Optical correlation system

• US 4,809,340 A
• Filed: 04/08/1988
• Issued: 02/28/1989
• Est. Priority Date: 04/08/1988
• Status: Expired due to Fees

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Mersereau, Keith O.
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Daley, Donald J.
• Application Number:
  US07/179,057
• Time in Patent Office: 326 Days
• Field of Search: 382/1, 382/9, 382/31, 350/162.13, 350/3.7, 350/3.82, 209/584, 209/900
• US Class Current: 382/101
• CPC Class Codes: G06E 3/005 using electro-optical or opto-electronic means
• CPC Class Codes: G06V 10/88 Image or video recognition using optical means, e.g. reference filters, holographic masks, frequency domain filters or spatial domain filters
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/146 Aligning or centring of the image pick-up or image-field
• CPC Class Codes: G06V 30/424 Postal images, e.g. labels or addresses on parcels or postal envelopes
• CPC Class Codes: Y10S 209/90 Sorting flat-type mail

Abstract

Invention provides optical correlation apparatus comprised of optical means producing a light image of the mailpiece including the address information, holographic filter means receiving the optical means light image and producing a filtered light image correlated to an address information reference pattern, detector means receiving the holographic filter means filtered light image and producing an output electronic signal which contains the degree of correlation of the mailpiece address information to the address information reference pattern, and signal processor means receiving the detector means output electronic signal and producing an address location signal based on a high degree of correlation of the mailpiece address information to the address information reference pattern.

Claims

1. Apparatus for use in a mail sorting system, comprising:

a. optical of a mailpiece having address information comprised of characters spaced in a line and character lines spaced in a block;

b. holographic filter means receiving the optical means light image and producing a filtered light image correlated with an address information reference pattern, wherein said reference pattern contains correlating data on the spacing of characters in a line and on the spacing of character lines in a block;

c. detector means receiving the holographic filter means filtered light image and producing an output electronic signal which contains the degree of correlation of said mailpiece address information to said address information reference pattern; and

d. signal processor means receiving said detector means output electronic signal and producing an address location signal based at least in part on correlation of said mailpiece address information to said address information reference pattern.

2. The apparatus defined by claim 1 wherein said holographic filter means is a correlation filter based on an object transparency having window features set within a background, said window features being spaced from each other in lines at distances which correspond to the spacing of characters in lines in said address information reference pattern and being spaced from each other in lines in a block at distances which correspond to the spacing of character lines in a block in said address information reference pattern.

3. The apparatus defined by claim 1 wherein said address information reference pattern character spacing in lines is at a distance in the range of approximately from 10 to 12 characters per inch, and said address information reference pattern lines in a block spacing is at a distance in the range of approximately 6 to 8 lines per inch.

4. The apparatus defined by claim 1 wherein said address information reference pattern character spacing in lines is at a distance of approximately 10 characters per inch.

5. The apparatus defined by claim 1 wherein said address information reference pattern lines in a block spacing is at a distance of approximately 8 lines per inch.

6. Optical correlation systems apparatus for use in a mail sorting application and comprising:

a. optical means which produces a light image of a mailpiece having address information comprised of characters spaced in a line and character lines spaced in a block;

b. holographic correlation filter means receiving the optical means light image and producing a filtered light image correlated with an address information reference pattern, wherein said reference pattern contains correlating data on the spacing of characters in a line and on the spacing of characters in a line and on the spacing of character lines in a block;

c. detector means receiving the holographic filter means filtered light image and producing an output electronic signal which contains the degree of correlation of said mailpiece address information to said address information reference pattern; and

d. signal processor means receiving said detector means output electronic signal and producing an address location signal based at least in part on correlation of said mailpiece address information to said address information reference pattern.

7. The apparatus defined by claim 6 wherein said optical means produces a coherent light image, and wherein said holographic correlation filter means is recorded from an object transparency having address information reference pattern window features set within a background, said object transparency window features having a coherent light wavefront transmission delay that is approximately one-half wavelength greater or less than the wavefront transmission wavelength delay of said object transparency address information reference background.

