Device and method for automatic exposure using dual targets

Abstract

The present application relates to an apparatus and method for automatic exposure using dual targets. An image acquisition apparatus is disclosed, comprising: an illumination subsystem, operative to project an illumination pattern; an imaging subsystem, comprising an image sensor array, and an imaging component operative to focus an image onto the image sensor array; a memory; and a processor, a memory including program code, the memory and the program code being configured to, using the processor, cause the apparatus to at least: acquire a first plurality of images based on a first control parameter, wherein the first control parameter comprises a first exposure value and at least one first other value; acquire a second plurality of images based on a second control parameter having a value different from the first control parameter, wherein the second control parameter comprises a second exposure value and at least one second other value, and wherein the acquisition of the first plurality of images is performed interleaved with the acquisition of the second plurality of images; and attempt to decode a decodable mark using one or more of the first plurality of images and the second plurality of images.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to US Patent Application Serial No. 13 / 250,282, filed on September 30, 2011, entitled "DEVICE AND METHOD FOR AUTOMATED EXPOSURE USING DUAL TARGETS," which claims priority and is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates generally to image data collection and, more particularly, to apparatus and methods employing dual-target automatic exposure, such as an image sensor-based indicia reading terminal. Background Art

[0004] Indicia reading terminals for reading decodable indicia come in many variations. For example, for point of sale applications, a minimally featured indicia reading terminal without a keyboard and display is often used. Indicia reading terminals without a keyboard and display are provided in a recognizable gun-style form factor, with a handle and a firing button (trigger) that can be actuated by an index finger.

[0005] Indicia reading terminals with keyboards and displays are also provided. Indicia reading terminals equipped with keyboards and displays are often used in transportation and warehouse applications, and are provided with a form factor that includes a display and a keyboard. In indicia reading terminals equipped with keyboards and displays, a trigger button for driving the output of a decoded message is typically provided in such a position that it can be driven by the thumb of an operator, or in some cases a handle and a trigger button that can be driven by an index finger are also provided.

[0006] Tags reading terminals, either without a keyboard and display or equipped with a keyboard and display, are commonly used in various data collection applications including point-of-sale applications, transportation applications, warehouse applications, security checkpoint applications, and patient care applications, as well as personal use, which is common in the case where a tags reading terminal equipped with a keyboard and display is provided by a personal mobile phone with a tags reading function.

[0007] Some indicia reading terminals are adapted to read bar code symbols, including one or more of one-dimensional (1D) bar codes, stacked 1D bar codes, and two-dimensional (2D) bar codes. Other indicia reading terminals are adapted to read optical character recognition (OCR) characters, while still other indicia reading terminals are configured to read bar code symbols, OCR characters, postal symbols, or other information bearing indicia.

[0008] Bar code symbols are typically provided on a substrate, such as paper. Recently, bar code symbols are being displayed on display screens. Some attempts have been made to provide an indicia reading terminal that can read bar codes on paper as well as bar codes displayed on display screens. For example, one attempt includes an indicia reading terminal that switches back and forth between frames with illumination on and illumination off, each with a customized fixed exposure.

[0009] There is a need for further image data collection, and in particular apparatus and methods employing dual-target automatic exposure, such as image sensor-based indicia reading terminals. Summary of the invention

[0010] In a first aspect, the present invention provides an apparatus for obtaining an image, the apparatus comprising: an imaging subsystem including an image sensor array and an imaging assembly operative to focus an image on the image sensor array; and a housing incorporating the imaging subsystem. The apparatus is adapted to obtain a first plurality of images based on a first control parameter, wherein the first control parameter is adjusted for a next image of the first plurality of images based on a previous image of the first plurality of images, and is adapted to obtain a second plurality of images based on a second control parameter, wherein the second control parameter is adjusted for a next image of the second plurality of images based on a previous image of the second plurality of images. The adjustment of the first control parameter is determined differently than the adjustment of the second control parameter. The acquisition of the first plurality of images is interleaved and substantially concurrent with the acquisition of the second plurality of images, and the acquisition of the first plurality of images and the adjustment of the first control parameter are separate from the acquisition of the second plurality of images and the adjustment of the second control parameter.

[0011] In a second aspect, the present invention provides an indicia reading terminal, comprising: an illumination subsystem operative to project an illumination pattern; an imaging subsystem including an image sensor array and an imaging component operative to focus an image on the image sensor array; and a housing incorporating the illumination subsystem and the imaging subsystem. The indicia reading terminal is adapted to acquire a first plurality of images exposed during an illuminated portion of the illumination pattern based on a first control parameter, wherein the first control parameter is adjusted for a next image of the first plurality of images based on a previous image of the first plurality of images, and is adapted to acquire a second plurality of images exposed during a non-illuminated portion of the illumination pattern based on a second control parameter, wherein the second control parameter is adjusted for a next image of the second plurality of images based on a previous image of the second plurality of images. The acquisition of the first plurality of images is interleaved with and obtained substantially in parallel with the acquisition of the second plurality of images, and the acquisition of the first plurality of images and the adjustment of the first control parameter are separate from the acquisition of the second plurality of images and the adjustment of the second control parameter. The indicia reading terminal is operable to attempt to decode a decodable indicia in ambient light and comprising a bar code disposed on a substrate using at least one of the first plurality of images, and is operable to attempt to decode a decodable indicia comprising a bar code disposed on a backlit display using at least one of the second plurality of images.

[0012] In a third aspect, the present invention provides a method for obtaining images. The method includes automatically adjusting a first control parameter in a device for capturing a first plurality of images, and automatically adjusting a second control parameter in a device for capturing a second plurality of images, such that the automatic adjustment of the first control parameter is performed interleaved with, separate from, and substantially obtained in parallel with the automatic adjustment of the second control parameter. The adjustment of the first control parameter is determined differently than the adjustment of the second control parameter.

[0013] In a fourth aspect, the present invention provides a method for decoding a decodable indicia. The method includes projecting an illumination pattern from an indicia reading terminal onto the decodable indicia, automatically adjusting a first control parameter in the indicia reading terminal for capturing a first plurality of images exposed during an illuminated portion of the illumination pattern, automatically adjusting a second control parameter in the indicia reading terminal for capturing a second plurality of images exposed during a non-illuminated portion of the illumination pattern, such that the automatic adjustment of the first control parameter is interleaved with and obtained substantially in parallel with the automatic adjustment of the second control parameter, and attempting to decode the decodable indicia using one or more of the first and second plurality of images. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The subject matter of the present invention is clearly pointed out and distinctly claimed at the end of the specification. However, the present invention may be better understood by reference to the following detailed description of the embodiments and the accompanying drawings, in which:

[0015] Figure 1 is a schematic physical form view of one embodiment of an indicia reading terminal according to an aspect of the present invention;

[0016] Figure 2 for Figure 1 A block diagram of a tag reading terminal;

[0017] Figure 3 For use Figure 1 A graphical illustration of an imager of an indicia reading terminal operating in video mode with a full frame shutter;

[0018] Figure 4 For illustration purposes Figure 1 A flowchart of an embodiment of a method for decoding a decodable tag by a tag reading terminal;

[0019] Figure 5 To illustrate the Figure 1 A timing diagram of an embodiment of a tag reading terminal for decoding a decodable tag; and

[0020] Figure 6 To correspond to Figure 4 Flowchart and Figure 5 A graphical illustration of the frame sequence of the timing diagram. DETAILED DESCRIPTION

[0021] Figure 1 An embodiment of an indicia reading terminal 1000 with dual target automatic exposure capability is explained according to one aspect of the present invention. For example, as explained below, the dual target automatic exposure may include different automatic exposure capabilities, one of which is customized to read a decodable indicia, such as a bar code 15 disposed on a substrate 17 (e.g., paper), such as affixed to a product 19 or a device having an electronic paper display, and the other is customized to read a decodable indicia, such as a bar code 115 displayed on an electronic device 120, such as a screen 125, such as a display, monitor, backlit screen, LCD display, or other screen, such as a mobile phone, cellular phone, satellite phone, smart phone, telemetry device, personal data assistant, and other devices.

