includes not only the data obtained by performing A/D conversion on the photoelectrically converted data from the image sensing device, but also the data obtained by performing lossless compression on A/D converted data. Moreover, RAW data indicates data maintaining output information from the image sensing device without a loss. For instance, RAW data is A/D converted analog image signals which have not been subjected to white balance processing, color separation processing for separating luminance signals from color signals, or color interpolation processing. Furthermore, RAW data is not limited to digitalized data, but may be of analog image signals obtained from the image sensing device. 
     According to the present embodiment, the JPEG compression mode includes, e.g., a normal mode and a fine mode. A user of the digital camera  100  can select the normal mode in a case of placing a high value on the data size of a shot image, and can select the fine mode in a case of placing a high value on the quality of a shot image. 
     In the JPEG compression mode, the compression/decompression circuit  32  reads image data written in the memory  30  to perform compression at a set compression rate, and records the compressed data in, e.g., the recording medium  200 . 
     In the RAW mode, analog image signals are read in units of line in accordance with the pixel arrangement of an unshown color filter of the image sensor(s), and image data written in the memory  30  through the A/D converter  16  and the memory controller  22  is recorded in non-volatile memory  56 , and/or in recording medium  200  or  210 . 
     The digital camera  100  according to the present embodiment has a plural-image shooting mode, where plural image data can be recorded in response to a single shooting instruction by a user. Image data recording in this mode includes image data recording typified by an auto bracket mode, where shooting parameters such as white balance and exposure are changed step by step. It also includes recording of image data having different post-shooting image processing contents, for instance, recording of plural image data having different data forms such as recording in a JPEG form or a RAW form, recording of image data having the same form but different compression rates, and recording of image data on which predetermined image processing has been performed and has not been performed. 
     A power controller  80  comprises a power detection circuit, a DC-DC converter, a switch circuit to select the block to be energized, and the like. The power controller  80  detects the existence/absence of a power source, the type of the power source, and a remaining battery power level, controls the DC-DC converter based on the results of detection and an instruction from the system controller  50 , and supplies a necessary voltage to the respective blocks for a necessary period. A power source  86  is a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as an NiCd battery, an NiMH battery or an Li battery, an AC adapter, or the like. The main unit of the digital camera  100  and the power source  86  are connected by connectors  82  and  84  respectively comprised therein. 
     The recording media  200  and  210  comprise: recording units  202  and  212  that are configured with semiconductor memories, magnetic disks and the like, interfaces  203  and  213  for communication with the digital camera  100 , and connectors  206  and  216 . The recording media  200  and  210  are connected to the digital camera  100  through connectors  206  and  216  of the media and connectors  92  and  96  of the digital camera  100 . To the connectors  92  and  96 , interfaces  90  and  94  are connected. The attached/detached state of the recording media  200  and  210  is detected by a recording medium attached/detached state detector  98 . 
     Note that although the digital camera  100  according to the present embodiment comprises two systems of interfaces and connectors for connecting the recording media, a single or plural arbitrary numbers of interfaces and connectors may be provided for connecting a recording medium. Further, interfaces and connectors pursuant to different standards may be provided for each system. 
     For the interfaces  90  and  94  as well as the connectors  92  and  96 , cards in conformity with a standard, e.g., PCMCIA cards, compact flash (CF) (registered trademark) cards and the like, may be used. In this case, connection utilizing various communication cards can realize mutual transfer/reception of image data and control data attached to the image data between the digital camera and other peripheral devices such as computers and printers. The communication cards include, for instance, a LAN card, a modem card, a USB card, an IEEE 1394 card, a P1284 card, an SCSI card, and a communication card for PHS or the like. 
     The optical finder  104  is configured with, e.g., a TTL finder, which forms an image utilizing prisms and mirrors. By utilizing the optical finder  104 , it is possible to shoot an image without utilizing an electronic view finder function of the image display unit  28 . The optical finder  104  includes indicators, which constitute part of image display unit  28 , for indicating, e.g., a focus state, a camera shake warning, a flash charge state, a shutter speed, an f-stop value, and exposure compensation. 
     A communication circuit  110  provides various communication functions such as USB, IEEE 1394, P1284, SCSI, modem, LAN, RS232C, and wireless communication. To the communication circuit  110 , a connector  112  can be connected for connecting the digital camera  100  to other devices, or an antenna can be provided for wireless communication. 
     A real-time clock (RTC, not shown) may be provided to measure date and time. The RTC holds an internal power supply unit independently of the power supply controller  80 , and continues time measurement even when the power supply unit  86  is OFF. The system controller  50  sets a system timer using a date and time obtained from the RTC at the time of activation, and executes timer control. 
       FIG. 3  is a view for explaining an image capture module according to one example embodiment. As previously discussed with respect to  FIG. 2B , image capture module  300  comprises computer-executable process steps stored on a non-transitory computer-readable storage medium, such as non-volatile memory  56 . More or less modules may be used, and other architectures are possible. 
     As shown in  FIG. 3 , image capture module  300  at least a capture module  301  for capturing first and second images of a scene using respectively different first and second optical paths. To that end, capture module  301  communicates with reconfigurable soft optics  150 , to gather image data from a scene. In that regard, data may be transmitted to the first or second optical paths based on action of a flip mirror, or through a half-silvered mirror, as described more fully below. Capture module  301  may also communicate with non-volatile memory  56  to store images captured via the first or second optical paths, particularly in the case of iterative convolution of the image data from first and second capture paths as discussed more fully below. 
     Capture module  301  also communicates with generation module  302 , which generates a synthesized image of the scene by calculations using the first and second captured images of the scene from capture module  301 , such that the synthesized image has improved image characteristics as compared to both of the first captured image and the second captured image. Generation module  302  additionally outputs the synthesized image. 
       FIG. 4  is a view for explaining image capture according to an example embodiment. 
     In particular,  FIG. 4  depicts an example embodiment of reconfigurable soft optics  150  in which incoming light from scene  400  is split by a half-silvered mirror or beam splitter  401  in a first processing stage, thereby generating a second optical path. 
     Briefly, optical path  1  includes a stack of microlens arrays (such as a Gabor superlens)  405  and first image sensor  406 , whereas optical path  2  includes mirror  402 , visible light lens  403  and second image capture sensor  404 . The images of both optical paths are captured by two substantially identical imaging sensor arrays  404  and  406 . Thus, both the first and second optical paths capture the same field of view, and provide two captures of the same scene  400 . The images of both the first and second optical paths are used to compute a final high resolution image  408  using blind deconvolution  407 . Blind deconvolution involves recovering the scene from blurred images using multiple algorithms that estimate a point spread function (a response of an imaging system to a light point which, due to practical physical resolution limitations, is not a point but a spatially extended region) from an image set, as discussed more fully below. 
     At a very high level of abstraction, the frequency information contained in the first and second optical paths, but lost in capture, is filled in to synthesize an image with enhanced resolution relative to the image captured by either one of the first and second optical paths. Put another way, and at a similar high level of abstraction, in the frequency domain, certain high level frequencies might be lost during capture of a single image and become unrecoverable. However, with two images of the same scene with different frequency content, there is ordinarily an opportunity to recover the lost high-frequency signals and use them to generate an improved synthesized image. 
     In that regard, there is ordinarily no need to have either of the first or second images be of better quality than the other, since recovery is based on the fact that the images are “blurred differently”. For example, in the example above, the resolution of visible light lens  403  need not be better than that of Gabor superlens  405 . 
     Mirror  402  may be incorporated in an assembly such as flip mirror assembly, and, in one embodiment, comprises a rotatable mirror which blocks or allows light, essentially acting as an ON/OFF switch to allow captures of a scene for each lens, at different timings. 
     In the embodiment shown in  FIG. 4 , the first optical path is processed by the Gabor superlens  405 , which includes, in one example, two stacked microlens arrays in a Kepler configuration (i.e., “positive” or convex microlenses as depicted in  FIG. 7 ). For one example of Gabor superlens  405 , and referring to  FIG. 7 , the pitch p 1  of microlens array  1 =253 μm, pitch p 2  of microlens array  2 =251.5 μm, focal length f 1 =500 μm, and focal length f 2 =625 μm. Naturally, these numbers are simply examples, and other pitches or focal lengths are possible. For example, another Gabor superlens arrangement could have pitch p 1 =253 μm and pitch p 2 =253 μm with the same focal length f 1 =f 2 =775 μm. In still another example, the Gabor superlens  405  could be in the “Galiliei configuration”, with one positive microlens array with pitch p 1 =253 μm and focal length f 1 =440 μm, and with one negative microlens array with pitch p 2 =250 μm and focal length f 2 =−850 μm. 
     Assuming far field imaging (i.e., the distance of the object in the scene to the Gabor superlens  405  is very large), one can determine the focal length of the Gabor superlens  405  using the following equation: 
     
       
         
           
             
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                   ) 
                 
               
             
           
         
       
     
     Given the parameters of the exemplary Gabor superlens parameters of p 1 =253 μm, p 2 =251.5 μm and f 1 =500 μm, and assuming that light from the object passes first through the microlens array with pitch p 1 , the effective focal length of the Gabor superlens  405  is 83.83 mm. Of course, the disclosure is not confined to far field imaging, and the above is intended only as an example. 
     Meanwhile, optical path  2  uses mirror  402  to reflect light from scene  400  to visible light lens  403 . In one embodiment, the focal length of the Gabor superlens  405  is matched by the lens  403  in the second optical path. Thus, the Gabor superlens  405  and the lens  403  will have substantially the same viewing angle. 
     In an alternative embodiment the focal length of the lens  403  in the second optical path can differ from the focal length of the Gabor superlens  405 . In that case, the resolution of the image sensor  404  in the second optical path has to match the focal length of the lens  403  in the second optical path such that both the first and the second optical path capture the same field of view. Put another way, the pixels can be made smaller to get the same field of view despite the different focal lengths. 
     In yet another alternative embodiment, one or two tunable microlens arrays comprised of e.g. liquid crystal lenslets are used in the Gabor superlens setup, such that the focal length can be varied. 
     In still another alternative embodiment, lens  403  could also be a Gabor superlens, but with a different configuration than Gabor superlens  405 . In this regard, if the Gabor superlens is configurable or tunable as discussed above, one embodiment might capture one image, change the microlens array configuration, and then capture the second image. Of course, lens  403  could also be embodied as a standard imaging lens. 
     At the next stage of the processing, the images of both the first and the second optical paths are captured using first and second imaging sensor arrays  404  and  406 , which may be identical. If the first and second image sensor arrays  404  and  406  are identical, the first and the second optical path capture both the same field of view. 
     Then, the images of both the first and second optical paths are used to compute a final high resolution image  408  using blind deconvolution  407 , as discussed more fully below with respect to  FIG. 6 . 
     Meanwhile, turning to  FIG. 5 ,  FIG. 5  is a view for explaining image capture according to another example embodiment. 
     In particular,  FIG. 5  depicts an embodiment for reconfigurable soft optics  150  in which only one image sensor is used, and in which images of scene  500  are blocked/allowed to Gabor superlens  502  or lens  503  by a flip mirror  501  (e.g., part of a flip mirror assembly). Thus, the first and second optical paths are time-sequentially generated by performing two captures at different timings with the same sensor  504 . Preferably, the timing of these two captures is closely-spaced, so that there is less chance of significant movement in the scene as between the two captures (unless the motion in the real-world scene is slow or nonexistent, in which case a longer timing between captures might be acceptable). The physical construction of the Gabor superlens  502  and lens  503  can be similar to those discussed above with respect to  FIG. 4 , including the discussion of alternatives. 
       FIG. 6  is a flow diagram for explaining enhanced resolution image capture according to an example embodiment. 
     Briefly, in  FIG. 6 , first and second images of a scene are captured using respectively different first and second optical paths. The first optical path includes an optical element comprising a stack of microlens arrays. A synthesized image of the scene is generated by calculations using the first and second captured images of the scene. The synthesized image has improved image characteristics as compared to both of the first captured image and the second captured image. 
     In more detail, in step  601 , the first and second optical paths for image capture are configured. For example, the first and second optical paths may be configured so as to capture two images at the same time using two sensors as shown in  FIG. 4 , or so as to capture two images at different timings with the same sensor, as shown in  FIG. 5 . Additionally, aspects of the physical configuration such as the pitch of the lenses, focal length and the like can be configured based on the needs of the user. 
     In step  602 , a first image of a scene is captured using the first optical path (e.g., the path including the stack of microlens arrays). 
     In step  603 , a second image of the scene is captured using the second optical path. 
     In step  604 , a synthesized image is generated from the first and second images. At a very high level of abstraction, the frequency information contained in the each optical path but lost in capture is filled in using information from both captures to enhance the resolution of the synthesized image. 
     In one example, the synthesized image is generated using blind deconvolution. In particular, a deconvolution can be used by finding the maximum a posteriori explanation x if both the two images y 1  and y 2  from the first and second optical paths, respectively, are observed: 
         x =arg max x   {P ( x |( y   1   ,y   2 ))=( P ( y   1   |x )+ P ( y   2   |x ))· P ( x )}
 
     In one example embodiment, it is assumed that noise in the imaging system is an independent and identically distributed Gaussian variable with a variance of a, such that the probability of observing y i  knowing x can be expressed as: 
     
       
         
           
             
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     In the above equation, C i  denotes the blur introduced by the first and second optical paths (e.g., the respective point spread functions), which are initially unknown. In this embodiment, however, the blur functions are initially assumed to be Gaussian, and are later refined by reiterating the deconvolution process. 
     Next, the prior information P(x) is chosen to be suitable for natural images, e.g.: 
         P ( x )=exp(−αΣ|g ij   *x|   2 )
 
     where i sums over the image pixels, and g id  denotes a set of filters. For natural images, the filters g ij  can be the horizontal and the vertical gradient, or any other suitable filter. 
     Computing the maximum a posteriori explanation x includes inserting P(x) and P(y i |x) into the deconvolution ansatz described above, and taking the logarithms results in finding the resulting high resolution image x by minimizing 
       ∥ y   1   −C   1   x∥   2   +∥y   2   −C   2   x∥   2   +ωΣ∥G   ij ∥ 2 →min
 
     where the weights ω are determined by parameters of the natural image prior and the noise in the imaging path as ω=ασ. Finding the minimum is done, for example, by taking the derivative as: 
     
       
         
           
             
               
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     which results in the linear system 
       ( C   1   T   y   1   +C   2   T   y   2 )=(( C   1   T   C   1   +C   2   T   C   2 )−ωΣ G   ij   T   G   ij ) x.  
 
     In the above, the matrices C 1 , C 2  and matrix G id  are band matrices. As such, 
       (( C   1   T   C   1   +C   2   T   C   2 )−ωΣ G   ij   T   G   ij )
 
