Patent Publication Number: US-2018035046-A1

Title: Block-based lensless compressive image acquisition

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to image acquisition and, more particularly but not exclusively, to lensless compressive image acquisition. 
     BACKGROUND 
     Image acquisition, as performed by contemporary digital image or video systems, generally involves the acquisition and immediate compression of large amounts of raw image or video data. This typically requires use of large numbers of sensors as well as significant computational capabilities. 
     SUMMARY 
     The present disclosure generally discloses block-based lensless compressive image acquisition. 
     In at least some embodiments, a lensless compressive camera includes at least two image acquisition blocks. The image acquisition blocks each include an aperture including a set of aperture elements wherein each of the aperture elements is configured to be controlled to permit or prevent passage of light therethrough, a sensor configured to detect light passing through the aperture, and an isolation chamber disposed between the aperture and the sensor wherein the isolation chamber is configured to isolate the light passing through the aperture to be incident on the sensor and to prevent comingling of the light passing through the aperture with light of other image acquisition blocks. 
     In at least some embodiments, a lensless compressive image acquisition device includes a lensless compressive camera, a memory, and a processor. The lensless compressive camera includes at least two image acquisition blocks. The image acquisition blocks each include an aperture including a set of aperture elements wherein each of the aperture elements is configured to be controlled to permit or prevent passage of light therethrough, a sensor configured to detect light passing through the aperture, and an isolation chamber disposed between the aperture and the sensor wherein the isolation chamber is configured to isolate the light passing through the aperture to be incident on the sensor and to prevent comingling of the light passing through the aperture with light of other image acquisition blocks. The memory is configured to store respective sets of compressive measurements associated with the respective image acquisition blocks. The processor is configured to reconstruct an image based on processing of the respective sets of compressive measurements of the respective image acquisition blocks. 
     In at least some embodiments, a lensless compressive camera includes an aperture assembly, a sensor assembly, and an isolation assembly. The aperture assembly includes a set of apertures, each of the apertures including a respective set of aperture elements configured to be controlled to permit or prevent passage of light therethrough. The sensor assembly includes a set of sensors, each of the sensors configured to detect light incident thereon. The isolation assembly is disposed between the aperture assembly and the sensor assembly. The isolation assembly includes a set of isolation chambers configured to isolate light passing through respective apertures of the aperture assembly to be incident on respective sensors of the sensor assembly and configured to prevent comingling of light between the isolation chambers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The teachings herein can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG. 1  depicts an exemplary block-based lensless compressive image acquisition system; 
         FIG. 2  depicts an exemplary block-based lensless camera for use in the block-based lensless compressive image acquisition system of  FIG. 1 ; 
         FIG. 3  depicts an exemplary aperture assembly including apertures and associated sensors for illustrating measurement basis information and compressive measurements for a block-based lensless camera; 
         FIGS. 4A-4C  depict exemplary cross-sectional views of aperture assemblies and sensor assemblies for a block-based lensless camera; 
         FIGS. 5A-5C  depict an exemplary concentration-sensor configuration of a block-based lensless camera using cellular-shaped apertures and cellular-shaped sensors; 
         FIG. 6  depicts an exemplary block-based lensless compressive image acquisition system including an image reconstruction process for reconstructing an image captured by a block-based lensless camera; 
         FIG. 7  depicts an exemplary embodiment of an image reconstruction process; and 
         FIG. 8  depicts a high-level block diagram of a computer suitable for use in performing various functions described herein. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. 
     DETAILED DESCRIPTION 
     The present disclosure generally discloses block-based lensless compressive image acquisition capabilities. The block-based lensless compressive image acquisition capabilities may include a block-based lensless camera. The block-based lensless camera may include a set of two or more image acquisition blocks (which also may be referred to more generally herein as blocks) configured to capture respective sets of image data (e.g., detector outputs or compressive measurements produced from detector outputs) for respective image portions of an image to be captured by the block-based lensless camera. The blocks of a block-based lensless camera may each include an aperture including a set of aperture elements, a sensor, and an isolation chamber disposed between the aperture and the sensor and configured to isolate the light passing through the aperture to be incident on the sensor and to prevent comingling of the light passing through the aperture with light of other blocks. The block-based lensless camera may include an aperture assembly, a sensor assembly, and an isolation assembly, where the isolation assembly may be disposed between the aperture assembly and the sensor assembly and where the isolation assembly may include a set of isolation chambers configured to isolate respective portions of the aperture assembly and respective portions of the sensor assembly to provide thereby the respective blocks. The aperture assembly may include a set of apertures and the sensor assembly may include a set of sensors, such that the respective isolation chambers of the isolation assembly isolate respective apertures of the aperture assembly and respective subsets of sensors of the sensor assembly to provide thereby the respective blocks. The aperture assembly, the sensor assembly, and the isolation assembly may be configured such that, for each of the respective blocks, the respective isolation chamber ensures that light passing through the respective aperture for the respective block is incident only on the sensor of the respective block and is not comingled with light from other blocks. These and various other embodiments and advantages of block-based lensless compressive image acquisition capabilities may be further understood by way of reference to the exemplary lensless compressive image acquisition system of  FIG. 1 . 
       FIG. 1  depicts an exemplary block-based lensless compressive image acquisition system. 
     As depicted in  FIG. 1 , incident light  101  reflecting from an object  102  is received by a block-based lensless compressive image acquisition system  100  that is configured to perform block-based compressive image acquisition to capture an image depicting the object  102 . 
     The block-based lensless compressive image acquisition system  100  includes a block-based lensless camera  110 , a memory  120 , and a processor  130 . The processor  130  is communicatively connected to the block-based lensless camera  110  and the memory  120 . 
     The block-based lensless camera  110  is configured to perform block-based compressive sampling for compressive image acquisition. An exemplary block-based lensless camera  110  is depicted and described with respect to  FIG. 2 . It will be appreciated that, although primarily presented with respect to embodiments in which block-based lensless camera  110  produces compressive measurements for compressive image acquisition, in at least some embodiments the compressive measurements for compressive image acquisition may be produced by an element other than block-based lensless camera  110  (e.g., processor  130  or a remote element) based on detector output data produced by block-based lensless camera  110  (e.g., detector output data produced by detectors of block-based lensless camera  110 ). 
