Accurately determining the position and orientation of each of a plurality of identical recognition target objects in a search target image

• US 9,704,061 B2
• Filed: 07/22/2015
• Issued: 07/11/2017
• Est. Priority Date: 07/31/2014
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chiaki, Oishi, Mori, Yumi, Nakano, Hiroki
• Primary Examiner(s): Abdi, Amara
• Application Number:
  US14/806,095
• Publication Number:
  US 20160034760A1
• Time in Patent Office: 720 Days
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 2207/30242 Counting objects in image
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: G06V 10/7515 Shifting the patterns to accommodate for positional errors

Abstract

Embodiments of the invention relate to detecting the number, position, and orientation of objects when a plurality of recognition target objects are present in a search target image. Dictionary image data is provided, including a recognition target pattern, a plurality of feature points of the recognition target pattern, and an offset (O_x, O_y) from the coordinates at the center of the image to the coordinates of the feature point. The sizes (R_t) and directions (θ_t) of feature vectors for the coordinates (T_x, T_y) of a plurality of feature points in the target image are also provided. The coordinates (F_x, F_y) of a virtual center point in the target image is derived. Additional virtual center points within a radius of the coordinates (F_x, F_y) is counted. Presence of a recognition target object is recognized near the virtual center point coordinates of the search target image.

Claims

1. A system executed by a computer to determine a recognition target pattern present in a target image, the system comprising:

a processing unit operatively coupled to memory;

dictionary image data including a recognition target pattern, a plurality of feature points of the recognition target pattern including a size (Rm) and direction (θ

m) of a feature vector, and an offset (Ox, Oy) from coordinates at a center of an image to coordinates of a feature point;

sizes (Rt) and directions (θ

t) of feature vectors for coordinates (Tx, Ty) of a plurality of feature points in the target image;

the processing unit to calculate coordinates (Fx, Fy) of a virtual center point in the target image derived from Tx, Ty, Ox, Oy, Rm, Rt, θ

m, and θ

t;

the processing unit to count additional virtual center points within a radius (r) of the coordinates (Fx, Fy) of the virtual center point; and

data storage to store the coordinates (Fx, Fy) of the virtual center point and the number of counted virtual center points as candidates, wherein each feature point in the plurality of feature points in the target image is a matching feature point of at least one feature point in the target image and at least one feature point in the recognition target pattern.

2. The system of claim 1, further comprising establishment of the coordinates (Fx, Fy) of the virtual center point of a maximum number of counted virtual center points as the center of the recognition target image.

3. The system of claim 2, further comprising establishment of the coordinates (Fx, Fy) as one recognition target image center and eliminating all of the virtual center points within a predetermined radius (r) of the coordinates (Fx, Fy).

4. The system of claim 1, wherein calculation of the coordinates of the virtual center point in the target image uses the following equations:

Fx=Tx+(Ox·

Rt/Rm)(cos(θ

t−

θ

m))+(Oy·

Rt/Rm)(sin(θ

t−

θ

m))

Fy=Ty+(Ox·

Rt/Rm)(−

sin(θ

t−

θ

m))+(Oy·

Rt/Rm)(cos(θ

t−

θ

m)).

5. A computer program product to determine a recognition target pattern present in a target image, the computer program product comprising a non-transitory computer readable storage device having program code therein, the program code being executable by a processor to:

provide dictionary image data including a recognition target pattern, a plurality of feature points of the recognition target pattern including a size (Rm) and direction (θ

m) of a feature vector, and an offset (Ox, Oy) from coordinates at a center of a target image to coordinates of a feature point;

provide a size (Rt) and direction (θ

t) of the feature vector for coordinates (Tx, Ty) of a plurality of feature points in the target image;

calculate coordinates (Fx, Fy) of a virtual center point in the target image derived from Tx, Ty, Ox, Oy, Rm, Rt, θ

m, and θ

t;

count a number of additional virtual center points within a predetermined radius (r) of the coordinates (Fx, Fy) of the virtual center point; and

store the coordinates (Fx, Fy) of the virtual center point and the number of counted virtual center points, wherein each feature point in the plurality of feature points in the target image is a matching feature point of at least one feature point in the target image and at least one feature point in the recognition target pattern.

6. The computer program product of claim 5, further comprising program code to repeat the counting and storing on all feature points in the target image.

7. The computer program product of claim 6, wherein the program code to repeat the counting and storing on all feature points in the target image includes program code to convert the coordinates (Fx, Fy) of the virtual center point of a maximum number of counted virtual center points to a recognition target image center.

8. The computer program product of claim 7, further comprising program code to establish the coordinate (Fx, Fy) as one recognition target image center and eliminate all of the virtual center points within a predetermined radius (r) of the coordinates (Fx, Fy).