What means 'blobs' on SIFT algorithm?

asked 2017-06-30 07:17:00 -0500

Kelvin gravatar image

Hi, I have a doubt about the SIFT algorithm.

In the OpenCV documentation it says:

For this, scale-space filtering is used. In it, Laplacian of Gaussian is found for the image with various σ values. LoG acts as a blob detector which detects blobs in various sizes due to change in σ.

I don't quite understand what means 'detects blobs', can someone explain to me?

Thanks in advance

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berak gravatar imageberak ( 2017-06-30 08:25:05 -0500 )edit

So, 'blobs' means 'color stains'?

Kelvin gravatar imageKelvin ( 2017-06-30 08:54:18 -0500 )edit

"clusters of points", maybe ?

berak gravatar imageberak ( 2017-06-30 09:18:42 -0500 )edit

Ok, thanks @berak.

Kelvin gravatar imageKelvin ( 2017-06-30 09:46:52 -0500 )edit

Quote from Blob_detection Wikipedia article:

In computer vision, blob detection methods are aimed at detecting regions in a digital image that differ in properties, such as brightness or color, compared to surrounding regions. Informally, a blob is a region of an image in which some properties are constant or approximately constant; all the points in a blob can be considered in some sense to be similar to each other.
Eduardo gravatar imageEduardo ( 2017-06-30 10:17:15 -0500 )edit