     The memory  120  is configured to store information associated with block-based lensless compressive image acquisition. The memory  120  is configured to store measurement basis information  122  for use by the block-based lensless camera  110  in performing block-based compressive sampling. The memory  120  is configured to store compressive measurements  124  that are produced by block-based lensless camera  110  while performing block-based compressive sampling. 
     The processor  130  is configured to control the operation of block-based lensless camera  110  to perform block-based compressive sampling for compressive image acquisition. The processor  130  may be configured to use the measurement basis information  122  to control or facilitate block-based compressive sampling by the block-based lensless camera  110 . The processor  130  may be configured to receive the compressive measurements  124  produced by the block-based lensless camera  110  while performing block-based compressive sampling and to control storage of the compressive measurements  124  produced by the block-based lensless camera  110  in the memory  120 . The processor  130  also may be configured to provide additional processing functions related to block-based lensless compressive image acquisition by block-based lensless camera  110 , such as performing image reconstruction processing in order to reconstruct the image captured by block-based lensless camera  110 , providing handling of the image captured by block-based lensless camera  110  (e.g., storage, display, transmission, or the like), or the like. 
     It will be appreciated that block-based lensless compressive image acquisition system  100  may be provided within various contexts. For example, block-based lensless compressive image acquisition system  100  may form part of a tablet, a smartphone, an Internet-of-Things (IoT) device, or the like. 
     It will be appreciated that, although primarily presented with respect to an embodiment in which the functions of the block-based lensless camera  110 , the memory  120 , and the processor  130  are integrated into a single device or system (illustratively, block-based lensless compressive image acquisition system  100 ), various functions of the block-based lensless camera  110 , the memory  120 , and the processor  130  may be separated into multiple devices or systems which may be centralized or distributed (e.g., physically, geographically, or the like, as well as various combinations thereof). 
       FIG. 2  depicts an exemplary block-based lensless camera for use in the block-based lensless compressive image acquisition system of  FIG. 1 . 
     The block-based lensless camera  200  includes an aperture assembly  210 , a sensor assembly  220 , and an isolation assembly  230 . The isolation assembly  230  is arranged between the aperture assembly  210  and the sensor assembly  220 . 
     The block-based lensless camera  200 , as discussed further below, is arranged into four equal-sized image acquisition blocks  251  which are referred to more generally as blocks  251  (although it will be appreciated that fewer or more blocks  251  may be used, blocks  251  may have different block sizes (e.g., in terms of the number of aperture elements per aperture, the number of pixels supported, physical size, or the like, as well as various combinations thereof), or the like, as well as various combinations thereof). 
     The aperture assembly  210  includes a set of apertures  211 . The aperture assembly  210  includes four apertures  211  (illustratively, apertures  211 - 1 ,  211 - 2 ,  211 - 3 , and  211 - 4 ) which correspond to the four blocks  251  of the block-based lensless camera  200 . The apertures  211  each include an array of aperture elements  212  (which also may be referred to herein as programmable aperture elements or programmable elements), respectively. The apertures  211  of aperture assembly  210  are each arranged as a two-dimensional array (8×8) of aperture elements  212  (where the notation [x,y] may be used to denote the aperture element  212  at row x/column y of the respective array of aperture elements  212  of the respective aperture  211 ), respectively. The aperture elements  212  of aperture assembly  210  are configured to be individually controlled to permit light to pass therethrough or to prevent light from passing therethrough. The transmittance of each of the aperture elements  212  can be programmable to be a specific value. The transmittance of each of the aperture elements  212  can be programmable to be a specific value using measurement basis information. For example, the measurement basis information may be in the form of a matrix (or other suitable data structure) having a set of entries corresponding to the aperture elements  212  of the programmable aperture  210 , respectively. The transmittance values for the aperture elements  212  may be binary values, such as where each entry may have a value of 0 (e.g., no transmittance of light through the respective aperture element  212 ) or a value of 1 (e.g., full transmittance of light through the respective aperture element  212 ). The transmittance values for the aperture elements  212  may support a range of values (e.g., between 0 and 1, or between any other suitable range of values), such that the transmittance value of a given aperture element  212  is indicative of the amount of transmittance of the aperture element  212  (e.g., intermediate values give some, but not full, transmittance of light). It will be appreciated that other values may be used to control the aperture elements  212  of the apertures  211  of the aperture assembly  210 . The aperture elements  212  of the apertures  211  of the aperture assembly  210  may be controlled electrically (e.g., under the control of a processor or other control element), mechanically (e.g., using a digital micromirror device (DMD) or other suitable device), or the like, as well as various combinations thereof. For example, the aperture elements  212  may be a transparent liquid crystal display (LCD) device having programmable LCD elements, a transparent liquid crystal on silicon (LCoS) device having programmable LCoS elements, or the like. The aperture elements  212  are controlled using measurement basis information, as presented in additional detail with respect to  FIG. 3 . It will be appreciated that, although the aperture assembly  210  is primarily presented as being composed of apertures  211  having respective sets of aperture elements  212 , in at least some embodiments the aperture elements  212  themselves may be considered to be apertures (e.g., the aperture assembly  210  may be considered to be an a two-dimensional array (64×64) of apertures such that it includes two-hundred and fifty-six apertures (e.g., which may be denoted as [1,1]-[16,16]) which may be considered to be logically divided into four subsets of apertures (e.g., four two-dimensional arrays (8×8) of apertures, such that each subset of apertures includes sixty-four apertures out of the two-hundred and fifty-six apertures, respectively). 
     The sensor assembly  220  includes a set of sensors  221 - 1 - 221 - 4  (collectively, sensors  221 ). The four sensors  221 - 1 - 221 - 4  of the set of sensors  221  correspond to the four blocks  251  of the block-based lensless camera  200 , respectively. The sensors  221  are each configured to detect light incident thereon (passing through aperture elements  212  of respective apertures  211  of aperture assembly  210 ) and to generate compressive measurements based on detection of the light incident thereon. More specifically, the first sensor  221 - 1  is arranged to detect light passing through aperture elements  212  of the first aperture  211 - 1 , the second sensor  221 - 2  is arranged to detect light passing through aperture elements  212  of the second aperture  211 - 2 , the third sensor  221 - 3  is arranged to detect light passing through aperture elements  212  of the third apertures  211 - 3 , and the fourth sensor  221 - 4  is arranged to detect light passing through aperture elements  212  of the fourth aperture  211 - 4 . The light passing through aperture elements  212  of apertures  211  is made incident on the sensors  221 , respectively, using the isolation assembly  230  (which prevents comingling of light between blocks  251  of the block-based lensless camera  200 ), which is discussed further below. The sensors  221  may each include (1) a detector that is configured to detect light and to produce a detector output based on the detected light and (2) a compressive measurement device configured to produce a compressive measurement based on the detector output of the detector. For example, the detector may be a photon detector (or other suitable device) and the compressive measurement device may be an analog-to-digital (A/D) converter (or other suitable device) configured to produce discretized compressive measurements based on the detector output. It will be appreciated that, although primarily presented with respect to embodiments in which the sensors  221  produce compressive measurements for compressive image acquisition, in at least some embodiments the compressive measurements for compressive image acquisition may be produced by an element other than sensors  221  (e.g., a processor or other device or element which receives the detector outputs from the sensors  221  where the sensors  221  include photon detectors but do not include compressive measurement devices such as A/D converters). 
     The isolation assembly  230  includes a set of isolation chambers  231 - 1 - 231 - 4  (collectively, isolation chambers  231 ). The four isolation chambers  231 - 1 - 231 - 4  correspond to the four blocks  251  of the block-based lensless camera  200 , respectively. The isolation chambers  231  are each configured to keep light passing through the isolation chambers contained therein, thereby preventing comingling of light between the isolation chambers  231 . More specifically, the first isolation chamber  231 - 1  is configured to contain light passing through aperture elements  212  of aperture  211 - 1  for detection by the first sensor  221 - 1 , the second isolation chamber  231 - 2  is configured to contain light passing through aperture elements  212  of the second aperture  211 - 2  for detection by the second sensor  221 - 2 , the third isolation chamber  231 - 3  is configured to contain light passing through aperture elements  212  of the third aperture  211 - 3  for detection by the third sensor  221 - 3 , and the fourth isolation chamber  231 - 4  is configured to contain light passing through aperture elements  212  of the fourth aperture  211 - 4  for detection by the fourth sensor  221 - 4 . The isolation assembly  230  may be configured in various ways (e.g., isolation assembly  230  may be composed of a housing configured to house the isolation chambers  231 , the isolation assembly may be composed of a housing which may be divided to provide the isolation chambers  231 , or the like). 
     The blocks  251  of the block-based lensless camera  200 , as indicated above, each include a respective combination of an aperture  211 - x  (including a respective set of aperture elements  212 - x ), a sensor  221 - x , and an isolation chamber  231 - x . As depicted in  FIG. 2 , a first block  251  includes aperture elements  212  of a first aperture  211 - 1 , a first sensor  221 - 1 , and a first isolation chamber  231 - 1 , which are arranged such that light passing through open aperture elements  212  of the first aperture  211 - 1  also passes through the first isolation chamber  231 - 1  such that it is detected only by the first sensor  231 - 1  (and not detected by any of the other sensors  231 - 2 ,  231 - 3 , and  231 - 4 ). Similarly, as depicted in  FIG. 2 , a second block  251 - 2  includes aperture elements  212  of a second aperture  211 - 2 , a second sensor  221 - 2 , and a second isolation chamber  231 - 2 , which are arranged such that light passing through open aperture elements  212  of the second aperture  211 - 2  also passes through the second isolation chamber  231 - 2  such that it is detected only by the second sensor  231 - 2  (and not detected by any of the other sensors  231 - 1 ,  231 - 3 , and  231 - 4 ). Similarly, as depicted in  FIG. 2 , a third block  251 - 3  includes aperture elements  212  of a third aperture  211 - 3 , a third sensor  221 - 3 , and a third isolation chamber  231 - 3 , which are arranged such that light passing through open aperture elements  212  of the third aperture  211 - 3  also passes through the third isolation chamber  231 - 3  such that it is detected only by the third sensor  231 - 3  (and not detected by any of the other sensors  231 - 1 ,  231 - 2 , and  231 - 4 ). Similarly, as depicted in  FIG. 2 , a fourth block  251 - 4  includes aperture elements  212  of a fourth aperture  211 - 4 , a fourth sensor  221 - 4 , and a fourth isolation chamber  231 - 4 , which are arranged such that light passing through open aperture elements  212  of the fourth aperture  211 - 4  also passes through the fourth isolation chamber  231 - 4  such that it is detected only by the fourth sensor  231 - 4  (and not detected by any of the other sensors  231 - 1 ,  231 - 2 , and  231 - 3 ). 
     The blocks  251  of the block-based lensless camera  200 , as illustrated in  FIG. 2 , each capture a respective portion of the image to be captured by the block-based lensless camera  200  (denoted as image portions). The image portions captured by the blocks  251  are overlapping, such that the image to be captured by the block-based lensless camera  200  may be reconstructed by stitching together the image portions captured by the blocks  251  of the block-based lensless camera  200 , respectively. The reconstruction of the image portions and associated reconstruction of the image from the image portions may be further understood by way of reference to  FIG. 6 . 
     It will be appreciated that, although primarily presented with respect to embodiments in which a single aperture assembly (illustratively, aperture assembly  210 ) is logically divided and operated (illustratively, as multiple apertures  211  each composed of aperture elements  212 ) to provide the multiple blocks  251  of the block-based lensless camera  200 , in at least some embodiments multiple aperture assemblies may be used to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, two aperture assemblies may be used, where either or both of the two aperture assemblies may be logically divided and operated to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, separate aperture assemblies may be used to provide each of the blocks  251  of the block-based lensless camera  200 . It will be appreciated that various other numbers of aperture assemblies may be used to support various numbers of blocks of a block-based lensless camera. 
     It will be appreciated that, although primarily presented with respect to embodiments in which a single sensor assembly (illustratively, sensor assembly  220 ) includes the multiple sensors (illustratively, sensors  221 ) to provide the multiple blocks  251  of the block-based lensless camera  200 , in at least some embodiments multiple sensor assemblies may be used to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, two sensor assemblies may be used, where each of the two sensor assemblies may include one or more sensors, to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, separate sensor assemblies may be used to provide each of the blocks  251  of the block-based lensless camera  200 . It will be appreciated that various other numbers of sensor assemblies may be used to support various numbers of blocks of a block-based lensless camera. 
