US 8,985,456 B2Granted

Auto-exposure method using continuous video frames under controlled illumination

AssigneeMetrologic Instruments, Inc.

InventorsXiaoxun Zhu, Ynjiun Paul Wang

Life of this patent

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Abstract

A strobe illumination control process for use in a digital image capture and processing system includes illuminating an object in the field of view with different pulses of illumination over a pair of consecutive video image frames, detecting digital images of the illuminated object over these consecutive image frames, and decode processing the digital images. In a first illustrative embodiment, upon failure to read a symbol in one of the first and second images, these digital images are analyzed in real-time, and based on the results of this real-time image analysis, the exposure time is adjusted during subsequent image frames. In a second illustrative embodiment, upon failure to read a symbol in one of the first and second images, these digital images are analyzed in real-time, and based on the results of this real-time image analysis, the energy level of the illumination is adjusted during subsequent image frames.

Claims20

Dependent claims

A method of controlling illumination processes within a digital image system having a field of view, comprising:

illuminating an object in the field of view at a first energy level;
capturing a first digital image of the object illuminated at the first energy level using a predetermined exposure duration;
attempting to read a symbol in the first digital image;
if a symbol is not read in the first digital image, illuminating the object in the field of view at a second energy level that is different from the first energy level;
capturing a second digital image of the object illuminated at the second energy level using the predetermined exposure duration;
attempting to read a symbol in the second digital image;
if a symbol is not read in the second digital image, analyzing the first digital image and the second digital image to measure whether:
the first digital image and the second digital image are both too dark;
the first digital image and the second digital image are both too bright;
or
one of the first digital image and second digital image is too bright and the other of the first digital image and second digital image is too dark;
determining a modified exposure duration based on the analysis of the first digital image and second digital image;
illuminating the object in the field of view at the first energy level;
capturing a first subsequent digital image of the object illuminated at the first energy level using the modified exposure duration;
attempting to read a symbol in the first subsequent digital image;
if a symbol is not read in the first subsequent digital image, illuminating the object in the field of view at the second energy level;
capturing a second subsequent digital image of the object illuminated at the second energy level using the modified exposure duration;
and
attempting to read a symbol in the second subsequent digital image.

16 more elements

A method of controlling illumination processes within a digital image system having a field of view, comprising:

illuminating an object in the field of view at a first energy level;
capturing a first digital image of the object illuminated at the first energy level using a predetermined exposure duration;
attempting to read a symbol in the first digital image;
if a symbol is not read in the first digital image, illuminating the object in the field of view at a second energy level that is different from the first energy level;
capturing a second digital image of the object illuminated at the second energy level using the predetermined exposure duration;
attempting to read a symbol in the second digital image;
if a symbol is not read in the second digital image, analyzing the first digital image and the second digital image to measure whether:
the first digital image and the second digital image are both too dark;
the first digital image and the second digital image are both too bright;
or
one of the first digital image and second digital image is too bright and the other of the first digital image and second digital image is too dark;
determining a modified energy level based on the analysis of the first digital image and second digital image;
illuminating the object in the field of view at the modified energy level;
capturing a subsequent digital image of the object illuminated at the modified energy level using the predetermined exposure duration;
and
attempting to read a symbol in the subsequent digital image.

13 more elements

A method of controlling illumination processes within a digital image system having a field of view, comprising:

illuminating an object in the field of view at a first energy level;
capturing a first digital image of the object illuminated at the first energy level using a predetermined exposure duration;
attempting to read a symbol in the first digital image;
if a symbol is not read in the first digital image, illuminating the object in the field of view at a second energy level that is different from the first energy level;
capturing a second digital image of the object illuminated at the second energy level using the predetermined exposure duration;
attempting to read a symbol in the second digital image;
if a symbol is not read in the second digital image, analyzing the first digital image and the second digital image to measure whether:
the first digital image and the second digital image are both too dark;
the first digital image and the second digital image are both too bright;
or
one of the first digital image and second digital image is too bright and the other of the first digital image and second digital image is too dark;
determining a modified exposure duration based on the analysis of the first digital image and second digital image;
illuminating the object in the field of view at the first energy level;
capturing a subsequent digital image of the object illuminated at the first energy level using the modified exposure duration;
and
attempting to read a symbol in the subsequent digital image.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/852,065Filed 28 Mar 2013 · continuation
Priority: 3 Feb 2011
Published: US 2013/0194451 A11 Aug 2013
Granted: 24 Mar 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H04N 23/56
Cameras or camera modules comprising electronic image sensors; Control thereof: provided with illuminating means
F21V 33/0052
Personal or domestic articles: audio or video equipment, e.g. televisions, telephones, cameras or computers; Remote control devices therefor
G06K 7/10732
Photodetector array or CCD scanning: light sources
G06K 7/10752
Photodetector array or CCD scanning: exposure time control

Family

Application13/020,044Parent of this continuation · filed 3 Feb 2011
US 8,408,464 B2Parent of this continuation · filed 2 Apr 2013
US 2013/0194451 A1Pre-grant publication · published 1 Aug 2013
US 2012/0199654 A1Published application
US 8,985,456 B2This patent

From the US filing history. Foreign family members aren’t listed.