Opto-electronic device for acquisition of images of codes in one and two dimensions

• US 6,328,214 B1
• Filed: 01/24/2000
• Issued: 12/11/2001
• Est. Priority Date: 01/22/1999
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Thuries, Serge, Puech, Jean-Michel, Massieu, Jean-Louis, Reuze, Patrick, Dumontier, Christophe, Akel, Khalid El
• Primary Examiner(s): Frech, Karl D.
• Assistant Examiner(s): Walsh, Daniel I.
• Application Number:
  US09/490,706
• Time in Patent Office: 687 Days
• Field of Search: 235/462.1, 235/462.11, 235/462.25, 235/462.27, 235/462.24, 235/462.41, 235/462.23, 235/462.8
• US Class Current: 235/462.27
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning

Abstract

The invention concerns an oplo-electronic device for acquisition of images of codes in one and two dimensions, comprising an electronic sensor constituted by a high-resolution photosensitive matrix, an analog/digital converter to convert the data emitted from the electronic sensor, and an image acquisition and processing module, comprising a preprocessing module and two processing modules, forming a pipe-line type architecture. The preprocessing module, acts in synchronous mode on the flow of digital data and implements simple image-processing operations. A number of cabled processing units can form the preprocessing modules. The processing modules, are constituted by programmable modules acting in asynchronous mode on the data emitted from the preceding module and stored in alternative manner in two memory blocks. The programmable modules are programmed to perform processing operations culminating in the obtaining of normalized data that are representative of the information “coded” in the captured code.

Claims

1. An opto-electronic device for acquisition of images of codes in one and two dimensions, comprising:

an electronic sensor;

optical means permitting images to be formed on said electronic sensor, illumination means adapted to illuminate the codes and to permit the acquisition of the images on the electronic sensor;

means for acquisition and processing of the images, adapted to control the electronic sensor and the illumination means and to ensure decoding of the images formed on said electronic sensor, wherein;

the electronic sensor is constituted by a high-resolution photosensitive matrix of size T=n×

n pixels, adapted to supply at a pixel frequency f a stream of data that are representative of the images formed on said electronic sensor,

the means for acquisition and processing of the images comprise;

means for analog/digital conversion of the stream of data emitted from the photosensitive matrix, adapted to digitize the stream of data and supply a stream of digital data coded in a predetermined number of levels of gray,

a preprocessing module realized by means of cabled processing units and adapted to ensure low-level processing of the stream of digital data and to provide, on one hand, a binarized representation of the images formed on the electronic sensor and, on another hand, of primary data which are characteristic of the codes, said preprocessing module comprising a buffer register for temporary storage of the binarized representation of the images and of the primary data,

a first programmable processing module comprising;

two memory blocks,

a logic circuit for management of the memory blocks, adapted to configure, in alternative manner, one of the memory blocks in a mode for writing data emitted from the buffer register and the other memory block in a mode for reading data stored therein,

and a programmable unit, of processor type, which is programmed from data stored in the memory block configured in reading mode, in order to test for presence or absence of a valid code, to locate each valid code, to identify each type of code, to determine, if need be, priority of the code to be processed, to edit and normalize each valid code,

and a second programmable processing module (3) comprising;

two memory blocks,

a logic circuit for management of the memory blocks, adapted to configure, in alternative manner, one of the memory blocks in a mode for writing data emitted from the first programmable module and the other memory block in a mode for reading data stored therein,

and a programmable unit, of processor type, which is programmed from data stored in the memory block configured in reading mode, in order to decode said data so as to supply normalized data that are representative of each captured code.

2. The opto-clectronic device as set forth in claim 1, wherein:

the photosensitive matrix comprises several parallel outputs,

the analog/digital conversion means are adapted to digitize in parallel data supplied at each output of the photosensitive matrix and comprise a multiplexer adapted to supply the digital data in series.

3. The opto-electronic device as set forth in claim 1, wherein the preprocessing module comprises:

a lines memory block, adapted to store the digital data in the form of a drop window of (x) consecutive lines each comprising n pixels,

a binarization circuit adapted to code the digital data in binary form as a function of an open-ended threshold calculated for each datum processed, taking account of the neighborhood of (x, x) data surrounding said datum.

4. The opto-electronic device as set forth in claim 3, wherein the preprocessing module comprises a detection circuit adapted to identify, from the binary data emitted from the binarization circuit, specific signatures of two-dimensional codes.

5. The opto-electronic device as set forth in claim 4, wherein the preprocessing module comprises, downstream of the lines memory block, two preprocessing sub modules arranged in parallel between said memory block and the buffer register:

a first processing submodule comprising the binarization circuit and the circuit for detection of signatures and adapted to supply a binary image and Cartesian coordinates of the specific signatures of the two-dimensional codes to the buffer register,

a second processing submodule comprising successively;

a replicate-sampling circuit capable of reducing the size T of the image formed on the photosensitive matrix and adapted to supply said reduced image to the buffer register,

a circuit for detection of contours in the reduced image emitted from a replicate-sampling circuit, adapted to supply images of said contours coded in one bit to the buffer register,

and a circuit for detection of straight-line segments in the reduced image, adapted to supply start and end coordinates and orientation of said straight-line segments to the buffer register.

6. The opto-electronic device as set forth in claim 5, wherein each memory block of the first programmable module comprises three blocks in which there are stored respectively:

the binary image,

the reduced image and the image of the contours,

data relating to the straight-line segments and to the specific signatures of the two-dimensional codes.