Patent Publication Number: US-2021165983-A1

Title: Apparatus for reading barcodes and capturing non-barcode images

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/422,816 (the &#39;816 Application) filed on May 24, 2019. The &#39;816 Application is a continuation of U.S. patent application Ser. No. 14/527,748 (the &#39;748 Application) filed on Oct. 29, 2014, and issued as U.S. Pat. No. 10,303,910 on May 28, 2019. The&#39;748 Application is a continuation-in-part of U.S. patent application Ser. No. 13/644,356, filed Oct. 4, 2012. The &#39;748 Application is also a continuation-in-part of U.S. patent application Ser. No. 13/708,835, filed Dec. 7, 2012. The &#39;748 Application is also related to U.S. application Ser. No. 14/319,193, filed Jun. 30, 2014, and issued as U.S. Pat. No. 9,699,004 on Jul. 4, 2017. All of the foregoing are incorporated by reference as though set forth herein in their entirety. 
    
    
     BACKGROUND 
     Smartphones (and other types of portable, hand-held computing devices, such as tablet computers) are in widespread use today, most often in connection with entertainment, communications and office productivity. Most smartphones include a camera. Therefore, with appropriate software, such smartphones can be used to read barcodes. However, smartphones typically have poor barcode reading capability. 
     SUMMARY 
     This patent specification relates generally to improving the barcode-reading capabilities of a smartphone, a tablet computer, or any other portable, hand-held computing device that comprises a camera (hereinafter, “mobile device”). More specifically, this patent specification describes components that maybe used in conjunction with mobile devices to facilitate barcode reading. One or more such components may be incorporated into an attachment for a mobile device. The attachment may include a target generating mechanism, a proximity sensor, targeting illumination that facilitates proper positioning of a barcode in the camera field-of-view, exposure illumination that is optimized for barcode reading, optics that provide an alternative optical path to the mobile device, and/or a supplementary lens system that is optimized for barcode reading. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1B  illustrate an example of a mobile device attachment that includes a target generating mechanism. 
         FIGS. 2-4  illustrate various targeting patterns that may be projected by the target generating mechanism shown in  FIGS. 1A-1B . 
         FIGS. 5A-5B  illustrate an example of a mobile device attachment that includes a proximity sensor. 
         FIG. 6  illustrates one way that a mobile device may utilize distance information provided by the proximity sensor shown in  FIGS. 5A-5B . 
         FIG. 7  illustrates another way that a mobile device may utilize distance information provided by the proximity sensor shown in  FIGS. 5A-5B . 
         FIGS. 8A-8B  illustrate an example of a mobile device attachment that includes illumination that is optimized for barcode reading. 
         FIG. 9  illustrates another example of a mobile device attachment that includes illumination that is optimized for barcode reading. 
         FIG. 10  illustrates an example of a mobile device attachment that includes a mirror that changes the optical path to the mobile device. 
         FIG. 11  illustrates an example of a mobile device attachment that includes a supplementary lens system that is optimized for barcode reading. 
         FIG. 12  illustrates an example of a mobile device attachment that automatically activates the components that improve the barcode reading capabilities of the mobile device in response to a detectable signal provided by the mobile device. 
         FIGS. 13A through 13C  illustrate one configuration of an attachment for a mobile device. 
         FIGS. 14A through 14C  illustrate another configuration of an attachment for a mobile device. 
         FIGS. 15A through 15C  illustrate another configuration of an attachment for a mobile device. 
         FIGS. 16A through 16B  illustrate another configuration of an attachment for a mobile device. 
         FIGS. 17A through 17B  illustrate two additional configurations of attachments for mobile devices. 
         FIGS. 18A through 18B  illustrate another configuration of an attachment for a mobile device. 
         FIGS. 19A through 19B  illustrate two more additional configurations of attachments for mobile devices. 
         FIGS. 20A through 20B  illustrate two more additional configurations of attachments for mobile devices. 
         FIG. 21  illustrates exemplary data flow for a barcode capture and decoding sequence driven by the attachment. 
         FIG. 22  illustrates exemplary data flow for a barcode capture and decoding sequence driven by an app running on the mobile device. 
         FIGS. 23A through 23B  illustrate a mobile device and an attachment including a first set of optics optimized for barcode reading, and a second set of optics optimized for capture of non-barcode images. 
         FIGS. 24A through 24B  illustrate a schematic block diagram of a mobile device including camera output in Y.U.V. and R.G.B. formats. 
         FIGS. 25A through 25B  illustrate exemplary autofocus and resolution binning options. 
         FIGS. 26A through 26B  illustrate methods of capturing and decoding barcodes with limited autofocus and with focus at a predetermined position, respectively. 
         FIGS. 27A through 27B  illustrate a mobile device with an attachment with optics for image capture, and optics for image illumination. 
     
    
    
     DETAILED DESCRIPTION 
     As used in this patent specification and the accompanying claims, the term “mobile device” will be used to describe a portable, hand-held computing device that comprises a camera. As indicated above, one example of a mobile device is a smartphone. Another example of a mobile device is a tablet computer. Yet another example is a hybrid tablet/smartphone device, often nicknamed a “phablet.” 
     As used herein, the term “camera” refers to an apparatus for capturing digital images. A camera that is included in a digital computing device (such as a smartphone, tablet computer, etc.) typically comprises a lens and an image sensor. 
     As used herein, the terms “attachment” and “accessory” are used synonymously, and may refer to an apparatus attached to a mobile device. An attachment for a mobile device may include just a single component that improves the barcode reading capabilities of the mobile device. Alternatively, an attachment may include multiple components that improve the barcode reading capabilities of the mobile device. In addition, an attachment for a mobile device may provide additional functionality that is unrelated to improving the barcode reading capabilities of the mobile device. 
     An attachment for a mobile device may cover a relatively small portion of the mobile device. Alternatively, an attachment for a mobile device may be a protective case that covers a substantial portion of the mobile device. Attachments may be designed for attachment to mobile devices in a wide variety of ways, including but not limited to corner-positioned attachment, encapsulating attachment, and mounting attachment. These attachment modes will be explained briefly as follows. 
     Corner-positioned attachments are attachments that are attached to cover one or more (but not all) corners of a mobile device. Corner-positioned attachments include, as examples, an attachment  100  as illustrated in  FIGS. 1A and 1B , an attachment  500  as illustrated in  FIGS. 5A and 5B , an attachment  800  as illustrated in  FIGS. 8A and 8B , an attachment  1900  as shown in  FIG. 19A , and an attachment  1950  as illustrated in  FIG. 19B . 
     Referring briefly to  FIGS. 19A and 19B , two exemplary embodiments further illustrate corner-positioned attachment to a mobile device.  FIG. 19A  illustrates an attachment  1900  secured to a single corner of the mobile device, and  FIG. 19B  illustrates an attachment  1950  secured to two corners of the mobile device by sliding it over the two corners to be covered. 
     In general, encapsulating attachments may be attachments that cover an entire side of a mobile device. Some encapsulating attachments may even cover a greater portion of the mobile device, such as the entire mobile device, or the entire mobile device with the exception of interface elements such as the display screen, buttons, electrical interfaces, infrared interfaces, and the like. 
     Examples of encapsulating attachments include an attachment  900  as illustrated in  FIG. 9 , an attachment  1300  as illustrated in  FIGS. 13A and 13B , an attachment  1400  as illustrated in  FIGS. 14A and 14B , an attachment  1500  as illustrated in  FIGS. 15A and 15B , and an attachment  1700  as illustrated in  FIGS. 17A and 7B . Each of these illustrates an attachment that encapsulates and/or serves as a protective case for the associated mobile device. 
     Mounted attachments generally are attachments that are secured to only one face and/or one edge of a mobile device. Mounted attachments may not cover any corner of the mobile device, and thus also may not encapsulate the mobile device. 
     Examples of mounting attachments include an attachment  1000  as illustrated in  FIG. 10 , an attachment  1100  as illustrated in  FIG. 11 , an attachment  2000  as illustrated in  FIG. 20A , and an attachment  2050  as illustrated in  FIG. 20B . 
     Referring briefly to  FIG. 20A  and  FIG. 20B , exemplary mounted attachments are shown. In  FIG. 20A , the attachment  2000  may be secured to a single side of the mobile device by, for example, threading, a bayonet fitting, or the like. In  FIG. 20B , the attachment  2050  may be secured to a single side of the mobile device by, for example, engagement of a spring clip of the attachment  2050  with a corresponding cavity of the mobile device. 
     An attachment may be attached to the corresponding mobile device via any attachment method known in the art, including but not limited to mechanical fasteners, frictional interfaces, adhesives, and the like. An attachment may have one or more attachment features that accomplish the selected mode of attachment. 
     For attachments that cover some portion of the mobile device from both sides (typically corner-positioned attachments and encapsulating attachments), attachment may be accomplished through the use of a frictional interface such as a modest interference fit between the interior dimension of the attachment and the exterior dimension of the portion of the mobile device that receives the attachment. For encapsulating attachments, a wide variety of attachment features are used in known examples of cases, covers, and other protectors for mobile devices. For attachments that are attached to only one side of the mobile device, other attachment modes and/or attachment features may be used, such as threaded fasteners, adhesives, snap-in interfaces, and the like. All of these attachment modes and attachment features are within the scope of the present disclosure. 
     In one aspect, this patent specification describes an attachment for a mobile device. The attachment may include: i) a supplemental power source for providing one of charging power and operating power to the mobile device; ii) one or more illumination and/or optical components that improve the barcode reading capabilities of the mobile device; and/or iii) electronics comprising hardware circuits, a processor, and/or software code stored in memory and executed by the processor that improve the barcode reading capabilities of the mobile device. The attachment, or any of the optics, circuits, or other components described in this application, may be embodied in any of a corner attachment, an encapsulating attachment, a mounted attachment, or any other attachment configuration. 
     In other aspects, this patent specification describes a mobile device and/or an application stored in a non-transient memory of the mobile device that may include: i) one or more illumination and/or optical components that improve the barcode reading capabilities of the mobile device; and/or ii) electronics comprising hardware circuits, a processor, and/or software code stored in memory and executed by the processor that improve the barcode reading capabilities of the mobile device. In this aspect, such a barcode reading enhanced mobile device may further include an attachment to further enhance barcode reading, such attachment being any of the attachments described herein embodying any of the optics, circuits, or other components described herein. 
     Target Generating Mechanism 
       FIGS. 1A-1B  illustrate an example of a mobile device attachment  100  that includes a target generating mechanism. The target generating mechanism may be utilized to facilitate rapid and optimal positioning of a mobile device  102  with respect to a barcode  104  that the mobile device  102  is attempting to read. This is especially useful when the mobile device  102  does not have a display, or the display is dimmed or turned off to conserve the battery power, or the display is difficult to be viewed when the mobile device  102  is operated as a barcode reader. 
     The target generating mechanism may include multiple targeting structures  106   a ,  106   b . These targeting structures  106   a ,  106   b  may project non-parallel targeting beams  108   a ,  108   b , each of which form a point or a pattern on the target area  110 . The targeting structures  106   a ,  106   b  may be configured so that (1) at the optimal distance from the camera  112 , the targeting beams  108   a ,  108   b  converge so that the projected patterns and/or points meet at the center of the camera&#39;s field of view  114 , and (2) at any distance from the camera  112  other than the optimal distance, the projected patterns and/or points do not meet. Thus, when the mobile device  102  is being used to read a barcode  104 , the user may move the mobile device  102  until the projected patterns and/or points meet, indicating that the mobile device  102  is at the optimal distance from the barcode  104  and that the barcode  104  is positioned within the center of the camera&#39;s field of view  114 . 
     The targeting structure  106   a  includes a light source  116   a , a prism  118   a , a collimating lens  120   a , and a pattern generating surface  122   a . The targeting structure  106   b  includes a light source  116   b , a prism  118   b , a collimating lens  120   b , and a pattern generating surface  122   b . The light sources  116   a ,  116   b  may be laser diodes, light-emitting diodes (LEDs), etc. 
     Each of the pattern generating surfaces  122   a ,  122   b  may be an interference pattern generating element or a diffractive element, such as a holographic element that may include one or more diffractive gratings. Alternatively, each of the pattern generating surfaces  122   a ,  122   b  may be a Fresnel type element that has been fabricated with the desired pattern in mind. 
       FIGS. 2-4  illustrate various targeting patterns that may be projected by the targeting structures  106   a ,  106   b . As shown in  FIG. 2 , one possible targeting pattern  224  that may be projected by the targeting structures  106   a ,  106   b  is a circle  226  with a dot  228  in the center. One targeting structure  106   a  may generate the circle  226 , while the other targeting structure  106   b  may generate the dot  228 . The targeting structures  106   a ,  106   b  may be configured so that when the mobile device  102  is an optimal distance from the barcode  104 , the dot  228  is substantially in the center of the circle  226  to form the depicted pattern  224 . 
