Image recognition apparatus

• US 4,955,060 A
• Filed: 07/02/1987
• Issued: 09/04/1990
• Est. Priority Date: 07/02/1987
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Inventors: Young, James R., Peppers, Norman A., Pierce, Gerald A., Katsuki, Kazuo, Nishi, Hisami
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Jung, Yon
• Application Number:
  US07/069,310
• Time in Patent Office: 1,160 Days
• Field of Search: 382/65, 382/67, 382/68, 382/31, 382/32, 382/38, 382/30
• US Class Current: 382/212
• 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

Abstract

In an image recognition apparatus for identifying an input image such as a character, any other graphic pattern or the like by comparing the input image with a plurality of reference image, an optical image recognition means simultaneously performs image information detection processing of a plurality of optical pattern images of substantially an identical shape obtained by multiplying the input image, thereby detecting a plurality of image information data corresponding to the plurality of optical pattern images and hence identifies the input image. When the input image cannot be identified by the optical image recognition means, an electronic image recognition means performs digital correlation calculations for limited ones of the reference images according to the above image information data. Therefore, image recognition can be performed by an inexpensive apparatus at high speed, and a high throughput can be obtained. In addition, a high recognition rate can be obtained.

Claims

1. An image recognition apparatus comprising, optical image recognizing means for performing image recognition processing including an optical process and electronic image recognizing means for performing electronic digital processing;

said optical image recognizing means being arranged to optically multiply an input image to be recognized to form simultaneously in parallel a plurality of optical pattern images of substantially an identical shape, to simultaneously perform image information detection processing, thereby detecting a plurality of image information data corresponding to the plurality of optical pattern images, and to identify the input image on the basis of the plurality of image information data;

said electronic image recognizing means being arranged to perform digital correlation calculations between digital pattern data representative of the input image and digital pattern data representative of a plurality of reference images and to identify the input image;

said optical image recognizing means comprising;

(b

     1) a first optical processing line including projection feature extracting means for extracting projection features of the optical pattern images and primitive pattern extracting means for extracting primitive patterns included in the optical pattern images, simultaneously in parallel with the extraction of said projection features;

(2) a second optical processing line including optical correlation calculating means for performing optical correlation between the optical pattern images and the reference image patterns, independently of and in parallel with said first optical processing line as well as by use of a different reference data base from the reference data base that is used for said first optical processing line; and

(3) a third optical processing line for reinforcing functions of said first and second optical processing lines;

said first optical processing line comparing the projection feature data of the input image which are output from said projection character extracting means, and the primitive feature data of the input image which are output from said primitive feature extracting means, respectively with the reference data of the reference images in order to determine the input image;

said second optical processing line being arranged to cause said optical correlation calculating means to perform the optical correlation calculations to determine the input image;

said third optical processing line being arranged such that the image information data from said first optical processing line and the image information data from said second optical processing line are collated and the input image is determined according to a result of the collation; and

the digital correlation calculations by said electronic image recognizing means being supplementally performed for limited ones of the reference images according to the image information data obtained by said optical image recognizing means, when the input image cannot be identified by the result of the determination of said third optical processing line.

2. An apparatus according to claim 1, wherein said projection feature extracting means comprises:

a multiplier for optically multiplying the input image to form a plurality of optical pattern images having a substantially identical shape; and

a plurality of means for detecting various types of projection features upon detection of projections from the optical images having the substantially identical shape;

wherein the plurality of optical images having the substantially identical shape and formed by said multiplier are independently supplied to said plurality of detecting means, and various types of projection features are simultaneously produced from said plurality of detecting means.

3. An apparatus according to claim 2, wherein said plurality of detecting means respectively have light-receiving surfaces each constituted as a combination of photosensor units, the combinations of said photosensor units constituting said light-receiving surfaces being different from each other in said detecting means, and

the plurality of optical images multiplied by said multiplier are respectively formed on said light-receiving surfaces of said plurality of detecting means.

4. An apparatus according to claim 3, wherein at least one of said detecting means comprises a large number of annular photosensor units whose diameters are sequentially changed, said annular photosensor units being adjacent to each other along a radial direction thereof.