[0022] As described below, the automatic exposure routines can generally run simultaneously in parallel and are decoupled from each other. For example, the indicia reading terminal can be used to obtain a sequence of odd-numbered images, wherein the exposure value of the next odd-numbered image is determined by an automatic exposure routine optimized for properly capturing a bar code image printed on paper or other non-backlit environment, and separately, obtain a sequence of even-numbered images, wherein the exposure value of the next even-numbered image is determined by an automatic exposure routine optimized for properly capturing a bar code image rendered on a backlit display. As used herein, the term "image" may refer to an image, a portion of an image, image data associated with an image, and a portion of image data associated with an image, and may be used interchangeably herein.

[0023] By adapting terminal 1000 to enable each of the automatic exposure capabilities to become active in response to activation of a trigger signal, terminal 1000 is made more suitable for reading decodable indicia within an extended range of operating environments. For example, if the decodable image is a bar code located on paper or electronic paper, the automatic exposure procedure for the odd-numbered image sequence may result in a captured image that is more suitable for reading and / or decoding the bar code than the even-numbered image sequence. If the decodable image is a bar code displayed on a display having its own illumination, the automatic exposure procedure for the even-numbered image sequence may result in a captured image that is more suitable for reading and / or decoding the bar code than the odd-numbered image sequence. By interleaving and alternating between the two automatic exposure procedures, terminal 1000 can improve or optimize its performance in reading screen-based indicia and paper-based indicia when there is a need to decode indicia in both situations.

[0024] From this description, it will be appreciated that the present invention solves problems associated with conventional indicia reading terminals that use fixed exposure or fixed image control parameters when decoding decodable indicia located, for example, on a cellular phone, while different cellular phones may have different brightness levels and surface reflectivities, which may make indicia decoding difficult. In addition, it will be appreciated that the present invention solves problems associated with conventional indicia reading terminals that use fixed exposure or fixed image control parameters when decoding decodable indicia located on a substrate (e.g., paper) or product, while the substrate and the indicia itself may have different colors and surface reflectivities, which may make indicia decoding difficult.

[0025] The following description uses terminology related to indicia reading terminals, generally including handheld indicia reading terminals or fixed indicia reading terminals optimized for reading printed or displayed indicia, but one of ordinary skill in the art will recognize that the present invention is applicable to various other devices having configurable imagers. Examples of such devices are mobile phones, cellular phones, satellite phones, smart phones, telemetry devices, personal data assistants, or other devices having imaging capabilities and capable of adjusting the imager configuration.

[0026] Figure 2 A block diagram of an indicia reading terminal 1000 is depicted according to an exemplary embodiment corresponding to indicia reading terminal 1000. In general, indicia reading terminal 1000 may include an illumination subsystem 800, an imaging subsystem 900, a handheld housing 1014, a memory 1085, and a processor 1060.

[0027] The illumination subsystem 800 is operable to project an illumination pattern 1260 ( Figure 1 and 2 ). The imaging subsystem 900 may include an image sensor array 1033 and an imaging optical assembly 200 operable to focus an image on the image sensor array 1033. In this exemplary embodiment, the handheld housing 1014 ( Figure 1 and 2 ) houses the illumination subsystem 800 and the imaging subsystem 900. The memory 1085 is capable of storing images, where the image data may represent light incident on the image sensor array 1033. The processor 1060 is operative to address the memory 1085 and process frames of the image data, such as to attempt to decode decodable indicia represented in the image data.

[0028] Figure 3 The basic operation of an imager employing a full frame shutter in video mode is illustrated, for example a mode in which frames are captured continuously. A vertical synchronization signal (VSYNC) 2002 is a signal generated by the imager, in this example, which is active high when a frame of image data is transferred from the device, and the transition between consecutive frames occurs during the active low period of the signal. In this figure, times A, B and C represent the transition times between consecutive frames. At or near this transition time, several events occur. The first event is the value of the exposure register being latched in the imager, which specifies the exposure duration to be used on the next frame. Therefore, the exposure can be written at any time during the frame, but at this transition time, the exposure value then located in the register(s) is latched in the imager for use on the next frame. The second event that occurs at the transition time is that the imager with a full frame shutter ends the charge buildup on the photosensitive pixels, i.e., the exposure window of the imager is closed at this time. This is in Figure 32004 is illustrated in FIG. 2004 by the exposure signal 2004 being active high during the period during which the photosensitive array is allowed to accumulate charge. The accumulation of charge in the photosensitive pixel determines the illumination level of the pixel. This charge accumulation is also referred to as an image being exposed, or exposing the image, which are used interchangeably herein. The third event that occurs at the transition time is that the charge built up on the photosensitive array is transferred to the storage and transfer array, and the pixel data placed in the storage and transfer array is transferred out of the imager during the high active period of the next VSYNC signal. After the photosensitive array data is transferred to the storage and transfer array, the photosensitive array is held in reset to avoid any charge building up until the exposure window opens and is allowed to acquire charge again for the next image.

[0029] Simply put, in Figure 3 In the example shown, the events during the transition time are processed as occurring at a single point in time. Actual implementations of imagers may synchronize these events at a single point in time, or occur independently within a range of times when the VSYNC signal is inactive. Thus, actual uses of imagers typically process these events as being possible at any time when VSYNC is inactive, and process frames from an edge of the VSYNC signal to a similar edge. More typically, frames are processed from one going edge of VSYNC to the next going edge of VSYNC.

[0030] Figure 3 The timeline of a single image event in FIG. 1 begins with the writing of a register value corresponding to exposure X into the exposure register(s) of the imager, which is shown as occurring just before time A. At time A, exposure X is latched into the imager and is effective for exposure of the photosensitive array during the frame between time A and time B. Immediately after time A, the photosensitive array is held in reset until an exposure window is opened so that the photosensitive array can accumulate charge. The time during which the photosensitive array is allowed to accumulate charge is time L. The time that elapses between time L and time B is the exposure time for exposure X and is shown by the active high exposure signal 2004 between time L and time B. At time B, the exposure window is closed and the photosensitive array data is transferred to the storage and transfer array. After time B, the pixel data generated by exposure X will be transferred out row by row and pixel by pixel during the active high period of VSYNC between time B and time C. Note that the register value corresponding to exposure X is written before time A, but the image data generated using exposure X is not seen transferred from the imager until after time B. A full frame is completed between writing exposure X and seeing new image data produced by exposure X. This illustrates a two frame pipeline.