     As shown in  FIG. 3 , another possible targeting pattern  324  that may be projected by the targeting structures  106   a ,  106   b  is a cross comprising a horizontal bar  330  and a vertical bar  332 . One targeting structure  106   a  may generate the horizontal bar  330 , while the other targeting structure  106   b  may generate the vertical bar  332 . The targeting structures  106   a ,  106   b  may be configured so that when the mobile device  102  is an optimal distance from the barcode  104 , the horizontal bar  330  and the vertical bar  332  intersect each other to form the depicted pattern  324 . 
     As shown in  FIG. 4 , another possible targeting pattern  424  that may be projected by the targeting structures  106   a ,  106   b  is a circle  434  comprising an X  436 . One targeting structure  106   a  may generate the circle  434 , while the other targeting structure  106   b  may generate the X  436 . The targeting structures  106   a ,  106   b  may be configured so that when the mobile device  102  is an optimal distance from the barcode  104 , the circle  434  and the X  436  may intersect each other to form the depicted pattern  424 . 
     Another possible targeting pattern may include one or more bars. The bar(s) may be, for example, blue LED bar(s). The length of the bar(s) may approximately coincide with the width of the field of view of the mobile device  102 . 
     Another possible targeting pattern may include multiple (e.g., two) circles. The circles may overlap at the optimal distance from the barcode  104 . 
     Proximity Sensor 
       FIGS. 5A-5B  illustrate an example of a mobile device attachment  500  that includes a proximity sensor  538 . The proximity sensor  538  may determine the distance  540  between the camera  512  and a barcode  504  that the mobile device  502  is attempting to read. The proximity sensor  538  may then provide distance information  542  about this distance  540  to the camera  512 . 
     The attachment  500  may include an interface  544  between the proximity sensor  538  and the camera  512 . The interface  544  may facilitate communication of the distance information  542  from the proximity sensor  538  to the camera  512  (e.g., to a control program  552  running on the camera  512 ). More specifically, the interface  544  may receive electrical signals  546  from the proximity sensor  538 . The electrical signals  546  may indicate the distance  540  between the camera  512  and the barcode  504  that the mobile device  502  is attempting to read. The interface  544  may convert the electrical signals  546  into distance information  542  that is in a format that the camera  512  is capable of understanding. Alternatively, the electrical signals  546  from the proximity sensor  538  may be sent to the control program  552  using a connector supported by the mobile device  502  or wirelessly. 
     The attachment  500  may also include circuitry  548  that sends control signals  550  to the camera  512 . The control signals  550  may cause the camera  512  to use the distance information  542  from the proximity sensor  538  to assist with focusing appropriately. 
     For example, referring to  FIG. 6 , the control signals  550  may cause the camera  512  to disable the camera&#39;s auto-focusing feature (step S 602 ) and set the camera&#39;s focus value based on the distance information  542  that is provided by the proximity sensor  538  (step S 604 ). 
     Alternatively, referring to  FIG. 7 , the control signals  550  may cause the camera  512  to temporarily disable the camera&#39;s auto-focusing feature (step S 702 ) and set the camera&#39;s focus value based on the distance information  542  that is provided by the proximity sensor  538  (step S 704 ). Then, the camera  512  may subsequently re-enable the camera&#39;s auto-focusing feature after the camera&#39;s focus value has been set based on the distance information  542  (step S 706 ). 
     Illumination Optimized for Barcode Reading 
       FIGS. 8A-8B  illustrate an example of a mobile device attachment  800  that includes illumination that is optimized for barcode reading. The attachment  800  may be used in connection with a mobile device  802  that includes a light source  852  that provides white illumination. This light source  852  may be referred to herein as a white light source  852 . The mobile device  802  may also include a lens  854 . 
     The attachment  800  may include one or more single-color light sources  856 . The single-color light sources  856  may be light-emitting diodes (LEDs). The single-color light sources  856  may provide red illumination (i.e., illumination having a wavelength of about 650 nm). 
     The attachment  800  may include circuitry  858  that activates and deactivates the single-color light sources  856 . This circuitry  858  may be referred to herein as activation/deactivation circuitry  858 . In addition, the attachment  800  may include circuitry  860  that detects when the white light source  852  of the mobile device  802  is activated and when the white light source  852  of the mobile device  802  is deactivated. This circuitry  860  may be referred to herein as illumination detection circuitry  860 . 
     The activation/deactivation circuitry  858  may activate the single-color light sources  856  in response to the white light source  852  of the mobile device  802  being activated. Similarly, the activation/deactivation circuitry  858  may deactivate the single-color light sources  856  in response to the white light source  852  of the mobile device  802  being deactivated. 
     For example, when the illumination detection circuitry  860  detects that the white light source  852  of the mobile device  802  has been activated, the illumination detection circuitry  860  may send control signals  862  to the activation/deactivation circuitry  858  that cause the activation/deactivation circuitry  858  to activate the single-color light sources  856 . Conversely, when the illumination detection circuitry  860  detects that the white light source  852  of the mobile device  802  has been deactivated, the illumination detection circuitry  860  may send control signals  862  to the activation/deactivation circuitry  858  that cause the activation/deactivation circuitry  858  to deactivate the single-color light sources  856 . 
       FIG. 9  illustrates another example of a mobile device attachment  900  that includes illumination that is optimized for barcode reading. The mobile device  902  includes a white light source  952 . The attachment  900  includes a light pipe  964  that redirects white illumination  966  provided by the white light source  952  of the mobile device  902 . Single-color filters  968   a ,  968   b  (e.g., red filters) within the light pipe  964  filter the redirected white illumination  966 , so that single-color illumination  970   a ,  970   b  (e.g., red illumination) is directed toward the target area  910 . A barcode  904  that is to be read through the use of the mobile device  902  and the attachment  900  may be present at the target area  910 . 
     The light pipe  964  may be configured so that the single-color illumination  970   a ,  970   b  is offset from the camera&#39;s image sensor  972  in order to prevent glare. In other words, the single-color illumination  970   a ,  970   b  may be directed toward the target area  910  from locations that are not directly in front of the camera&#39;s image sensor  972 . 
     Optics that Change the Optical Path to the Mobile Device 
     With many mobile devices, the focusing lens for the image sensor is located on the back side of the mobile device. Therefore, in order to attempt to read a barcode, the mobile device must be positioned so that the back side of the mobile device is aimed at the barcode. 
       FIG. 10  illustrates an example of a mobile device attachment  1000  that includes a mirror  1074  that changes the optical path to the mobile device  1002 . The attachment  1000  permits a user of the mobile device  1002  to attempt to read a barcode  1004  by aiming the top side  1076  of the mobile device  1002  at the barcode  1004 . Light  1078  is reflected from the barcode  1004  and redirected by the mirror  1074  toward the mobile device&#39;s focusing lens  1054 , which focuses the reflected light  1078  onto the mobile device&#39;s image sensor  1072 . 
     In the depicted example, the mirror  1074  is positioned so that the reflected light  1078  is redirected by 90°. Alternatively, however, the mirror  1074  may be positioned so that the reflected light  1078  is redirected by a different angle. 
     Supplementary Lens System Optimized for Barcode Reading 
       FIG. 11  illustrates an example of a mobile device attachment  1100  that includes a supplementary lens system that is optimized for barcode reading. The mobile device attachment  1100  may be attached to a mobile device  1102 . 
     The supplementary lens system may include an aperture  1180 . The aperture  1180  limits the amount of light that reaches the camera&#39;s image sensor  1172  through the camera&#39;s lens  1154 . This may improve the depth of field of the camera  1112 . With enhanced depth of field, the need for auto-focusing is reduced and decode response is improved. 
     The supplementary lens system may include a lens  1182  that is optimized for barcode reading. For example, the lens  1182  may minimize distortion. The lens  1182  can produce images having a relatively small field of view and a relatively large barcode element size, thus making it easier to read barcodes with small printing size (e.g., between 3 millimeters and 6 millimeters). 
     The supplementary lens system may include a single-color filter  1184  (e.g., a red filter). The single-color filter  1184  may be positioned in front of the lens  1182  that is optimized for barcode reading. 
     Activation of Components that Improve Barcode Reading Capabilities 
     As indicated above, this patent specification describes an attachment for a mobile device, wherein the attachment includes one or more components that improve the barcode reading capabilities of the mobile device. An attachment as described herein may be configured to automatically activate the components that improve the barcode reading capabilities of the mobile device in response to a detectable signal provided by the mobile device. This signal may include, for example, a recognizable illumination pattern of the mobile device. 
     An example will be described in relation to  FIG. 12 , which illustrates an attachment  1200  for a mobile device  1202 . The attachment  1200  may include one or more targeting structures  1204 . The targeting structure(s)  1204  may be similar to the targeting structures  106   a ,  106   b  shown in  FIG. 1B . The targeting structure(s)  1204  may produce targeting beams, which may be similar to the targeting beams  108   a ,  108   b  shown in  FIG. 1B . 
     The attachment  1200  may also include one or more illumination sources  1206 . The illumination source(s)  1206  may be similar to the single-color light sources  856  shown in  FIG. 8A . 
     The attachment  1200  may also include a photo-detector  1208 . The photo-detector  1208  may be an image sensor. 
     The mobile device  1202  may include one or more white illumination sources  1210 . In addition, the mobile device  1202  may include a barcode reading application  1212 . 
     The mobile device  1202  may be used to attempt to read a barcode (such as the barcode  104  shown in  FIG. 1A ). The barcode reading application  1212  may receive user input to begin attempting to read the barcode. For example, the user may press a “scan” button that is displayed via a user interface  1214  of the mobile device  1202 . In response, the white illumination source(s)  1210  of the mobile device  1202  may be activated and deactivated in accordance with a pattern that is recognizable to the photo-detector  1208  in the attachment  1200 . For example, the white illumination source(s)  1210  of the mobile device  1202  may be briefly turned on and then turned off again. 
     The photo-detector  1208  in the attachment  1200  may detect this pattern. In response, the targeting structure(s)  1204  and the illumination source(s)  1206  of the attachment  1200  may be activated for a defined time period  1216 . This time period  1216  may be configurable. During this time period  1216 , the user can aim the targeting beams at the barcode and use the mobile device  1202  to attempt to read the barcode. 
     The attachment  1200  may include its own battery  1218  to power the photo-detector  1208 , the targeting structure(s)  1204  and the illumination source(s)  1206 . 
     Attachments with Protective Cases, Batteries, and/or Magnetic Stripe Readers 
       FIGS. 13A through 13C  illustrate one configuration of an attachment  1300  for a mobile device  1302 . The attachment  1300  includes a protective case  1304 . The electronic device  1302  is insertable into the protective case  1304 . When the electronic device  1302  has been inserted into the protective case  1304 , the protective case  1304  provides a relatively hard outer shell that encompasses the side portions and the back portion of the electronic device  1302 . The display screen  1306  of the electronic device  1302  remains visible, but may be protected by a clear cover, after the electronic device  1302  has been inserted into the protective case  1304 . 
     In the depicted configuration, it is assumed that the electronic device  1302  is a smartphone or a portable media player. Consequently, the attachment  1300  is shaped so that a smartphone or a portable media player may be inserted into the attachment  1300 . However, alternative configurations of an attachment in accordance with the present disclosure may be designed and shaped for use in connection with other types of electronic devices, including any of those mentioned previously. 
     The attachment  1300  includes a battery  1308  that provides auxiliary power to the electronic device  1302 . The attachment  1300  may be configured so that when the electronic device  1302  is not connected to a DC power source and the internal battery of the electronic device  1302  becomes depleted, the electronic device  1302  receives power from the battery  1308  of the attachment  1300 . Thus, the attachment  1300  may perform the function of extending the life of the electronic device&#39;s  1302  internal battery. The battery  1308  also provides power to the attachment  1300 . 
     The battery  1308  is replaceable without having to remove the electronic device  1302  from the protective case  1304 . The protective case  1304  includes a back side  1314  (shown in  FIG. 13B ). An exterior surface of the back side  1314  of the protective case  1304  includes a battery cover  1316 . Replacing the battery  1308  comprises opening the battery cover  1316 , removing the battery  1308  from the attachment  1300 , inserting a new battery into the attachment  1300 , and closing the battery cover  1316 . 
     In the depicted configuration, opening the battery cover  1316  comprises sliding the battery cover  1316  in one direction, and closing the battery cover  1316  comprises sliding the battery cover  1316  in the opposite direction. The battery cover  1316  does not become detached from the protective case  1304  when the battery cover  1316  is opened or closed. However, other types of configurations may be utilized instead. For example, in one alternative configuration, the battery cover may be opened by completely detaching the battery cover from the protective case, and the battery cover may be closed by reattaching the battery cover to the protective case. In another alternative configuration, the battery cover may be attached to the protective case via a hinge. In such a configuration, the battery cover may be opened by lifting up on one side of the cover, and the battery cover may be closed by pushing down on the same side of the battery cover. 
     The battery  1308  may be rechargeable. There are many different types of rechargeable batteries  1308  that may be used (e.g., lithium-ion, lithium-ion polymer, nickel-cadmium, nickel-metal hydride, etc.). The attachment  1300  comprises a power interface  1310  that enables the attachment  1300  to be connected to a power source (e.g., an electrical outlet, a personal computer, a docking station, etc.) in order to charge the battery  1308 . The power interface  1310  may comprise a type of USB interface (e.g., micro, mini, or standard). 
     The attachment  1300  also comprises a barcode scan engine  1318 , which scans and decodes barcodes. The barcode scan engine  1318  may be configured to scan and decode one-dimensional and/or two-dimensional barcodes. The barcode scan engine  1318  may be, for example, the Code Reader™ 8000 Scan Engine, which is sold commercially by The Code Corporation (the assignee of the present application). However, another barcode scan engine  1318  may be utilized instead. 
     The attachment  1300  may also include a magnetic stripe reader  1320 , which reads magnetic stripe cards. A magnetic stripe card is a type of card that includes a band of magnetic material (referred to as a magnetic stripe), and that stores data by modifying the magnetism of iron-based magnetic particles on the magnetic stripe. Examples of magnetic stripe cards include credit cards, driver&#39;s licenses, access badges, etc. 
     The attachment  1300  also includes a communication interface  1322  (shown in  FIG. 13C ). The electronic device  1302  may include a similar communication interface  1324 . The communication interfaces  1322 ,  1324  may be, for example, RS232 interfaces. Data that is generated by the barcode scan engine  1318  and data that is generated by the magnetic stripe reader  1320  may be provided to the electronic device  1302  via the communication interfaces  1322 ,  1324 . The electronic device  1302  may include one or more applications  1326  that read the communication interface  1324  in order to obtain the data from the barcode scan engine  1318  and/or the magnetic stripe reader  1320 . 
     Attachments with Two-Part Cases 
       FIGS. 14A through 14C  illustrate another configuration of an attachment  1400  for a mobile device  1402 . This attachment  1400  is similar to the attachment  1300  described previously, except as indicated below. 
     In this attachment  1400 , the protective case  1404  comprises a first part  1404   a  and a second part  1404   b . The electronic device  1402  is insertable into the first part  1404   a  of the protective case  1404 . The first and second parts  1404   a ,  1404   b  of the protective case  1404  are detachable from one another, as shown in  FIG. 14A . The first and second parts  1404   a ,  1404   b  are also attachable to one another, as shown in  FIG. 14B . 
     Attaching the first and second parts  1404   a ,  1404   b  comprises positioning the first and second parts  1404   a ,  1404   b  in the manner shown in  FIG. 14A , and then sliding the second part  1404   b  into the first part  1404   a  such that connectors  1428   a ,  1428   b  in the second part  1404   b  engage receptacles  1430   a ,  1430   b  in the first part  1404   a . Friction or a mechanical latch between the connectors  1428   a ,  1428   b  and the receptacles  1430   a ,  1430   b  keep the first and second parts  1404   a ,  1404   b  attached to one another. 
       FIG. 14B  shows the protective case  1404  with the first and second parts  1404   a ,  1404   b  attached together. As shown in  FIG. 14C , when the first and second parts  1404   a ,  1404   b  are attached, there is an electrical connection between the rechargeable battery  1408  and the electronic device  1402 , so that the rechargeable battery  1408  can provide power to the electronic device  1402  when needed. 
       FIG. 14C  also shows that the first part  1404   a  of the protective case  1404  comprises a barcode scan engine  1418  and a magnetic stripe reader  1420 . The second part  1404   b  of the protective case  1404  comprises the rechargeable battery  1408  and a power interface  1410  that allows the attachment  1400  to be connected to a power source in order to charge the battery  1408 . In an alternative configuration, the power interface  1410  may be included in the first part  1404   a  of the protective case  1404 . 
     The battery  1408  is replaceable without having to remove the electronic device  1402  from the protective case  1404 . Replacing the battery  1408  comprises detaching the second part  1404   b  of the protective case  1404  from the first part  1404   a  of the protective case  1404 , and attaching a replacement second part (which includes a new battery) to the first part  1404   a.    
       FIGS. 15A through 15C  illustrate another configuration of an attachment  1500  for a mobile device  1502 . This attachment  1500  is similar to the attachment  1400  described previously, except as indicated below. 
     In this attachment  1500 , inserting the electronic device  1502  into the protective case  1504  comprises pushing the top part of the electronic device  1502  into the first part  1504   a  of the protective case  1504 , and sliding the second part  1504   b  of the protective case  1504  onto the bottom part of the electronic device  1502 . After the electronic device  1502  has been inserted into the protective case  1504 , the protective case  1504  remains in place for at least two reasons. First, the dimensions of the first and second parts  1504   a ,  1504   b  are such that the electronic device  1502  fits tightly within them. Second, the interior portions of the first and second parts  1504   a ,  1504   b  comprise felt pads  1532 . Friction between the felt pads  1532  and the electronic device  1502  also helps to keep the protective case  1504  in place. 
     The battery  1508  is replaceable without having to remove the electronic device  1502  from the protective case  1504 . Replacing the battery  1508  comprises removing the second part  1504   b  of the protective case  1504  from the bottom part of the electronic device  1502 , and sliding a replacement second part (which includes a new battery) onto the bottom part of the electronic device  1502 . The attachment  1500 , and more specifically, the first part  1504   a  of the protective case  1504 , may have a power interface  1510  that allows the attachment  1500  to be connected to a power source in order to charge the battery  1508 , a barcode scan engine  1518 , and a magnetic stripe reader  1520 . 
     Charging the Electronic Device Battery with the Attachment Battery 
     Another attachment  1600  for a mobile device  1602  will be described in connection with  FIGS. 16A and 16B . The attachment  1600  includes a battery  1608  that provides auxiliary power to the electronic device  1602 . The attachment  1600  also includes a component  1634  that is configured to charge an internal battery  1636  of the electronic device  1602  from the attachment&#39;s battery  1608  based on the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  and the remaining capacity  1640  of the attachment&#39;s battery  1608 . This component  1634  may be referred to as a charging optimization component  1634 . 
     The charging optimization component  1634  may be configured to operate as shown in  FIG. 16B . In step S 1602 , the charging optimization component  1634  may monitor the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  and the remaining capacity  1640  of the attachment&#39;s battery  1608 . In step S 1604 , the charging optimization component  1634  may determine whether the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is below the first threshold  1642 . If so, then in step S 1606  the charging optimization component  1634  may determine whether the remaining capacity  1640  of the attachment&#39;s battery  1608  is above the second threshold  1644 . If so, then in step S 1608  the charging optimization component  1634  may charge the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . 
     Charging may continue until the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is above a third threshold  1652 . More specifically, in step S 1610 , it may be determined whether the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is above the third threshold  1652 . If not, then the charging performed in step S 1608  may continue. However, once it is determined that the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is above the third threshold  1652 , then in step S 1612  charging may be discontinued. The third threshold  1652  is higher than the first threshold  1642 , and may also be higher than the second threshold  1644 . 
     The charging optimization component  1634  may include battery charging circuitry  1646  that charges the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . Charging the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608  involves putting additional energy into the electronic device&#39;s internal battery  1636 , where such additional energy is supplied by the attachment&#39;s battery  1608 . 
     The charging optimization component  1634  may also include battery capacity monitoring circuitry  1648  that monitors the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  and that also monitors the remaining capacity  1640  of the attachment&#39;s battery  1608 . The charging optimization component  1634  may also include a battery charging control module  1650  that controls the operation of the battery charging circuitry  1646  based on input from the battery capacity monitoring circuitry  1648 . 
     For example, the battery capacity monitoring circuitry  1648  may notify the battery charging control module  1650  about the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  and the remaining capacity  1640  of the attachment&#39;s battery  1608 . If the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is below the first threshold  1642  and the remaining capacity  1640  of the attachment&#39;s battery  1608  is above the second threshold  1644 , then the battery charging control module  1650  may cause the battery charging circuitry  1646  to charge the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . For example, the battery charging control module  1650  may send control signals to the battery charging circuitry  1646 , and these control signals may cause the battery charging circuitry  1646  to charge the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . As indicated above, this charging may continue until the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is above the third threshold  1652 . 
     However, if the remaining capacity  1638  of the electronic device&#39;s internal battery  1636  is not below the first threshold  1642  and/or the remaining capacity  1640  of the attachment&#39;s battery  1608  is not above the second threshold  1644 , then the battery charging control module  1650  may cause the battery charging circuitry  1646  to refrain from charging the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . For example, the battery charging control module  1650  may take no action at all, and such inaction may cause the battery charging circuitry  1646  to refrain from charging the electronic device&#39;s internal battery  1636  from the attachment&#39;s battery  1608 . 
     The battery charging circuitry  1646  and the battery capacity monitoring circuitry  1648  may be implemented via hardware. The battery charging control module  1650  may be implemented via software. 
     The attachment  1600  may include a protective case  1604 , which may be similar to any of the protective cases  1304 ,  1404 ,  1504  described previously. The electronic device  1602  may be insertable into the protective case  1604 . 
     Attachments with Additional Optics 
       FIG. 17A  illustrates an attachment  1700  for a mobile device  1702  according to another embodiment. As shown, the attachment  1700  may be of the encapsulating type referenced previously, and may thus be designed to substantially contain the mobile device  1702 . The attachment  1700  may optionally act as a protective case for the mobile device  1702  in addition to providing enhanced barcode reading capability. 
     The mobile device  1702  may be of any known type, including but not limited to smartphones, tablets, and smartphone/tablets (“phablets). The mobile device  1702  may have a variety of components, some of which are illustrated in  FIG. 17A . For example, the mobile device  1702  may have a housing  1704  that contains and/or retains the remaining components of the mobile device  1702 . The housing  1740  may a plurality of external surfaces, such as a top surface  1706 , a bottom surface  1708 , a back surface  1710 , and a bezel  1712 . Any of these surfaces may abut an attachment according to the present disclosure. 
     In the embodiment of  FIG. 17A , the attachment  1700  may be designed to serve as a protective case for the mobile device  1702 , and may thus abut all of the external surfaces of the mobile device  1702  listed above (the top surface  1706 , the bottom surface  1708 , the back surface  1710 , and the bezel  1712 ). The bezel  1712  may frame a display screen  1714  on a face surface of the mobile device  1702 , which may be left exposed by the attachment  1700  so that a user can use the display screen  1714  in a substantially unimpeded manner. Optionally, the attachment  1700  may have a clear cover or coating (not shown) that covers the display screen  1714 . 
     The housing  1704  may also contain a processor  1716 , memory  1718 , a camera  1720 , a mobile device communications interface  1722 , and a mobile device battery  1724 . Each of these may have various configurations, as known in the art. The mobile device communications interface  1722  may optionally include a universal serial bus (USB) port or other connector commonly used in mobile devices. The memory  1718  may contain various executable pieces of executable code, including but not limited to an operating system  1726  and one or more applications, or “apps.” The apps may include many different programs, one of which may be an app  1728  that can be used to capture and/or decode barcodes with the aid of the attachment  1700 . 
     The camera  1720  may include a camera lens  1730  and an image sensor array, which may include one or more sensors such as CCD (charge-coupled display) sensors, CMOS (complementary metal-oxide-semiconductor) sensors, or the like. The image sensor array may include an image sensor  1732 , as shown. The camera lens  1730  may receive light from within a camera field of view  1734 , which may, if left unmodified by the attachment  1700 , have a camera angular size  1736  as shown. The camera angular size  1736  may generally be the angle at which the camera field of view  1734  spreads. The camera  1720  may also have other parameters such as a range of focus depths, a depth of field, and the like. These parameters, along with the camera angular size  1736  of the camera field of view  1734 , may be designed primarily for general purpose photography, and may therefore not be ideal for barcode capture and/or decoding. The attachment  1700  may modify one or more of these parameters in a manner that facilitates barcode capture and/or decoding, as will be described subsequently. 
     The attachment  1700  may also have a housing  1740 . The housing  1740  may contain and/or retain various components, and may also have various interior surfaces that facilitate retention of the mobile device  1702  relative to the attachment  1700 . For example, the attachment  1700  may have a top surface  1742  that abuts the top surface  1706  of the mobile device  1702 , a bottom surface  1744  that abuts the bottom surface  1708  of mobile device  1702 , a back surface  1746  that abuts the back surface  1710  of the mobile device  1702 , and/or a bezel surface  1748  that abuts the bezel  1712  of the mobile device  1702 . 
     These surfaces may be termed “interior surfaces” because they face inward to define a cavity (not shown, as it is occupied by the mobile device  1702 ). These surfaces may be spaced apart in such a manner that the mobile device  1702  is snugly retained within the cavity, and is thus held in place relative to the attachment  1700  via frictional engagement. More specifically, the top surface  1742  and the bottom surface  1744  may face toward each other, and may be spaced apart so as to exert pressure against the top surface  1706  and the bottom surface  1708  of the mobile device  1702 , respectively, so as to retain the mobile device  1702  within the cavity. Additionally or alternatively, the back surface  1746  and the bezel surface  1748  may face toward each other, and may be spaced apart so as to exert pressure against the back surface  1710  and the bezel  1712 , respectively, so as to retain the mobile device  1702  within the cavity. Additionally or alternatively, the housing  1740  may have lateral surfaces (not shown) that face each other to retain lateral surfaces (i.e., left and right surfaces—not shown) of the mobile device  1702 . The mobile device  1702  may thus be retained relative to the attachment  1700  via frictional engagement. However, other attachment modes may be used in the alternative to or in addition to frictional engagement. 
     The housing  1740  may be divided into one or more chambers in order to restrict light passage from one component to another. For example, the housing  1740  may have a first chamber  1752  and a second chamber  1754 . A barrier  1756  may separate the first chamber  1752  from the second chamber  1754  in a manner that prevents light from either of the first chamber  1752  and the second chamber  1754  from passing directly into the other chamber. 
     The first chamber  1752  may be larger than the second chamber  1754 , and may contain components such as an attachment lens  1760 , a barrier  1762 , circuitry  1764 , and an attachment battery  1766 . The barrier  1762  may be shaped to define an aperture  1768 , which may control the system field of view  1770  within which light may be captured by the camera  1720  with the attachment  1700  in place. The system field of view  1770  may be different from the camera field of view  1734 , as will be described subsequently. 
     The circuitry  1764  may include or be electrically connected to an attachment communications interface  1772 , which may be coupled to the mobile device communications interface  1722  of the mobile device  1702  via a link  1774 . The link  1774  may be designed to convey data and/or electrical power. The first chamber  1752  may further contain a user control  1776 , which may be actuated by the user to perform various functions, such as initiating the capture of a barcode. The user control  1776  may include any form of user inputs known in the art, including but not limited to switches, levers, knobs, touch screens, microphones coupled to voice-operation software, and the like. The user control  1776  may advantageously take the form of a trigger that can be actuated, for example, with the index finger of the user. In alternative embodiments, the housing  1740  may be modified to have a pistol grip or other grip that enhances the ergonomics of the housing  1740  and/or facilitates actuation of the user control  1776 . 
     The housing  1740  may also retain a window  1778  in alignment with the attachment lens  1760  so that light is able to enter the first chamber  1752  via the window  1778  to reach the attachment lens  1760 , and after passing through the attachment lens  1760 , be received and captured by the camera  1720 . In some embodiments, the window  1778  may act as not only an exterior window that helps enclose the first chamber  1752 , but also a filter for light entering the first chamber  1752 . For example, it may be desirable to capture predominantly light of a relatively narrow segment of the visible portion of the electromagnetic spectrum, such as red light with a wavelength of approximately 660 nm. The window  1778  may thus have a colored tint and/or polarization that helps restrict light entry into the first chamber  1752  to only a narrow wavelength band desired for image capture for effective barcode decoding. In other embodiments, the window  1778  need not act as a filter, but may instead permit visible light of any wavelength to enter the first chamber  1752 . In such an event, a separate filter (not shown) may optionally be positioned within the first chamber  1752 , along the system optical pathway  1786 . 
     The attachment lens  1760 , the barrier  1762 , and the window  1778  may all be parts of an optic system of the attachment  1700 . An “optic system” may be any set of one or more components positioned in the field of view of a camera to modify one or more parameters regarding light received by the camera, such as the quantity of light received, the optical pathway along which light is received, the angular size of the field of view, the depth of field, the focus distance, and/or the wavelength(s) of light received. Thus, an optic system, in various components, may include any of various components such as lenses, filters, mirrors, apertures, and the like. 
     The second chamber  1754  may have one or more illumination systems. More specifically, the second chamber  1754  may have a targeting illumination system  1780  and an exposure illumination system  1782 . The targeting illumination system  1780  may provide a distinct illumination pattern that projects into the attachment field of view  1770 . The illumination pattern may indicate to the user whether the barcode is properly positioned for capture and/or decoding. Such an illumination pattern may include various projected features such as crosshairs, circles, boxes, and the like. The targeting illumination system  1780  may include various components that project such features, including but not limited to lasers, light-emitting diodes (LED&#39;s), incandescent lights, fluorescent lights, and the like. Light sources such as lasers may advantageously project a narrow beam of light. Where the targeting illumination system  1780  includes a light source with a wider broadcast area, it may be desirable to use a mask with relatively narrow lines, small points, or other apertures that provide the desired distinction in the projected light. 
     The targeting illumination system  1780  may be designed to project light only prior to and/or after image capture so as to avoid interfering with decodability of the barcode image. Conversely, the exposure illumination system  1782  may illuminate objects (such as barcodes) within the system field of view  1770  during image capture. The exposure illumination system  1782  may thus act like the flash present on many cameras, and may provide a diffuse illumination pattern to enhance decodability of the barcode image by ensuring that has been sufficiently illuminated to provide the contrast in pixel luminance values necessary for reliable decoding. The exposure illuminating system  1782  may include various light sources, including but not limited to lasers, LED&#39;s, incandescent lights, fluorescent lights, and the like. The exposure illuminating system  1782  may advantageously have one or more light sources with a wide broadcast area, such as LED lights. If desired, the broadcast area of the exposure illumination system  1782  may be tuned to generally match the system field of view  1770 . 
     In this application, a “distinct illumination pattern” is an illumination pattern produced by light that is focused to provide relatively crisp lines or other shapes. Thus, the illumination produced by a laser is an example of light that would typically produce a distinct illumination pattern. By contrast, a “diffuse illumination pattern” is an illumination pattern produced by light that is not focused at any particular location, but rather emanating into a broad area. Thus, the illumination produced by a typical light bulb is an example of light that would typically produce a diffuse illumination pattern. 
     In some embodiments, the light for such an exposure illumination system may not be generated by the attachment  1700 , but may instead be generated by the mobile device  1702 . For example, the mobile device  1702  may have an illumination torch incorporated into the camera  1720 ; the illumination from such an illumination torch may be redirected and/or focused into the system field of view  1770  by an exposure illumination system. 
     Returning to the embodiment of  FIG. 17A , the targeting illumination system  1780  and the exposure illumination system  1782  may be electrically connected to the circuitry  1764  as shown. The targeting illumination system  1780  and the exposure illumination system  1782  may also be connected to the attachment battery  1766 , either independently of the electrical connection to the circuitry  1764 , or via the electrical connection to the circuitry  1764 . Thus, the targeting illumination system  1780  and the exposure illumination system  1782  may be controlled by the circuitry  1764  and powered by the attachment battery  1766 . 
     As mentioned previously, the barrier  1756  may serve to keep light from passing directly between the first chamber  1752  and the second chamber  1754 . Thus, light from the targeting illumination system  1780  and/or the exposure illumination system  1782  may be unable to spillover from the second chamber  1754  into the first chamber  1752  during image capture. Such spillover could otherwise cause interference with image capture by permitting light that did not come from within the system field of view  1770  to pass into and be captured by the image sensor  1732  of the camera  1720 . 
     As mentioned previously, the parameters of the camera  1720 , such as the camera angular size  1736  of the camera field of view  1734 , the range of focus depths, and the depth of field, of the camera  1720  may not be ideal for barcode capture and/or decoding. Thus, any or all of these parameters may be modified by the attachment  1700 . Thus, the system field of view  1770  may have a system angular size  1784  that is significantly smaller than the camera angular size  1736  of the camera field of view  1734 . This may be because conventional photography often uses a wider lens angle than is needed for capturing barcode images. 
     The system field of view  1770  may provide a system ratio of focal length to entrance pupil diameter that is greater than a camera ratio of focal length to entrance pupil diameter of the camera  1720  without the attachment  1700 . Thus, the attachment  1700  may act to increase the f-stop of the camera  1720 . 
     The system field of view  1770  may be centered on a system optical pathway  1786 , which may be the same as the optical pathway for the camera  1720  without the attachment  1700 . More specifically, the camera  1720  may be designed to capture images centered on an optical pathway perpendicular to the back surface  1710  of the mobile device  1702 . This optical pathway may not be modified by the attachment  1700  in this embodiment; thus, the system optical pathway  1786  may be the same as the optical pathway for the camera  1720 , unaided. However, in other embodiments, it may be desirable for an attachment to provide a different optical pathway for barcode scanning, as will be shown and described subsequently. 
     The mobile device  1702  and the attachment  1700 , combined, may also have a system focus depth  1788 , which may advantageously be adjustable. The range of focus depths to which the mobile device  1702  and the attachment  1700  are adjustable may be different from those applicable to the camera  1720 , alone. Barcodes may be scanned from relatively close (typically a distance ranging from a few inches to a few feet), which may be significantly shorter than the average focus depth for a non-barcode image captured with a mobile device. Thus, it may be beneficial for the attachment lens  1760  to facilitate image capture at shorter focus depths. 
     Further, the mobile device  1702  and the attachment  1700 , combined, may have a depth of field (not shown), consisting of the depth along the system optical pathway  1786  through which an object may remain in focus (to a degree acceptable for barcode capture and/or decoding) on either side of the system focus depth  1788 . A relatively large depth of field may advantageously permit barcode capture and/or decoding at a wider ranges of distances between the mobile device  1702  and the barcode to be captured. Thus, the attachment lens  1760  may advantageously provide a relatively larger depth of field, particularly at shorter focus depths, than the camera  1720 , unaided. 
     The process of capturing a barcode image containing a barcode, with the attachment  1700  and the mobile device  1702 , may be relatively straightforward. In some embodiments, the user may perform all operations via the app  1728 . The app  1728  may have a user interface (not shown) with one or more graphical elements displayed on the display screen  1714 . The user may use such graphical elements to initiate the barcode scanning process (for example, by tapping a “scan” soft button on the display screen  1714 ). In response, the mobile device  1702  may transmit a scan initiation signal to the attachment  1700  over the link  1774 . The initiation signal may activate the targeting illumination system  1780 , which may project targeting illumination that helps the user to properly position the barcode within the system field of view  1770 . 
     After a predetermined period of time, or upon determining that the barcode is properly positioned, the mobile device  1702  may transmit a capture initiation signal to the attachment over the link  1774 . The initiation signal may deactivate the targeting illumination system  1780  and/or activate the exposure illumination system  1782 . The mobile device may then capture the image containing the barcode with the image sensor  1732 , while the exposure illumination system  1782  is active. The mobile device  1702  may then send a completion signal to the attachment  1700  via the link  1774 . In response, the attachment  1700  may deactivate the exposure illumination system  1782 . Additionally or alternatively, the mobile device  1702  may transmit, for example, with the capture signal, a duration of the exposure. The attachment  1700  may then deactivate the exposure illumination system  1782  automatically when the specified exposure duration has elapsed. Once the image containing the barcode has been captured, it may be automatically be decoded, for example, by the app  1728 . In the alternative, the image containing the barcode may be transmitted to a remote decoder, such as a server, for decoding. 
     It should be noted that his process enables altering between the targeting illumination system  1780  being active (while the exposure illumination system  1782  is de-active) and the exposure illumination system  1782  being active (while the targeting illumination system  1780  is de-active) such that the user may utilizing targeting illumination to continually aim, or adjust aim, of the field of view in reliance on the targeting illumination while the image sensor may capture images of the barcode in reliance on the exposure illumination. 
     It is also envisioned that the system could determine that the barcode is properly positioned by providing a control, such as graphical element to initiate capture of an image containing the barcode. This may be done, for example, by the user tapping a “capture” soft button on the display screen  1714  when the properly positioned. 
     In addition to or in the alternative to the use of the app  1728 , the scanning, capture, and/or decoding steps may be carried out through the use of the user control  1776 . For example, the user control  1776  may be actuated by the user to launch the app  1728 , which may either run in the foreground or the background. Actuation of the user control  1776  may cause the attachment communications interface  1772  to transmit an initiation signal to the mobile device  1702  to launch the app  1728 . 
     The features and functionality set forth in the descriptions of previous embodiments may also be applied to the attachment  1700 . Thus, for example, the attachment battery  1766  may optionally be used to power the mobile device  1702  and/or recharge the mobile device battery  1724 . 
     Attachments with Nonparallel Optical Pathway 
     As mentioned previously, the system optical pathway  1786  of the mobile device  1702  and the attachment  1700  may be perpendicular to the back surface  1710  of the attachment  1700 . In some embodiments, it may be desirable to have the optical pathway extend along a different direction from that of the camera of the mobile device. One such example will be shown and described in connection with  FIG. 17B . 
