TrackMate Determination of Quality Value in LoG Detector

I’m using the LoG detector and couldn’t find any documentation as to how the ‘quality’ value is determined, only that it is an arbitrary measure. Is there an equation/description of how this works so I’m able to set a threshold based on experimental values.

Hey @Mohacool!

@tinevez can obviously help you in more detail… but you can always check the Trackmate source code if you want/need. The LoG Detector code is here. This ImageJ wiki page on “How to write your own detection algorithm for Trackmate” might also be helpful?

eta :slight_smile:

Hi @Mohacool thanks @etadobson

The TrackMate PDF manual gives information about this (page 51):

The LoG detector is the best detector for Gaussian-like particles in the presence of noise. It is based on applying a LoG filter on the image and looking for local maxima. The Laplacian of Gaussian result is obtained by summing the second order spatial derivatives of the gaussian- filtered image, and normalizing for scale.

Local maxima in the filtered image yields spot detections. Each detected spot is assigned a quality value by taking the local maxima value in the filtered image.

So by properties of the LoG filter, this quality value is larger for :

  • bright spots;
  • spots which diameter is close to the specified diameter.
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