     It will be appreciated that, although primarily presented with respect to embodiments in which a single isolation assembly (illustratively, isolation assembly  230 ) includes the multiple isolation chambers (illustratively, isolation chambers  231 ) to provide the multiple blocks  251  of the block-based lensless camera  200 , in at least some embodiments multiple isolation assemblies may be used to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, two isolation assemblies may be used, where each of the two isolation assemblies may include one or more isolation chambers, to provide the multiple blocks  251  of the block-based lensless camera  200 . For example, separate isolation assemblies may be used to provide each of the blocks  251  of the block-based lensless camera  200 . It will be appreciated that various other numbers of isolation assemblies may be used to support various numbers of blocks of a block-based lensless camera. 
     It will be appreciated that, although primarily presented with respect to embodiments in which block-based lensless camera  200  includes a specific arrangement of blocks  251  (e.g., including four blocks  251  which are each of the same size, arranged in a particular pattern, and so forth), in at least some embodiments the block-based lensless camera  200  may include various other arrangements of blocks  251  (e.g., using fewer or more blocks, using blocks having different block sizes, using different arrangements of the blocks with respect to each other, or the like, as well as various combinations thereof). 
       FIG. 3  depicts exemplary blocks of a block-based lensless camera for illustrating measurement basis information and compressive measurements for the block-based lensless camera. 
     The block-based lensless camera  300  includes four blocks  310 - 1 - 310 - 4  (collectively, blocks  310 ). The blocks  310 - 1 - 310 - 4  include apertures  320 - 1 - 320 - 4  (collectively, apertures  320 ), respectively. The blocks  310 - 1 - 310 - 4  also include sensors  330 - 1 - 330 - 4  (collectively, sensors  330 ), respectively. It is noted that the isolation chambers for the blocks  310  have been omitted from  FIG. 3  for purposes of clarity. 
     The apertures  320 - 1 - 320 - 4  each include aperture elements  321 , respectively. As depicted in  FIG. 3 , each of the apertures  320  includes an 8×8 array of aperture elements  321 , respectively (although, as indicated above, each of apertures  320  may include fewer or more aperture elements  321 ). The closing (to prevent light from passing therethrough) and opening (to permit light to pass therethrough) of the respective aperture elements  321  of the apertures  320 - 1 - 320 - 4  is controlled based on measurement basis information  322 - 1 - 322 - 4  (collectively, measurement basis information  322 ) that is associated with the apertures  320 - 1 - 320 - 4 , respectively. 
     In general, the measurement basis information  322 - x  for a given aperture  320 - x  includes, where m compressive measurements are to be made based on detection of light passing through aperture elements  321  of the given aperture  320 - x , m arrays of measurement basis values (denoted using the notation Bx-y), where each array of measurement basis values includes a respective bit value corresponding to each of the respective aperture elements  321  of the given aperture  320 - x  (denoted using the notation Bx-y-z). For example, the measurement basis information  322 - 1  for aperture  320 - 1  includes m arrays of measurement basis values (denoted as B 1 - 1 , B 1 - 2 , . . . , B 1 - m ), where measurement basis value array B 1 - 1  includes 64 values (denoted as B 1 - 1 - 1  through B 1 - 1 - 64 ), measurement basis value array B 1 - 2  includes 64 values (denoted as B 1 - 2 - 1  through B 1 - 2 - 64 ), and so forth, through measurement basis value array B 1 - m . It will be appreciated that, for a given aperture  320 , at least some of the measurement basis value arrays Bx-y of the given aperture  320  may be different (i.e., the sets of bit values of the measurement basis value arrays Bx-y for the given aperture  320 - x  may be different) so as to make different quantities and patterns of light incident on the associated sensor  330 - x  of the given aperture  320 - x  during the m compressive measurements associated with the given aperture  320 - x.    
     In general, the bit value of a measurement basis value array Bx-y that corresponds to a particular aperture element  321  of an aperture  320 , for a given compressive measurement to be made based on acquisition of light by a corresponding sensor  330  associated with the aperture  320 , may be set to a value indicative of the transmittance of the aperture element  321  (e.g., a value of “0” to indicate that there is to be no transmittance of light through the aperture element  321  or a value of “1” to indicate that there is to be a full transmittance of light through the aperture element  321 ). In  FIG. 3 , for purposes of clarity, it is assumed that the bit value of a measurement basis value array Bx-y that corresponds to a particular aperture element  321  of an aperture  320  may be set to a first value (e.g., “0” or other suitable value) to indicate that the particular aperture element  321  is closed during the compressive measurement or may be set to a second value (e.g., “1” or other suitable value) to indicate that the particular aperture element  321  is open during the compressive measurement (i.e., it is assumed, for purposes of clarity, that intermediate values (e.g., which give partial, but not full, transmittance of light) are not supported). For example, the measurement basis information  322 - 1  for aperture  320 - 1  may include sets of measurement basis value arrays (e.g., a first measurement basis value array B 1 - 1  [0, 1, 1, 0, 1, . . . ], a second measurement basis value array B 1 - 1  [1, 1, 0, 0, 0, . . . ], and so forth, through measurement basis value array B 1 - m ), the measurement basis information  322 - 2  for aperture  320 - 2  may include sets of measurement basis value arrays (e.g., a first measurement basis value array B 2 - 1  [1, 1, 1, 1, 0, . . . ], a second measurement basis value array B 2 - 1  [1, 0, 1, 0, 1, . . . ], and so forth, through measurement basis value array B 2 - m ), the measurement basis information  322 - 3  for aperture  320 - 3  may include sets of measurement basis value arrays (e.g., a first measurement basis value array B 3 - 1  [0, 0, 1, 1, 0, . . . ], a second measurement basis value array B 3 - 1  [0, 0, 0, 1, 1, . . . ], and so forth, through measurement basis value array B 3 - m ), and the measurement basis information  322 - 4  for aperture  320 - 4  may include sets of measurement basis value arrays (e.g., a first measurement basis value array B 4 - 1  [1, 0, 1, 1, 0, . . . ], a second measurement basis value array B 4 - 1  [1, 0, 0, 0, 1, . . . ], and so forth, through measurement basis value array B 4 - m ). It will be appreciated that, in the exemplary block-based lensless camera  300 , in which each of the apertures  320  includes an 8×8 array of aperture elements  321 , each of the measurement basis value arrays Bx-y for a given aperture  320  will include sixty-four bit values (only some of which are given in the preceding examples) which correspond to the sixty-four aperture elements  321  of the given aperture  320 . It will be appreciated that, in at least some embodiments, aperture elements  321  may be configured to controlled to be partially open/closed (e.g., using values between “0” and “1” or using other suitable values) such that, for a given aperture element  321 , a portion of the light incident on the aperture element  321  is allowed to pass through the aperture element  321  and a portion of the light incident on the aperture element  321  is prevented from passing through the aperture element  321 ). 