8. The apparatus defined by claim 7, wherein said object transparency address information reference pattern window features are spaced from each other in lines at a distance which corresponds to a spacing of approximately 10 to 12 characters per inch in said address information reference pattern, and in lines in a block at a distance which corresponds to a spacing of approximately 6 to 8 lines per inch in said address information reference pattern.

9. The apparatus defined by claim 7 wherein said object transparency address information reference pattern window features are spaced from each other in lines at a distance which corresponds to a spacing of approximately 10 characters per inch in said address information reference pattern.

10. The apparatus defined by claim 7 wherein said object transparency address information reference pattern window features are spaced from each other in lines in a block at a distance which corresponds to a spacing of approximately 8 lines per inch in said address information reference pattern.

11. The apparatus defined by claim 6 wherein said optical means produces an incoherent light image, and wherein said holographic correlation filter means is based on an object transparency having address information reference pattern window features set within a background, said object transparency window features being relatively transparent to light and said object transparency background being relatively opaque to light.

12. The apparatus defined by claim 11 wherein said object transparency address information reference pattern window features are spaced from each other in lines at a distance which corresponds to a spacing of approximately 10 to 12 character per inch in said address information reference pattern, and in lines in a block at a distance which corresponds to a spacing of approximately 6 to 8 lines per inch in said address information reference pattern.

13. The apparatus defined by claim 11 wherein said object transparency address information reference pattern window features are spaced from each other in lines at a distance which corresponds to a spacing of approximately 10 characters per inch in said address information reference pattern.

14. The apparatus defined by claim 11 wherein said object transparency address information reference pattern window features are spaced from each other in lines in a block at a distance which corresponding to a spacing of approximately 8 lines per inch in address information reference pattern.

15. Multi-channel apparatus for use in a mail sorting system to develop address location information, comprising:

a. optical means producing light images of a mailpiece having address information comprised of characters spaced in a line and character lines spaced in a block,

b. multiple holographic correlation filter means each receiving an optical means light image and producing a different filtered light image correlated to a different address information reference pattern, wherein said reference pattern contains correlating data on the spacing of characters in a line and on the spacing of characters lines in a block;

c. multiple detector means each receiving a different holographic correlation filter means filtered light image and producing an output electronic signal which contains the degree of correlation of said mailpiece address information to said different address information reference pattern; and

d. signal processor means receiving said multiple detector means output electronic signals and producing an address location signal based at least in part on the highest correlation of said mailpiece address information to said different address information reference character pattern spacings in lines and character line pattern spacings in blocks.

16. In a method of locating address information on the face of a mailpiece, the steps of:

a. generating an image of a mailpiece having address information comprised of characters spaced in a line and character lines spaced in a block;

b. filtering said image in a spatial filter apparatus having a holographic filter made from an object transparency pattern comprised of windows spaced in a line corresponding to said character spacing and window lines spaced in a block corresponding to said character line spacing; and

c. converting said filtered image in a detector means to a correlation signal indicative of the correlation of said mailpiece address information with said filter apparatus object transparency window pattern.

17. The method defined by claim 16 wherein said object transparency windows are spaced in lines at a distance which is proportional to an address information character spacing in lines in the range of approximately 10 to 12 characters per inch, and in window lines at a distance which is proportional to an address information character line spacing in a block in the range of approximately 6 to 8 character lines per inch.

18. The method defined by claim 17 wherein said object transparency windows are spaced in lines at a distance which is proportional to an address information character spacing in lines of approximately 10 characters per inch, and in window lines at a distance which is proportional to an address information character line spacing in a block of approximately 8 lines per inch.

19. The method defined by claim 17 wherein said object transparency windows are spaced in lines at a distance which is proportional to an address information character spacing in lines of approximately 12 characters per inch, and in window lines at a distance which is proportional to an address information character line spacing in a block of approximately 8 lines per inch.