       FIG. 17B  illustrates an attachment  1750  for a mobile device  1702  according to another embodiment. Like the attachment  1700 , the attachment  1750  may also be of the encapsulating type referenced previously, and may thus be designed to substantially contain the mobile device  1702 . The attachment  1750  may optionally act as a protective case for the mobile device  1702  in addition to providing enhanced barcode reading capability. 
     The attachment  1750  may have a configuration generally similar to that of the attachment  1700  of  FIG. 17A . Various parts of the attachment  1750  that are similar to or identical to their counterparts of the attachment  1700  will not be described. 
     As shown, the attachment  1750  may have a housing  1790  that contains components similar to those of the housing  1740  of the attachment  1700 . The housing  1790  may have a first chamber  1792  and a second chamber  1794 . The first chamber  1792  may have an enlarged top portion (i.e., the portion of the first chamber  1792  positioned on the left in  FIG. 17B ) that accommodates a reflective surface in the form of a mirror  1795 . If desired, the bottom portion of the first chamber  1792  may be relatively compact, like that of the first chamber  1752  of the previous embodiment. This shape may make it easier for a user to grip the bottom portion of the housing  1790  with one or two hands and point the top portion of the housing  1790  toward the barcode to be scanned. 
     The mirror  1795  may redirect the optical pathway of the camera and attachment lens from a first direction  1796  perpendicular to the back surface  1710  of the mobile device  1702  to a second direction  1798  parallel to the back surface  1710  of the mobile device  1702 . The second direction  1798  may extend into an area above the top surface  1706  (i.e., the top side) of the mobile device  1702 . Thus, a user holding the mobile device  1702  horizontally, as oriented in  FIG. 17B , may easily point the mobile device  1702  and the attachment  1750  such that the optical pathway extends laterally, toward objects located forward of or lateral to the user. 
     The mirror  1795  is only one of multiple reflective surfaces that may be used according to the invention. In alternative embodiments, redirection may be accomplished through the use of one or more prisms, fiber optic wiring, and/or any other light redirection hardware known in the art. 
     The housing  1790  may retain a window  1799  that extends perpendicular to the second direction  1798 . Like the window  1778  of the previous embodiment, the window  1799  may optionally be tinted to permit only light of a selected wavelength range to enter the first chamber  1792 . 
     The second chamber  1794  may have a shape similar to that of the second chamber  1754  of the previous embodiment. The second chamber  1794  may contain a targeting illumination system  1780  and an exposure illumination system  1782 , both of which may be substantially as described in  FIG. 17A . The second chamber  1794  may be isolated from the first chamber  1792  so that illumination from the second chamber  1794  is unable to pass directly into the first chamber  1792  to interfere with barcode imaging. 
     As shown, the second chamber  1794  may be oriented to project the targeting illumination and exposure illumination into the area over the top of the mobile device  1702  (to the left in the view of  FIG. 17B ). Thus, the targeting illumination system  1780  and the exposure illumination system  1782  may both project illumination into the field of view of the system made up of the mobile device  1702  and the attachment  1750 . This field of view (not shown) may be centered on the second direction  1798  shown in  FIG. 17B . 
       FIGS. 18A and 18B  illustrate another configuration of an attachment  1800  for a mobile device  1802 .  FIGS. 18A and 18B  are a side elevation view and a top elevation view, respectively, of the attachment  1800  and the mobile device  1802 . Like the attachment  1750  of  FIG. 17B , the attachment  1800  may also be of the encapsulating type referenced previously, and may thus be designed to substantially contain the mobile device  1802 . The attachment  1800  may optionally act as a protective case for the mobile device  1802  in addition to providing enhanced barcode reading capability. 
     The attachment  1800  may generally be similar to the attachment  1750  of  FIG. 17B . Various parts of the attachment  1800  that are similar to or identical to their counterparts of the attachment  1750  will not be described. The mobile device  1802  may be similar in configuration to the mobile device  1702  of  FIGS. 17A and 17B ; some features of the mobile device  1802  have not been shown for clarity. 
     As shown, the attachment  1800  may have a housing  1840  with a first chamber  1852  and a second chamber  1854 . The housing  1840  may have an enlarged top portion and a relatively compact bottom portion, which may be sized to be readily gripped in the hand of a user. The first chamber  1852  may contain various components, which may include, but need not be limited to, circuitry  1864 , an attachment battery  1866 , an attachment communications interface  1872  connected to the mobile device communications interface  1722  by a link  1874 , a user control  1876 , a system lens  1860 , and a mirror  1845 . 
     As in the previous embodiment, the attachment  1800  may utilize the mirror  1845  to redirect an optical pathway of the camera  1720  from a first direction  1896  perpendicular to a back surface  1710  of the mobile device  1802  to a second direction  1898  generally parallel to the back surface  1710 . The second direction  1898  may thus be substantially orthogonal to the first direction  1896 . 
     The second chamber  1854  may house a targeting illumination system  1880  and an exposure illumination system  1882 , which may be similar in function to their counterparts of the previous embodiment. The second chamber  1854  may effectively isolate the targeting illumination system  1880  and the exposure illumination system  1882  from the components within the first chamber  1852  to prevent light from entering the first chamber  1852  directly from the targeting illumination system  1880  and/or the exposure illumination system  1882 . 
     A window  1899  may be retained by the housing  1840  and may define a wall of the housing that covers the first chamber  1852  and the second chamber  1854 . The window  1899  may optionally be tinted, polarized, or otherwise configured to define a filter that permits passage of light of only certain wavelengths to enter and/or leave the first chamber  1852  and/or the second chamber  1854 . Advantageously, when positioned to cover the second chamber  1854 , the window  1899  may serve to control the wavelength of light that can be emitted from the housing  1840  by the targeting illumination system  1880  and the exposure illumination system  1882 . Thus, barcodes to be imaged with the mobile device  1802  may be illuminated only with light of the frequencies that are best suited to illuminate the barcode for capture and decoding. Such an arrangement may also help make the mobile device  1802  and the attachment  1800  less obtrusive by reducing the emission of visible light of the brighter, more noticeable frequencies. 
     In addition to or in the alternative to filtering, the window  1899  may act as a supplemental lens, and may thus further modify the optical properties (besides wavelength) of the light entering the first chamber  1852  and/or the light leaving the second chamber  1854 . For example, the window  1899  may be shaped to act in concert with the system lens  1860  to help control a depth of field, a focus distance, an angular size, and/or other qualities of the resulting system field of view of the mobile device  1802  combined with the attachment  1800 . 
       FIG. 18B  illustrates a section view of the mobile device  1802  and the attachment  1800  from the top, providing a view into the first chamber  1852 .  FIG. 18B  illustrates the mirror  1845 , which may be positioned alongside a barcode scanning engine  1850 . The barcode scanning engine  1850  may function in tandem with the mirror  1845  and the camera  1720  of the mobile device  1802 , or may function separately therefrom. The barcode scanning engine  1850  may contain various components for scanning barcodes, such as a specialized camera, targeting illumination system, exposure illumination system, decoding hardware, and/or controller. In some embodiments, the barcode scanning engine  1850  may be used to image and decode some barcodes, while other types are imaged by the camera  1720  and decoded by the mobile device  1802 . 
     The presence, in the attachment  1800 , of both the barcode scanning engine  1850  and the remaining components that facilitate barcode scanning with the mobile device  1802  is optional. In alternative embodiments, an attachment may have only a barcode scanning engine  1850  that functions substantially independently of the hardware of the mobile device  1802 , or only components that facilitate barcode image capture and/or decoding with the hardware of the mobile device  1802 . 
     Corner-Positioned Attachments 
     As mentioned previously, some attachments that facilitate barcode image capture and/or decoding may cover only some (but not all) corners of a mobile device. Such attachments may advantageously be relatively compact and unobtrusive. 
       FIGS. 19A through 19B  illustrate two more additional configurations of attachments for mobile devices, which utilize corner-positioned attachment. More specifically,  FIG. 19A  illustrates an attachment  1900  secured to a mobile device  1902 , and  FIG. 19B  illustrates an attachment  1950  secured to a mobile device  1902  like that of  FIG. 19A . 
     The mobile device  1902  of  FIGS. 19A and 19B  may be a smartphone with a top surface  1906  (not visible in  FIG. 19B ), a back surface  1910 , a bezel  1912 , a right side  1916 , and a left side  1918 . The mobile device  1902  may have a camera with a lens that receives light through an aperture on the back surface  1910 . The aperture may be covered by the attachment  1900  or the attachment  1950 . 
     The attachment  1900  may provide an optic system, which may modify one or more parameters of the light received by the camera of the mobile device  1902 . As set forth previously, these parameters may include, but need not be limited to, the quantity of light received, the optical pathway along which light is received, the angular size of the field of view, the depth of field, the focus distance, and/or the wavelength(s) of light received. The optic system of the attachment  1900  may include one or more components that provide such modification. Such components may include, but need not be limited to, lenses, filters, mirrors, apertures, and the like. 
     If desired, the attachment  1900  may have all of the elements of attachment  1800  described in  FIGS. 18A and 18B  or it may have a simplified design compared to the attachment  1800 . For example, the attachment  1900  may not have circuitry, a battery, or an illumination system. Rather, the attachment  1900  may have only the optic system. Hence, the attachment  1900  may not need electrical power or an electrical connection to the mobile device  1902 . The attachment  1900  may simply have an aperture  1920  through which light enters the attachment  1900  to pass through the optic system and enter the camera of the mobile device  1902 . 
     Mechanically, the attachment  1900  may be secured to the mobile device  1902  via frictional engagement. More specifically, the attachment  1900  may have a plurality of interior surfaces that cooperate to define a cavity sized to retain the corner of the mobile device  1902  with some moderate interference. 
     For example, the attachment  1900  may have a back surface  1930  that faces the back surface  1910  of the mobile device  1902 , and a front surface  1932  that faces the bezel  1912 . When the attachment  1900  is installed on the mobile device  1902 , the back surface  1930  may abut the back surface  1910 , and the front surface  1932  may abut the bezel  1912 . The distance between the back surface  1930  and the front surface  1932  may be sufficiently large to permit the attachment  1900  to be inserted onto the corner of the mobile device  1902  without excessive difficulty, but also small enough that, once installed, the attachment  1900  will not slide free of the mobile device  1902 . Since the attachment  1900  only covers a single corner of the mobile device  1902 , the attachment  1900  may be installed on the mobile device  1902  by sliding the attachment  1900  along the top surface  1906  and/or parallel to the right side  1916 . 
     The attachment  1950  may have a configuration similar to that of the attachment  1900 , except that the attachment  1950  may cover not one, but two corners of the mobile device  1902 . Thus, the attachment  1950  may cover the entirety of the top surface  1906 . The attachment  1950  may slide into engagement with the mobile device by sliding the attachment  1950  along the back surface  1910 , the bezel  1912 , the right side  1916 , and the left side  1918 . 
     The attachment  1950  may have a back surface  1980  that faces the back surface  1910  of the mobile device  1902 , a front surface  1982  that faces the bezel  1912 , a left surface  1986  that faces the right side  1916 , and a right surface  1988  that faces the right surface  1988 . The back surface  1980  and the front surface  1982  may be spaced apart to provide the moderate interference fit described above in connection with the attachment  1900  of  FIG. 19A . Additionally or alternatively, the left surface  1986  and the right surface  1988  may be spaced apart to provide the moderate interference fit described above. In either case, the attachment  1950  may grip the top portion of the mobile device  1902  to remain securely in place until the user desires to remove it. 
     In the alternative to frictional engagement, the attachment  1900  and the attachment  1950  may be secured to the mobile device  1902  through the use of various other attachment methods. Such attachment methods include, but need not be limited to, mechanical fasteners, adhesives, and the like. 
     Mounted Attachments 
     As mentioned previously, another attachment mode for attachments that facilitate barcode image capture and/or decoding is a mounted attachment. Such attachments need not cover any corners of the mobile device in order to remain in place, and may also be relatively compact and unobtrusive. 
       FIGS. 20A through 20B  illustrate two more additional configurations of attachments for mobile devices, which utilize mounted attachment. More specifically,  FIG. 20A  illustrates an attachment  2000  secured to a mobile device  2002 , and  FIG. 20B  illustrates an attachment  2050  secured to a mobile device  2052 . 
     The mobile device  2002  of  FIG. 20A  may be a smartphone with a top surface  2006 , a back surface  2010 , a bezel  2012 , a right side  2016 , and a left side  2018 . The mobile device  2002  may have a camera with a lens that receives light through an aperture  2020  on the back surface  2010 . The aperture  2020  may be covered by the attachment  2000  when the attachment  2000  is mounted on the mobile device  2002 . 
     Like the attachment  1900  and the attachment  1950  of  FIGS. 19A and 19B , respectively, the attachment  2000  may provide an optic system, which may modify one or more parameters of the light received by the camera of the mobile device  1902 . The attachment  2000  may thus include any of the components mentioned previously to accomplish such modification. The attachment  2000  may also have a simplified design with only the optic system, and may have an aperture  2030  through which light enters the attachment  2000  to pass through the optic system and enter the camera of the mobile device  1902 . 
     Mechanically, the attachment  2000  may be secured to the mobile device  2002  via a fastening interface, which may include a mobile device element  2022  on the mobile device  2002 , proximate the aperture  2020 , and an attachment element  2034  on the attachment  2000 . The mobile device element  2022  and the attachment element  2034  may each have generally circular (or cylindrical) configuration. 
     In some embodiments, the mobile device element  2022  may take the form of a threaded receptacle, and the attachment element  2034  may take the form of a threaded extension. The attachment  2000  may be secured to the mobile device  2002  by simply screwing the attachment element  2034  into the mobile device element  2022 . In alternative embodiments, different fastening systems may be used. Such fastening systems may include bayonet fasteners, frictional engagements, snap-in fastening systems, and the like. 
     The mobile device  2052  may be similar to the mobile device  2002 . However, in place of the aperture  2020  and the mobile device element  2022 , the mobile device  2052  may have an aperture  2070  and a mobile device element  2072  of a different shape. More precisely, the mobile device element  2072  may be rectangular in shape rather than round. The mobile device element  2072  may take the form of a recess surrounding the aperture  2070  with the rectangular shape. 
     Similarly, the attachment  2050  may be rectangular in shape, and may be sized to fit into the mobile device element  2072 . The attachment  2050  may have an aperture  2080  and an attachment element  2084  in the form of a plurality of bumps around the periphery of the rectangular shape of the attachment  2050 . If desired, the mobile device element  2072  may include corresponding detents that receive the bumps so that the attachment  2050  snaps into place when pressed into the mobile device element  2072 . 
     The attachment  2000  and the attachment  2050  represent only two of many examples of mounted attachments that may be mounted to mobile devices to facilitate barcode capture and/or decoding. In other embodiments, different attachment shapes and/or mounting methods may be used. In some embodiments, attachments may be adhesive bonded, fastened, otherwise mounted to, or even integrally formed with the back cover of a mobile device. Such a back cover may be a panel that is attachable to the remainder of the mobile device to define, for example, the back surface  2010  of the mobile device  2002 . 
     Attachment Control of Barcode Capture 
     As mentioned in the description of  FIG. 17A , the process of capturing and/or decoding a barcode may be managed from a mobile device and/or from an attachment.  FIGS. 21 and 22  illustrate how this may be accomplished with respect to any of the mobile devices and/or attachments disclosed in this specification. 
       FIG. 21  illustrates exemplary data flow for a barcode capture and decoding sequence driven by the attachment. Thus, as carried out in  FIG. 21 , barcode capture may be accomplished through the use of a user control such as the user control  1776  of  FIG. 17A . 
     As shown, barcode image capture and decoding may be initiated from the attachment via a trigger  2102 , such as user actuation of a user control on the attachment. Additionally or alternatively, the user may initiate barcode capture via a soft trigger  2104 , which may be a soft button of an app, such as the app  1728  of  FIG. 17A . The app  1728  may be software that is specific to a certain attachment, or may be a hardware-independent barcode scanning app. 
     In response to receipt of the trigger  2102  or the soft trigger  2104 , the attachment may transmit a disable autofocus instruction  2106  to the mobile device to cause the operating system or other camera control software to perform a step  2110  in which the autofocus feature of the camera is disabled, the camera is set to focus at a given focus distance, the autofocus feature of the camera is set to operate within a limited range of focus depths, and/or other steps are taken to establish the focus settings of the camera. The attachment may also perform a step  2112  in which the attachment activates the targeting illumination system, such as the targeting illumination system  1780  of  FIG. 17A . 
     The attachment may receive a focus set confirmation  2114  from the mobile device. The focus set confirmation  2114  may confirm that the subject matter to be imaged is in proper focus. In the event that the autofocus feature of the camera is used in some capacity, the focus set confirmation  2114  may be sent in response to convergence of the focusing operations on a consistent focus setting. 
     The attachment may then, in a step  2120 , turn off the targeting illumination system, and then in a step  2122 , turn on the exposure illumination system. Once the exposure illumination system has been activated, the attachment may transmit an image capture signal  2124  to the mobile device. In response, the mobile device may perform a step  2130  in which it captures one or more images with the camera, each of which may be with a different exposure duration and/or gain setting with respect to the other images. 
     After image capture is complete, the mobile device may transmit an image capture complete signal  2132  to the attachment. The attachment may perform a step  2140  in which the exposure illumination system is deactivated. The attachment may perform a step  2142  in which it reactivates the targeting illumination system in preparation for recapture of the barcode, if needed. 
     Meanwhile, the mobile device may perform a step  2134  in which it attempts to decode the barcode using the captured image(s) containing the barcode. As mentioned previously, this may be done locally (i.e., within the mobile device) or by a different computing device remote from the mobile device. The mobile device may transmit a decode failure/decode success signal  2144  to the attachment. 
     The attachment may receive the decode failure/decode success signal  2144  and turn off the targeting illumination system in a step  2150 . This may be done regardless of whether decoding was successful because in either case, the targeting illumination system will be deactivated (because the barcode was successfully decoded or because a new image of the barcode needs to be captured). 
     Pursuant to a query  2152 , if the decoding was successful, the capture/decoding process may end  2154 . If the decoding failed  2160 , the apparatus may return to the step  2122  and turn on the image exposure illumination once again to re-capture the image and attempt to re-decode the barcode. The process may repeat until the barcode has been successfully decoded. 
       FIG. 22  illustrates exemplary data flow for a barcode capture and decoding sequence driven by the mobile device. Barcode image capture and decoding may be accomplished through the use of an app such as the app  1728  of  FIG. 17A . A user control such as the user control  1776  of  FIG. 17A  may also optionally be used. 
     As shown, barcode capture may be initiated from the attachment via a trigger  2202 , such as user actuation of a user control on the attachment. A trigger signal  2204  may be transmitted to the mobile device in response to receipt of the trigger  2202  by the attachment. Additionally or alternatively, the user may initiate barcode capture via a soft trigger  2206 , which may be a soft button of an app as described previously. 
     In response to receipt of the trigger signal  2204  or the soft trigger  2206 , the app may transmit an instruction to the operating system or other camera control software to perform a step  2210  in which the autofocus feature of the camera is disabled, the camera is set to focus at a given focus distance, the autofocus feature of the camera is set to operate within a limited range of focus depths, and/or other steps are taken to establish the focus settings of the camera. 
     The app may also transmit a start exposure signal  2212  to the attachment. In response, the attachment may perform a step  2220  in which the exposure illumination system is turned on. The attachment may transmit an illumination on signal  2222  back to the mobile device to confirm that the exposure illumination system has been activated. The app may then initiate capture of one or more images, each with a different exposure period and/or gain setting, with the camera in a step  2224 . 
     Once the barcode image has been captured by the camera, the mobile device may transmit an image capture complete signal  2230  to the attachment. In response to receipt of the image capture complete signal  2230 , the attachment may perform a step  2232  in which the exposure illumination is deactivated. The attachment may also perform a step  2242  in which the targeting illumination is activated in case there is a need to capture a new barcode image. 
     Meanwhile, the mobile device may, in a step  2240 , attempt to decode the barcode image(s). The mobile device may transmit a start exposure or complete signal  2250  to the attachment to indicate whether the process is complete (indicating successful decode) or there is a need to capture a new barcode image. In response to receipt of the start exposure or complete signal  2250 , the attachment may perform a step  2252  in which the targeting illumination system is deactivated. 
     Pursuant to a query  2260 , if the start exposure or complete signal  2250  indicated that the process is complete, the process may end  2262 . If, instead, the start exposure or complete signal indicated that a new barcode image is to be captured, the attachment may commence the process to start an exposure  2264  by returning to the step  2220 , in which the exposure illumination system is activated. 
     It should be appreciated that each of the signals sent between the mobile device and the attachment as described may be through the hardwired communication interface ( 1722 ,  1774 ,  1772   FIG. 1A ) or through a wireless link such as Bluetooth®. 
     System with Multiple Sets of Optics 
     It may be desirable for a single device to be capable of capturing barcode images and non-barcode images with a minimum of reconfiguration. Such a system may be used, for example, to take ordinary photographs and barcode images interchangeably. One way in which this may be accomplished is through the use of multiple sets of optics, which may coexist within a mobile device ( FIG. 23A ) or an attachment for a mobile device ( FIG. 23B ). 
       FIG. 23A  illustrates a mobile device  2302  that has two sets of optics for capturing different types of images. The mobile device  2302  may have a configuration that is otherwise similar to other mobile devices described previously in this disclosure. 
     Thus, the mobile device  2302  may have a housing  2304  that contains and/or retains a variety of components. The housing  2304  may have various exterior surfaces as well, including a top surface  2306  and a back surface  2310 . The housing  2304  may retain a display screen  2314  on its face side. Within the housing  2304 , the mobile device  2302  may have a processor  2316 , memory  2318 , a mobile device battery  2324 , a controller  2342 , a zoom module  2344 , and an autofocus module  2346 , an image sensor array with an image sensor  2332 . The processor  2316 , memory  2318 , and mobile device battery  2324  may be as described in connection with previous embodiments. The memory  2318  may contain an operating system  2326  and a plurality of apps, including an app  2328  that controls the operation of a camera (not shown for clarity) of which the image sensor  2332  is a part. 
     The zoom module  2344  and the autofocus module  2346  may serve to control the optical zoom setting and/or autofocus setting of the camera. They may be controlled by the controller  2342 . As shown, the camera may include two separate optic systems: a first optic system and a second optic system. The first optic system may be designed to facilitate the capture and/or decoding of barcode images, and may include a first lens  2380 , a first window  2382 , and a reflective surface in the form of a mirror  2348 . The second optic system may be designed to facilitate the capture of non-barcode images, and may include a second lens  2390  and a second window  2392 . 
     As shown, the first optic system may have a first optical pathway  2384  extending parallel to the back surface  2310 , perpendicular to the top surface  2306 . As in the embodiment of  FIG. 17B , this arrangement may facilitate the capture of images for barcodes positioned generally in-plane with the mobile device  2302 . If desired, a targeting illumination system and/or an exposure illumination system (not shown) may be included, and may be oriented to project light into a first field of view  2386  of the first optic system. The first field of view  2386  may be centered on the first optical pathway  2384 . 
     As shown, the second optic system may have a second optical pathway  2394  extending parallel to the top surface  2306 , perpendicular to the back surface  2310 . This arrangement may facilitate the capture of non-barcode images because people are generally accustomed to digital photography in which the optical pathway is generally along their line of sight (i.e., parallel to the direction in which they look to view the display screen  2314 ). If desired, an exposure illumination system and/or illumination torch (not shown) may be used to illuminate non-barcode objects to be imaged; the illumination from such systems may be projected into a second field of view  2396  of the second optic system. The second field of view  2396  may be centered on the second optical pathway  2394 . 
     If desired, the first field of view  2386  and the second field of view  2396  need not be the same size. For example, if barcodes are to be imaged at very close range, the first field of view  2386  may have an angular size that is larger than that of the second field of view  2396 . Conversely, if barcodes are to be imaged from a greater distance, or wide-angle non-barcode photography is desired, the angular size of the second field of view  2396  may be larger than that of the first field of view  2396 . 
     Additionally or alternatively, other parameters of the first and second optic systems may be different. For example, the first and second optic systems may have different focus depths, depths of field, f-stop values, or the like. Typically the first optic system for reading barcode may have a higher f-stop value and therefore a greater depth of field. The second optic system may have a smaller f-stop value (i.e. larger aperture) with a small depth of field and wherein an auto focus system provides for a greater range of focus depths for photography. 
     As another example, the first optic system may have a filter that limits passage of light through the first optic system to certain wavelengths, while the second optic system may have no such filter. 
     The image sensor  2332  may have a first portion  2334  and a second portion  2336 . The first portion  2334  may be positioned to receive light from the first field of view  2386 , which light may be redirected toward the first portion  2334  by the mirror  2348 . The second portion  2336  may be positioned to receive light from the second field of view  2396 , which may pass directly into the second portion  2336  without the need for redirection. 
     Thus, the image sensor  2332  may receive light from the first field of view  2386  for barcode images, and from the second field of view  2396  for non-barcode images. Barcode image data captured by the first portion  2334  of the image sensor  2332  may be transmitted to the memory  2318  or to a separate decoding module or a separate device, and may be decoded to obtain barcode data. The barcode image data may then be deleted. Conversely, non-barcode image data captured by the second portion  2336  of the image sensor  2332  may be transmitted to the memory  2318  and stored until the user wishes to move or delete it. 
     In some embodiments the images captured by image sensor  2334  are used only for reading barcodes and decoded data may be displayed on display  2314  and the image itself is not displayed on display  2314 . Images captured by image sensor  2336 , which may be photographs, are displayed on display  2314  with the appropriate app. 
     In operation, the user may, if desired, use the app  2328  to select the type of image to be captured (i.e., a barcode image or non-barcode image). The applicable portion (i.e., the first portion  2334  or the second portion  2336 ) of the image sensor  2332  may then be activated to capture the desired image. If desired, the app  2328  may also enable the user to select applicable image storage and/or decoding settings that will be applied to barcode images and/or non-barcode images captured by the image sensor  2332 . 
     Additionally or alternatively, the first portion  2334  and the second portion  2336  may be utilized to capture barcode and non-barcode image data, respectively, without the user needing to select which type of image to capture. Both may be captured with each exposure, and the user may, after completion of the exposure, have the option to save or delete either the barcode image or the non-barcode image, or to decode the barcode image, for example, via menus or other selection prompts within the app  2328 . Alternatively, barcode images and/or non-barcode images may be automatically stored and/or decoded by the app  2328  after image capture without requiring user input. Further, the app  2328  may be designed to automatically delete barcode images after they are successfully decoded or overwritten by subsequent barcode image capture actions. 
     If desired, the image sensor  2332  may capture a single composite image based on the light from the first field of view  2386  and the light from the second field of view  2396 . The user may then optionally have the option to divide the composite image into barcode and non-barcode portions. 
       FIG. 23B  illustrates an attachment  2350  for a mobile device  2352 . The attachment  2350  may have two sets of optics for capturing different types of images. The mobile device  2352  may have a housing  2354  with a configuration similar to that of other mobile devices described previously in this disclosure. In addition to the components shown in  FIG. 23A , the mobile device  2352  may have a mobile device communications interface  2322  connected to the attachment  2350  via a link  2374 .  FIG. 23B  also illustrates the mobile device  2352  with a camera  2320  that includes the image sensor  2332  and a camera lens  2330 . 
     The attachment  2350  may have a housing  2340  that houses various components, such as circuitry  2364 , an attachment battery  2366 , a user control  2376 , and an attachment communications interface  2372  connected to the link  2374 . Further, the housing  2340  may house a first optic system and a second optic system. 
     The first and second optic systems of the attachment  2350  may be similar in configuration to those of the mobile device  2302  of  FIG. 23A . The first optic system may be designed to capture barcode image data, while the second optic system may be designed for general purpose photography. The first optic system may also include the mirror  2348  such that the optical path  2384  of the first optic system is oriented generally transverse to the optical path  2394  of the second optic system, as in  FIG. 23A . 
     Rather than conveying light from the first field of view  2386  and the second field of view  2396  directly to the image sensor  2332 , the first and second optic systems may instead convey the light to the image sensor  2332  via the camera lens  2330 . This may enable the attachment  2350  to be attached to the mobile device  2352  without the need to modify the camera  2320 , for example, to remove the camera lens  2330 . In some embodiments, the camera lens  2330 , the first lens  2380 , and/or the second lens  2390  may be specially designed to help correct for any distortion, image reversal, or other effects that may occur as a result of passage of the light through the camera lens  2330  in addition to the first lens  2380  or the second lens  2390 . Additionally or alternatively, one or more additional lenses may be added to the attachment  2350  and/or the mobile device  2352  to correct for any such effects. Further additionally or alternatively, such effects may be corrected through post-processing of the barcode and non-barcode images. 
     Although the first portion  2334  and the second portion  2336  appear the same size as each other in  FIGS. 23A and 23B , they need not have the same size or aspect ratio. Low resolution images may be sufficient for barcode reading, particularly if they have a high aspect ratio. One-dimensional barcodes may be decoded from images of very low width. Thus, according to one example, the first portion  2334  may be much thinner than the second portion  2336 . The first portion  2334  may equate to a narrow (i.e., high aspect ratio) strip along the top, bottom, or side of a larger image captured by the second portion  2336 . 
     Further, the first portion  2334  and the second portion  2336  need not store images in the same format. A high color depth may be advantageous for non-barcode images, but barcodes may, in many cases, be properly decoded from barcode images having a low color depth, or even an image with only pixel intensity values, and no color information, as will be discussed subsequently. Thus, for example, the first portion  2334  may capture and/or output image data in YUV format, while the second portion  2336  may capture and/or output image data in RGB, CYM, or other formats. 
     The differences between the first portion  2334  and the second portion  2336  may also extend to the structure of the first portion  2334  and the structure of the second portion  2336 . For example, the second portion  2336  may utilize a Bayer pattern or other mosaic pattern designed to record color values, and the first portion  2334  may have a structure designed to record only pixel intensities. Thus, the first portion  2334  may, in effect, capture only monochrome luminance data. 
     In alternative embodiments, a mobile device and/or an attachment may have an image sensor array that includes multiple image sensors. The light from the second optic system may then be directed to a different image sensor from that which receives the light from the first optic system. Each of the various image sensors may then have a size, chromatic storage capability, and/or other parameters that are more suited to the type of image it is to capture. 
     In other alternative embodiments, one or more of the optic systems may have adjustable parameters. For example, the second optic system, which is configured for non-barcode photography, may have a lens with an adjustable position and/or a deformable, adjustable shape to allow for changes in focus depth, zoom level, etc. 
     In still other alternative embodiments, the optic systems may not all be aligned with the image sensor or image sensor array at the same time. For example, a mobile device or an attachment may have multiple modular elements that can be coupled to it in alignment with the image sensor; each modular element may have a different optic system. Thus, in order to capture a barcode image, the user may first attach the appropriate modular element to the mobile device or attachment to align the optic system suitable for barcode image capture with the image sensor. In some embodiments, such modular elements may be movably coupled to the mobile device or attachment so that each can slide, rotate, or other wise move into and out of alignment with the image sensor. This may be accomplished through the use of a carousel, slider, or other movable feature on which the modular elements are mounted such that the movable feature can be shifted to align the desired modular element with the image sensor. 
     In other alternative embodiments, more than two optic systems may be provided. For example, a first optic system may be used for capturing barcode images, while a second optic system is used for low-light photography, and a third optic system is used for bright conditions. Optic systems according to the invention may be differentiated according to a wide variety of conditions, including but not limited to desired focus depth, desired depth of field, desired chrominance, desired f-stop, and the like. 
     Color Space Architecture 
     As mentioned previously, the color space requirements for barcode images may be different from those of non-barcode images. Expedited processing, reduced data storage requirements, and enhanced decodability are some of the benefits that may be obtained through proper utilization of color space according to the present disclosure. 
       FIGS. 24A through 24B  illustrate a schematic block diagram of a mobile device  2402  including camera which utilizes an image sensor that is capable of colored image output in both Y.U.V. and R.G.B. formats. The mobile device  2402  may have a configuration similar to those of other mobile devices disclosed previously; however, additional components are shown in  FIG. 24A . 
     More specifically, the mobile device  2402  may have a housing  2404  that houses and/or retains a variety of components, which may include a display screen  2412 , a mobile device communications interface  2422 , a mobile device battery  2424 , memory  2418 , a processor  2416 , an image sensor  2432 , and a lens  2430 ; these components may be substantially as disclosed in previous embodiments. Additionally, the housing  2404  may house power circuits  2440 , a control circuitry  2446 , an autofocus actuator  2452 , a zoom actuator  2454 , and system on chip circuits  2460 . 
     The power circuits  2440  may facilitate power management and/or consumption of the mobile device  2402 . The autofocus actuator  2452  and the zoom actuator  2454  may move or re-shape the lens  2430  in a manner that provides the desired focus depth and/or zoom level. The control circuitry  2446  may transfer image data, system commands, and other data among the various other components of the mobile device  2402 . 
     The memory  2418  may contain the operating system  2426  and multiple apps. The apps may include the first app  2428 , which may be a barcode scanning app, as described previously and which may further control the camera as described herein. The app  2428  may issue commands to the image sensor  2432 , the zoom actuator  2454 , and/or the autofocus actuator  2452 , either directly through hardware control circuitry  2446 , through the operating system  2426 , or through other control circuitry. 
     The memory  2418  may also have an image buffer  2448  that stores images captured by the image sensor  2432  on a temporary basis. If desired, the memory  2418  may also have more permanent storage for barcode images and/or non-barcode images. 
     The system may include a direct memory access (DMA) system  2444  which may be part of the processor system  2416 . DMA  2444  provides for direct writing of a captured image to buffer memory  2448  without requiring use of the processor. 
     The image sensor  2432  may be secured to the system on chip circuits  2460 . The system on chip circuits  2460  may further have an output module  2462  and an auto-white balance module  2464 . The auto-white balance module  2464  may perform auto-white balance algorithms to enhance the quality of color photographs captured by the color image sensor  2432  under different illumination conditions. In certain circumstances, such as when the illumination focused onto the image sensor  2432  is passed through a narrow band filter (as described with respect to previous figures) the application of auto-white balance algorithms may significantly degrade image contrast. As such, the first app  2428  may disable auto-white balance module  2464  when utilizing the image sensor  2432  for barcode reading. 
     The output module  2462  generates the image output  4270  in R.G.B format  4274  and/or Y.U.V format  2472  from the signal values from the analog to digital converts of the image read out circuitry and makes the image output available for writing DMA  2444  for writing to memory  2418 . 
     As further illustrated in  FIG. 24B , the Y.U.V. data  2472  may include, for each pixel, a luminous intensity  2480  indicative of the overall intensity of light received by the pixel, a first chromatic  2482  representative of a first dimension of color of light of the pixel, and a second chromatic  2484  representative of a second dimension of color of light of the pixel. The R.G.B. data  2474  may include, for each pixel, a red intensity  2490  indicating the intensity of red light received by the pixel, a green intensity  2492  indicating the intensity of green light received by the pixel, and a blue intensity  2494  indicating the intensity of blue light received by the pixel. 
     The R.G.B. data  2474  may commonly be used for general-purpose photography. However, for barcode reading and/or decoding, it may be advantageous to use the Y.U.V. data  2472  instead. This is because decoding a barcode image may be mostly reliant upon the pattern defined by the luminous intensity  2480  of each pixel in the barcode image. Optionally, the first chromatic  2482  and the second chromatic  2484  may even be ignored by the application that decodes the barcode image. 
     Thus, the output module  2462  of the system on chip circuits  4260  may advantageously be set to provide the output  2470  in the form of the Y.U.V. data  2472 . Accordingly, the first app  2428  may instruct the output module  2462 , directly, through the operating system  2426 , or through other control circuitry  2446  to cause the output module  2462  to provide the output  2470  in the form of the Y.U.V. data when the image sensor  2432  is to be used for capturing a barcode image and return to R.G.B format for general photography when barcode capturing operations are complete. 
     If desired, for barcode images, the output module  2462  may be set to provide the output  2470  only in the form of the luminous intensity  2480  for each pixel, without the first chromatic  2482  and the second chromatic  2484  may not even be provided. This may reduce the traffic on the data bus, reduce the processing load of the processor  2416 , and/or save space in the image buffer  2448  of the memory  2418 . 
     Autofocus Limitations 
     The autofocus settings applied to the camera of a mobile device (such as the camera  1720  of the mobile device  1702  of  FIG. 17A ) may also advantageously be customized for barcode image capture. More specifically, the range between the mobile device  1702  and the barcode to be scanned may be relatively predictable. Thus, using customized autofocus settings for barcode image capture may facilitate obtaining proper focus and/or expedite the image capture process. 
       FIG. 25A  illustrates exemplary autofocus options in the form of a graph  2500 . As shown, a horizontal axis  2510  represents a nonlinear continuum of focus depths. The camera of a mobile device (such as the camera  1720  of the mobile device  1702  of  FIG. 17A ) may have a full range  2520  of focus depths. However, those on the upper and lower ends of the full range  2520  may not be useful for barcode image capture. Accordingly, the autofocus settings of the camera  1720  may advantageously be configured for barcode image capture, for example, via commands to an autofocus module such as the autofocus module  2346  of the mobile device  2302  of  FIG. 23  and/or commands to a controller such as the controller  2342  of the mobile device  2302 . 
     By way of example, the autofocus module may receive instruction to only allow the camera to focus as depths within a limited range  2530  of focus depths. The limited range  2530  may represent the useful range of focus depths for barcode image capture. Alternatively, the autofocus module may receive instruction to only allow the camera to focus at certain discrete depths, such as a first depth  2540 , a second depth  2542 , and a third depth  2544 . The first depth  2540 , the second depth  2542 , and the third depth  2544  may represent useful depth levels for barcode image capture. 
     Further, setting auto focus to discreet focus settings may be faster than implementing the feedback-loop algorithms for auto focus when performing photography wherein the image is analyzed for sharpness and focus adjusted based on the analysis. 
     Binning 
     Further speed enhancements and/or storage space savings may be obtained by altering the resolution of the image data when using the image data for decoding barcodes (e.g., the output  2470  of  FIG. 24A ). While high resolution images (8 megapixel or more) may be desirable for conventional photography, they may not be needed for barcode imaging and decoding. As long as the resolution is sufficient for successful decoding, there is typically no need for a large image. 
       FIG. 25B  illustrates exemplary binning options that can be used to reduce the resolution of a barcode image. An exemplary barcode image  2550  may be handled, by way of example, in three different ways. In a first schema  2560 , no binning may be applied, and the output  2470  may have one pixel for each pixel captured by the image sensor  2432 . The resulting image data may thus be full resolution. In a second schema  2570 , moderate binning may be applied so that the output  2470  has one pixel for every four pixels captured by the image sensor  2432 . The resulting output image data may thus be one-quarter of the resolution of the captured image data. In a third schema  2580 , more aggressive binning may be applied so that the output  2470  has one pixel for every six pixels captured by the image sensor  2432 . The resulting output image data may thus be vertical binning (non-square) and one-sixth of the resolution of the captured image data. 
     When binning is applied, various mathematical algorithms may be used to obtain the value of an output pixel, based on its constituent pixels of the captured image. According to some examples, the intensity values of the constituent pixels may be averaged to provide the value of the resulting output pixel. 
     Image Capture and Decoding 
     A variety of methods may be applied to capture and/or decode a barcode through the use of the mobile devices and/or attachments disclosed herein. Two of these will be shown and described in connection with  FIGS. 26A and 26B . Some of the steps mentioned previously for optimizing image capture for barcode images are included in these methods; other optimization steps may be included in addition to or in place of any of these steps within the scope of the present disclosure. Additionally, the methods of  FIGS. 26A and 26B  may be used with any of the mobile devices and/or attachments described previously and may be implemented in an app operating on the mobile device, within the operating system of the mobile device, or within certain components of the accessory. 
       FIG. 26A  illustrates a method  2600  of capturing and decoding barcodes with limited autofocus. The method  2600  may start  2602  with a query  2604  in which the mobile device and/or attachment determine whether the image sensor and/or associated circuitry has been set to provide output in the Y.U.V. color space. If not, the method  2600  proceeds to a step  2606  in which the app issuing commands to the operating system, the controller, or the image sensor and/or associated circuitry are set to provide the output in the Y.U.V. color space. 
     Once the step  2606  has been carried out, or if, pursuant to the query  2604 , a determination is made that the image sensor and/or associated circuitry have already been set to provide output in the Y.U.V. color space, the method  2600  may proceed to a step  2610  in which the autofocus limits are set. This may entail the app issuing a command to the operating system, the autofocus module or controller to establish lower and/or upper bounds for focus depth, as illustrated in  FIG. 25A . 
     The method  2600  may proceed to a step  2612  in which the app may issue a command to the operating system, the controller, or the auto-white balance module to disable the auto-white balance function of the image sensor and/or associated circuitry. This may be done, as indicated previously, to avoid degrading contrast when only a narrow band of illumination frequency is focused onto the image sensor for barcode reading. 
     The method  2600  may proceed to a step  2614  in which the resolution for the output image is determined by the app. This may be done, for example, based on the type of barcode to be scanned, the size of the barcode within the output image, and other factors, which may be determined from previous images captured of the barcode. The resolution selected may be full resolution (i.e., one output pixel for each pixel captured by the image sensor) or binned (i.e., one output pixel for each group of x pixels captured by the image sensor). 
     The method  2600  may proceed to a step  2620  in which the resolution and binning are set. This may entail the app issuing a command to operating system, control circuitry, or the image sensor and/or associated circuitry to provide output in a certain image size, and/or to bin the captured barcode image according to a certain pattern. 
     The app may then issue a command to the operating system, control circuitry, or camera so that it may be focused at a focus depth within the limited range provided to the autofocus module or controller. The method  2600  may execute a query  2622  to wait until this has been accomplished prior to proceeding. 
     Once limited autofocus is complete, the method  2600  may proceed to a step  2630  in which capture of the barcode image is initiated by the image sensor. Once the barcode image has been captured, the mobile device and/or attachment may attempt to decode it based on the intensity values in the Y.U.V. color space in a step  2632 . Pursuant to a query  2640 , if decoding was successful, the method  2600  may end  2642 . If decoding was unsuccessful, then a new barcode image may need to be captured. This may be done by returning to the step  2620  to re-set resolution, binning, exposure, gain and/or auto focus setting. The remaining steps may flow as set forth above until the barcode image has been successfully decoded, or until the user cancels further image capture and/or decoding attempts. 
       FIG. 26B  illustrates a method  2650  of capturing and decoding barcodes with the camera focus at a predetermined position. The method  2650  may start  2652  with a query  2654  in which the mobile device and/or attachment determine whether the image sensor and/or associated circuitry has been set to provide output in the Y.U.V. color space. If not, the method  2650  proceeds to a step  2656  in which the app may issue a command to the operating system, control circuitry or image sensor and/or associated circuitry to provide the output in the Y.U.V. color space. 
     Once the step  2656  has been carried out, or if, pursuant to the query  2604 , a determination is made that the image sensor and/or associated circuitry have already been set to provide output in the Y.U.V. color space, the method  2600  may proceed to a step  2660  in which the focus position (i.e., focus depth) is determined by the app. This may be done, for example, based on the type of barcode to be decoded, the distance between the mobile device and/or attachment and the barcode, and/or other factors. Performance of the step  2660  may entail selection of the most suitable one of a plurality of predetermined focus depths, such as the first depth  2540 , the second depth  2542 , and the third depth  2544  of  FIG. 25A . 
     Once the focus position has been determined, the method  2650  may proceed to a step  2662  in which focus position of the camera is set to the determined position. Then, in a step  2664 , the autofocus function of the camera may be disabled. Performance of steps may entail issuing one or more commands by the app to the operating system, control circuitry or to the autofocus module or controller to establish the focus depth, for example, as one of the discrete values illustrated in  FIG. 25A . 
     The method  2650  may proceed to a step  2670  in which the app may issue a command to the operating system, the controller, or the auto-white balance module to disable the auto-white balance function of the image sensor and/or associated circuitry. This may be done, as indicated previously, to avoid degrading contrast when only a narrow band of illumination frequency is focused onto the image sensor for barcode reading. 
     The method  2650  may proceed to a step  2672  in which the resolution for the output image is determined. This may be done, for example, based on the type of barcode to be scanned, the size of the barcode within the output image, and other factors. The resolution selected may be full resolution (i.e., one output pixel for each pixel captured by the image sensor) or binned (i.e., one output pixel for each group of x pixels captured by the image sensor). 
     The method  2650  may proceed to a step  2680  in which the resolution and binning are set. This may entail the app issuing a command to the operating system, control circuitry, or image sensor and/or associated circuitry to provide output in a certain image size, and/or to bin the captured barcode image according to a certain pattern. 
     The method  2600  may proceed to a step  2682  in which capture of the barcode image is initiated by the image sensor. Once the barcode image has been captured, the mobile device and/or attachment may attempt to decode it based on the intensity values in the Y.U.V. color space in a step  2690 . Pursuant to a query  2692 , if decoding was successful, the method  2650  may end  2694 . If decoding was unsuccessful, then a new barcode image may need to be captured. This may be done by returning to the step  2672  to re-set resolution and binning. The remaining steps may flow as set forth above until the barcode image has been successfully decoded, or until the user cancels further image capture and/or decoding attempts. 
     Optic System for Illuminating Torch 
     In some embodiments, a mobile device may have an illumination torch, or “flash,” in addition to the remaining camera components. For such mobile devices, it may be advantageous to provide attachments that utilize the light provided by the illumination torch, rather than providing a separate exposure illumination system. 
       FIGS. 27A and 27B  illustrate a mobile device  2702  with an attachment  2700  with optics for image capture, and optics for image illumination that utilize the illumination system of the mobile device. More particularly, the mobile device  2702  may have a housing  2704  having a plurality of exterior surfaces, including a top surface  2706 , a bottom surface  2708 , a back surface  2710 , a right side  2716 , and a left side  2718 . The housing  2704  may retain a display screen  2712 , which may be generally parallel to the back surface  2710 . 
     The housing  2704  may contain and/or retain components including a camera lens  2730 , an image sensor  2732 , and an illuminating torch  2790 . The illuminating torch  2790  may act as a “flash” for conventional photographs taken by the mobile device  2702 . The illuminating torch  2790  may emit illumination through a torch illumination field  2792 . 
     The attachment  2700  may have a housing  2740  with a first chamber  2752  and a second chamber  2754 . The first chamber  2752  may house a first optic system that cooperates with the camera lens  2730  and the image sensor  2732 , and a second optic system that cooperates with the illuminating torch  2790 . 
     More specifically, the first optic system may be designed to modify properties of the light passing through the camera lens  2730  to reach the image sensor  2732 . The first optic system may include an attachment lens  2760  positioned substantially within a camera field of view  2734  of the camera lens  2730 , and a barrier  2762  that defines an aperture  2768 . The camera field of view  2734  may be modified by the attachment lens  2760  and the aperture  2768  to provide a system field of view  2770 . The system field of view  2770  may be more suitable for capturing barcode images than the camera field of view  2734 . The system field of view  2770  may have a system angular size  2784  different from a camera angular size (not shown) of the camera field of view. 
     The second optic system may be an illumination optic system designed to modify the properties of light emitted by the illumination torch  2790 . The second optic system may include an illumination lens  2794  that is positioned within a torch illumination field  2792  of the illumination torch  2790 . The torch illumination field  2792  may be modified by the illumination lens  2794  to provide a system illumination field  2796 . The system illumination field  2796  may be more suitable for illuminating barcodes for decoding than the torch illumination field  2792 . The system illumination field  2796  may have a system angular size  2798  different from a torch angular size (not shown) of the torch illumination field  2792 . The first chamber  2752  may be isolated from the second chamber  2754  to keep illumination from the illumination torch  2790  form passing directly from the second chamber  2754  into the first chamber  2752 . 
     As shown, the system illumination field  2796  may substantially overlap with the system field of view  2770 . Thus, with the aid of the illumination optic (i.e., the second optic), the system field of view  2770  may be effectively illuminated. This enhanced illumination may facilitate the effective capture and decoding of barcode images with the mobile device  2702  and the attachment  2700 . 
     Potential Uses 
     Barcode verification is the process of measuring the print quality of a printed barcode to analyze how it will perform in different environments with different types of scanning equipment. The process of verification involves checking the visual aspects (for modulation, decodability and more) of printed barcodes against standards made by international organizations. 
     An attachment that improves the barcode reading capabilities of a mobile device, as described herein, may enable a mobile device to be used for barcode verification, print verification, and/or other types of verification, and/or for reading direct part marks. 
     For barcode print quality verification or general printing analysis, the attachment must provide fixed reading distance and ensure there is no distortion when capturing an image of the target to be verified. When the imaging distance is fixed, the mobile device can be calibrated to remove lens distortion and establish a conversion factor between the number of pixels and the actual physical size. 
     For reading direct part marks, ambient lighting or LED lighting from the mobile device is usually not suitable to create sufficient contrast for decoding the marks. A special lighting attachment that provides diffused on-axis illumination and/or low angle illumination is needed. 
     Anti-Microbial Housing 
     An attachment as described herein may include an anti-microbial housing, i.e., a housing that includes one or more additives (e.g., a silver iodide additive) that inhibit the growth of mold and bacteria on the surface of the housing. This type of housing may be beneficial if a mobile device is going to be used in a medical environment. 
     Chemical-Resistant Housing 
     Mobile devices are often made with a housing of amorphous plastics, such as polycarbonate/acrylonitrilebutadiene-styrene (PC/ABS). Housings made of PC/ABS contain a loosely packed structure which makes it easier for chemicals to penetrate the plastic. Repeated use of chemical cleansers (e.g., cleansers that include isopropyl alcohol) may damage such housings. However, the use of chemical cleansers may be important. For example, if a mobile device is going to be used as a barcode reader in a medical environment, it is important to frequently disinfect the mobile device in order to try to prevent or limit the spread of infection. 
     An attachment as described herein may include a housing that is designed to resist the harmful effects of chemical cleansers. Such a housing may be referred to as a “chemical-resistant” (or a “disinfectant-ready”) housing. A chemical-resistant housing may include one or more additives (e.g., silicone) that reduce the harmful effects of chemical cleansers. 
     It should be appreciated that components and structures described with respect to any attachment embodiment may be implemented in other attachment embodiments and similarly components and structures described with respect to any embodiment of a camera device, mobile device, or app, operating system, or circuitry therein, may be implemented any other embodiments. The claims are not limited to the specific implementations described above. Various modifications, changes and variations may be made in the arrangement, operation and details of the implementations described herein without departing from the scope of the claims.