Method for determining article orientation in an article handling system using a sampling of a CCD array

• US 5,353,358 A
• Filed: 07/12/1993
• Issued: 10/04/1994
• Est. Priority Date: 09/24/1990
• Status: Expired due to Fees

• Current Assignee: Meier Flough & Corde LLC (Intellectual Ventures LLC)
• Original Assignee: FMC Corporation
• Inventors: Baird, Randy K., Turcheck, Stanley P. Jr.
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Prikockis, Larry J.
• Application Number:
  US08/090,443
• Time in Patent Office: 449 Days
• Field of Search: 382/1, 382/8, 382/15, 382/14, 356/394, 209/577, 209/586, 364/559, 358/101
• US Class Current: 382/141
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: G06V 10/507 Summing image-intensity values; Histogram projection analysis

Abstract

In an article handling system that functions to make article discrimination-identification determinations, the possible article orientations A, B, C . . . are stored and compared to establish maximum pixel difference numbers and identification of longitudinal window position along the article where such maximum difference occurs. Each of the possible orientations is compared with all other possible orientations so that a small number of windows is identified as part of a setting procedure. When operating, the work articles are scanned and only the data at window locations are used to make article orientation identifications to reduce time and memory requirements for data processing.

Claims

1. In a method for determining orientation of singulated articles on a conveyor by sensing article orientation with an array of optical sensors effective to provide information data relating to a pattern of article edge points via successive linear scans of said article the steps comprising:

during a setting-up procedure;

a) storing image edge point data for a plurality of predetermined possible article orientations;

b) determining a maximum data difference between each pair of possible orientations based on image edge point data stored in step a; and

c) identifying at least one linear scan of the article which corresponds to a maximum image edge point data difference between each different pair of orientations;

during a running procedure;

d) acquiring image edge point data from singulated work articles which is compared with the stored image edge point data at each of said maximum image edge point data identified in step "b" hereof; and

(e) determining an orientation mismatch of the work article orientation and the stored article orientation if the image edge point data difference between said stored image edge point data and said scan image edge point data identified in step "b" hereof is greater than or less than a predetermined value; and

f) determining a plurality of linear scans of image edge point data along the article length where major differences occur for each of the possible orientations; and

g) totaling the sum of the difference at each of said plurality of linear scans of image edge point data determined in step "f" hereof; and

using said sum of differences for identifying work article orientation.

2. The method of claim 1 wherein the plurality of linear scans of image edge point data is at least four linear scans and less than about ten percent of the total number of possible linear scans of image edge point data.

3. The method of claim 2 including a further step during the setting-up procedure of expanding the linear scan from one scan to include not more than about two adjacent scans on each side of an image edge point data position.

4. In a method for determining orientation of work articles transported past a sensing station by comparison of profile data obtained by sequentially scanning each article at spaced positions along the article length as the article moves at a constant speed to form sequential scan slices with each of said sequential scan slices having article edge point information data, the steps of:

during a setting-up procedure

a) supplying to a memory scan slice information data relating to part geometry for a plurality of different part orientations A and B by data accumulated as the article is transported past said sensing station in orientations A and B thereby to provide learned information data;

b) determining a first sequential number of said scan slice when a maximum difference exists between article edge points when orientation A is compared with orientation B;

c) determining a second sequential number of said scan slice when a maximum difference exists between article edge point information data when orientation B is compared with orientation A;

d) storing sequential scan slice numbers as numbered windows;

thereafter making an orientation determination by;

e) moving singulated work articles past said sensing station;

f) sequentially scanning each work article to form sequential scan slices having article edge point information data at each sequential scan slice;

g) subtracting article edge point information data from learned information data only at said numbered windows to produce a score relating to a difference corresponding to each window location for each of the possible orientations sequentially, whereby the lowest score is used to identify the work article orientation.

5. In a method for determining orientation of work articles transported past a sensing station by comparison of profile data obtained by sequentially scanning each article at spaced positions along the article length as the article moves at a constant speed to form sequential scan slices with each of said sequential scan slices having article edge point information data, the steps of:

during a setting procedure

a) supplying to a memory, scan slice information data relating to part geometry for a plurality of different part orientations A, B and C by data accumulated as the article is transported past said sensing station in orientations A, B and C thereby to provide learned information data;

b) determining sequential scan slice members where a maximum difference exists between article edge points when orientation A is compared with orientation B and with orientation C, respectively;

c) determining two additional sequential scan slice numbers where a maximum difference exists between article edge points when orientation B is compared with orientation A and with orientation C, respectively;

d) determining two additional sequential scan slice numbers where a maximum difference exists between article edge points when orientation C is compared with orientation A and with orientation B, respectively;

e) storing all six of said sequential scan slice numbers as numbered windows;

thereafter making an orientation determination by;

f) moving singulated work articles past said sensing station;

g) sequentially scanning each work article to form scan slices having article edge point information data at least where each scan slice window occurs; and

h) subtracting article edge point information data from learned information data only at said numbered windows to produce a score relating to a difference corresponding to each window location;

i) totaling the scores produced by subtracting work article information data from learned information data at said numbered windows for each of the three orientations, and

j) utilizing the lowest score to identify the work article orientation.