5. An apparatus according to claim 3, wherein at least one of said detecting means comprises a large number of substantially sector-shaped photosensor units whose vertices substantially come together at one point such that sides of each of said sector-shaped photosensor units are adjacent to those of an adjacent one thereof.

6. An apparatus according to claim 1, wherein said optical correlation calculating means comprises:

a multiplier for optically multiplying the input image to form a plurality of optical pattern images having a substantially identical shape;

a plurality of reference masks respectively having reference patterns to be pattern-matched with the optical pattern images, said plurality of reference masks being adapted to respectively receive the plurality of optical pattern images; and

photodetecting means for detecting beams emitted through said plurality of reference masks upon pattern matching between the optical pattern images and the reference patterns.

7. An apparatus according to claim 6, wherein the reference patterns formed on said reference masks have predetermined shapes which cannot be changed into other shapes.

8. An apparatus according to claim 6, wherein said reference patterns formed on said reference masks are respectively constituted by spatial modulation elements, the reference patterns constituted by said spatial modulation elements being changed in response to reference data transferred from a data base.

9. An apparatus according to claim 1, wherein

said primitive image recognizing means respectively compares the projection feature data of the input image which are output from said projection character extracting means, and the primitive feature data of the input image which are output from said primitive feature extracting means, with the reference data of the reference images in order to identify the input image.

10. An apparatus according to claim 9, wherein said primitive pattern extracting means comprises:

a multiplier for optically multiplying the input image to form a plurality of optical pattern images having substantially an identical shape;

a plurality of primitive masks respectively having various types of primitive patterns respectively consisting of basic shapes commonly included in a plurality of input images, said plurality of primitive masks being adapted to respectively receive the plurality of optical pattern images corresponding to the various types of primitive patterns; and

photodetecting means for detecting beams emitted through said plurality of primitive masks upon optical comparison between the optical pattern images and the primitive patterns.

11. An apparatus according to claim 10, wherein said primitive patterns formed on said primitive masks have predetermined shapes which cannot be changed to other shapes.

12. An apparatus according to claim 10, wherein said primitive patterns formed on said primitive masks are respectively constituted by spatial modulation elements, and the primitive patterns constituted by said spatial modulation elements can be changed in response to reference data transferred from a data base.

13. An apparatus according to claim 1, wherein said optical image recognizing means comprises vector discriminating means for discriminating a vector which corresponds to at least one projection feature derived from the input image and which is constituted by a plurality of vector components,

said vector discriminating means comprising:

a display for displaying a plurality of optical patterns at positions respectively corresponding to sizes of the plurality of vector components;

a plurality of reference masks each having a reference pattern group corresponding to the reference images in order to perform optical pattern matching with an optical pattern group consisting of the plurality of optical patterns;

a multiplier for optically multiplying the optical pattern group displayed on said display to form a plurality of optical pattern groups each having a substantially identical shape in the vicinities of said plurality of reference masks; and

light detecting means for optically detecting beams emitted respectively through said plurality of reference masks by matching the optical pattern group with the reference pattern group.

14. An apparatus according to claim 13, wherein the reference patterns formed on said reference masks have predetermined shapes which cannot be changed to other shapes.

15. An apparatus according to claim 13, wherein said reference patterns formed on said reference masks are respectively constituted by spatial modulation elements, and the reference patterns constituted by said spatial modulation elements can be changed in correspondence to reference data transferred from a data base.

16. An apparatus according to claims 14 or 15, wherein the reference patterns are constituted as a gray scale.

17. An apparatus according to claim 1, wherein at least one type of projection feature of the input image which is output from said projection feature extracting means is compared with the reference data, and said optical correlation calculating means performs optical correlation calculations for the reference images, the number of which is limited by a comparison result.

18. An apparatus according to claim 1, wherein said second optical processing line is operative when said first optical processing line cannot identify the input image.

19. An apparatus according to claim 1, wherein said third optical processing line is arranged such that a degree of similarity between the image information data from said first optical processing line and the image information data from said second optical processing line is detected and the input image is identified according to a detection result of the degree of similarity.