US 12,079,997 B2
Method for correcting a contour
Van Trung Pham, Le Perreux sur Marne (FR); Yves Lucas, Saint Eloy de Gy (FR); Sylvie Treuillet, Sigloy (FR); and Laurent Debraux, Paris (FR)
Assigned to DENTAL MONITORING, Paris (FR); and UNIVERSITE D'ORLEANS, Orleans (FR)
Appl. No. 17/432,910
Filed by DENTAL MONITORING, Paris (FR); and UNIVERSITE D′ORLEANS, Orleans (FR)
PCT Filed Feb. 21, 2020, PCT No. PCT/EP2020/054627
§ 371(c)(1), (2) Date Aug. 21, 2021,
PCT Pub. No. WO2020/169802, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 1901755 (FR), filed on Feb. 21, 2019.
Prior Publication US 2022/0207748 A1, Jun. 30, 2022
Int. Cl. G06T 7/13 (2017.01); G06T 5/70 (2024.01); G06T 7/12 (2017.01)
CPC G06T 7/13 (2017.01) [G06T 5/70 (2024.01); G06T 7/12 (2017.01); G06T 2207/20084 (2013.01); G06T 2207/30036 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method for determining, by computer, a contour, referred to as “actual contour”, of the representation, on a photo, of an object composed of one or more elements, said method comprising the following steps:
1) application of a first processing to the photo in such a manner as to obtain a first image showing a first contour of said object;
2) application of a second processing to the photo in such a manner as to obtain a second image showing a second contour of said object;
3) association, according to a predetermined association algorithm and for each point of the second contour, of a respective point of the first contour, then elimination of the points of the first contour not having been associated with a point of the second contour, the first image then showing a corrected contour of said object, said corrected contour following the actual contour,
in which
the first processing is a contour detection processing, and
the second processing comprises the following steps:
A. segmentation of the photo, in such a manner as to obtain a segmented image showing, for each “element”, an elementary mask superposed in registry onto the representation of said element on the photo when the photo and the segmented image are superposed in registry;
B. comparison of the segmented image and of the photo in such a manner as to obtain a probability map, each point of the probability map having a probability value defined as a function of the probability that the point of the corresponding segmented image represents a point of the representation of the element on the photo;
C. determination of the second contour using the probability map, said step C. comprising the following steps:
C1. binarization of the probability map in such a manner as to obtain a framing image composed of first and second probability regions, the first region substantially covering said at least one elementary mask when the framing image is superposed onto the segmented image, the limit of the first region being referred to as “frame”;
C3. after superposition in registry of the framing image and of the segmented image, expansion of the elementary masks, simultaneously, at the same speed and uniformly, until continuing the expansion no longer leads to an additional filling of the frame, the expansion of an elementary mask being locally stopped when the expanded elementary contour which bounds it comes into contact with another elementary mask;
C4. union of the set of expanded elementary contours for defining the second contour.