Pattern recognition and orientation system

• US 4,435,837 A
• Filed: 03/05/1981
• Issued: 03/06/1984
• Est. Priority Date: 03/05/1981
• Status: Expired due to Fees

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Abernathy, Frederick H.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/240,878
• Time in Patent Office: 1,097 Days
• Field of Search: 340/146.3 H, 364/463, 364/470, 364/478, 364/515, 364/559, 364/560, 364/564, 358/101, 358/107, 356/152-153, 356/373, 356/375, 356/379-380, 356/399-400, 356/390-394, 356/398, 356/238, 250/548, 250/557, 250/561, 250/202, 270/58-59, 271/226-227, 112/275, 382/28, 382/41, 382/45
• US Class Current: 382/111
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: B26D 5/00 Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
• CPC Class Codes: B26D 5/007 Control means comprising cameras, vision or image processing systems
• CPC Class Codes: B26D 5/34 scanning being effected by a photosensitive device
• CPC Class Codes: B26D 7/015 for sheet material or piles of sheets B26D7/018 and B26D7/02 take precedence
• CPC Class Codes: B26D 7/018 Holding the work by suction
• CPC Class Codes: B26F 1/40 using a press, e.g. of the ram type presses in general B30B
• CPC Class Codes: B26F 1/405 Travelling head presses
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/435 Computation of moments

Abstract

A system that automatically scans the shape of a flat object located in a viewing field, recognizes the shape by identifying at least one moment (e.g., the first moment, area; the second moments, products of inertia; or a higher moment), calculates the centroid and angle of inclination of a principal axis, and then moves the object to a desired location and into a desired orientation.

Claims

1. A method for recognizing a flat piece of cloth comprising

placing said piece on a viewing surface within a field of interest having perpendicular coordinate axes,

generating image signals corresponding to the existence or nonexistence of said piece in discrete areas of said field,

said discrete areas being arranged in rows and columns along said axes,

processing said image signals to obtain observed moment signals representative of the first (area) and the second (sum of the products of inertia I_xx, I_yy) moments of said piece,

generating desired signals for the corresponding first and second moments of a desired piece,

identifying said piece by comparing said observed moment signals with said desired moment signals, and

generating a default signal when a difference between said observed and desired signals exceeds a certain limit.

2. The method of claim 1 including the additional steps, carried out when no default signal is generated, comprising

processing said image signals to obtain signals representative of the angle between the principal axis of said piece and one of said field axes, and

moving said piece to a desired location in response to the last said signals.

3. Clothing manufacturing apparatus for recognizing a flat piece of cut cloth placed within a field of interest having perpendicular coordinate axes, said apparatus comprising

a member having flat viewing surface for supporting said piece,

a viewer to generate image signals corresponding to the existence or nonexistence of said piece in discrete areas of said field,

said discrete areas being arranged in rows and columns along said axes,

means to process said image signals to obtain observed moment signals representative of the first (area) and the second (sum of the products of inertia I_xx, I_yy) moments of said piece,

means to generate desired signals for the corresponding first and second moments of a desired piece, and

means to generate a default signal when a difference between said observed and desired signals exceeds a certain limit.

4. Apparatus as claimed in claim 3 including

further processing means, operative when no default signal is generated, to obtain signals representative of the the angle between the principal axis of said piece and one of said field axes, and

means responsive to the last signals to move said piece to a desired location.