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ORB pyramid explanation

asked 2016-05-15 08:53:40 -0500

USER_123 gravatar image

For ORB pyramid, anyone have some references/explanation on the code segment at https://github.com/Itseez/opencv/blob...

I have downloaded books, lecture notes, papers, and articles to read, but I could not understand the maths involved in ORB pyramid. Any ideas ?

Thanks !

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answered 2016-05-15 17:10:18 -0500

Tetragramm gravatar image

The pyramid makes a set of reduced sized images (a pyramid) and performs ORB on each of them. That lets you track the points across scale changes, where the object gets closer or farther from the camera. For example, you find a point on the first, unresized image. Then the object gets closer and you will find the same keypoint on the second layer of the pyramid because it's larger.

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Thanks for the general explanation that I am more aware of the real purpose of the pyramid. Do you have other references talking about how to generate the pyramid mathematically ?

USER_123 gravatar imageUSER_123 ( 2016-05-15 21:08:41 -0500 )edit

Generally, blur and resize down. The factor by which you resize is variable, with 0.8 and 0.5 being popular.

Tetragramm gravatar imageTetragramm ( 2016-05-16 18:18:19 -0500 )edit
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Asked: 2016-05-15 08:53:40 -0500

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Last updated: May 15 '16