EP0532823A2
Expired / Lapsed
EP
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Method and apparatus for detecting the contour and separating a given subject from an image
Assignee: Hitachi Ltd
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Filing: 1992-02-19
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Granted: —
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Expires: 2012-02-19
Abstract
Abstract A method for detecting a countour of a given subject to be separated from images and an image separating system. First, a plurality of candidate points (110...120) which have been input by a user are displayed on a screen. A smooth curve (100) which connects the plurality of candidate points is determined and is displayed on a display apparatus (Fig. 4A). The intensity of light on a straight line (130) extending in a direction normal to each candidate point is determined (Fig. 4B). The position of the candidate point is corrected based upon the rate of change in the intensity of light which is determined for each candidate point. A smooth curve (101, 102) which passes the corrected points is determined and is displayed on the display apparatus (Figs. 4C, 4D).
Inventors
- 👤 Mitsuru Ikezawa
- 👤 Takafumi Hitachi Koyasudai Apato A204 Miyatake
- 👤 Hirotada Ueda
- 👤 Shigeo Sumino
- 👤 Satoshi Yoshizawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 18:43
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/10; G06T7/12; G06T7/194; G06T2207/00; G06T2207/10; G06T2207/10016; G06T2207/20; G06T2207/20092; G06T2207/20101
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
A method for detecting image separating points where only a given subject image is separated from images, comprising the steps of: a first step (21) for displaying on a screen a plurality of candidate points in the vicinity of a boundary of said given subject image, which are inputted by a user; a second step (26) for determining and displaying a smooth curve which connects the plurality of candidate points; a third step (27) for determining intensity of light along a straight line normal to said curve at each of the plurality of the candidate points; a fourth step (32) for correcting the position of said candidate point based upon the rate of change in the intensity of light determined in each of the candidate points; and a fifth step (33) for determining and displaying a smooth curve passing said corrected candidate points.
Claim 2
Dependent Claim
83 words
A process for detecting image separating points according to Claim 1, further including the steps of: individually processing the same image in each of components having different wave lengths by using the third and fourth steps; determining the positions of the corrected candidate points for each component; calculating the position of one corrected candidate point from a plurality of corrected candidate points after processing of said fourth step; performing the sixth step for determining the final position; and thereafter performing said fifth step.
Claim 3
Dependent Claim
50 words
A method for detecting image separating points according to Claim 1 or 2 in which when the rate of change in the intensity of light is determined in said fourth step, the designated values of the threshold parameters for determining the rate of change for detecting an edge are changed.
Claim 4
Dependent Claim
74 words
A method for detecting image separating points according to Claim 1 or 2 in which when a smooth curve connecting the plurality of candidate points is determined in the second step, the position of at least one of the candidate points is preliminarily fixed and processing in said third and fourth steps is stopped for the fixed candidate point, while processing of the second to fifth steps is performed for the other candidate points.
Claim 5
Dependent Claim
98 words
A method for detecting image separating points according to Claim 1 or 2 in which, in the fourth stop, processing for determining the rate of change in the intensity of light is sequentially performed from the external to internal slide at each candidate point on a coarse curve traced in the vicinity of the contour of the subject and a point which satisfies conditional formulae (Eqs. (1), (2) and (3)) representing that the rate of change for correcting said plurality of candidate points is higher than a threshold is determined as the position of the corrected candidate point.
Claim 6
Dependent Claim
83 words
A method for detecting image separating points according to Claim 5 in which after processing of said fifth step, said threshold of the rate of change is changed for at least one of candidate points which are determined as not satisfying said conditional formulae as a result of the determination of the rate of change in light intensity in said fourth step, and then processing of said third to fifth steps is repeated at least once for said at least one candidate point.
Claim 7
Dependent Claim
70 words
A method for detecting image separating points according to Claim 5, further including determining a candidate point inputted in the first step to be the position of the corrected candidate point; and adding to said candidate point an attribute representing that it does not satisfy the conditional formulae for correcting the position, including displaying said candidate point in a color different from that of the other point on the screen.
Claim 8
Dependent Claim
70 words
A method for detecting image separating points according to Claim 5, further including determining a candidate point inputted in the fourth step to be the position of the corrected candidate point; and adding to said candidate point an attribute representing that it does not satisfy the conditional formulae for correcting the position, including displaying said candidate point in a color different from that of the other point on the screen.
Claim 9
Dependent Claim
78 words
A method for detecting image separating points according to Claim 1 or 2 in which if processing is repeated again from the second step after completion of said fifth step, at least one candidate point is fixed and the third and fourth steps are stopped for the fixed candidate point and each processing of the third, fourth and fifth steps is repeated at least once from a point adjacent to the fixed point for the other candidate points.
Claim 10
Dependent Claim
106 words
An image separating apparatus for separating a given subject image from images, comprising: means for determining a coarse contour curve for the given subject image which is desired to be separated; means for determining a plurality of candidate points on said contour curve; means for correcting the position of each of said candidate points in each spectral component based upon the rate of change in light intensity of each spectral component; means for comparing the candidate points corrected in each spectral component with each other; means for specifying the separating points from the results of comparing; and means for separating the image from the specified points.
References Cited (Backward Citations)
No citation records indexed.
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