     It will be appreciated that, if different aperture control patterns are used to control passage of light through the respective apertures  320 - 1 - 320 - 4 , then different sets of measurement basis information  322 - 1 - 322 - 4  need to be used to control the respective aperture elements  321  of the apertures  320 - 1 - 320 - 4  (thereby requiring storage and use of different sets of measurement basis information  322 - 1 - 322 - 4  for the apertures  320 - 1 - 320 - 4  and, thus, increasing the storage requirements at the block-based lensless camera  300 ). It will be further appreciated that, if the same aperture control patterns are used to control each of the apertures  320 - 1 - 320 - 4 , then the sets of measurement basis information  322 - 1 - 322 - 4  used to control the respective aperture elements  321  of the apertures  320 - 1 - 320 - 4  are the same and, thus, only a single set of measurement basis information  322 - x  is needed to control the respective aperture elements  321  of the apertures  320 - 1 - 320 - 4  (thereby requiring storage and use of only a single set of measurement basis information  322 - x  for the apertures  320 - 1 - 320 - 4  and, thus, significantly decreasing the storage requirements at the block-based lensless camera  300  while also reducing the image reconstruction time). It is noted that other intermediate arrangements (e.g., sharing of measurement basis information by some, but less than all, of the apertures  320  or other types of sharing) are contemplated. 
     The sensors  330  are each configured to detect light incident thereon and to generate sets of compressive measurements  332  based on detection of the light incident thereon. For example, as discussed above, each sensor  330  may include a photon detector configured to detect light incident on the sensor  330  and may include a compressive measurement device (e.g., an A/D converter or the like) configured to generate the sets of compressive measurements  332 . More specifically, the sensor  330 - 1  generates a compressive measurement set  332 - 1  based on detection of light passing through aperture elements  321  of aperture  320 - 1  based on measurement basis information  322 - 1 , the sensor  330 - 2  generates a compressive measurement set  332 - 2  based on detection of light passing through aperture elements  321  of aperture  320 - 2  based on measurement basis information  322 - 2 , the sensor  330 - 3  generates a compressive measurement set  332 - 3  based on detection of light passing through aperture elements  321  of aperture  320 - 3  based on measurement basis information  322 - 3 , and the sensor  330 - 4  generates a compressive measurement set  332 - 4  based on detection of light passing through aperture elements  321  of aperture  320 - 4  based on measurement basis information  322 - 4 . In general, a given sensor  330 - x  is arranged to detect light passing through open (or at least partially open) aperture elements  321  of the associated aperture  320 - x  for each of the m measurement basis value arrays Bx-y of the associated aperture  320 - x  and to generate a set of m compressive measurements (denoted as Yx- 1  through Yx-m) for the m measurement basis value arrays Bx-y of the associated aperture  320 - x , respectively. For example, the sensor  330 - 1  is arranged to detect light passing through open aperture elements  321  of the associated aperture set  320 - 1  for each of the m measurement basis value arrays B 1 - y  (namely, B 1 - 1  through B 1 - m ) of the measurement basis information  322 - 1  of the associated aperture  320 - 1  and to generate a set of m compressive measurements (denoted as Y 1 - 1  through Y 1 - m ) for the m measurement basis value arrays B 1 - y  of the associated aperture  320 - 1 , respectively. The sensors  330 - 2 ,  330 - 3 , and  330 - 4  are similarly arranged to generate respective sets of m compressive measurements for the m measurement basis value arrays of the sets of measurement basis information  322 - 2 ,  322 - 3 , and  322 - 4  for the associated apertures  320 - 2 ,  320 - 3 , and  320 - 4 , respectively. 
     It will be appreciated that the sets of m compressive measurements of the blocks of block-based lensless camera  300  represent the respective compressed image portions of the image captured by block-based lensless camera  300  (namely, the m compressive measurements of a block collectively represent the compressed image portion captured by the block) and, thus, together (where the collective set may be denoted as M compressive measurements), represent the compressed image captured by block-based lensless camera  300 . It will be appreciated that, in compressive sense imaging, the number M of the compressive measurements that are acquired is typically significantly less than the N raw data values that are typically acquired in a conventional camera system having an N-pixel sensor for generating an N-pixel image, thus reducing or eliminating the need for further compression of the raw data values after acquisition. It is noted that, in at least some embodiments, the number of compressive measurements M (and, similarly, the number of per-block compressive measurements m) may be pre-selected relative to the number of aperture elements  321  based upon a pre-determined (e.g., desired or required) balance between compression level and image quality. 
     It will be appreciated that, although primarily presented with respect to specific numbers and arrangements of various elements of the block-based lensless camera  300  (e.g., four blocks, with each block having an aperture  320  including sixty-four aperture elements  321  and a sensor  330 - x , respectively), the block-based lensless camera  300  may include various other numbers and/or arrangements of elements. 
       FIGS. 4A-4C  depict exemplary cross-sectional views of aperture assemblies and sensor assemblies for a block-based lensless camera. 
       FIG. 4A  depicts an exemplary cross-sectional view for a block-based lensless camera  410 . The block-based lensless camera  410  has a planar aperture assembly  411  and a planar sensor assembly  412 . The planar aperture assembly  411  includes a set of apertures arranged on a planar surface. The planar sensor assembly  412  includes a set of sensors arranged on a planar surface. The isolation chambers  413  are configured to isolate the light from the respective apertures of the planar aperture assembly  411  to be incident on the respective sensors of the planar sensor assembly  412  while preventing comingling of light with other isolation chambers  413  (and, thus, preventing comingling of light between blocks). 
       FIG. 4B  depicts an exemplary cross-sectional view for a block-based lensless camera  420 . The block-based lensless camera  420  has a planar aperture assembly  421  and a spherical sensor assembly  422 . The planar aperture assembly  421  includes a set of apertures arranged on a planar surface. The spherical sensor assembly  422  includes a set of sensors arranged on a spherical surface (illustratively, on the outer surface of the sphere). The isolation chambers  423  are configured to isolate the light from the respective apertures of the planar aperture assembly  421  to be incident on the respective sensors of the spherical sensor assembly  422  while preventing comingling of light with other isolation chambers  423  (and, thus, preventing comingling of light between blocks). It is noted that the block-based lensless camera  420  may be configured to provide an increased angular resolution for far scenes (e.g., as compared with the block-based lensless camera  410  of  FIG. 4A ). 
