Identify crossing lines in image

Question

Vangelis Vladimirov 2022-3-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1677739-identify-crossing-lines-in-image

评论： Image Analyst 2022-3-31

I am trying to read images of magnetograms (Original image) by binarising the image and using bwboundaries, with the signal curves of interest being divided into segments. I would like to avoid burning connecting lines into the image as suggested here, so I am searching for adjacent boundaries and changing their labels to be the same (simplified script with simplified example image). In non-quiet days, like in the example, some signal curves cross the baselines (straight lines) or other curves, causing them to be marked as one boundary - is there a way of detecting cross-overs in bwboundaries() and separating the boundary into parts? It does not necessarily have to be using bwboundaries(), it is just the function I started with.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2022-3-22

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1677739-identify-crossing-lines-in-image#answer_924099

在 MATLAB Online 中打开

mask = bwskel(mask);
crossingPoints = bwmorph(mask, 'branchpoints');

6 个评论
显示 4更早的评论隐藏 4更早的评论

Vangelis Vladimirov 2022-3-30

编辑：Vangelis Vladimirov 2022-3-30

I am identifying the curves on the images by using bwboundaries. The curves however are not continuous, and instead of burning a connecting line or dilating the image, I am matching segments which start near an area where another one ends.

In the first attached image, I show the changes of labels I am able to achieve on a test image I drew, which consists of three broken curves. By using the end points (min/max(boundary(:,2)) of each segment, I am able to match the segments which I think to be belonging to one curve (label 1) even if there are breaks and jumps (either introduced by the binarisation or not present in the original image). The second curve, however, crosses a baseline (or another curve), which causes both the part I want to join with the second curve (red, label 2) and the part which should be part of the baseline (blue, label 6) to appear as one boundary. I would like to separate them, so I have something like in the second image I attach instead, where I can match what I think is part of the continuation of the (red, label 2) to itself and the start of the baseline (green, 6) to its other part (blue, 6). I don't mind if the branch points (where (teal, 2) and (green,6) cross in the second image) are included in both resulting curves, either of them or in neither of them (i.e. teal or/and green curves get broken into 4/3 separate pieces).

Vangelis Vladimirov 2022-3-31

编辑：Vangelis Vladimirov 2022-3-31

The figure being processed in my previous comment is only an exagerrated example of what I want to do (initial image is label_and_crossing.png). I also attach a minimal working script which generates and shows the binary and skeletonised images of the example figure and the Original_image.jpg I want to process. Line 6 is supposed to look like the baseline curves in Original_image.jpg, which are used to calculate the recorded fields, field = baseline + the distance of the recorded curve to that baseline times the scale (field/mm).

Image Analyst 2022-3-31

在 MATLAB Online 中打开

I'd suggest you get rid of the axes right away by summing the image horizontally

verticalProfile = sum(grayImage, 2);

and then erasing peaks that fall into the certain, known zones where the axes lie. Then maybe some morphology to thicken the line, like imopen() or imerode(). Then perhaps edge linking. Then scan the image column by column looking for dark places.

There are several graph digitizing apps in the File Exchange if you don't want to build one yourself.

请先登录，再进行评论。

Identify crossing lines in image

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

6 个评论
显示 4更早的评论隐藏 4更早的评论

更多回答（0 个）

另请参阅

类别

标签

产品

版本

Community Treasure Hunt

Identify crossing lines in image

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

6 个评论 显示 4更早的评论隐藏 4更早的评论

更多回答（0 个）

另请参阅

类别

标签

产品

版本

Community Treasure Hunt

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

6 个评论
显示 4更早的评论隐藏 4更早的评论