Method and apparatus for compensating for fixed pattern noise in an imaging system
First Claim
1. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and being in communication with a control processor, said method comprising the steps of:
- exposing said pixel array to a scene having a known radiance;
capturing a predetermined number of image signal frames of said known radiance scene and finding a column white value for each column of said pixel array when said each frame is captured, wherein said finding step includes the step of discarding a predetermined number of pixel values in at least one column based on gray scale values of said pixel values;
averaging said column white values to determine an average column white value for each column of said pixel array;
comparing said each average column white value to a predetermined reference value for each column, and therefrom determining a correction value for each column of said array; and
storing said each correction value into a storage location for retrieval by said processor when said processor processes image signals from said image sensor in said run mode of operation.
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Accused Products
Abstract
There is described a pixel value adjustment method and apparatus. In one embodiment, pixel values can be adjusted by execution of an algorithm for adjusting pixel values. In one embodiment, an apparatus capable of executing an algorithm for adjusting pixel values is capable of operating in a decoding operating application. In one embodiment, an apparatus capable of executing an algorithm for adjusting pixel values is capable of operating in a video display operating application.
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Citations
73 Claims
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1. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and being in communication with a control processor, said method comprising the steps of:
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exposing said pixel array to a scene having a known radiance; capturing a predetermined number of image signal frames of said known radiance scene and finding a column white value for each column of said pixel array when said each frame is captured, wherein said finding step includes the step of discarding a predetermined number of pixel values in at least one column based on gray scale values of said pixel values; averaging said column white values to determine an average column white value for each column of said pixel array; comparing said each average column white value to a predetermined reference value for each column, and therefrom determining a correction value for each column of said array; and storing said each correction value into a storage location for retrieval by said processor when said processor processes image signals from said image sensor in said run mode of operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and being in communication with a control processor, said method comprising the steps of:
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exposing said pixel array to a first scene having a first known radiance; capturing a predetermined number of image signal frames of said first scene into predetermined storage locations of said processor and finding a first column white value for at least one column of said array when said each frame is captured, said each frame comprising a plurality of pixel values, wherein said finding step includes the step of discarding a predetermined number of pixel values in said at least one column; averaging column white values of at least one of said columns to determine a first average column white value for said at least one column of said pixel array when said pixel array is exposed to said first scene; subjecting said pixel array to a second scene having a second known radiance; reading a predetermined number of image signal frames of said second scene into predetermined storage locations of said processor and identifying a second column white value for at least one column of said array when said each frame is captured, said each frame comprising a plurality of pixel values; calculating an average of column white values of at least one of said columns to determine a second average column white value for said at least one column of said pixel array when said pixel array is exposed to said second scene; determining additive term and multiplicative term correction values for said at least one pixel based on a relationship between said first and second average white values pertaining to said at least one pixel and on said first and second scene radiances; and storing said multiplicative term and said additive term correction values into predetermined storage locations of said processor for retrieval by said processor when said processor processes image signals from said image sensor in a run mode of operation. - View Dependent Claims (11, 12, 13, 14, 15)
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16. The method for operating an imaging system so that said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and a control processor, said method comprising the steps of:
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in a setup mode of operation, determining a plurality of correction values corresponding to a plurality of pixels or columns of said array; and storing said plurality of correction values in a first predetermined memory location of said control processor; in a run mode of operation, capturing a frame of image data comprising uncorrected pixel values into a second predetermined memory location of said processor; and applying correction values only to selected pixel values of said frame when reading said selected pixel values from said second predetermined memory location for further processing, wherein said selected pixel values comprise less than all pixel values of said frame. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and being in communication with a control processor, said method comprising the steps of:
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exposing said pixel array to a scene having a known radiance; capturing a predetermined number of image signal frames of said known radiance scene and finding a column white value for each column of said array when said each frame is captured; averaging said column white values to determine an average column white value for each column of said pixel array; comparing said each average column white value to a reference value for each column, and therefrom determining a correction value for each column of said array, wherein said reference value for each column is found by considering average column white values in columns in positional proximity with said column for which said reference value is presently being determined preferentially to those columns not in positional proximity with said column for which said reference value is presently being determined; and storing said each correction value into a storage location of said processor for retrieval by said processor when said processor processes image signals from said image sensor in said run mode of operation. - View Dependent Claims (23, 24, 25, 26)
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27. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a pixel array and being in communication with a control processor, said method comprising the steps of:
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exposing said pixel array to a scene having a known radiance, said pixel array comprising a plurality of pixels; capturing a predetermined number of image signal frames of said scene into predetermined storage locations of said processor, said each frame comprising a plurality of white values, said each white value corresponding to one of said pixels; averaging white values corresponding to at least one of said pixels to determine an average white value for said at least one pixel of said pixel array; comparing said average white value to a reference value for said at least one pixel, and therefrom determining a correction value for said at least one pixel of said array, wherein said reference value is found by considering average white values of pixels in positional proximity with said pixel for which said reference value is currently being determined preferentially to those of pixels not in positional proximity with said pixel for which said reference value is presently being determined; and storing said correction value into a storage location of said processor for retrieval by said processor when said processor processes image signals from said image sensor in said run mode of operation. - View Dependent Claims (28, 29, 30, 31)