       FIG. 4C  depicts an exemplary cross-sectional view for a block-based lensless camera  430 . The block-based lensless camera  430  has a spherical aperture assembly  431  and a spherical sensor assembly  432 . The spherical aperture assembly  431  includes a set of apertures arranged on a spherical surface. The spherical sensor assembly  432  includes a set of sensors arranged on a spherical surface (illustratively, on the outer surface of the sphere). The isolation chambers  433  are configured to isolate the light from the respective apertures of the spherical aperture assembly  431  to be incident on the respective sensors of the spherical sensor assembly  432  while preventing comingling of light with other isolation chambers  433  (and, thus, preventing comingling of light between blocks). The block-based lensless camera  430  may be used as a wide-angle camera (which may be seen from the wide coverage area given by the lines of sight between the respective apertures of the spherical aperture assembly  431  and the respective sensors of the spherical sensor assembly  432 . It is noted that the block-based lensless camera  430  may be configured to provide an increased angular resolution for far scenes (e.g., as compared with the block-based lensless camera  410  of  FIG. 4A ). In at least some embodiments, an exemplary embodiment of which is presented with respect to  FIGS. 5A-5C , the block-based lensless camera  430  may be configured to use cellular-shaped apertures in the spherical aperture assembly  431  and cellular-shaped sensors in the spherical sensor assembly  432 . 
       FIGS. 5A-5C  depict an exemplary concentration-sensor configuration of a block-based lensless camera using cellular-shaped apertures and cellular-shaped sensors. 
       FIG. 5A  depicts an exemplary layout  510  of the concentration-sensor regime for a block-based lensless camera using cellular-shaped apertures and sensors. The layout  510  illustrates the cellular arrangement of elements, where the elements may be apertures of an aperture assembly or sensors of a sensor assembly. The cellular shapes of the elements may be hexagonal or approximately hexagonal. It will be appreciated that, in the case in which the elements are the apertures of the block-based lensless camera, each element may include a respective set of aperture elements which, depending on the shape of the aperture elements (e.g., hexagonal, square, rectangular, or the like) and/or other factors, may or may not fill the entire element. 
       FIG. 5B  depicts an exemplary spherical arrangement  520  of the concentration-sensor regime for a block-based lensless camera using cellular-shaped apertures and sensors. The spherical arrangement  520  may be used to provide a spherical arrangement of apertures of the aperture assembly, such as presented with respect to  FIG. 4C . For example, where spherical arrangement  520  is used to provide a spherical arrangement of apertures of the aperture assembly, the spherical arrangement  520  may be implemented as a curved LCD or using other suitable spherical arrangements of cellular-shaped apertures. The spherical arrangement  520  may be used to provide a spherical arrangement of sensors of the sensor assembly, such as presented with respect to  FIG. 4C . It will be appreciated that, in the case in which the hexagonal elements of the spherical arrangement  520  are the apertures of the block-based lensless camera, each hexagonal element may include a respective set of aperture elements which, depending on the shape of the aperture elements (e.g., hexagonal, square, rectangular, or the like) and/or other factors, may or may not fill the entire hexagonal element. 
       FIG. 5C  depicts an exemplary block  530  of the concentration-sensor regime for a block-based lensless camera using cellular-shaped apertures and sensors. The block  530  has a cellular-shaped aperture  531 , a cellular-shaped sensor  532 , and a hexagonal “trumpet”-shaped isolation chamber  533 . The “trumpet”-shaped cellular-shaped isolation chamber  533  is an elongated cellular-shaped chamber extending from the cellular-shaped aperture  531  toward the cellular-shaped sensor  532  while gradually getting smaller in the direction from the cellular-shaped aperture  531  toward the cellular-shaped sensor  532 . 
       FIG. 6  depicts an exemplary block-based lensless compressive image acquisition system including an image reconstruction process for reconstructing an image captured by a block-based lensless camera. 
     As depicted in  FIG. 6 , block-based lensless compressive image acquisition system  600  of  FIG. 6  is similar to the block-based lensless compressive image acquisition system  100  of  FIG. 1 . As depicted in  FIG. 6 , block-based lensless compressive image acquisition system  600  includes a block-based lensless camera  610 , a memory  620 , and a processor  630 , which are similar to block-based lensless camera  110 , memory  120 , and processor  130 , respectively, of the block-based lensless compressive image acquisition system  100  of  FIG. 1 . As further depicted in  FIG. 6 , the memory  620  is storing measurement basis information  622  and compressive measurements  624 , which are similar to measurement basis information  122  and compressive measurements  124  stored in memory  120  of the block-based lensless compressive image acquisition system  100  of  FIG. 1 . Additionally, as further depicted in  FIG. 6 , the memory  620  also is storing an image reconstruction process  626  and an associated image  627  that is produced based on the image reconstruction process  626  (which were omitted from  FIG. 1  for purposes of clarity). 
     The image reconstruction process  626  is configured to reconstruct the image  627  based on compressive measurements  624  captured by the block-based lensless camera  610 . The image reconstruction process  626  is configured to reconstruct image portions associated with the blocks of the block-based lensless camera  610 , respectively, and to reconstruct the image  627  by stitching together the image portions associated with the blocks of the block-based lensless camera  610 . 
     The image reconstruction process  626 , for each block of the block-based lensless camera  110 , is configured to reconstruct an image portion captured by that block of the block-based lensless camera  110  based on the set of compressive measurements captured by that block of the block-based lensless camera  110 . 
     The image reconstruction process  626 , for a given block of the block-based lensless camera  610 , may be configured to reconstruct an image portion captured by that block of the block-based lensless camera  610  by using a dictionary-based inversion and a Gaussian mixture model (GMM), a discussion of which follows. 
     In at least some embodiments in which the same patterns (same sets of measurement basis information) are used for each of the blocks, a compressive measurement may be considered as follows: Y=AX+N, where (1)×ε   P×N     p    with P denoting the dimension of the block (with size √{square root over (P)}×√{square root over (P)}) and N P  is the number of blocks used in the block-based lensless camera, (2) Aε   M×P  with M&lt;&lt;P denoting the compressive measurements captured for each of the blocks, and (3) N signifying the additive noise. Here, Yε   M×N     p    is the measurement matrix with each column denoting the measurements corresponding to each of the blocks. 
     In at least some embodiments, in which the same patterns (same sets of measurement basis information) are used for each of the blocks, reconstruction of the image may be performed using a dictionary-based inversion. For example, by introducing a basis (or block-based) dictionary D, compressive measurement equation Y=AX+N can be reformulated as Y=ADS+N, where Dε   P×Q  can be an orthonormal basis with Q=P or an over-complete dictionary. This dictionary may be pre-learned for fast inversion. It is noted that it may be desirable for Sε   Q×N     p    to be sparse so that various l 1  algorithms may be used to solve the following problem: min∥S∥ 1 , subject to Y=ADS given A and D. It is noted that various algorithms may be used to solve this problem. In at least some embodiments, as discussed further below, a GMM may be used to solve this problem, as a GMM generally does not require any iterations since closed-form analytic solutions exist. 
     In at least some embodiments, in which the same patterns (same sets of measurement basis information) are used for each of the blocks, reconstruction of the image may be performed using a dictionary-based inversion that is based on a GMM. The GMM has recently been re-recognized as an efficient dictionary learning algorithm. As indicated above, the image blocks that re extracted from the image may be denoted as Xε   P×N     p   . For the i-th patch x i , it may be modeled as a GMM with K Gaussians as 
     
