Method of extracting a selected configuration from an image according to a range search and direction search of portions of the image with respect to a reference point

• US 5,881,171 A
• Filed: 09/03/1996
• Issued: 03/09/1999
• Est. Priority Date: 09/13/1995
• Status: Expired due to Term

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Kinjo, Naoto
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US08/707,287
• Time in Patent Office: 917 Days
• Field of Search: 382/197, 382/199, 382/202, 382/203, 382/204
• US Class Current: 382/199
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06V 10/40 Extraction of image or video features
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

A method of extracting a specific configuration including: measuring a density or luminance of portions of an image; determining a change in density or luminance for each direction at each portion of the image. Based on the results of the measurement, setting a reference point corresponding to a portion whose amount of change along a predetermined direction of the image is greater than or equal to a predetermined value; setting a search range, corresponding to a distance from the reference point which is within an angle range with respect to the reference point. The angle range is determined in accordance with a contour configuration of the region based on a direction determined in advance or a direction in change in density or luminance at the reference point which is greater than or equal to a predetermined value; and setting a search direction pattern in the search range which expresses a direction in which the density or luminance changes, and searching for portions which exist within the search range and whose amount of change in density or luminance along a direction expressed by the search direction is greater than or equal to a predetermined value; and when a portion which satisfies a search condition is detected, repeating setting of a detected portion as a next reference point; and extracting the line formed by connecting a plurality of reference points as the contour line.

Claims

1. A method of extracting a region of a specific contour configuration from an image comprises:

a) measuring a density or a luminance of each of a plurality of portions of the image;

b) determining an amount of change in density or an amount of change in luminance in a plurality of directions at each of said plurality of portions of the image, according to the density or the luminance measured in said measuring step;

c) setting, as a reference point, a portion from said plurality of portions having an amount of change in density along a predetermined direction of the image or having an amount of change in luminance along a predetermined direction of the image is greater than or equal to a predetermined value;

d) setting, as a search range for proximate portions near the reference point, a range of portions whose distance from the reference point is within a predetermined distance and which is within an angle range with respect to the reference point, wherein the angle range is determined in accordance with a contour configuration in a direction determined in advance, or a direction in which the amount of change in density at the reference point is greater than or equal to a predetermined value, or the amount of change in luminance at the reference point is greater than or equal to a predetermined value;

e) setting a search direction pattern which is to be searched at respective portions in said search range and which expresses a direction in which the density or the luminance changes, based on the contour configuration in a direction determined in advance, or a direction in which the amount of change in density at the reference point is greater than or equal to a predetermined value, or the amount in change in luminance at the reference point is greater than or equal to a predetermined value;

f) searching for portions which exist within said search range and whose amount of change in density along a direction expressed by said search direction pattern or amount of change in luminance along the direction expressed by said search direction pattern is greater than or equal to a predetermined value to thereby satisfy a search condition, and wherein when a portion which satisfies the search condition is detected, setting the detected portion as a next reference point; and

g) extracting, as a contour line a line formed by connecting a plurality of portions of the image which were set in order as reference points.

2. A method according to claim 1, wherein when a plurality of portions are detected as portions satisfying said search condition, said method further comprises performing at least one of:

setting as the next reference point the portion, among said plurality of portions, whose amount of change in density along the direction expressed by said search direction pattern or amount of change in luminance along the direction expressed by said search direction pattern is the greatest, and

setting as the next reference point the portion, among said plurality of portions, which is positioned at a position having a higher priority, in accordance with a predetermined priority of the position of the next reference point with respect to a current reference point.

3. A method according to claim 2,

wherein the angle range corresponds to a contour configuration of a person;

said method further comprising;

judging whether the extracted contour line corresponds to a person'"'"'s face; and

when it is judged that the extracted contour line corresponds to a person'"'"'s face, determining copy conditions for copying the image onto a copy material, on the basis of an image characteristic amount in the region judged to be region corresponding to a person'"'"'s face.

