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Blobs
John Wood from United Kingdom  [64 posts]
2 years
Hi Steven,

I have a outdoor camera that pans quite a large area and looks for boats at anchor after filtering and cropping to a small area allowing for most light conditions and weather I have got 95% of the required blobs relating to moored boats.
The problem is the final blob filtering, the boats for example are say 60% of the cropped area but as the camera pans I get odd spurious waves etc that can cause blobs of say 20% of the cropped area.
I can not use filter the largest as these waves would be the largest if no boat had come into view.Is there a % window/blob size filter or something similar that I could use or any guidance using the available filters.
John
Steven Gentner from United States  [1370 posts] 2 years
John,

There are quite a few filters available ... and more being created all the time as we come across situations that are not well represented. Would you be able to post an example of the issue? Its often easier if we have something to look at which will either tell us which filter to use or what possible filter that may not already exist could do the job.

Please also include the source (unprocessed image) so that we can try our own experiments.

Just to understand your situation better ... are you using a stable sized crop or does the crop size change? It should be possible to create a variable that is 20% of the viewable area and use that variable within the blob size filter criteria but I'm not sure if that would do the trick. i.e. in a VBScript (or even in a set_variable)

w = GetVariable("CROP_X_END") - GetVariable("CROP_X_START")
h = GetVariable("CROP_Y_END") - GetVariable("CROP_Y_START")
SetVariable "size_thres", CInt((w*h)*0.20)

and use in the blob filter size parameter.

Min Size: [size_thres]

STeven.
John Wood from United Kingdom  [64 posts] 2 years
Hi Steven.
It is a static cropped area.
I can post the RR file here but less the cam link as it is used as a security cam.
I could PM you the RR file with the Cam link included.

John
John Wood from United Kingdom  [64 posts] 2 years
Hi Steven,

I think using "COG area" will achieve my goal, so many paths that I forgot this variable, should work OK as the filter I need with a bit of VB.
If not I will get back for some guidance.
John

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