     is a Toeplitz matrix, as well as sparse. Solving this sparse linear system results in the final high resolution output image x. 
     In that regard, there are many methods to solve a system of linear equations, such as the Gauss-Jordan elimination, the application of Cramer&#39;s rule, the LU decomposition or the Levinson recursion (which is vary fast for Toeplitz matrices). In addition, there are various methods to solve sparse systems of linear equations, for example the conjugate gradient method. Thus, the final high resolution output image can be found. 
     Using the found high resolution output image x and the observed image y 1 , a refinement C′ 1  (of the blur function C 1 ) can be computed. Similarly, a refinement C′ 2  (of the blur function C 2 ) can be computed. Using those refined blur functions, the deconvolution process is repeated and a refined output image x′ is generated. 
     Accordingly, the synthesized image is generated by repeating the deconvolution process. 
     In an alternative embodiment, the deconvolution is carried out on the first optical path as 
         x =arg max x   {P ( x |( y   1 ))= P ( y   1   |x ))· P ( x )}
 
     and the image observed in the second optical path is used to derive the image prior P(x). 
     Returning to  FIG. 6 , in step  605 , the synthesized image is output. 
     By virtue of the above arrangements, it is ordinarily possible to augment the image of a stack of microlens arrays such as a Gabor superlens with additional information via another image path, in order to, for example, generate a higher-resolution image. 
     Other Embodiments 
     According to other embodiments contemplated by the present disclosure, example embodiments may include a computer processor such as a single core or multi-core central processing unit (CPU) or micro-processing unit (MPU), which is constructed to realize the functionality described above. The computer processor might be incorporated in a stand-alone apparatus or in a multi-component apparatus, or might comprise multiple computer processors which are constructed to work together to realize such functionality. The computer processor or processors execute a computer-executable program (sometimes referred to as computer-executable instructions or computer-executable code) to perform some or all of the above-described functions. The computer-executable program may be pre-stored in the computer processor(s), or the computer processor(s) may be functionally connected for access to a non-transitory computer-readable storage medium on which the computer-executable program or program steps are stored. For these purposes, access to the non-transitory computer-readable storage medium may be a local access such as by access via a local memory bus structure, or may be a remote access such as by access via a wired or wireless network or Internet. The computer processor(s) may thereafter be operated to execute the computer-executable program or program steps to perform functions of the above-described embodiments. 
     According to still further embodiments contemplated by the present disclosure, example embodiments may include methods in which the functionality described above is performed by a computer processor such as a single core or multi-core central processing unit (CPU) or micro-processing unit (MPU). As explained above, the computer processor might be incorporated in a stand-alone apparatus or in a multi-component apparatus, or might comprise multiple computer processors which work together to perform such functionality. The computer processor or processors execute a computer-executable program (sometimes referred to as computer-executable instructions or computer-executable code) to perform some or all of the above-described functions. The computer-executable program may be pre-stored in the computer processor(s), or the computer processor(s) may be functionally connected for access to a non-transitory computer-readable storage medium on which the computer-executable program or program steps are stored. Access to the non-transitory computer-readable storage medium may form part of the method of the embodiment. For these purposes, access to the non-transitory computer-readable storage medium may be a local access such as by access via a local memory bus structure, or may be a remote access such as by access via a wired or wireless network or Internet. The computer processor(s) is/are thereafter operated to execute the computer-executable program or program steps to perform functions of the above-described embodiments. 
     The non-transitory computer-readable storage medium on which a computer-executable program or program steps are stored may be any of a wide variety of tangible storage devices which are constructed to retrievably store data, including, for example, any of a flexible disk (floppy disk), a hard disk, an optical disk, a magneto-optical disk, a compact disc (CD), a digital versatile disc (DVD), micro-drive, a read only memory (ROM), random access memory (RAM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), dynamic random access memory (DRAM), video RAM (VRAM), a magnetic tape or card, optical card, nanosystem, molecular memory integrated circuit, redundant array of independent disks (RAID), a nonvolatile memory card, a flash memory device, a storage of distributed computing systems and the like. The storage medium may be a function expansion unit removably inserted in and/or remotely accessed by the apparatus or system for use with the computer processor(s). 
     This disclosure has provided a detailed description with respect to particular representative embodiments. It is understood that the scope of the appended claims is not limited to the above-described embodiments and that various changes and modifications may be made without departing from the scope of the claims.