Halcon.NET region loses data / Region is cropped unintentionally

Question

I encountered strange behaviour in Halcon.NET that I am trying to understand.

I have ~100 regions and I want to merge the ones that overlap. To merge the regions I use Union1() and then Connection() to separate non-overlapping ones.

But in the resulting region there are a lot of regions missing. After some troubleshooting I noticed that only the regions that would fit in the standard 512*512 graphics window would be in the result regions, but this is Halcon.NET so I dont have a graphics window.

If I use the line: HOP.GenImageConst(out HO unusedImage, "byte", 1200, 1000); first, everything works fine. The generated empty image is not used in any way in the application.

So this loses data:

HOperatorSet.Union1(Regions_eroded, out HO Regions_unified)
HOperatorSet.Connection(Regions_unified, out HO Regions_connected);

And this doesnt:

HOperatorSet.GenImageConst(out HO unusedImage, "byte", 1200, 1000); // creating unused image
HOperatorSet.Union1(Regions_eroded, out HO Regions_unified)
HOperatorSet.Connection(Regions_unified, out HO Regions_connected);

Is this a bug, am I doing something wrong, or is this how it's supposed to be for some reason?

score 1 · Accepted Answer · answered May 25 '23 at 10:08

1

Default window size for region creation is 512x512 in Halcon. To work around this, you can simply turn off region clipping outside of this window with:

set_system ('clip_region', 'false')

Or in C#:

HSystem.SetSystem("clip_region", "false");

answered May 25 '23 at 10:08

Vladimir Perković

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Thanks, that did it! Why on earth would this be default `True` for Halcon.NET? – Malinko May 25 '23 at 10:55
To avoid possible memory issue because of hidden region, I think. – Vladimir Perković May 25 '23 at 11:06

Halcon.NET region loses data / Region is cropped unintentionally

1 Answers1