       
         
           
             
               x 
               i 
             
             ∼ 
             
               
                 ∑ 
                 
                   k 
                   = 
                   1 
                 
                 K 
               
                
               
                   
               
                
               
                 
                   π 
                   k 
                 
                  
                 
                   N 
                    
                   
                     ( 
                     
                       
                         μ 
                         k 
                       
                       , 
                       
                         Σ 
                         k 
                       
                     
                     ) 
                   
                 
               
             
           
         
       
     
     where 
     
       
         
           
             
               { 
               
                 
                   μ 
                   k 
                 
                 , 
                 
                   Σ 
                   k 
                 
               
               } 
             
             
               k 
               = 
               1 
             
             K 
           
         
       
     
     represent me mean and covariance matrix of the k-th Gaussian and 
     
       
         
           
             
               { 
               
                 π 
                 k 
               
               } 
             
             
               k 
               = 
               1 
             
             K 
           
         
       
     
     denotes the weights of these Gaussian components. Dropping the block index i, in a linear model 
     
       
         
           
             
               y 
               = 
               
                 Ax 
                 + 
                 ɛ 
               
             
             , 
             
               ɛ 
               ∈ 
               
                 N 
                  
                 
                   ( 
                   
                     0 
                     , 
                     R 
                   
                   ) 
                 
               
             
             , 
             
               
                 if 
                  
                 
                     
                 
                  
                 x 
               
               ∼ 
               
                 
                   p 
                    
                   
                     ( 
                     x 
                     ) 
                   
                 
                  
                 
                     
                 
                  
                 in 
                  
                 
                     
                 
                  
                 
                   x 
                   i 
                 
               
               ∼ 
               
                 
                   ∑ 
                   
                     k 
                     = 
                     1 
                   
                   K 
                 
                  
                 
                     
                 
                  
                 
                   
                     π 
                     k 
                   
                    
                   
                     N 
                      
                     
                       ( 
                       
                         
                           μ 
                           k 
                         
                         , 
                         
                           Σ 
                           k 
                         
                       
                       ) 
                     
                   
                 
               
             
             , 
           
         
       
     
     then p(x|y) has the following analytical form 
     
       
         
           
             
               p 
                
               
                 ( 
                 
                   x 
                   | 
                   y 
                 
                 ) 
               
             
             = 
             
               
                 ∑ 
                 
                   k 
                   = 
                   1 
                 
                 K 
               
                
               
                   
               
                
               
                 
                   
                     π 
                     ~ 
                   
                   k 
                 
                  
                 
                   N 
                    
                   
                     ( 
                     
                       
                         
                           μ 
                           ~ 
                         
                         k 
                       
                       , 
                       
                         
                           Σ 
                           ~ 
                         
                         k 
                       
                     
                     ) 
                   
                 
               
             
           
         
       
     
     where {tilde over (π)} k =[π k (y|Ax k , R −1 +AΣ k A T )]/[Σ l=1   K π l N(y|Ax l ,R −1 +AΣ l A T )], {tilde over (Σ)} k =(A T RA+Σ k   −1 ), and {tilde over (μ)} k ={tilde over (Σ)} k (A T Ry+Σ k   −1 μ k ). While {tilde over (π)} k  provides a posterior distribution for x, we obtain the point estimate of {tilde over (x)} via the posterior mean 
     
       
         
           
             
               
                 E 
                  
                 
                   [ 
                   
                     x 
                     ^ 
                   
                   ] 
                 
               
               = 
               
                 
                   ∑ 
                   
                     k 
                     = 
                     1 
                   
                   K 
                 
                  
                 
                     
                 
                  
                 
                   
                     
                       π 
                       ~ 
                     
                     k 
                   
                    
                   
                     
                       μ 
                       ~ 
                     
                     k 
                   
                 
               
             
             , 
           
         
       
     
     which is a closed-form solution. It is noted that 
     
       
         
           
             
               { 
               
                 
                   
                     π 
                     k 
                   
                    
                   
                     μ 
                     k 
                   
                 
                 , 
                 
                   Σ 
                   k 
                 
               
               } 
             
             
               k 
               = 
               1 
             
             K 
           
         
       