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32. A method for operating an imaging system, said imaging system having an image sensor including a pixel array and a control processor, said method comprising the steps of:
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determining a correction value for at least one pixel or column of said array; and storing said at least one correction value in a first predetermined memory location of said control processor; in a run mode of operation, capturing a frame of image data into a second predetermined memory location of said processor; correcting at least one pixel value of said frame using said correction value stored in said first memory location; and launching a bar code decoding algorithm for attempting to decode for decodable bar code indicia which may be represented in said frame of image data including said at least one corrected pixel value corrected in said correcting step, wherein said storing step includes the step of storing a column correction value for substantially each column of said pixel array. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40)
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41. A method for operating an imaging system, said imaging system having an image sensor including a pixel array and a control processor, said method comprising the steps of:
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determining a correction value for at least one pixel or column of said array; and storing said at least one correction value in a first predetermined memory location of said control processor; in a run mode of operation; capturing a frame of image data into a second predetermined memory location of said processor; and correcting at least one pixel value of said frame using said correction value stored in said first memory location; and launching a bar code decoding algorithm for attempting to decode for decodable bar code indicia which may be represented in said frame of image data including said at least one corrected pixel value corrected in said correcting step, wherein said determining step comprises an exposing step including the step of exposing said pixel array to at least two scenes having different radiances and wherein said storing step includes the step of storing a correction value having both a multiplication component and an additive component. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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49. An indicia decoding device configured to correct for fixed pattern noise, said indicia decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said indicia decoding device is configured to store into said memory unit at least one correction parameter for correcting a pixel value of a frame of image data, said at least one correction parameter having a value and being a pixel correction value or a column correction value, and wherein said indicia decoding device has an indicia decoding operating application and is operable in a run mode of operation; and wherein said indicia decoding device when operated in said run mode of operation with said indicia decoding operating application active (i) stores into said memory unit said frame having a plurality of pixel values, (ii) utilizes said at least one correction parameter to correct at least one pixel value of said frame, and (iii) activates a decoding algorithm for attempting to decode decodable indicia represented in image data including at least one pixel value corrected utilizing said at least one correction parameter, wherein said value of said at least one correction parameter is determined prior to a time that said indicia decoding device is operated in said run mode of operation and wherein said value of said at least one correction parameter is independent of any image represented in said frame. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57)
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58. A bar code decoding device, said bar code decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said bar code decoding device is configured to operate in accordance with a video display operating application and a decoding operating application; and wherein said bar code decoding device is configured to execute a first fixed pattern noise correction algorithm when said video display operating application is active and a second fixed pattern noise correction algorithm when said decoding operating application is active, the first fixed pattern noise correction algorithm being different from said second fixed pattern noise correction algorithm. - View Dependent Claims (59, 60)
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61. A bar code decoding device, said bar code decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said bar code decoding device is configured to operate in accordance with a video display operating application and a decoding operating application; and wherein said bar code decoding device is configured to execute a first algorithm for adjusting pixel values when said video display operating application is active and a second algorithm for adjusting pixel values when said decoding operating application is active, the first algorithm being different from said second algorithm. - View Dependent Claims (62, 63, 64)
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65. A bar code decoding device, said bar code decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said bar code decoding device is configured to operate in accordance with a video display operating application and a decoding operating application; and wherein said bar code decoding device is configured to execute a certain fixed pattern noise correction algorithm when said video display operating application is active, said bar code decoding device further being configured to avoid executing said certain fixed pattern noise correction algorithm when said decoding operating application is active. - View Dependent Claims (66)
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67. A bar code decoding device, said bar code decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said bar code decoding device is configured to operate in accordance with a video display operating application and a decoding operating application; and wherein said bar code decoding device is configured to execute a certain algorithm for adjusting pixel values when said video display operating application is active, said bar code decoding device further being configured to avoid executing said certain algorithm for adjusting pixel values when said decoding operating application is active. - View Dependent Claims (68, 69, 70, 71)
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72. A bar code decoding device, said bar code decoding device comprising:
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an image sensor having a plurality of pixels formed in a two dimensional array of light sensitive pixels, said two dimensional array of light sensitive pixels including a plurality of rows and a plurality of columns of pixels; a control processor processing image data, said control processor being in communication with said image sensor; a memory unit including a program memory coupled to said control processor and a working memory coupled to said control processor; wherein said bar code decoding device is configured to operate in accordance with a video display operating application and a decoding operating application; and wherein said bar code decoding device is configured to execute a certain algorithm for adjusting pixel values when said decoding operating application is active, said bar code decoding device further being configured to avoid executing said certain algorithm for adjusting pixel values when said video display operating application is active. - View Dependent Claims (73)
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Specification