Apparatus and process for two-stage decoding of high-density optical symbols
AssigneeMicroscan Systems, Inc.
InventorRobert Liu
Life of this patent
Estimating the term…
Abstract
A process comprising computing a histogram of pixel intensity data collected from a digital image of an optically readable symbol including light and dark elements, thresholding the histogram to classify individual pixels as light pixels, dark pixels or gray pixels, thresholding only the portion of the histogram corresponding to gray pixels to re-classify the gray pixels into dark pixels, light pixels or unresolved gray pixels, and heuristically analyzing each string of unresolved gray pixels to determine the elements of the optically readable symbol that created the string of unresolved gray pixels. An apparatus and system to implement the process.
Claims24
A process comprising:
- computing a histogram of pixel intensity data collected from a digital image of an optically readable symbol including light and dark elements of varying width;
- thresholding the histogram, wherein thresholding the histogram comprises:
- thresholding the histogram to classify individual pixels as light pixels, dark pixels or gray pixels, and
- thresholding only the portion of the histogram corresponding to gray pixels to re-classify the gray pixels into dark pixels, light pixels or unresolved gray pixels;
- and
- heuristically analyzing each string of unresolved gray pixels to determine the elements of the optically readable symbol that created the string of unresolved gray pixels.
An apparatus comprising:
- a decoder including a processor programmed with instructions to:
- compute a histogram of pixel intensity data collected from a digital image of an optically readable symbol including light and dark elements of varying widths;
- threshold the histogram to classify individual pixels as light pixels, dark pixels or gray pixels, and
- threshold only the portion of the histogram corresponding to gray pixels to re-classify the gray pixels into dark pixels, light pixels or unresolved gray pixels;
- and
- heuristically analyze each string of unresolved gray pixels to determine the elements of the optically readable symbol that created the string of unresolved gray pixels.
A system comprising:
- a camera to capture a digital image of an optically readable symbol, wherein the optically readable symbol includes light elements and dark elements of varying widths;
- a decoder coupled to the camera;
- a storage or memory coupled to the decoder, the storage or memory having stored thereon instructions that, when executed by the decoder, cause the decoder to:
- compute a histogram of pixel intensity data collected from a digital image of an optically readable symbol including light and dark elements;
- threshold the histogram to classify individual pixels as light pixels, dark pixels or gray pixels, and
- threshold only the portion of the histogram corresponding to gray pixels to re-classify the gray pixels into dark pixels, light pixels or unresolved gray pixels;
- and
- heuristically analyze each string of unresolved gray pixels to determine the elements of the optically readable symbol that created the string of unresolved gray pixels.
Dependencies are inferred from the claim text.