[0031] Reference again Figure 3, a two frame pipeline is characterized in that the pipeline can be kept full. Note that the register value corresponding to exposure Y is written to the exposure register(s) of the imager just before time B. Therefore, exposure Y is written to the exposure register(s) when the imager is exposing the pixel array with exposure X. At time B, exposure Y is active in the imager, and while the image with exposure X is transferred out of the imager, the photosensitive array is held reset and then allowed to accumulate charge at time M. The time that elapses between time M and time C is the exposure time of exposure Y, and is shown by the exposure signal 2004 being active high between time M and time C. At time C, the image data generated by exposure X completes its transfer out of the imager, and the image data generated by exposure Y is transferred to the storage and transfer array, and after time C, the image data generated by exposure Y is transferred out of the imager.

[0032] This sequence of writing of an exposure value and obtaining the data resulting from that exposure value 2 frames later (i.e., a two-frame pipeline) can continue indefinitely as long as the imager is powered and operating in video mode.

[0033] By designing the auto-exposure routine to evaluate the pixel data as it is being transferred from the imager, and then setting the exposure value to the imager before the end of the frame, the auto-exposure routine has a 2-frame turnaround. In other words, the auto-exposure system evaluates the pixel data as it is being generated by the imager, sets a new exposure value before the transfer of the pixel data is complete, and generates data with the new exposure value 2 frames later. This means that every other frame, a particular auto-exposure routine will perform a sampling process and set a new exposure value. Thus, two auto-exposure routines that can sample and update every other frame can be interspersed with one routine operating on odd frames and the other operating on even frames.

[0034] Figure 4 4000 for decoding a decodable indicia according to an aspect of the present invention. In block 4002, terminal 1000 ( Figure 1 and 2 ) waits for a scan to be initiated, and in block 4006, the scan is initiated, for example, by trigger 1220 ( Figure 1 The trigger signal may be activated by the drive of the imager ). The trigger signal may also be activated by, for example, object detection, or a serial command from an external computer. Activation may include powering on the imaging device and / or starting the imager to begin recording image data by allowing photosensitive pixels to accumulate charge.

[0035] In block 4010, the system synchronizes with the imager's frame boundary and initiates the capture of an image data frame. This synchronization is accomplished by monitoring the imager's VSYNC frame synchronization pulse. When VSYNC goes inactive, this indicates that the output of frame X has ended and the output of frame X+1 is about to begin. When this pulse goes inactive, the system needs to be configured to prepare for outputting image data to memory. Typically, this configuration includes a DMA (direct memory access) 1070 ( Figure 2 ) and / or routing the image frame data to other system components in RAM 1080 for setup. This needs to be done before VSYNC becomes valid again, otherwise the image frame data will be missed.

[0036] Once synchronization with the imager is complete and capture is initiated, at block 4012, a determination is made as to whether the last frame of data captured was evaluated using a first auto-exposure method referred to as Method A. If not, the system samples and evaluates the frame data using Method A at step 4020 as it is captured into memory. Once the evaluated data from that frame is sufficient to make a decision, a new exposure value is calculated at step 4022 and communicated to the imager by configuring the imager's exposure register(s) at step 4030. In order to optimally operate the system, it is important that step 4030 be completed while VSYNC is still active, as typical imager operation is such that the configuration of the exposure value registers is latched into imager operation as the exposure value for the next image at some time when VSYNC is inactive.

[0037] Returning to 4010, the system once again waits for VSYNC to become inactive, indicating that capture of the previous frame has been completed, and then starts capturing other frames in the same manner as before.

[0038] Once synchronization with the imager is complete and capture is initiated, at block 4012, a determination is made as to whether the last frame of data captured was evaluated using a first auto-exposure method, referred to as Method A. If so, then as the frame data is captured into memory, the system samples and evaluates the frame data at step 4040 using Method B, which differs in some respects from Method A. Once sufficient data from that frame has been evaluated to make a decision, a new exposure value is calculated at step 4042 and communicated to the imager by configuring the imager's exposure register(s) at step 4030. In order to optimally operate the system, it is important that step 4030 be completed while VSYNC is still active, as typical imager operation is such that the configuration of the exposure value registers is latched into imager operation as the exposure value for the next image at some time when VSYNC is inactive.

[0039] While the above described procedures are explained using distinct and different sampling and / or auto-exposure methods A and B, it should be appreciated that other methods, configurations, or control parameters may be used. For example, other methods, configurations, or control parameters may include different uses of gain, frame rate, gamma correction, filtering, image windowing or image sampling at lower resolution, and / or other methods that affect the properties of pixels reported by the imager. Likewise, other configurations, such as using an onboard illumination system 800 during frame exposure as explained below, and / or turning off illumination during frame exposure are also part of the methods used in the present invention. Furthermore, other methods, configurations, or control parameters may also include different uses of illumination, alignment patterns, focusing, aperture adjustment, and / or zoom.

[0040] In other aspects of the invention, an indicia reading terminal may have a light source for emitting an illumination pattern on a decodable indicia. The illumination pattern may be configured to be turned on and off. The indicia reading terminal may be used to acquire a sequence of odd-numbered images during exposure of the pixel array with the integrated light source on, wherein an exposure value of a next image with the light on is automatically adjusted based on a previous image with the light on, and separately, to acquire a sequence of even-numbered images during exposure of the pixel array with the integrated light source off, wherein an exposure value of a next image with the light off is automatically adjusted based on a previous image with the light off.

[0041] For example, if the decodable image is a barcode on paper or electronic paper, a sequence of odd-numbered images captured with illumination on during the exposure window is more suitable for reading and / or decoding the barcode than a sequence of even-numbered images. If the decodable image is a barcode displayed on a display that has its own illumination, a sequence of even-numbered images captured with illumination off during the exposure window is more suitable for reading and / or decoding the barcode than a sequence of odd-numbered images. By performing both illuminated and unilluminated exposures, interleaving and alternating between the two automatic exposure routines, the performance of terminal 1000 in reading both screen-based indicia and paper-based indicia is improved or optimized, where decoding of indicia in both situations is desired, and either illuminated or unilluminated exposures can provide optimal conditions for imaging and decoding indicia.

[0042] In addition, various screen technologies have various optical properties and can vary widely in reflectivity or other characteristics that optically interfere with successful imaging of the screen under various forms of illumination, depending, for example, on factors such as the underlying technology, the number and type of layers contained in or on the screen, whether the screen is color or black and white, or whether the screen is touch-enabled. Various types of screens can, for example, induce substantially specular reflections of external illumination sources. By refraining the illumination subsystem from projecting illumination during exposure periods in which the imaging subsystem is exposing frames of image data, the imaging subsystem can image the target indicia without optical interference results from the screen, such as specular reflections, which can allow the terminal 1000 to better image and decode the indicia.

[0043] For example, a frame may be captured using a first method, such as using illumination (e.g., using an illumination subsystem to emit light), and using a first control parameter, such as a first control exposure parameter or a first exposure value. In an initial capture, illumination may be provided, and the first control parameter may be a first control parameter that is preset or predetermined when using the illumination, or may be a last calculated first control parameter determined using the illumination stored in the last triggered scan.

[0044] The illumination exposure period and the non-illumination exposure period can be activated in any order in the reading cycle. For example, in various exemplary embodiments, the first exposure in the cycle can be an illumination exposure, and the second exposure in the cycle can be a non-illumination exposure, or the first exposure in the cycle can be a non-illumination exposure, and the second exposure in the cycle can be an illumination exposure.

[0045] Figure 5 Shows Figure 4 A timing diagram related to the operation of the terminal 1000 during the execution of the method indicated by the flowchart shown. Figure 5 The timing diagram shows that signal 5002 is a trigger signal, which is generated by trigger 1220 ( Figure 1 ) is driven and becomes valid and can be activated by releasing the trigger 1220 ( Figure 1 The trigger signal may also become inactive after a timeout period or after successfully decoding a decodable indicia.

[0046] Signal 5102 is a signal of the lighting subsystem 800 with varying excitation levels ( Figure 2 ) input signal, for example, shows a lighting pattern, wherein the lighting or light can be alternately turned on and off. Periods 5110, 5120, 5130, 5140, and 5150 show the lighting being turned on, while periods 5115, 5125, 5135, and 5145 show the lighting being turned off.

[0047] Signal 5202 is an exposure signal, wherein the valid state defines the image sensor array 1033 ( Figure 2 ) is exposed to light, and the inactive state is in the middle of the exposure period of the image sensor of the terminal. For example, in the active state, the terminal 1000 ( Figure 2 ) is exposed to light incident therein. Exposure control signal 5202 is an output signal of the imager that is the result of the exposure configuration for a given frame. The active high state of this signal represents the duration of exposure of the image sensor array to light for a given frame of data. Figure 5 As shown in, for example, in exposure periods 5210, 5230, and 5250, when the illumination subsystem is in an activated state, the image sensor array of terminal 1000 is exposed to light incident therein. In exposure periods 5215 and 5235, when the illumination subsystem is in an inactive state (for example, when the illumination subsystem is turned off), the image sensor array of terminal 1000 is exposed to light incident therein.

[0048] It should be noted that illumination periods 5120 and 5140 are not aligned with any active portion of exposure signal 5202. This is done to maintain a high frequency duty cycle of the illumination pattern, which avoids flicker when also producing images exposed with and without illumination from the illumination subsystem.

[0049] Signal 5302 is the VSYNC (vertical synchronization) signal, or otherwise known as the frame valid signal. During the transition between frames, the VSYNC control signal is low. During this time, the exposure settings written to the imager's (multiple) exposure registers are latched for the next frame, and the exposure window for a given frame is closed, as indicated by the negative edge of signal 5202, while the sensor array 1033 ( Figure 2 ) is stored in a secondary storage device in preparation for transferring the data outside the device. Figure 2 ) or other system memory routing device from the imager secondary storage device to the system memory 1085 ( Figure 2 ) (On most systems to RAM memory 1080 ( Figure 2 )), the VSYNC control signal is valid high.

[0050] exist Figure 5 In the timing diagram of FIG. 1 , time periods 5410, 5415, 5430, 5435, and 5450 are time periods during which the processor 1060 can process a frame of pixel data, for example, to determine the quality of the image data. For example, time periods 5410, 5430, and 5450 correspond to when the illumination subsystem 800 ( Figure 2 ) is illuminating the field of view of the imager and the sensor array 1033 ( Figure 2 ) is accumulating charge, and periods 5415 and 5435 correspond to periods when illumination subsystem 800 is not illuminating the imager's field of view and sensor array 1033 ( Figure 2 ) Determination of the quality of pixel data produced during the exposure period when charge is being accumulated.

[0051] Additionally, during the quality determination of the pixel data, near the end of the processing of the pixel data, or at the end of the processing of the pixel data, new image control parameters may be calculated for subsequent control of the image sensor array. For example, for an image sensor array that uses illumination subsystem 800 ( Figure 2 ) is evaluated during time period 5410 of the image exposed. Figure 2 ) during time period 5415 during which the image exposed is evaluated. In one aspect of the invention, control parameter CP1 may be used during time period 5230, for example, using illumination subsystem 800 ( Figure 2 ) in the next exposure of the array, the exposure control signal is controlled, and the control parameter CP2 can be used in the period 5235, for example, when the illumination subsystem 800 ( Figure 2 ) in the next exposure of the array, controlling the exposure control signal. It should be appreciated that the control parameter can control other parameters used to acquire various images.

[0052] Figure 6 For the corresponding Figure 4 Methods and Figure 5 A graphical illustration of a sequence of frames of a timing diagram illustrating image capture, determining new control parameters, and using the new parameters in subsequent image capture. Figure 6, two separate and / or decoupled traces are shown, e.g., one trace corresponding to a case where the decodable image is illuminated and the other trace where the decodable image is not illuminated. For example, the indicia reading terminal may provide an illumination period of approximately 500 microseconds and a non-illumination period of approximately 5 to approximately 15 milliseconds. It should be appreciated that the indicia reading terminal may use two different automatic exposure algorithms, one of which is optimized for reading bar codes located on paper and uses frames with illumination turned on, and the other of which is optimized for reading bar codes from a screen such as a cell phone display and uses frames with illumination turned off. In this example, the indicia reading terminal includes two frame pipelines. When the exposure is set to be the result of information collected from frame X, it affects frame X+1, but the result can only be seen in image X+2. Similarly, when the exposure is set to be the result of information collected from frame X+1, it affects frame X+2, but the result can only be seen in image X+3. A full-frame shutter imager can cope with the apparent jump in frame-by-frame exposure, so the two exposure routines can be interspersed with each other while being completely decoupled from each other.

[0053] It will be appreciated from this description that separate and decoupled third, fourth, or more tracks may be implemented in accordance with the present invention. For example, the third track may employ an illumination subsystem at a reduced excitation value. It will further be appreciated that the indicia reading terminal of the present invention may also determine or calculate more than one control parameter, the determined or calculated control parameters being used for subsequent image capture.

[0054] It should also be appreciated that the image control parameters may be internal operating parameters of the imager, such as exposure period values, gain control values, frame rate values, gamma values, filter coefficients, or other suitable control parameters, but they may also be used for external control parameters used for imaging, such as illumination control, focus adjustment, aperture adjustment, or other functions that can affect how image data is captured and / or analyzed.

[0055] Image control parameters can be determined, for example, based on an algorithm. The process of receiving or capturing a frame of image data (i.e., a 1D or 2D symbol, text, image, or other indicia) that meets threshold criteria for signal contrast, brightness, focus, or other image characteristics used by the imager control algorithm is hereinafter referred to as acquiring an acceptable image. Thus, an acceptable image is one that falls within the configuration tolerances of the target image requirements set by the algorithm. There are a variety of factors that can affect how an acceptable image is acquired. For example, the ambient light level in the imaging environment, the distance from the imager to the object, the contrast characteristics of the object, and others can all affect the quality of the acquired image. In an image reader, the quality of the imager control algorithm can be judged by its ability to utilize multiple configuration settings and adapt itself to various imaging situations when acquiring acceptable images. Therefore, the quality of the imager control algorithm can be further measured by how quickly the algorithm can configure the imager to obtain an acceptable image in any given scanning environment.

[0056] For example, the algorithm may monitor or evaluate the brightness of pixels, such as the top 5 percent of pixels. If the pixels are determined to be too bright, the length of time that the exposure control parameter is decreased during the acquisition of the next image. If the pixels are determined to be too dark, the length of time that the exposure control parameter is increased during the acquisition of the next image.

[0057] As mentioned above, the control parameters for one track may include a first algorithm and the control parameters for a second track may include a second algorithm. The first and second control parameters may be different and / or the first and second control parameters may be the same but have different values. Further algorithms used in the present invention include those described in U.S. Patent No. 7,874,485 to Meier et al., entitled "Adaptive Optical Image Reader," and U.S. Patent No. 7,148,923 to Harper et al., entitled "Method and Apparatus for Automatic Exposure Control," the entire contents of which are incorporated herein by reference.

[0058] In one embodiment, the terminal 1000 ( Figure 1 ) may be adapted to exempt a frame of image data from a decoding attempt unless the frame is determined to be of a quality suitable for a decoding attempt. Referring again to Figure 5 A timing diagram showing a specific example, CPU1060 ( Figure 2 ) According to the decoding processing thread in the decoding attempt processing period 5500 with respect to the specific frame, the decoding processing will not be started until the evaluation of the specific frame is determined to have a quality suitable for the decoding attempt as a result of the processing occurring during the processing period such as the period 5410, 5415, 5430, etc. Although the terminal 1000 ( Figure 1) may be operable to subject each frame of a sequence of frames to an image quality assessment process, and to select a subset of the sequence of frames for decoding processing, it being appreciated that not every frame need be assessed. For example, when one of the image tracks (e.g., with illumination) provides a higher quality assessment than the other tracks (e.g., without illumination), only one track is then assessed. The assessment of the image quality may be compared to a predetermined standard and / or to a prior image quality of the image track. A quality score above a threshold predetermined standard or above a prior image quality may cause the frame image to be decoded by the processor 1060 ( Figure 2 ) for decoding processing. Various filters may be applied when processing the image frame quality. IQ filters may be used for filtering. Other processing filters that may be incorporated into the preset invention include US Patent Application Publication No. 2010 / 0108769 and US Patent Application Publication No. 2010 / 0108769 both proposed by Wang et al., the entire subject matter of which is incorporated herein by reference. The scanning of the terminal 1000 is terminated based on the successful decoding of the marker of one or more selected image frames.

[0059] Reference again Figure 2 , the indicia reading terminal 1000 may include an image sensor 1032 including a multi-pixel image sensor array 1033 having pixels arranged in pixel rows and pixel columns, associated column circuits 1034, and row circuits 1035. Associated with the image sensor 1032 is an amplifier circuit 1036 (amplifier), and an analog-to-digital converter 1037 that converts image information in the form of analog signals read out from the image sensor array 1033 into image information in the form of digital signals. The image sensor 1032 may also have associated timing and control circuits 1038 (incorporating the control parameter algorithms described above) for controlling, for example, the exposure period of the image sensor 1032, the gain applied to the amplifier 1036, and the like. The circuit components 1032, 1036, 1037, and 1038 indicated may be packaged in a common image sensor integrated circuit 1040. The image sensor integrated circuit 1040 may incorporate fewer components than the number of components indicated.

[0060] In one example, the image sensor integrated circuit 1040 may be provided by an image sensor integrated circuit such as the MT9V022 (752×480 pixel array) or MT9V023 (752×480 pixel array) image sensor integrated circuit available from Micron Technology, Inc. In one example, the image sensor array 1033 may be a monochrome and color hybrid image sensor array having a first subset of monochrome pixels without color filter elements and a second subset of color pixels having color sensitive filter elements. In one example, the image sensor integrated circuit 1040 may incorporate a Bayer pattern filter such that red pixels at red pixel locations, green pixels at green pixel locations, and blue pixels at blue pixel locations are defined in the image sensor array 1033. A frame provided using such an image sensor array incorporating a Bayer pattern may include red pixel values ​​at red pixel locations, green pixel values ​​at green pixel locations, and blue pixel values ​​at blue pixel locations. In an embodiment incorporating a Bayer pattern image sensor array, processor 1060 may interpolate pixel values ​​at frame pixel positions intermediate green pixel positions using green pixel values ​​before submitting the frame for further processing to generate a monochrome frame of image data. Optionally, processor 1060 may interpolate pixel values ​​intermediate red pixel positions using red pixel values ​​before submitting the frame for further processing to generate a monochrome frame of image data. Processor 1060 may also optionally interpolate pixel values ​​intermediate blue pixel positions using blue pixel values ​​before submitting the frame for further processing. An imaging subsystem of terminal 1000 may include image sensor 1032 and lens assembly 200 for focusing an image on image sensor array 1033 of image sensor 1032.

[0061] During operation of the terminal 1000, image signals are read from the image sensor 1032, converted, and stored in a system memory, such as RAM 1080. The memory 1085 of the terminal 1000 may include the RAM 1080, a non-volatile memory such as an EPROM 1082, and a storage device 1084 such as provided by a flash memory or a hard drive memory. In one embodiment, the terminal 1000 may include a processor 1060, which may be adapted to read the image data stored in the memory 1080 and submit the image data to various image processing algorithms. The terminal 1000 may include a direct memory access unit (DMA) 1070 to route the image information read from the image sensor 1032 that has been submitted for conversion to the RAM 1080. In another embodiment, the terminal 1000 may use a system bus (e.g., a PCI bus) that provides a bus arbitration mechanism so that a central DMA controller is not required. Those skilled in the art will recognize that other embodiments of the system bus architecture and / or direct memory access components that provide efficient data transfer between the image sensor 1032 and the RAM 1080 are also within the scope and spirit of the present invention.

[0062] Still reference Figure 2 , and referring to further aspects of terminal 1000, imaging lens assembly 200 is adapted to focus an image of decodable indicia 15 on a substrate or screen within field of view 1240 onto image sensor array 1033. The spatial size of an object of field of view 1240 of terminal 1000 can be varied in a number of selectable ways. The spatial size of an object of field of view 1240 can be varied by, for example, changing the distance from the terminal to the object, changing the imaging lens assembly settings, changing the number of pixels to be read out of image sensor array 1033. Imaging light can propagate along imaging axis 25. Lens assembly 200 is adapted to achieve a variety of focal lengths and a variety of optimal focus planes (best focus distances).

[0063] The terminal 1000 may include an illumination subsystem 800 for illuminating a target and projecting an illumination pattern 1260. In the illustrated embodiment, the illumination pattern 1260 may be projected to be close to but larger than an area defined by the field of view 1240, but may also be projected in an area smaller than the area defined by the field of view 1240. The illumination subsystem 800 may include a light source bank 500, which includes one or more light sources. The light source assembly 800 may further include one or more light source banks, for example, each of which includes one or more light sources. In an exemplary embodiment, such a light source may exemplarily include a light emitting diode (LED). In various embodiments, an LED having any one of a plurality of wavelengths and filters or a combination of wavelengths or filters may be applied. Other types of light sources may also be applied in other embodiments. The light source may exemplarily be mounted on a printed circuit board. It may be the same as the printed circuit board on which the image sensor integrated circuit 1040 having the image sensor array 1033 is exemplarily mounted.

