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Object orientation (horizontal/vertical)

asked 2019-06-12 06:58:23 -0500

Hi All - I am looking for help where i need to identify if the particular object is placed as horizontal or vertical. Did somebody try this?

Thanks, Abhijit

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Did somebody try this? -- for sure!

please have a look at the faq and try to improve your question.

berak gravatar imageberak ( 2019-06-12 07:00:32 -0500 )edit

Yes, orientation is a common problem in computer vision. Can you share some images with us?

Chris gravatar imageChris ( 2019-06-12 10:46:09 -0500 )edit

Ok. Please see the image attached. I want to know a) how to find out what's is pen's tip b) what's pen's orientation and what degree w.r.t. horizontal edge of the picture

Thanks, Abhijit


Abhijit B gravatar imageAbhijit B ( 2019-06-21 03:07:59 -0500 )edit
sturkmen gravatar imagesturkmen ( 2019-06-21 07:32:01 -0500 )edit

@Abhijit B. Python or c++?

supra56 gravatar imagesupra56 ( 2019-06-23 04:41:57 -0500 )edit

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answered 2019-06-21 10:46:24 -0500

Chris gravatar image

OpenCV has a useful tool called PCA (principal component analysis) Here is how I used it:

  • resized the image by 1/4 as we don't really need such high resolution here
  • extract the red channel so that the blue part of the pen is darker than the surroundings
  • apply a threshold using binary_inverse with treshold value about 90
  • do some morphology to clean up the threshold image: one iteration of erosion with 3x3 rect and 5 iterations of dilation with 3x3 rect
  • do some contour filtering to only include the contour whose center is nearest the center of the image
  • now do PCA on this remaining contour to give 2 eigenvectors that tell us the orientation

From here, you can apply some test to tell if it is in some desired orientation.

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Asked: 2019-06-12 06:58:23 -0500

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Last updated: Jun 21