Device for displaying feature of contour image

• US 4,361,830 A
• Filed: 09/10/1980
• Issued: 11/30/1982
• Est. Priority Date: 09/10/1979
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Square Enix
• Original Assignee: Agency of Industrial Science & Technology (Government of Japan), Ministry of International Trade & Industry (Government of Malaysia)
• Inventors: Honma, Kazuhiro, Shimizu, Kajuro, Nakatani, Tetsu, Takenaka, Eiichi
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/185,775
• Time in Patent Office: 811 Days
• Field of Search: 340/146.3 AE, 340/146.3 AC, 340/146.3 H, 340/146.3 Y, 340/146.3 R, 235/92 PC, 364/413, 364/515, 358/96, 358/101, 358/107, 356/39, 250/202
• US Class Current: 382/199
• CPC Class Codes: G06V 10/46 Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56

Abstract

The x-y coordinates are determined of a multiplicity of points set at very small intervals of a fixed value on a contour line, the coordinates of a selected number of points on either side of one (central point) of the aforementioned multiplicity of points are averaged, the two points corresponding to the two sets of averaged coordinates are connected by a straight line, a perpendicular line is drawn to this straight line from the aforementioned central point, and the distance from the central point to the foot of the perpendicular line on the straight line is calculated. This distance varies with the change in the shape of the contour line. By finding this distance with respect to each of the points on the contour line and displaying the distances found, there can be obtained a figure indicative of features of the shape of the contour image.

Claims

1. A device for the extraction of features of a contour image, which comprises:

(a) means for converting a multiplicity of points set at a fixed, very small interval on the contour line consecutively into coordinates in an x-y coordinate system,

(b) a first adder for adding the x coordinates of a selected number of points on either side of the first point of said multiplicity of points,

(c) a second adder for adding the y coordinates of said selected number of points on either side of said first point,

(d) a first divider for dividing each of the two outputs of said first adder by said selected number,

(e) a second divider for dividing each of the two outputs of said second adder by said selected number,

(f) a first subtractor for subtracting the x coordinates of said first point from the first output of said first divider and subtracting said first output from the second output of said first divider,

(g) a second subtractor for subtracting the first output of said second divider from the second output of said second divider and subtracting said first output of the second divider from the y coordinate of said first point,

(h) a third divider for dividing the first output of said second subtractor by the second output of said first subtractor,

(i) a first multiplier for multiplying the first output of said first subtractor by the output of said third divider,

(j) a third adder for adding the output of said first multiplier and the second output of said second subtractor,

(k) a first arithmetic means for squaring the output of said third divider,

(l) a fourth adder for adding the value "1" to the output of said first arithmetic means,

(m) a second arithmetic means for deriving the square root of the output of said fourth adder,

(n) a fourth divider for dividing the output of said third adder by the output of said second arithmetic means, and

(o) display means for displaying the output of said fourth divider.

2. The device according to claim 1, wherein the output of the fourth divider is displayed in the form of a corresponding absolute value.

3. The device according to claim 1, wherein the multiplicity of points set on the contour line are the points at which as many straight lines extended radially from a point fixed within the contour line at a fixed angular interval intersect the contour line.

4. The device according to claim 1, wherein the multiplicity of points set on the contour line are points incrementally separated from one point fixed on the contour line by a fixed, very small interval.