CODEWITHSUNDEEP
opencvcontouredge-detection
Shivanand
Shivanand

Reputation: 144

Fitting curved edges separated by sharp corners

EDIT: To further clarify if my question is not clear,

My problem here is to detect points and fit separate curves to each of the curved edges of objects like what is shown below (The image shown is one example. The actual shape of each object is different, but there will be either a sharp corner or change in slope from one edge to another):

enter image description here

One way to approach this is to separate out the points/pixels on each edge (the four lines in the above example) and fit polynomials on each of them. By searching a little bit, I learnt that Hough Transform is available for detecting straight edges in OpenCV, but not for curved edges. I also tried detecting contours, but it does not separate out edges of a closed shape. The main criterion for an edge to be considered separate from an adjacent one is that there is a sharp change in slope.

Could anyone give me ideas on how to achieve this? I prefer using C++ with OpenCV due to the other modules of my task.

Upvotes: 1

Views: 687

Answers (1)

user1196549
user1196549

Reputation:

What you are trying to do is essentially to find high curvature points in the outline. There are several methods for curvature estimation. Some are based on local derivatives of the intensity, and some are based on the arrangement of the pixels along the curve. This problem is very close to that of corner detection.

You may be interested by the following references: "A Comparative Study on 2D Curvature Estimators, Simon Hermann and Reinhard Klette" or "Curvature estimation in noisy curves, Thanh Phuong Nguyen, Isabelle Debled-Rennesson". Notice that there is large litterature on the topic as curvature estimation in the digital domain is uneasy because it takes second order derivatives.

Upvotes: 3

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