Extract grid data from noisy image in Halcon

Question

I am trying to get clean grid data from this image (don't mind the tilt, it is incidental).

This means no noisy dots and a uniform grid representing the situation. I am doing fairly well using morphology, doing:

closing_rectangle1 ()
opening_rectangle1 ()
select_shape ('rectangularity')

in different orders and amounts to clean up some noise.

It is not as complete and uniform as I'd like to achieve, so I'm wondering if Halcon has a better way of doing this (other than morphology or as an addition to) that I am not aware of. The rectangle-orientation and pattern in the grid can be different but the size is always the same.

What is the exact output that you need from this image? Coordinates of the intersections or something else? — Vladimir Perković
– Vladimir Perković, Commented Jul 20, 2022 at 14:48
Uniform and complete regions, region center coordinates, coordinates of the intersections would probably also work I think. — Malinko
– Malinko, Commented Jul 20, 2022 at 14:56
Is the number of compartments always familiar e.g. 5x4 like now? — Vladimir Perković
– Vladimir Perković, Commented Jul 20, 2022 at 14:59

Vladimir Perković · Accepted Answer · 2022-07-20 15:13:31Z

2

read_image (Image, 'D:/OneDrive - Subpixel d.o.o/Other/Stackoverflow/5/uZKGw.png')
threshold (Image, Region, 128, 255)
connection (Region, ConnectedRegions)
select_shape_std (ConnectedRegions, SelectedRegions, 'max_area', 70)

** One region is disconnected, which interferes with watershed algorithm
dilation_circle (SelectedRegions, RegionDilation, 1.5)

get_image_size (Image, Width, Height)
gen_image_const (Image1, 'byte', Width, Height)
paint_region (RegionDilation, Image1, ImageResult, 255, 'fill')

watersheds (ImageResult, Basins, Watersheds)
select_shape (Basins, SelectedRegions1, 'area', 'and', 4000, 8000)

** Transform everything to rectangles 2 (rect1 if you can ignore the angle)
shape_trans (SelectedRegions1, RegionTrans, 'rectangle2')

** Reduce the regions a bit to achive separation
erosion_circle (RegionTrans, RegionErosion, 3.5)

answered Jul 20, 2022 at 15:13

Vladimir Perković

1,4723 gold badges16 silver badges33 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Malinko Over a year ago

Awesome, watershed is THE solution to my issue!

Collectives™ on Stack Overflow

Extract grid data from noisy image in Halcon

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related