     
     are pre-trained on other datasets and, given A, {tilde over (Σ)} k  only needs to be computed once and saved. The same techniques may be used for AΣ k A T . Then, all that is left for each block is to calculate {{tilde over (μ)} k ,{tilde over (π)} k }, which can be obtained very efficiently. It is noted that, using this GMM process, no iteration is required and, as a result, real-time reconstruction of blocks may be realized. Additionally, in at least some embodiments, each block may be reconstructed in parallel using one or more graphics processing units (GPUs). 
     The image reconstruction process  626  is configured to reconstruct the image  627  by stitching together the image portions reconstructed for the blocks of the block-based lensless camera  110 , respectively. The stitching of the image portions may be performed using a real-time stitching algorithm, such that the image  627  may be obtained nearly instantly. 
       FIG. 7  depicts an exemplary embodiment of an image reconstruction process. The method  700  of  FIG. 7  may be performed by a computing element which may be local to the block-based lensless camera (e.g., a processor of a block-based lensless compressive image acquisition system including the block-based lensless camera, such as by processor  630  of the block-based lensless compressive image acquisition system  600  of  FIG. 6 ) or which may be remote from the block-based lensless camera (e.g., a remote computing element, such as where the compressive measurements captured by the block-based lensless camera may be transmitted by the block-based lensless camera to the remote computing element for processing). It will be appreciated that, although primarily presented as being performed serially, at least a portion of the functions of method  700  of  FIG. 7  may be performed contemporaneously or in a different order than as presented in  FIG. 7 . 
     At step  701 , method  700  begins. 
     At step  710 , sets of compressive measurements are received. The sets of compressive measurements may be sets of compressive measurements produced by blocks of the block-based lensless camera or produced by one or more other devices based on detector output data produced by blocks of the block-based lensless camera. The sets of compressive measurements each include compressive measurements produced based on respective sets of measurement basis information used for controlling the light capture patterns of the aperture sets of the respective blocks of the block-based lensless camera (which, as discussed herein, may be the same or different for the respective blocks of the block-based lensless camera). 
     At step  720 , the sets of compressive measurements associated with the respective blocks of the block-based lensless camera are processed to reconstruct respective image portions captured by the respective blocks of the block-based lensless camera. The sets of compressive measurements associated with the respective blocks of the block-based lensless camera may be processed, to reconstruct respective image portions captured by the respective blocks of the block-based lensless camera, as presented with respect to  FIG. 6 . 
     At step  730 , the image portions reconstructed for the respective blocks of the block-based lensless camera are processed to reconstruct the image captured by the block-based lensless camera. The image portions reconstructed for the respective blocks of the block-based lensless camera are processed by stitching together the image portions to reconstruct the image captured by the block-based lensless camera. The image portions may be stitched together to reconstruct the image as presented with respect to  FIG. 6 . 
     At step  740 , the image captured by the block-based lensless camera may be stored. The image also may be handled in other ways. For example, the image may be presented via a presentation interface associated with the block-based lensless camera (e.g., via a display of a tablet associated with the block-based lensless camera, via a display of a smartphone in which the block-based lensless camera is disposed, or the like). For example, the image may be transmitted via one or more communication paths (e.g., for storage and/or presentation at one or more remote devices). The image may be handled in various other ways in which images typically may be handled. 
     At step  799 , method  700  ends. 
     It will be appreciated that, although primarily presented herein with respect to embodiments in which the sensors of the block-based lensless camera produce compressive measurements for compressive image acquisition, in at least some embodiments the compressive measurements for compressive image acquisition may be produced by one or more devices other than the sensors of the block-based lensless camera. For example, where the sensors of a block-based lensless camera include photon detectors, the detector output data from the sensors of the block-based lensless camera may be provided to one or more other devices (e.g., which may be disposed within the block-based lensless camera, external to but local to the block-based lensless camera, external to and remote from the block-based lensless camera, or the like, as well as various combinations thereof) configured to produce the compressive measurements based on the detector output data from the sensors of the block-based lensless camera (e.g., one or more devices such as one or more A/D converters, one or more processors configured to support A/D conversions functions, or the like, as well as various combinations thereof). 
     Various embodiments of the block-based lensless compressive image acquisition capabilities may provide various advantages. For example, since each block may be relatively small (e.g., 8×8, 16×16, or the like), only a relatively small number of compressive measurements (e.g., approximately 10 compressive measurements for an 8×8 block) are needed in order to achieve a relatively good reconstruction of the image and, thus, capture time may be quite short. For example, use of multiple equal-sized blocks may enable reuse of the same aperture pattern for each of the blocks such that the measurement basis for each of the blocks is also the same and, thus, is only of block size, thereby reducing the amount of memory needed to maintain the measurement basis information (reducing memory requirements) and enabling reductions in the image reconstruction time). For example, use of multiple blocks that produce compressive measurements for overlapping image portions enables parallel processing to produce the image portions as well as use of real-time image stitching algorithms for near-real-time or real-time image reconstruction. For example, use of multiple blocks weakens the diffraction effect since it will only come from limited pixels in each block. For example, the number of blocks that are used in the block-based lensless camera may be increased in order to increase image resolution while keeping the capture rate low and maintaining fast image reconstruction (since, again, the image capture by the respective blocks may be performed in parallel such that increasing the number of blocks does not (or at least not significantly) increase image reconstruction times). It is noted that various other potential advantages are contemplated. 
       FIG. 8  depicts a high-level block diagram of a computer suitable for use in performing various functions presented herein. 
     The computer  800  includes a processor  802  (e.g., a central processing unit (CPU), a processor having a set of processor cores, a processor core of a processor, or the like) and a memory  804  (e.g., a random access memory (RAM), a read only memory (ROM), or the like). The processor  802  and the memory  804  are communicatively connected. 
     The computer  800  also may include a cooperating element  805 . The cooperating element  805  may be a hardware device. The cooperating element  805  may be a process that can be loaded into the memory  804  and executed by the processor  802  to implement functions as discussed herein (in which case, for example, the cooperating element  805  (including associated data structures) can be stored on a non-transitory computer-readable storage medium, such as a storage device or other storage element (e.g., a magnetic drive, an optical drive, or the like)). 
     The computer  800  also may include one or more input/output devices  806 . The input/output devices  806  may include one or more of a user input device (e.g., a keyboard, a keypad, a mouse, a microphone, a camera, or the like), a user output device (e.g., a display, a speaker, or the like), one or more network communication devices or elements (e.g., an input port, an output port, a receiver, a transmitter, a transceiver, or the like), one or more storage devices (e.g., a tape drive, a floppy drive, a hard disk drive, a compact disk drive, or the like), or the like, as well as various combinations thereof. 
     It will be appreciated that computer  800  of  FIG. 8  may represent a general architecture and functionality suitable for implementing functional elements described herein, portions of functional elements described herein, or the like, as well as various combinations thereof. For example, computer  800  may provide a general architecture and functionality that is suitable for implementing all or part of one or more of block-based lensless compressive image acquisition system  100 , block-based lensless compressive image acquisition system  600 , or the like. 
     It will be appreciated that at least some of the functions depicted and described herein may be implemented in software (e.g., via implementation of software on one or more processors, for executing on a general purpose computer (e.g., via execution by one or more processors) so as to provide a special purpose computer, and the like) and/or may be implemented in hardware (e.g., using a general purpose computer, one or more application specific integrated circuits (ASIC), and/or any other hardware equivalents). 
     It will be appreciated that at least some of the functions discussed herein as software methods may be implemented within hardware, for example, as circuitry that cooperates with the processor to perform various functions. Portions of the functions/elements described herein may be implemented as a computer program product wherein computer instructions, when processed by a computer, adapt the operation of the computer such that the methods and/or techniques described herein are invoked or otherwise provided. Instructions for invoking the various methods may be stored in fixed or removable media (e.g., non-transitory computer-readable media), transmitted via a data stream in a broadcast or other signal bearing medium, and/or stored within a memory within a computing device operating according to the instructions. 
     It will be appreciated that the term “or” as used herein refers to a non-exclusive “or” unless otherwise indicated (e.g., use of “or else” or “or in the alternative”). 
     It will be appreciated that, although various embodiments which incorporate the teachings presented herein have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings.