Code reader with extended reading range

Abstract

A code reader with an extended reading range is disclosed. An image-based code reader includes an image sensor. The image sensor is configured to acquire an image of the code. Additionally, the image-based code reader includes: a lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls the focal length of the image-based code reader. The image-based code reader further includes: a processor operatively coupled to the image sensor and the lens. The processor is configured to acquire the image of the code using only pixels located within a region of interest of the sensor, and the size of the region of interest is selected based on the focal length of the reader.

Description

[0001] This application is a divisional application of the invention patent application with the application date of March 12, 2018, the application number of "201810199544.3", and the invention name of "Code Reader with Extended Reading Range".

[0002] Cross - reference to related applications

[0003] Not applicable Background art

[0004] The present technology relates to imaging systems and methods for reading and decoding symbols, and more particularly to imaging systems and methods for reading symbols within an extended reading range.

[0005] An imaging system uses an image acquisition device including an image sensor to transmit information about a viewed subject. The system then interprets this information according to various algorithms to perform programmed decision - making and / or identification functions. To enable the sensor to most effectively acquire images in the visible light range and near - visible light range, the subject is typically illuminated.

[0006] Semiotics reading (also commonly called "barcode" scanning) using an image sensor requires an image acquisition system including optics (lenses) and a sensor (CMOS camera, CCD, etc.) to aim at a position on an object containing a symbol (such as a "barcode") and acquire an image of the symbol. The symbol contains a set of predetermined patterns representing a group of ordered characters or shapes from which an attached data processor (such as a microcomputer) can obtain useful information about the object (such as its serial number, type, model, price, etc.). Symbols / barcodes can have various shapes and sizes. The two most commonly used types of symbols for marking and identifying objects are the so - called one - dimensional barcodes consisting of a series of bars and spaces of different widths and the so - called two - dimensional barcodes consisting of a two - dimensional array of dots or rectangles.

[0007] The range within which a code reader can accurately read and decode an image is usually limited. When attempting to broaden the reading range, there are significant challenges to overcome: obtaining a clear image at long range, sufficient resolution at a distance, a sufficiently large field of view at close range, and sufficient illumination to prevent blurring. Additionally, there are significant challenges associated with achieving what is perceived by the user as continuous illumination. Using a conventional image formation system makes it difficult to overcome these challenges. This is especially true for handheld devices where available space and electrical power are limited.

[0008] There is a need for improved systems and methods for acquiring and decoding symbols, and in particular for overcoming the shortcoming of the reading range of conventional image formation systems. Summary of the invention

[0009] An image-based code reader is disclosed. The image-based code reader includes an image sensor, and the image sensor is configured to acquire an image of a code. The image-based code reader further includes: a lens configured to project an image scene including the code onto the image sensor. The lens includes a variable optical power that controls the focal length of the image-based code reader. The image-based code reader includes: a processor operably coupled to the image sensor and the lens, and the processor is configured to acquire the image of the code using only pixels located within a region of interest of the sensor. Further, the size of the region of interest is selected based on the focal length of the reader.

[0010] An image-based code reader is disclosed. The image-based code reader includes an image sensor, and the image sensor is configured to acquire an image of a code. The image-based code reader includes: a lens configured to project an image scene including the code onto the image sensor. The lens includes a variable optical power that controls the focal length of the image-based code reader. The image-based code reader further includes: a processor operably coupled to the image sensor and the lens. The processor is configured to acquire the image of the code using the image sensor at a certain exposure time and / or gain setting. The exposure time and / or the gain setting is selected based on the focal length of the reader.

[0011] A handheld image-based code reader is disclosed. The handheld image-based code reader includes an image sensor, and the image sensor is configured to acquire an image of a code. The handheld image-based code reader includes: a lens configured to project an image scene including the code onto the image sensor. The lens includes a variable optical power that controls the focal length of the image-based code reader. The handheld image-based code reader further includes: an orientation sensor configured to determine an angle of the reader relative to an external reference frame. A processor is operably coupled to the image sensor, the lens, and the orientation sensor, and the processor is configured to receive an orientation signal from the orientation sensor. The orientation signal represents the angle, and the processor is configured to control the variable optical power of the lens based on the angle.

[0012] A method of reading an image-based code using an image-based code reader is disclosed. The image-based code reader includes an image sensor, a lens, and a processor. The method includes: selecting an operating mode from a plurality of operating modes, the plurality of operating modes including at least a first mode and a second mode. The method further includes: using the processor and setting an optical power of the lens based on the operating mode. Additionally, the method includes: defining a region of interest of the sensor based on the operating mode, and acquiring an image of the code using only pixels of the image sensor that are within the region of interest.

[0013] A method of reading an image-based code using an image-based code reader is disclosed. The image-based code reader includes an image sensor, a lens, and a processor. The method includes: using the processor to set an optical power of the lens. Further, the method includes: determining a focal length of the image-based code reader; and defining an exposure time and / or a gain setting based on the focal length of the reader. The method additionally includes: acquiring an image of the code using the image sensor at the exposure time and / or the gain setting.

[0014] A method of reading an image-based code using a handheld image-based code reader is disclosed. The image-based code reader includes an image sensor, an orientation sensor, a lens, and a processor. The method includes: using the orientation sensor to determine an angle of the reader relative to an external reference frame. The method additionally includes: sending an orientation signal representative of the angle to the processor; and determining an optical power of the lens based on the orientation signal. The method includes: using the processor to set the optical power of the lens.

[0015] The foregoing and other aspects and advantages of the present invention will become apparent in the following description. In the description, the accompanying drawings form a part of the description and illustrate preferred embodiments of the present invention by way of illustration. However, such embodiments do not necessarily represent the full scope of the present invention, and reference is therefore made to the claims and the present text to interpret the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be better understood when consideration is given to the following detailed description thereof, and features, aspects, and advantages other than those set forth above will become apparent. Such detailed description refers to the following drawings.

[0017] Figure 1A is a perspective view of an image-based code reader according to the present disclosure.

[0018] Figure 1B is a front view of an image-based code reader according to the present disclosure.

[0019] Figure 2A Shows an exemplary liquid lens according to the present disclosure.

[0020] Figure 2B Shows an exemplary liquid lens according to the present disclosure.

[0021] Figure 3A Shows a code type according to the present disclosure.

[0022] Figure 3B Shows a code type according to the present disclosure.

[0023] Figure 4A Shows an aspect of an orientation sensor according to the present disclosure.

[0024] Figure 4B Shows an aspect of an orientation sensor according to the present disclosure.

[0025] Figure 4C Shows an aspect of an orientation sensor according to the present disclosure.

[0026] Figure 5A Shows an aspect of the size of a region of interest according to the present disclosure.

[0027] Figure 5B Shows an aspect of the size of a region of interest according to the present disclosure.

[0028] Figure 5C Shows an aspect of the size of a region of interest according to the present disclosure.

[0029] Figure 5D Shows an aspect of the size of a region of interest according to the present disclosure.

[0030] Figure 6A Shows an aspect of the placement of a region of interest according to the present disclosure.

[0031] Figure 6B Shows an aspect of the placement of a region of interest according to the present disclosure.

[0032] Figure 7 Is a graph of the ratio of exposure time to distance for different code types according to the present disclosure.

[0033] Figure 8 Is a flowchart according to the present disclosure.

[0034] Figure 9 Is a flowchart according to the present disclosure.

[0035] Figure 10 Is a flowchart according to the present disclosure.

[0036] Since the described technology is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and described in detail herein. However, it should be understood that the description of specific embodiments herein is not intended to limit the technology to the specific forms disclosed, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the technology as defined by the appended claims. Detailed Description

[0037] Aspects of the subject technology are now described with reference to the drawings, wherein like reference numerals throughout the several views correspond to like elements. However, it should be understood that the associated drawings and detailed description hereafter are not intended to limit the claimed subject matter to the specific forms disclosed. Instead, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the claimed subject matter.

[0038] As used herein, the terms "component", "system", "device", etc. are intended to refer to hardware, a combination of hardware and software, software, or software in execution. The word "exemplary" is used herein to mean an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs.

[0039] In addition, the disclosed subject matter may be implemented as a system, method, apparatus, or article of manufacture using standard programming and / or engineering techniques and / or procedures to produce hardware, firmware, software, or any combination thereof to control an electronic-based device to perform the aspects detailed herein.

[0040] Unless otherwise specified or limited, the terms "connected", "coupled", and their variants are used broadly and include direct and indirect mounting, connecting, supporting, and coupling. Further, "connected" and "coupled" are not limited to physical or mechanical connection or coupling. As used herein, unless otherwise expressly stated, "connected" means that one element / feature is directly or indirectly connected to another element / feature, and not necessarily electrically or mechanically connected. Similarly, unless otherwise expressly stated, "coupled" means that one element / feature is directly or indirectly coupled to another element / feature, and not necessarily electrically or mechanically coupled.

[0041] As used herein, the term "processor" may include one or more processors and memory and / or one or more programmable hardware elements. As used herein, the term "processor" is intended to include any type of processor, CPU, microcontroller, digital signal processor, or other device capable of executing software instructions.

[0042] As used herein, the term "three-dimensional field of view" refers to the three-dimensional portion of an image scene sampled by an imaging device. As used herein, the term "two-dimensional field of view" refers to the two-dimensional portion of the image scene projected onto an image sensor. The three-dimensional field of view and the two-dimensional field of view are related to each other. Reducing the three-dimensional field of view in the dimension projected onto the image sensor (i.e., the dimension not parallel to the optical axis) will correspondingly reduce the two-dimensional field of view, and vice versa.

[0043] In a non-limiting example, the disclosed systems and methods can be implemented in a code reader having a specific range from 0.3 meters to 15 meters. This reading range can utilize a liquid lens to improve focal length control. A first mode can be defined by a focal length range from 0.3 meters to 1.5 meters. A second mode can then be defined by a focal length range from 1.5 meters to 15 meters. These systems and methods can be extended to any additional range. For example, throughout the present disclosure, the various ranges can be replaced by other ranges. Although the range from 0.3 meters to 15 meters is recited, ranges from 0.3 meters to 8 meters, 0.3 meters to 12 meters, and 0.5 meters to 10 meters are also explicitly contemplated. Although the range from 0.3 meters to 1.5 meters is recited, other distances are also contemplated. Although the range from 1.5 meters to 15 meters is recited, other distances are also contemplated. Although two modes are recited, three, four, five, or more modes can also be utilized.

[0044] Figure 1A is a perspective view of an image-based code reader 100 according to the present disclosure. The image-based code reader 100 can include a housing 130 having a grip portion 110, a body / barrel portion 170 having a trigger 120, a user input device 185, an optical device / lens 180, an orientation sensor 150, a processor 140, an image sensor 155, and one or more LED groups 160. Each of the processor 140, the orientation sensor 150, the image sensor 155, and the lens 180 can be mounted in the housing 130 or otherwise supported by the housing. The processor 140 can be coupled to each of the orientation sensor 150, the lens 180, the image sensor 155, and the LED group 160.

[0045] Figure 1B is Figure 1A is a front view of the illustrated image-based code reader 100. On the one hand, the LED group 160 can provide illumination substantially parallel to the field of view (FOV) axis 190 to provide a bright field of view illumination source. The FOV axis 190 can be illuminated via an illumination beam 175. The LED group 160 can define at least two illuminations. Each of the at least two illuminations is configured with a different emission angle, and the at least two illuminations can be selected according to the focal length of the reader. The LED group 160 can be used with a plurality of lenses 165 to configure the focal length of the reader.

[0046] Referring to Figure 1A , in a non-limiting aspect, the first set of LEDs can have an emission angle wide enough to illuminate the FOV 195 at close range, and the second set of LEDs can generate a small-angle collimated beam optimized for long range, where collimation, as used herein, refers to light that is substantially parallel and thus spreads minimally as the light propagates. In some cases, the first set of LEDs can have an emission angle of at least 30 to 50 degrees.

[0047] The collimated beam can be defined as having a small angle with an emission angle less than 20 degrees. The two illuminations can be alternately excited with an LED on-time of 5 milliseconds and a constant high frequency, which the average user would perceive as a continuously-on illumination. In some cases, it may be advantageous to first excite the first set of LEDs at a specified LED on-time and then the second set of LEDs at a specified LED on-time. This particular sequence thus first illuminates the close range and then the long range. In some cases, it may be advantageous to have a frequency within the range of 40 Hz to 60 Hz. Instead of using LED sets, a two-dimensional LED array can be used and optically coupled to a collimating lens, and the size of the excited central region of this array defines the emission angle of the collimated beam.

[0048] The lens 180 focuses the FOV 195 to generate data of an image including an item located within the FOV 195. The FOV 195 is centered along the FOV axis 190. Thus, when the FOV 195 is pointed at the code 420 applied to the item 430 and the code reader 100 is excited to generate an image, an image including the code 420 can be obtained. In some cases, the lens 180 includes a liquid lens. As used herein, a "liquid lens" refers to a lens module having electronically controllable variable focal length.

[0049] Still referring to Figure 1A, the FOV axis 190 extends from the code 420 to the image sensor located within the image-based code reader 100. The length of the FOV axis 190 can vary between 0.3 meters and 15 meters. The first mode can be used for a focal length range of 0.3 meters to 1.5 meters. The second mode can be used for a focal length range of 1.5 meters to 15 meters. The orientation sensor 150 can determine which mode to use first when scanning the code 420. The user can set the mode of the image-based code reader 100 via the user input device 185. The user input device 185 can be a switch or a touch screen. The user can select an operating mode from a variety of operating modes via the user input device 185. In some cases, it may be advantageous to control the selection via user input when using a mobile terminal. The user input can include a touch screen with first and second selection buttons. Alternatively, the selection of the operating mode can be controlled based on available distance information. The selection of the operating mode can also be controlled by alternately switching between operating modes.

[0050] Figure 2A and Figure 2B depicts a liquid lens according to the present disclosure. The liquid lens 200 uses two isodensity liquids: oil as an insulator and water as a conductor. A change in voltage can cause a change in the curvature of the liquid-liquid interface, which in turn causes a change in the focal length of the installed optical lens. The external shape of the liquid lens can be fixed, and only the internal liquid changes shape. Figure 2A illustrates a non-limiting example of a liquid lens 200 with a low voltage level. Figure 2B illustrates a non-limiting example of a liquid lens 200 with a relatively high voltage level. Another non-limiting example of a liquid lens is produced by the Swiss company Optotune.

[0051] In one non-limiting aspect, the code can be paper-based or retroreflective. For paper-based codes, the required exposure time and gain value can increase at longer distances. For retroreflective codes, the required exposure time and gain value may not be as high as at longer distances. This is due to the inherently higher light reflectivity of retroreflective codes. Different parameters can be used in the first mode and the second mode respectively to optimize the brightness control of the image.

[0052] Figure 3A and Figure 3B illustrates different types of codes according to the present disclosure. The first code 420 can be applied to the article 430. The first code 420 can be, for example, a paper code. The second code 300 can also be applied to the article 430. The second code 300 can be, for example, a retroreflective code. The image-based code reader 100 can be configured to acquire an image of the first code 420 and can also be configured to acquire an image of the second code 300.

[0053] Figures 4A to 4CShows aspects of the orientation sensor 150 in accordance with the present disclosure. The orientation sensor 150 can be used to select between modes. In one non-limiting example, the orientation sensor will be used to select an initial focal length or an initial mode for capturing an image. If a code cannot be found in the captured image, then the orientation sensor can select a different focal length or a different mode before capturing a second image. For the purposes of the present disclosure, the x-axis 450 corresponds to a substantially horizontal direction, and the y-axis 460 corresponds to a substantially vertical direction. Figure 4A Depicts an image-based code reader 100 on a horizontal plane with respect to the x-axis 450. A user 440 can aim the image-based code reader 100 at a code 420 that can be applied to an item 430. A field of view 410 can be determined by the image-based code reader 100. The distance from the image-based code reader 100 to the code 420 can be from 0.3 meters to 15 meters. Alternatively, the distance from the image-based code reader 100 to the code 420 can be within a different specified range.

[0054] Figure 4B Illustrates an image-based code reader 100 at an angle between 0 degrees and +90 degrees with respect to the x-axis 450. A user 440 can aim the image-based code reader 100 at a code 420 that can be applied to an item 430. A field of view 410 can be determined by the image-based code reader 100. The distance from the image-based code reader 100 to the code 420 can be from 0.5 meters to 10 meters. The image-based code reader 100 can utilize an orientation signal from the orientation sensor 150, which can represent the angle. The mode of the image-based code reader 100 can be set based on the orientation signal. When the image-based code reader 100 is oriented, for example, between 0 degrees and +90 degrees with respect to the x-axis 450, the image-based code reader 100 can be in a mode configured to read the code 420 from a distance of 1.5 meters to 10 meters. This mode can be a second mode (this mode can be referred to as, for example, a far mode and can be used to attempt to decode candidate codes at a greater distance). Alternatively, the image-based code reader 100 can be in a mode with a different specified reading range.

[0055] Figure 4CAn image-based code reader 100 is shown at an angle between 0 degrees and -90 degrees relative to the x-axis 450. A user 440 can aim the image-based code reader 100 at a code 420 that can be applied to an item 430. A field of view 410 can be determined by the image-based code reader 100. The distance from the image-based code reader 100 to the code 420 can be, for example, from 0.3 meters to 15 meters. The image-based code reader 100 can utilize an orientation signal from an orientation sensor, and the orientation signal can represent the angle. The mode of the image-based code reader 100 can be set based on the orientation signal. When the image-based code reader 100 is oriented, for example, between 0 degrees and -90 degrees relative to the x-axis 450, the image-based code reader 100 can be in a mode configured to read the code 420 from 0.3 meters to 1.5 meters away. This mode can be a first mode (this mode can be called, for example, the near mode and can be used to attempt to decode candidate codes at a relatively short distance). Alternatively, the image-based code reader 100 can be in a mode with a different specified reading range.

[0056] In some cases, when the image-based code reader 100 is oriented at an angle between -90 degrees and -15 degrees relative to the x-axis 450, the image-based code reader 100 can be configured to read the code 420 from 0.3 to 1.5 meters away (or in the first mode or near mode), including but not limited to angles between -85 degrees and -80, between -80 degrees and -75 degrees, between -75 degrees and -70 degrees, between -70 degrees and -65 degrees, between -65 degrees and -60 degrees, between -60 degrees and -55 degrees, between -55 degrees and -50 degrees, between -50 degrees and -45 degrees, between -45 degrees and -40 degrees, between -40 degrees and -35 degrees, between -35 degrees and -30 degrees, between -30 degrees and -25 degrees, between -25 degrees and -20 degrees, between -20 degrees and -15 degrees, between -15 degrees and -10 degrees, between -10 degrees and -5 degrees, and between -5 degrees and 0 degrees, as well as combinations of the upper and lower bounds of these ranges not explicitly listed.

[0057] In some cases, when the image-based code reader 100 is oriented at an angle between 90 degrees and 0 degrees relative to the x-axis 450, the image-based code reader 100 can be configured to read codes from 1.5 meters to 15 meters away (or in a second or far mode), including but not limited to angles between 85 degrees and 80 degrees, between 80 degrees and 75 degrees, between 75 degrees and 70 degrees, between 70 degrees and 65 degrees, between 65 degrees and 60 degrees, between 60 degrees and 55 degrees, between 55 degrees and 50 degrees, between 50 degrees and 45 degrees, between 45 degrees and 40 degrees, between 40 degrees and 35 degrees, between 35 degrees and 30 degrees, between 30 degrees and 25 degrees, between 25 degrees and 20 degrees, between 20 degrees and 15 degrees, between 15 degrees and 10 degrees, between 10 degrees and 5 degrees, and between 5 degrees and 0 degrees, as well as combinations of the upper and lower bounds of these ranges not explicitly listed.

[0058] Figures 5A to 5D Shows the aspect of the size of the region of interest according to the present disclosure. Figure 5A Shows a code 420 that can be applied to an object 430. The image-based code reader 100 can be used to read the code 420. Figure 5B Depicts the projection of an image scene onto the image sensor 155, where the code 420 is projected onto the two-dimensional field of view 500 of the image sensor 155 and additionally projected within a region of interest 510 that occupies a certain proportion of the two-dimensional field of view 500. In some cases, only the pixels located within the region of interest 510 can be used to acquire the image. When the image-based code reader 100 is, for example, 0.5 meters to 3 meters away from the code 420, the region of interest can occupy at least a predetermined proportion of the image sensor 155. In some cases, when the image-based code reader 100 is 0.5 meters to 3 meters away from the code 420, the region of interest can be the entire image sensor 155 (e.g., all pixels of the image sensor 155 can be used to acquire the image). The region of interest can be determined by the current mode of the image-based code reader 100.

[0059] Figure 5C Shows a code 420 that can be applied to an item 430. The image-based code reader 100 can be used to read the code 420. Figure 5D Depicts the code 420 within the field of view 500 and additionally within the region of interest 510. Furthermore, in some cases, only the pixels located within the region of interest 510 can be used to acquire the image. When the image-based code reader 100 is, for example, 3 meters to 10 meters away from the code 420, the region of interest can occupy at most the predetermined proportion of the image sensor 155. The region of interest can be determined by the current mode of the image-based code reader 100.

[0060] In some cases, the predetermined ratio can be 10%, 25%, or 50%.

[0061] In yet another non - limiting aspect, the processor can perform pixel binning and / or sub - sampling for short focal lengths. To achieve a sufficient field of view, a full image sensor can be used at close range. In some cases, it may be advantageous to perform 2x2 pixel binning.

[0062] The image sensor 155 can have a resolution of, for example, 1.2 megapixels. In some cases, the image sensor 155 can have a resolution of 1280x800 pixels, 1280x1024 pixels, or 2592x1944 pixels.

[0063] Figure 6A and Figure 6B Illustrates an aspect of region of interest placement according to the present disclosure. In some cases, it may be advantageous to place the region of interest 510 in different regions within the two - dimensional field of view 500. Figure 6A Illustrates an example where the region of interest 510 is not centered within the two - dimensional field of view 500. The region of interest 510 can be moved based on the position of the code 420 within the two - dimensional field of view 500. The region of interest 510 can appear anywhere within the two - dimensional field of view 500. When in the second mode, the region of interest 510 can include the central portion of the image sensor. At long distances, the two - dimensional field of view 500 can be much larger than required to capture the code 420. By shrinking the region of interest 510, the amount of data to be processed and the power required to illuminate the field of view 500 are reduced.

[0064] Figure 6B Illustrates an example where the region of interest 510 is centered within the field of view 500. The region of interest 510 can be moved based on the position of the code 420 within the two - dimensional field of view 500. As Figure 1B shown, in some cases, it may be advantageous to use the illumination beam 175 to project a small dot on or near the optical axis. The projected small dot can assist the user in aiming and orienting the image - based code reader 100.

[0065] The processor 140 can include software that learns the trends of a given user and adjusts the region of interest 510 based on the usage history of the given user. For example, if the software identifies that the user has historically aimed the image - based code reader 100 to the right (from the user's perspective) when aiming approximately horizontally at long distances, then the region of interest 510 can be moved within the two - dimensional field of view 500 to compensate for this trend under these acquisition conditions.

[0066] Figure 7It is a graph of the ratio of exposure time to distance for retroreflective code 710 and paper code 700. The distance measurement result represents the distance from the code to the reader. For paper code 700, the required exposure time and gain value can be increased at longer distances. For retroreflective code 710, the required exposure time and gain value are not as high at longer distances. This is due to the relatively high light reflectivity inherent in retroreflective code 710. The search algorithm time starts with settings close to the optimal curve for paper code 700 or retroreflective code 710. Different parameters can be used to optimize the brightness control of the image in the first mode and the second mode.

[0067] Referring to Figure 8 , the present disclosure provides a method 800 for reading an image-based code using an image-based code reader. At process block 810, method 800 may include selecting an operation mode. At process block 820, method 800 may include setting the optical power of a lens based on the operation mode. At process block 830, method 800 may include defining a region of interest based on the operation mode. At process block 840, method 800 may include acquiring an image of the code. At process block 850, method 800 may include attempting to decode the code.

[0068] Referring to Figure 9 , the present disclosure provides an additional method 900 for reading an image-based code using an image-based code reader. At process block 910, method 900 may include setting the optical power of a lens. At process block 920, method 900 may include determining the focal length. At process block 930, method 900 may include defining an exposure time and / or a gain setting. At process block 940, method 900 may include acquiring an image of the code. At process block 950, method 900 may include attempting to decode the code.

[0069] Referring to Figure 10 , the present disclosure provides another method 1000 for reading an image-based code using an image-based code reader. At process block 1010, the method may include determining the angle of the reader. At process block 1020, the method may include sending an orientation signal to a processor. At process block 1030, the method may include determining the optical power of a lens based on the angle of the reader. At process block 1040, the method may include setting the optical power of the lens. At process block 1050, method 1000 may include acquiring an image. At process block 1060, method 1000 may include attempting to decode any candidate code located within the image.

[0070] The present disclosure includes an image-based code reader, comprising: an image sensor configured to acquire an image of a code; a lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls the focal length of the image-based code reader; a processor operably coupled to the image sensor and the lens, the processor being configured to acquire the image of the code using only pixels located within a region of interest of the sensor, wherein the size of the region of interest is selected based on the focal length of the reader. The image-based code reader may be further configured to operate in multiple operation modes, and the processor is configured to select from the multiple operation modes. Further, the multiple operation modes may at least include a first mode and a second mode, the first mode having a first region of interest and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. Further, when in the second mode, the second region of interest may include a central portion of the image sensor. Additionally, a desired operation mode may be selected by a user from the multiple operation modes. The image-based code reader may further include one or more illuminators configured to illuminate the image scene with light having at least two emission angles, and the processor is configured to select from the at least two emission angles based on the focal length of the reader. Further, the one or more illuminators may include at least two groups of light-emitting diodes. Additionally, the at least two emission angles may be alternately enabled with a fixed pulse duration and a fixed frequency. Additionally, the image may be captured by synchronizing the exposure time with light having one of the at least two emission angles. Further, the exposure time may be less than the illumination time. Additionally, the processor may perform pixel binning when the focal length is less than half of the maximum reading distance for a specified code size. Additionally, the processor may perform subsampling when the focal length is less than half of the maximum reading distance for a specified code size. Further, the code may be paper-based or retroreflective. The processor may be configured to select the size of the region of interest. The image-based code reader may further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and the size of the LED array (the number of excited LEDs) is based on the focal length of the reader, and the size of the LED array is defined by the number of excited LEDs.

[0071] The present disclosure includes an image-based code reader, comprising: an image sensor configured to acquire an image of a code; a lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls a focal length of the image-based code reader; and a processor operatively coupled to the image sensor and the lens, the processor being configured to acquire the image of the code using the image sensor with a certain exposure time and / or gain setting, wherein the exposure time and / or gain setting is selected based on the focal length of the reader. The image-based code reader may be further configured to operate in a plurality of operating modes, and the processor is configured to select from the plurality of operating modes. Additionally, the plurality of operating modes may at least include a first mode and a second mode, the first mode having a first region of interest and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. Further, when in the second mode, the second region of interest may include a central portion of the image sensor. Additionally, a desired operating mode may be selected by a user from the plurality of operating modes. The image-based code reader may further include one or more illuminators configured to illuminate the image scene with light having at least two emission angles, and the processor is configured to select from the at least two emission angles based on the focal length of the reader. Additionally, the one or more illuminators may include at least two sets of light-emitting diodes. Further, the at least two emission angles may be alternately enabled with a fixed pulse duration and a fixed frequency. Further, the image may be captured by synchronizing the exposure time with light having one of the at least two emission angles. Additionally, the exposure time may be less than the illumination time. Further, the processor may perform pixel binning when the focal length is less than half of a maximum reading distance for a specified code size. Additionally, the processor may perform sub-sampling when the focal length is less than half of a maximum reading distance for a specified code size. Further, the code may be paper-based or retro-reflective. Moreover, the processor may be configured to select the size of the region of interest. The image-based code reader may further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and a size of the LED array (a number of excited LEDs) is based on the focal length of the reader, the size of the LED array being defined by the number of excited LEDs.

[0072] The present disclosure includes a handheld image-based code reader, comprising: an image sensor configured to acquire an image of a code; a lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls the focal length of the image-based code reader; an orientation sensor configured to determine the angle of the reader relative to an external reference frame; and a processor operatively coupled to the image sensor, the lens, and the orientation sensor, the processor being configured to receive an orientation signal from the orientation sensor, the orientation signal representing the angle, and the processor being configured to control the variable optical power of the lens based on the angle. The handheld image-based code reader may be further configured to operate in a plurality of operating modes, and the processor is configured to select from the plurality of operating modes. Additionally, the plurality of operating modes may at least include a first mode and a second mode, the first mode having a first region of interest, and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. Further, when in the second mode, the second region of interest may include a central portion of the image sensor. Additionally, a desired operating mode may be selected by a user from the plurality of operating modes. The handheld image-based code reader may further include one or more illuminators configured to illuminate the image scene with light having at least two emission angles, and the processor is configured to select from the at least two emission angles based on the focal length of the reader. Further, the one or more illuminators may include at least two sets of light-emitting diodes. Additionally, the at least two emission angles may be alternately enabled with a fixed pulse duration and a fixed frequency. Additionally, the image may be captured by synchronizing the exposure time with light having one of the at least two emission angles. Further, the exposure time may be less than the illumination time. Additionally, the processor may perform pixel binning when the focal length is less than half of the maximum reading distance for a specified code size. Further, the processor may perform sub-sampling when the focal length is less than half of the maximum reading distance for a specified code size. Additionally, the code may be paper-based or retro-reflective. Further, the processor may be configured to select the size of the region of interest. The handheld image-based code reader may further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and the size of the LED array (the number of excited LEDs) is based on the focal length of the reader, and the size of the LED array is defined by the number of excited LEDs.

[0073] The present disclosure includes a method of using an image-based code reader to read an image-based code, the image-based code reader including an image sensor, a lens, and a processor. The method includes: selecting an operating mode from a plurality of operating modes, the plurality of operating modes including at least a first mode and a second mode; setting an optical power of the lens based on the operating mode using the processor; defining a region of interest of the sensor based on the operating mode; acquiring an image of the code using only pixels of the image sensor that are within the region of interest. Additionally, the processor can select from the plurality of operating modes. The method of using an image-based code reader to read an image-based code can further include: the first mode having a first region of interest and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. The method of using an image-based code reader to read an image-based code can further include: when in the second mode, the second region of interest includes a central portion of the image sensor. Additionally, the method of using an image-based code reader to read an image-based code can further include: a user selecting a desired operating mode from the plurality of operating modes. Additionally, one or more illuminators can illuminate the image scene with light having at least two emission angles, and the processor selects from the at least two emission angles based on a focal length of the reader. Additionally, the one or more illuminators can include at least two sets of light-emitting diodes. Further, the at least two emission angles can be alternately enabled with a fixed pulse duration and a fixed frequency. Additionally, the image can be captured by synchronizing an exposure time with light having one of the at least two emission angles. Further, the exposure time can be less than an illumination time. The method of using an image-based code reader to read an image-based code can further include: the processor performing pixel binning when the focal length is less than half of a maximum reading distance for a specified code size. The method of using an image-based code reader to read an image-based code can further include: the processor performing subsampling when the focal length is less than half of a maximum reading distance for a specified code size. Further, the code can be paper-based or retroreflective. The method of using an image-based code reader to read an image-based code can further include: the processor selecting a size of the region of interest. The method of using an image-based code reader to read an image-based code can further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and a size of the LED array (number of excited LEDs) is based on the focal length of the reader, and the size of the LED array is defined by the number of excited LEDs.

[0074] The present disclosure includes a method of using an image-based code reader to read an image-based code, the image-based code reader including an image sensor, a lens, and a processor, the method including: setting, using the processor, an optical power of the lens; determining a focal length of the image-based code reader; defining an exposure time and / or a gain setting based on the focal length of the reader; acquiring an image of the code using the image sensor at the exposure time and / or the gain setting. The method of using an image-based code reader to read an image-based code may be further configured to operate in multiple operating modes, and the processor selects from the multiple operating modes. Further, the multiple operating modes may at least include a first mode and a second mode, the first mode having a first region of interest and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. Additionally, when in the second mode, the second region of interest may include a central portion of the image sensor. The method of using an image-based code reader to read an image-based code may further include: a user selecting a desired operating mode from the multiple operating modes. Further, one or more illuminators may illuminate the image scene with light having at least two emission angles, and the processor selects from the at least two emission angles based on the focal length of the reader. Additionally, the one or more illuminators may include at least two sets of light-emitting diodes. Additionally, the at least two emission angles may be alternately enabled with a fixed pulse duration and a fixed frequency. Further, the image may be captured by synchronizing the exposure time with light having one of the at least two emission angles. Additionally, the exposure time may be less than the illumination time. The method of using an image-based code reader to read an image-based code may further include: the processor performing pixel binning when the focal length is less than half of a maximum reading distance for a specified code size. The method of using an image-based code reader to read an image-based code may further include: the processor performing subsampling when the focal length is less than half of a maximum reading distance for a specified code size. Further, the code may be paper-based or retroreflective. The method of using an image-based code reader to read an image-based code may further include: the processor selecting a size of the region of interest. The method of using an image-based code reader to read an image-based code may further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and a size of the LED array (a number of excited LEDs) is based on the focal length of the reader, the size of the LED array being defined by the number of excited LEDs.

[0075] The present disclosure includes a method of using a handheld image-based code reader to read an image-based code, the image-based code reader including an image sensor, an orientation sensor, a lens, and a processor. The method includes: determining, using the orientation sensor, an angle of the reader relative to an external reference frame; sending an orientation signal representative of the angle to the processor; determining, based on the orientation signal, an optical power of the lens; and setting, using the processor, the optical power of the lens. The handheld image-based code reader may be further configured to operate in a plurality of operating modes, and the processor selects from the plurality of operating modes. Further, the plurality of operating modes may at least include a first mode and a second mode, the first mode having a first region of interest and the second mode having a second region of interest, the first region of interest being larger than the second region of interest. Additionally, when in the second mode, the second region of interest may include a central portion of the image sensor. The method of using a handheld image-based code reader to read an image-based code may further include: a user selecting a desired operating mode from the plurality of operating modes. Further, one or more illuminators may illuminate the image scene with light having at least two emission angles, and the processor selects from the at least two emission angles based on a focal length of the reader. Additionally, the one or more illuminators may include at least two sets of light-emitting diodes. Further, the at least two emission angles may be alternately enabled with a fixed pulse duration and a fixed frequency. Additionally, the image may be captured by synchronizing an exposure time with light having one of the at least two emission angles. Further, the exposure time may be less than an illumination time. The method of using a handheld image-based code reader to read an image-based code may further include: the processor performing pixel binning when the focal length is less than half of a maximum reading distance for a specified code size. The method of using a handheld image-based code reader to read an image-based code may further include: the processor performing subsampling when the focal length is less than half of a maximum reading distance for a specified code size. Further, the code may be paper-based or retroreflective. The method of using a handheld image-based code reader to read an image-based code may further include: the processor selecting a size of the region of interest. The method of using a handheld image-based code reader to read an image-based code may further include a two-dimensional LED array, wherein a central portion of the LED array is excited to illuminate the code, and a size of the LED array (a number of excited LEDs) is based on the focal length of the reader, the size of the LED array being defined by the number of excited LEDs.

[0076] For the avoidance of doubt, aspects of the present disclosure described for these systems apply to these methods and aspects described for these methods apply to these systems.

[0077] Those skilled in the art will understand that although the invention has been described above in conjunction with specific embodiments and examples, the invention is not necessarily so limited, and many other embodiments, examples, uses, modifications, and departures from the embodiments, examples, and uses are intended to be encompassed by the appended claims.

Claims

1. A handheld image - based code reader, comprising: An image sensor configured to acquire an image of a code; A lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls the focal length of the handheld image - based code reader; An orientation sensor configured to determine the angle of the reader relative to an external reference frame; A first illumination source configured to illuminate the image scene with light having a first illumination angle; A second illumination source configured to illuminate the image scene with a second illumination angle different from the first illumination angle; Wherein the handheld image - based code reader is configured to operate in a plurality of operation modes, and wherein the plurality of operation modes at least include a first mode and a second mode; And A processor operably coupled to the image sensor, the lens, the orientation sensor, and the first and second illumination sources, the processor being configured to: Receive an orientation signal from the orientation sensor, the orientation signal representing the angle; Use the orientation signal representing the angle to determine the focal length of the reader; And Use the focal length to select the first illumination source to illuminate the image scene instead of selecting the second illumination source that illuminates the image scene; Wherein the processor sets the variable optical power such that the focal length is in the range of 0.3 meters to 1.5 meters when in the first mode, and wherein the processor sets the variable optical power such that the focal length is in the range of 1.5 meters to 15 meters when in the second mode.

2. The handheld image-based code reader according to claim 1, wherein, The processor is further configured to select from the plurality of operation modes.

3. The handheld image-based code reader according to claim 2, wherein, The first mode has a first region of interest and the second mode has a second region of interest, the first region of interest being larger than the second region of interest.

4. The handheld image-based code reader according to claim 3, wherein, The processor selects the first mode when receiving the orientation signal representing the angle in the range of - 5 degrees to - 90 degrees.

5. The handheld image-based code reader according to claim 3, wherein, The processor selects the second mode when receiving the orientation signal representing the angle in the range of 0 degrees to + 90 degrees.

6. The handheld image-based code reader according to claim 3, wherein, When in the second mode, the second region of interest includes the central portion of the image sensor.

7. An image - based code reader, comprising: An image sensor configured to acquire an image of a code; A lens configured to project an image scene including the code onto the image sensor, the lens including a variable optical power that controls the focal length of the image - based code reader; One or more illuminators configured to illuminate the image scene with light having at least two emission angles, the one or more illuminators including at least two groups of light - emitting diodes, wherein a first group of the at least two groups of light - emitting diodes has an emission angle of at least 30 degrees to 50 degrees, and a second group of the at least two groups of light - emitting diodes has an emission angle less than 20 degrees; And A processor, operably coupled to the image sensor and the lens, the processor being configured to: Determine the focal length of the image-based code reader; Determine a gain setting or an exposure time using the focal length; and Acquire the image of the code using the image sensor at the exposure time or the gain setting, Wherein the image-based code reader is configured to operate in a plurality of operating modes, and wherein the plurality of operating modes at least include a first mode and a second mode, Wherein the processor sets the variable optical power such that the focal length is in the range of 0.3 meters to 1.5 meters when in the first mode, and wherein the processor sets the variable optical power such that the focal length is in the range of 1.5 meters to 15 meters when in the second mode.

8. The image-based code reader according to claim 7, wherein, The first mode has a first region of interest and the second mode has a second region of interest, the first region of interest being larger than the second region of interest.

9. The image-based code reader according to claim 7, wherein, The processor is further configured to select from the at least two emission angles based on the focal length of the reader.

10. The image-based code reader according to claim 9, wherein, The at least two emission angles are alternately enabled with a fixed pulse duration and a fixed frequency of a plurality of pulses.

Images