CODEWITHSUNDEEP
image-processingopencvcomputer-vision
AruniRC
AruniRC

Reputation: 5148

How to specify a threshold angle in Corner detection using OpenCV?

I'm trying to get corners that are formed by two approximately perpendicular line segments, and not all the possible corners that are detected by either Shi-Tomasi or the Harris corner detectors provided in OpenCV.

Eg:

000000000000000110
000000000000001100
000000000000011000
000000000000110000
000000000001100000
111111111111111111
000000000000000000
000000000000000000

Something like the above would generate a corner as required - the two lines are close enough to being perpendicular.

However, here's what I'm trying to avoid:

000000000000000000
000000000000001111
000000000011110000
111111111100000000
000000000000000000

Here the lines are definitely not nearly-perpendicular however there's no argument to specify a threshold angle to the detectors. Is there any way to implement this using OpenCV? If not, then resources that point how to code one from scratch using C/C++ would be really helpful.

FURTHER DETAILS: This came up while trying to implement offline sketch interpretation - the "Corner Detection" portion from this paper.

Upvotes: 2

Views: 1059

Answers (1)

mpenkov
mpenkov

Reputation: 21932

Are there many such lines/corners in your image? One thing I can think of is to try a Hough transform to get all the lines first, then examine the angles between line pairs.

Upvotes: 1

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