[0064] Terminal 1000 may also include an alignment subsystem 600 for projecting an alignment pattern (not shown). Alignment subsystem 600 including a light source bank may be coupled to an alignment light source bank power input unit 1208 to provide electrical power to the light source bank of alignment subsystem 600. Power input unit 1208 may be coupled to system bus 1500 via interface 1108 to communicate with processor 1060.

[0065] In one embodiment, in addition to the light source bank 500, the illumination subsystem 800 may further include an illumination lens assembly 300, such as Figure 2 In addition to or in lieu of the illumination lens assembly 300, the illumination subsystem 800 may include optional light shaping optics, such as one or more diffusers, mirrors, and prisms. In use, the terminal 1000 may be positioned by an operator relative to a target (e.g., a sheet of paper, a package, a screen, or other type of substrate, etc.) bearing the decodable indicia 15 in such a manner that the illumination pattern 1260 is projected onto the decodable indicia 15. In other uses, the terminal 1000 may be positioned by an operator relative to a target (e.g., a sheet of paper, a package, a screen, or other type of substrate, etc.) bearing the decodable indicia 15 in such a manner that the target substrate itself emits light. Figure 1 ) is positioned on a target (backlit screen, LCD monitor, cathode ray tube, etc.). In this case, the illumination pattern generated by the illumination subsystem 800 is not required. Figure 2In the example of , the decodable mark 15 is provided by a 1D bar code symbol. The decodable mark 15 can also be provided by a 2D bar code symbol or an optical character recognition (OCR) character. Referring to further aspects of the terminal 1000, the lens assembly 200 can be controlled using an electrical power input unit 1202, which provides energy for changing the optimal focus plane of the lens assembly 200. In one embodiment, the electrical power input unit 1202 can be operated as a controlled voltage source, and in another embodiment, it is a controlled current source. The electrical power input unit 1202 can apply a signal to change the optical characteristics of the lens assembly 200, for example, to change the focal length and / or the best focus distance (of the optimal focus plane) of the lens assembly 200. The light source bank electrical power input unit 1206 can provide energy to the light source bank 500. In one embodiment, the electrical power input unit 1206 can be operated as a controlled voltage source. In another embodiment, the electrical power input unit 1206 can be operated as a controlled current source. In another embodiment, the electrical power input unit 1206 can be operated as a combined controlled voltage and controlled current source. The electrical power input unit 1206 can change the electrical power level provided to (the excitation level of) the light source bank 500, for example, to change the lighting level output by the light source bank 500 of the lighting subsystem 800 to generate the lighting pattern 1260.

[0066] In another aspect, terminal 1000 may include a power supply 1402 that provides power to a power grid 1404 connected to electrical components of terminal 1000. Power supply 1402 may be coupled to various power sources, such as a battery 1406, a serial interface 1408 (e.g., USB, RS232), and / or an AD / DC converter 1410.

[0067] Further focusing on the power input unit 1206, the power input unit 1206 may include a charging capacitor that is continuously charged by the power supply 1402. The power input unit 1206 may be configured to output energy within a range of excitation levels. The average excitation level of the illumination subsystem 800 during the exposure period in which the first illumination and exposure control configuration is effective may be higher than the average excitation level in which the illumination and exposure control configuration is effective.

[0068] The terminal 1000 may also include a plurality of peripheral devices, including a trigger 1220 ( Figure 1), which may be used to assert a trigger signal to activate readout of frames and / or certain decoding processes. Terminal 1000 may be adapted such that activation of trigger 1220 activates the trigger signal and initiates a decoding attempt. In particular, terminal 1000 may be operable to capture consecutive frames in response to activation of the trigger signal by reading image information (typically in the form of analog signals) from image sensor array 1033 and then storing the image information in memory 1080 (which is capable of buffering one or more consecutive frames at a given time) after conversion. Processor 1060 may be operable to submit one or more consecutive frames for a decoding attempt.

[0069] To attempt to decode a bar code symbol, such as a one-dimensional bar code symbol, processor 1060 may process image data of a frame corresponding to a row of pixel locations (e.g., a row, a column, or a diagonal set of pixel locations) to determine a spatial pattern of dark and light cells and convert each determined pattern of light and dark cells into a character or string of characters via a lookup table. When the decodable indicia is represented as a 2D bar code symbol, the decoding attempt may include the steps of locating a viewfinder pattern using a feature detection algorithm, locating a matrix line that intersects the viewfinder pattern based on a predetermined relationship to the viewfinder pattern, determining a pattern of dark and light cells along the matrix line, and converting each light pattern into a character or string of characters via a lookup table.

[0070] The terminal 1000 may include various interface circuits for coupling various peripheral devices to the system address / data bus (system bus) 1500 to communicate with the processor 1060 also coupled to the system bus 1500. The terminal 1000 may include an interface circuit 1028 for coupling the image sensor timing and control circuit 1038 to the system bus 1500, an interface circuit 1102 for coupling the electrical power input unit 1202 to the system bus 1500, an interface circuit 1106 for coupling the illumination light source bank power input unit 1206 to the system bus 1500, and an interface circuit 1120 for coupling the trigger 1220 to the system bus 1500. The terminal 1000 may also include a display 1222 coupled to the system bus 1500 through an interface 1122 and in communication with the processor 1060, and a pointer mechanism 1224 in communication with the processor 1060 through an interface 1124 connected to the system bus 1500. Terminal 1000 may also include a range detector unit 1210 coupled to system bus 1500 via interface 1110. In one embodiment, range detector unit 1210 may be an acoustic range detector unit. Various interface circuits of terminal 1000 may share circuit components. For example, a common microcontroller may be established to provide control inputs to both image sensor timing and control circuit 1038 and power input unit 1206. A common microcontroller that provides control inputs to circuit 1038 and to power input unit 1206 may be provided to coordinate timing between image sensor array control and illumination subsystem control.

[0071] The continuous frames of image data captured and submitted for the described processing may be full frames (including pixel values ​​corresponding to each pixel of the image sensor array 1033 or the maximum number of pixels read out from the image sensor array 1033 during operation of the terminal 1000). The continuous frames of image data captured and submitted for the described processing may also be "windowed frames" that include pixel values ​​corresponding to less than a full frame of pixels of the image sensor array 1033. The continuous frames of image data captured and submitted for the above described processing may also include a combination of full frames and windowed frames. A full frame may be captured by selectively addressing and reading out the pixels of the image sensor 1032 having the image sensor array 1033 corresponding to the full frame. A windowed frame may be captured by selectively addressing and reading out the pixels of the image sensor 1032 having the image sensor array 1033 corresponding to the windowed frame. In one embodiment, the plurality of pixels submitted to be addressed and read out determines the picture size of the frame. Thus, the full frame may be considered to have a first relatively large picture size, while the windowed frame may be considered to have a relatively small picture size relative to the picture size of the full frame. The picture size of the windowed frame may vary depending on the number of pixels submitted to be addressed and read out in order to capture the windowed frame.

[0072] Terminal 1000 can capture frames of image data at a rate known as a frame rate. A typical frame rate is 60 frames per second (FPS), which translates to a frame time (frame period) of 16.6 ms. Another typical frame rate is 30 frames per second (FPS), which translates to a frame time (frame period) of 33.3 ms per frame. The frame rate of terminal 1000 can be increased (and the frame time reduced) by reducing the frame picture size.

[0073] In one embodiment, another aspect of terminal 1000 is referred to herein by reference Figure 1 The trigger 1220, the display 1222, the pointer mechanism 1224 and the keyboard 1226 can be arranged on the same side of the handheld housing 1014, such as Figure 1 As shown. The display 1222 and the pointer mechanism 1224 are combined together to be considered as the user interface of the terminal 1000. In one embodiment, the display 1222 may incorporate a touch panel for navigation and virtual actuator selection, in which case the user interface of the terminal 1000 may be provided by the display 1222. The user interface of the terminal 1000 may also be provided by configuring the terminal 1000 to be operable to be reprogrammed by decoding a programming bar code symbol. The handheld housing 1014 of the terminal 1000 may not have a display in another embodiment and have a gun-type form factor. An imaging module 1040 including an image sensor array 1033 and an imaging lens assembly 200 may be incorporated in the handheld housing 1014.

[0074] A1. An apparatus for obtaining an image, the apparatus comprising: an imaging subsystem including an image sensor array and an imaging component operative to focus an image on the image sensor array; a housing incorporating the imaging subsystem; wherein the apparatus is adapted to acquire a first plurality of images based on a first control parameter, wherein the first control parameter is adjusted for a next image of the first plurality of images based on a previous image of the first plurality of images, and adapted to acquire a second plurality of images based on a second control parameter, wherein the second control parameter is adjusted for a next image of the second plurality of images based on a previous image of the second plurality of images, the adjustment of the first control parameter being determined differently than the adjustment of the second control parameter; and wherein the acquisition of the first plurality of images is interleaved and substantially concurrent with the acquisition of the second plurality of images, and the acquisition of the first plurality of images and the adjustment of the first control parameter are separate from the acquisition of the second plurality of images and the adjustment of the second control parameter. A2. The apparatus of A1, further comprising: the apparatus is operable to attempt to decode decodable indicia using one or more of the first and second plurality of images. A3. The apparatus of A1, further comprising: an illumination subsystem operative to project an illumination pattern operable to acquire the first plurality of images and the second plurality of images. A4. The apparatus of A1, wherein the first plurality of images and the second plurality of images are evenly interleaved such that the first control parameter obtained at image N is used for image N+2 and such that the second control parameter obtained at image N+1 is used for image N+3. A5. The apparatus of A1, wherein the first control parameter and the second control parameter comprise the same control parameter with different values. A6. The apparatus of A1, wherein the first control parameter comprises a first exposure control parameter and the second control parameter comprises a second exposure control parameter. A7. The apparatus of A1, wherein the apparatus is operable to determine a quality assessment based on the quality of pixel data of at least one of the first plurality of images and the second plurality of images. A8. The apparatus of A1, further comprising: the apparatus is operable to attempt to decode a decodable indicia from a selected image based on the quality assessment. A9. The apparatus of A1, wherein the apparatus is operable to attempt to decode a decodable indicia comprising a barcode. A10. The apparatus of A1, wherein the apparatus is operable to attempt to decode a decodable indicia comprising at least one of a barcode disposed on a substrate and a barcode disposed on a backlit display. A11. The apparatus of A1, wherein the apparatus comprises a handheld indicia reading terminal.

[0075] B1. An indicia reading terminal comprising: an illumination subsystem operative to project an illumination pattern; an imaging subsystem comprising an image sensor array and an imaging component operative to focus an image on the image sensor array; a housing incorporating the illumination subsystem and the imaging subsystem; wherein the indicia reading terminal is adapted to acquire a first plurality of images exposed during an illuminated portion of the illumination pattern based on a first control parameter, wherein the first control parameter is adjusted for a next image of the first plurality of images based on a previous image of the first plurality of images, and adapted to acquire a second plurality of images exposed during a non-illuminated portion of the illumination pattern based on a second control parameter, wherein the second control parameter is adjusted for a next image of the second plurality of images based on a previous image of the second plurality of images; wherein the acquisition of the first plurality of images is interleaved with the acquisition of the second plurality of images and is obtained substantially in parallel, and the acquisition of the first plurality of images and the adjustment of the first control parameter are separate from the acquisition of the second plurality of images and the adjustment of the second control parameter; and wherein the indicia reading terminal is operable to attempt to decode a decodable indicia comprising a bar code disposed on a substrate using at least one of the first plurality of images, and is operable to attempt to decode a decodable indicia comprising a bar code disposed on a backlit display using at least one of the second plurality of images. B2. The indicia reading terminal of B1, wherein the first plurality of images and the second plurality of images are evenly interleaved such that a first control parameter obtained at image N is used for image N+2 and such that a second control parameter obtained at image N+1 is used for image N+3. B3. The indicia reading terminal of B1, wherein the first image control parameter and the second image control parameter comprise the same image control parameter with different values. B4. The indicia reading terminal of B1, wherein the first control parameter comprises a first exposure control parameter and the second control parameter comprises a second exposure control parameter. B5. The indicia reading terminal of B1, wherein the indicia reading terminal is operable to determine a quality rating of at least one of the first plurality of images and the second plurality of images, and wherein the indicia reading terminal is operable to attempt to decode decodable indicia comprises the indicia reading terminal being operable to attempt to decode decodable indicia from a selected image based on the quality rating. B6. The indicia reading terminal of B1, wherein the indicia reading terminal comprises a handheld indicia reading terminal.

[0076] C1. A method for obtaining an image, the method comprising:

[0077] automatically adjusting a first control parameter in the apparatus for capturing a first plurality of images; and automatically adjusting a second control parameter in the apparatus for capturing a second plurality of images, such that the automatic adjustment of the first control parameter is interleaved with, separate from, and substantially concurrently obtained with the automatic adjustment of the second control parameter, and the adjustment of the first control parameter is determined differently than the adjustment of the second control parameter. C2. The method of claim C1, further comprising attempting to decode decodable indicia using one or more of the first and second pluralities of images. C3. The method of claim C1, further comprising providing an illumination pattern operable to acquire the first and second pluralities of images. C4. The method of claim C1, wherein the first and second pluralities of images are evenly interleaved such that a first control parameter obtained at image N is used for image N+2, and such that a second control parameter obtained at image N+1 is used for image N+3. C5. The method of C1, wherein the first and second control parameters comprise the same control parameter having different values. C6. The method of C1, wherein the first control parameter comprises a first exposure control parameter, and the second control parameter comprises a second exposure control parameter. C7. The method of C1, wherein the first plurality of images is suitable for decoding decodable indicia disposed on a substrate, and the second plurality of images is suitable for decoding decodable indicia disposed on a backlit display. C8. The method of C1, further comprising determining a quality rating of at least one of the first plurality of images and the second plurality of images, and further comprising attempting to decode the decodable indicia using one or more images selected from the images based on the quality rating. C9. The method of C1, wherein the decodable indicia comprises a barcode.