4. A method according to claim 3, further comprising:

setting, as a second angle range, an angle range corresponding to a contour configuration which is different than the contour of a person; and

searching for portions which exist within said search range using said second angle range and whose amount of change in density along a direction expressed by said search direction pattern or amount of change in luminance along the direction expressed by said search direction pattern is greater than or equal to a predetermined value to thereby satisfy a second search condition, and wherein when a portion which satisfies the second search condition is detected, setting the detected portion as a second next reference point; and

extracting, as a second contour line a line formed by connecting a plurality of portions of the image which were set as second reference points;

judging whether the region extracted in said step (g) corresponds to a person'"'"'s face by also taking into consideration the arrangement of the second extracted contour line.

5. A method according to claim 1, further comprising:

while setting said search range and said search direction pattern, and searching for a portion which satisfies said search condition, and setting of a detected portion as the next reference point,

determining a position on the contour, of a portion which has been set as the reference point; and

changing the angle range with respect to the reference point, in accordance with the configuration of the contour at the determined position.

6. A method according to claim 5,

wherein the angle range corresponds to a contour configuration of a person;

said method further comprising;

judging whether the extracted contour line corresponds to a person'"'"'s face; and

when it is judged that the extracted contour line corresponds to a person'"'"'s face, determining copy conditions for copying the image onto a copy material, on the basis of an image characteristic amount in the region judged to be region corresponding to a person'"'"'s face.

7. A method according to claim 6, further comprising:

setting, as a second angle range, an angle range corresponding to a contour configuration which is different than the contour of a person; and

searching for portions which exist within said search range using said second angle range and whose amount of change in density along a direction expressed by said search direction pattern or amount of change in luminance along the direction expressed by said search direction pattern is greater than or equal to a predetermined value to thereby satisfy a second search condition, and wherein when a portion which satisfies the second search condition is detected, setting the detected portion as a second next reference point; and

extracting, as a second contour line a line formed by connecting a plurality of portions of the image which were set as second reference points;

judging whether the region extracted in said step (g) corresponds to a person'"'"'s face by also taking into consideration the arrangement of the second extracted contour line.

8. A method according to claim 1,

wherein the angle range corresponds to a contour configuration of a person;

said method further comprising;

judging whether the extracted contour line corresponds to a person'"'"'s face; and

when it is judged that the extracted contour line corresponds to a person'"'"'s face, determining copy conditions for copying the image onto a copy material, on the basis of an image characteristic amount in the region judged to be region corresponding to a person'"'"'s face.

9. A method according to claim 8, further comprising:

setting, as a second angle range, an angle range corresponding to a contour configuration which is different than the contour of a person; and

searching for portions which exist within said search range using said second angle range and whose amount of change in density along a direction expressed by said search direction pattern or amount of change in luminance along the direction expressed by said search direction pattern is greater than or equal to a predetermined value to thereby satisfy a second search condition, and wherein when a portion which satisfies the second search condition is detected, setting the detected portion as a second next reference point; and

extracting, as a second contour line a line formed by connecting a plurality of portions of the image which were set as second reference points;

judging whether the region extracted in said step (g) corresponds to a person'"'"'s face by also taking into consideration the arrangement of the second extracted contour line.

10. The method according to claim 1, said method further comprising:

repeating said steps (a)-(g) in sequence, wherein each of said plurality of portions is reduced in size and said the sequence is performed, until the sequence of steps (a)-(g) is performed a predetermined number of times;

judging whether a region of the image demarcated by the extracted contour line corresponds to a person'"'"'s face.

11. The method according to claim 1, wherein said angle range subtends an arc which is less than half of a full circle.

12. The method according to claim 1, said method further comprising:

repeated said steps (a)-(g) in sequence, wherein said predetermined distance is changed and the sequence is performed, until the sequence of steps (a)-(g) is performed a predetermined number of times;

judging whether a region of the image demarcated by the extracted contour line corresponds to a person'"'"'s face.