how to calculate irregular shape area in the image

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norfaizayu 2011-12-28

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评论： Image Analyst 2019-4-12

hi..i have i project that need me to detect and extract the irregular shape in the image.then i should to calculate the area in the unit cm.can you help me,how can i detect the irregular shape in the image automatic and how can i calculate that irregular shape area.i hope you can help me.Thank you.

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Piya 2019-4-11

What is the unit of area

Image Analyst 2019-4-12

Pixels.

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回答（3 个）

Florin Neacsu 2012-1-4

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Hi,

Given your example I would suggest this approach:

after your edge detection:

create structural element of radius 4 (or 5 or whatever works for you)

dilate your edge map

erode (with the same strel)

imclearborder

create metric to eliminate "noise" (you can do something similar to circle detection : perimeter/area)

determine the area (in pixels; you need to know the spatial resolution of your initial image to obtain it in cm2).

Hope this helps.

Regards, Florin

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Image Analyst 2012-1-26

Have you imaged your known object yet? When you have, call improfile() to interactively get the length by calculating the two line endpoints that improfile will provide to you. Then you conversion factor is your real world length (e.g. 10 mm) divided by the number of pixels that the distance is.

Walter Roberson 2012-1-26

Urgency does not make the impossible possible.

Perhaps, though, it would be appropriate to ask about your accuracy goals. If your accuracy goals are not especially high, then you could make use of the average of the real-world measurements that have been studied; see http://uclue.com/?xq=4504

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Image Analyst 2011-12-28

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You might be able to adapt my BlobsDemo tutorial to your image:

http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

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Sean de Wolski 2012-1-4

How about a threshold, a borderclearing, and a sum?

norfaizayu 2012-1-5

i cannot do the threshold..always error.what's mean for threshold?border clearing already there.sum for what?i didn't get the source code for area.can u help me?

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