[0078] D1. A method for decoding decodable indicia, the method comprising: projecting an illumination pattern onto decodable indicia from an indicia reading terminal; automatically adjusting a first control parameter in the indicia reading terminal for capturing a first plurality of images exposed during an illuminated portion of the illumination pattern; automatically adjusting a second control parameter in the indicia reading terminal for capturing a second plurality of images exposed during a non-illuminated portion of the illumination pattern, such that the automatic adjustment of the first control parameter is interleaved with the automatic adjustment of the second control parameter and is obtained substantially in parallel; and attempting to decode the decodable indicia using one or more of the first and second plurality of images. D2. The method of D1, wherein the first plurality of images and the second plurality of images are evenly interleaved such that the first control parameter obtained at image N is used for image N+2 and the second control parameter obtained at image N+1 is used for image N+3. D3. The method of D1, further comprising optimizing the control parameter for images exposed during the illuminated portion of the illumination pattern to decode decodable indicia disposed on a substrate; and optimizing the control parameter for images exposed during the non-illuminated portion of the illumination pattern to decode decodable indicia disposed on a backlit display. D4. The method of D1, wherein the first image control parameter and the second image control parameter comprise the same image control parameter having different values. D5. The method of D1, wherein the first control parameter comprises a first exposure control parameter and the second control parameter comprises a second exposure control parameter. D6. The method of D1, further comprising determining a quality rating of at least one of the first plurality of images and the second plurality of images, and wherein attempting to decode comprises attempting to decode the decodable indicia using one or more images selected from the images based on the quality rating.

[0079] Although the present invention has been described with reference to certain specific embodiments, it should be understood that the true spirit and scope of the present invention should be determined only by the claims supported by this specification. Further, although in many cases herein, systems and devices and methods are described as having a specific number of elements, it should be understood that these systems, devices and methods may in practice have less than the specific number of elements mentioned. Similarly, although certain specific embodiments have been described, it should be understood that the features and aspects described with reference to each specific embodiment can be used with each other specific described embodiment.

Claims

1. An image acquisition device, comprising: an illumination subsystem operative to project an illumination pattern; an imaging subsystem including an image sensor array, and an imaging assembly operative to focus an image onto the image sensor array; Memory; as well as A processor, a memory including program code, the memory and program code being configured to, with the processor, cause the apparatus to at least: acquiring a first plurality of images based on first control parameters, wherein the first control parameters include a first exposure value and at least one first other value; acquiring a second plurality of images based on a second control parameter having a different value than the first control parameter, wherein the second control parameter comprises a second exposure value and at least one second other value, and wherein the acquisition of the first plurality of images is interleaved with the acquisition of the second plurality of images, wherein the at least one first other value or the at least one second other value is at least one of a brightness value, an ambient lighting value, a contrast characteristic of the image, a frame rate value, a gamma correction value, and / or a filter coefficient; as well as attempting to decode the decodable indicia using one or more images of the first plurality of images and the second plurality of images, wherein the first plurality of images are acquired during an illuminated portion of the illumination pattern and the second plurality of images are acquired during a non-illuminated portion of the illumination pattern. The apparatus according to claim 1 , wherein the second control parameter is set based on the first control parameter.

3. The apparatus according to claim 1 or 2, wherein the memory and the program code are further configured to, with the processor, cause the apparatus to at least: adjusting the first control parameter for a first subsequent image in the first plurality of images based on a first preceding image in the first plurality of images; and The second control parameter is adjusted for a second subsequent image in the second plurality of images based on a second preceding image in the second plurality of images.

4. The apparatus of claim 1 , wherein the first plurality of images and the second plurality of images are evenly interleaved such that a first control parameter obtained at image N is used for image N+2, and a second control parameter obtained at image N+1 is used for image N+3.

5. The apparatus of claim 1, wherein the first plurality of images and the second plurality of images are continuously interleaved such that a first control parameter obtained at image N is used for image N+1, and a second control parameter obtained at image N+2 is used for image N+3. The apparatus of claim 1 , wherein the number of images in the first plurality of images is greater than the number of images in the second plurality of images.

7. The apparatus of claim 6, wherein an illuminated portion of the illumination pattern is not aligned with the first exposure value.

8. The apparatus of claim 1 , wherein the memory and the program code configured to, with the processor, cause the apparatus to at least attempt to decode the decodable indicia using one or more of the first and second pluralities of images are further configured to: Locate the viewfinder pattern using a feature detection algorithm; positioning matrix lines that intersect the viewfinder pattern according to a predetermined relationship to the viewfinder pattern; Determine the pattern of dark and light cells along the matrix lines, and Each bright pattern is converted into a character or string through a lookup table.

9. The apparatus of claim 1, wherein the image sensor array is a full frame shutter image sensor array.

10. An image acquisition method, comprising: acquiring a first plurality of images based on first control parameters, wherein the first control parameters include a first exposure value and at least one first other value; acquiring a second plurality of images based on a second control parameter having a different value than the first control parameter, wherein the second control parameter comprises a second exposure value and at least one second other value, and wherein the acquisition of the first plurality of images is interleaved with the acquisition of the second plurality of images, wherein the at least one first other value or the at least one second other value is at least one of a brightness value, an ambient lighting value, a contrast characteristic of the image, a frame rate value, a gamma correction value, and / or a filter coefficient; as well as attempting to decode decodable indicia using one or more of the first plurality of images and the second plurality of images, Wherein, the first plurality of images are acquired during an illuminated portion of an illumination pattern and the second plurality of images are acquired during a non-illuminated portion of the illumination pattern. The method according to claim 10 , wherein the second control parameter is set based on the first control parameter.

12. The method according to claim 10 or 11, further comprising: adjusting the first control parameter for a first subsequent image of the first plurality of images based on a first preceding image of the first plurality of images; and The second control parameter is adjusted for a second subsequent image of the second plurality of images based on a second preceding image of the second plurality of images.

13. The method of claim 10, wherein the first plurality of images and the second plurality of images are evenly interleaved such that a first control parameter obtained at image N is used for image N+2, and a second control parameter obtained at image N+1 is used for image N+3.

14. The method of claim 10, wherein the first plurality of images and the second plurality of images are continuously interleaved such that a first control parameter obtained at image N is used for image N+1, and a second control parameter obtained at image N+2 is used for image N+3.

15. The method of claim 10, wherein the number of images in the first plurality of images is greater than the number of images in the second plurality of images.

16. The method of claim 10, wherein an illuminated portion of the illumination pattern is not aligned with the first exposure value.

17. The method according to claim 10, further comprising: Locate the viewfinder pattern using a feature detection algorithm; positioning matrix lines that intersect the viewfinder pattern according to a predetermined relationship to the viewfinder pattern; Determine the pattern of dark and light cells along the matrix lines, and Each bright pattern is converted into a character or string through a lookup table.

Images