Method of driving focusing element in barcode imaging scanner
First Claim
Patent Images
1. A method comprising:
- detecting light from a target object through an imaging lens arrangement with an imaging sensor having photosensitive elements to capture multiple images of the target object while substantially maintaining the distance between the target object and the imaging lens arrangement, wherein the imaging lens arrangement is configured to change a focus position thereof with a lens-driving-parameter, and wherein at least one of the multiple images is captured during a time period when an extended-aiming-pattern having at least one line of visible illumination is generated on the target object by projecting visible light through an aiming pattern generating element;
processing the at least one of the multiple images to determine a feature-size measuring a size of the at least one line of visible illumination on the same focus plane in the at least one of the multiple images;
processing at least two of the multiple images to find an optimal lens-driving-parameter that results in the maximum image sharpness; and
storing both the feature-size and the optimal lens-driving-parameter into a memory for changing a calibration table.
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Abstract
A method includes the following: (1) detecting light from a target object to capture multiple images of the target object while substantially maintaining the distance between the target object and the imaging lens arrangement that is configured to have a focus position thereof changed with a lens-driving-parameter; (2) processing the at least one of the multiple images to determine a feature-size in an aiming pattern; (3) processing at least two of the multiple images to find an optimal lens-driving-parameter that results in the maximum image sharpness; and (4) storing both the feature-size and the optimal lens-driving-parameter into a memory.
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Citations
20 Claims
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1. A method comprising:
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detecting light from a target object through an imaging lens arrangement with an imaging sensor having photosensitive elements to capture multiple images of the target object while substantially maintaining the distance between the target object and the imaging lens arrangement, wherein the imaging lens arrangement is configured to change a focus position thereof with a lens-driving-parameter, and wherein at least one of the multiple images is captured during a time period when an extended-aiming-pattern having at least one line of visible illumination is generated on the target object by projecting visible light through an aiming pattern generating element; processing the at least one of the multiple images to determine a feature-size measuring a size of the at least one line of visible illumination on the same focus plane in the at least one of the multiple images; processing at least two of the multiple images to find an optimal lens-driving-parameter that results in the maximum image sharpness; and storing both the feature-size and the optimal lens-driving-parameter into a memory for changing a calibration table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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generating an extended-aiming-pattern having at least one line of visible illumination on a target object by projecting visible light through an aiming pattern generating element upon detecting a triggering event; detecting light from a barcode through an imaging lens arrangement with an imaging sensor having photosensitive elements to capture a first image of the barcode on the target object during a first time period when the extended-aiming-pattern is on the target object; processing the first image to determine a present feature-size measuring a size of the at least one line of visible illumination on the same focus plane in the first image; upon detecting an actuating event, detecting light from the barcode through the imaging lens arrangement to capture a second image of the barcode when a lens-driving-parameter for the imaging lens arrangement is set with an expected optimal lens-driving-parameter, wherein the expected optimal lens-driving-parameter is determined from the present feature-size and data in a calibration table for establishing a corresponding relationship between a feature-size and an optimal lens-driving-parameter; and processing the second image to decode the barcode.
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13. An apparatus comprising:
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an aiming pattern generating element; an aiming light source configured to project visible light through the aiming pattern generating element to generate an extended-aiming-pattern on a target object, the extended-aiming-pattern including at least one line of visible illumination; an illumination source operative to generate an illumination light projected towards the target object; an imaging lens arrangement configured to change a focus position thereof with a lens-driving-parameter; an imaging sensor having photosensitive elements configured to detect light from the target object through the imaging lens arrangement and configured to capture multiple images of the target object while substantially maintaining the distance between the target object and the imaging lens arrangement, with at least one of the multiple images being captured during a time period when the extended-aiming-pattern is generated on the target object; a controller for processing the at least one of the multiple images to determine a feature-size measuring a size of the at least one line of visible illumination on the same focus plane in the at least one of the multiple images, and for processing at least two of the multiple images to find an optimal lens-driving-parameter that results in the maximum image sharpness; and a memory configured to store both the feature-size and the optimal lens-driving-parameter into a look-up table having a corresponding relationship established between the feature-size and the optimal lens-driving-parameter. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification