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Calculating the area of selected parts in an aerial image

asked 2013-04-29 01:48:33 -0500

sharan gravatar image

updated 2013-04-29 01:50:49 -0500

i am trying to calculate the area of vegetation in aerial image, i don't have the information regarding the height at which the image is taken. i have extracted vegetation in the image by using RGB values, the rest of the image i have set it to a pixel value 0(i.e black). how do i proceed from this step. please help. thank you image description

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answered 2013-04-29 02:11:26 -0500

If by any chance, you are the same person as the question about the banana plant vegetation, then please stick to a single topic and direct the two questions to that, since they are heavily related.

Like mentioned in that topic, look at the findcontour function, by first creating a binary mask and then looking for contours. The contours then provide an area functionality.

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not the same person, how will i be able to obtain the area without any scaling reference

sharan gravatar imagesharan ( 2013-04-29 02:20:46 -0500 )edit

You can get the area which will be expressed in amount of pixels. It will be impossible to get the actual area since you do not know your camera settings, like the height of your flight. This means that you can only calculate a relative area, not an absolute one.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-04-29 07:14:47 -0500 )edit

if i do relative area i would be better of expressing the area in terms of percentage right??

sharan gravatar imagesharan ( 2013-04-29 11:40:47 -0500 )edit

You only need to know one dimension, for example the size of your image in real measurements. Then you can calculate how much a pixel is. This way each pixel area can be converted into real area measurements.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-04-29 12:46:27 -0500 )edit

thanks a lot!!!!!!!!

sharan gravatar imagesharan ( 2013-04-30 00:32:24 -0500 )edit
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Asked: 2013-04-29 01:48:33 -0500

Seen: 780 times

Last updated: Apr 29 '13