Spot detector gives different result for the cropped image

[Dmitry Sorokin]

Hello!

I've just accidentally found a strange behavior of Spot Detector. I don't know whether it's a bug or not though.

I tried spot detection on an image and then on a cropped version of the image with the same parameters and got different detection result.

As far as I understand the result should not depend on image size if the content is the same. Should it work like that?

The images and results are here: https://www.dropbox.com/sh/1o97y51ckx8yy40/rVwPuS3exA

Best,

--Dmitry

[Stephane]

Hi,

It's a normal behavior, Spot Detector uses the whole image to estimate the noise level and so detect spots according to this noise level. When you crop the image, the noise level estimation change and so the detections, it may seems strange but that is normal as when you crop an image, the cropped part has its own contrast, noise level which are taken in account by the spot detector.
It's exactly the same problem the automatic segmentation, doing it on a cropped part of the image won't give the same result as on the whole image.

Best,

- Stephane

[Dmitry Sorokin]

Hi Stephane,

Thanks for the answer. I have one more question regarding Spot Detector and Particle Tracking, just not to start another thread.

Could you advise what is the best way to load my own points for the particle tracker without using the spot detector?

I tried to use Spot Detection Import/Export plugin. It imports the detection set successfully, but when I choose the imported detection set as an input for the Particle Tracker it gives me NullPointerException. And I'm importing the detection set which I previously got by Spot Detector and exported using Import/Export plugin. So there is no doubt about its consistency.

So basically if I use the detection from the Swimming Pull just after spot detection - Particle Tracker works, but if I import the same set using Import/Export plugin - it gives exception.

Thanks,

--Dmitry

Best wishes,

   Dmitry Sorokin

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[Stephane]

Hi Dmitry,

To be honest i think that is a bug, it should work as the imported detections should be exactly the same as the ones you generally export in the swimming pool. Did you reported the bug when you got it ? If you do it that will warn the author of the plugin about it and hopefully he will fix and update it =)

Best,

- Stephane

[Dmitry Sorokin]

Yeah, I've reported the bug. Hope it will be fixed soon.. :)

Best,

--Dmitry

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