How to crop/mask image using matlab ?

how to do cropping on an image ?

[KSSV]

Read about imcrop. What exactly you are expecting?

[Armylia Dewi]

I only expected the lungs in the picture

[KSSV]

You want to mask the black pixel region?

[Armylia Dewi]

Yes, like that.

here's an example

[Armylia Dewi]

just focus on the part chest- x ray

Answer 1

[T.Nikhil kumar]

Hey Armylia !

I understand that you want to crop one of the chest x-rays from the bigger image.

I suggest you to try using imcrop function for the purpose

(Link: https://www.mathworks.com/help/images/ref/imcrop.html)

Also, MATLAB has an interactive crop image tool which helps you decide the boundaries for your cropped image interactively using mouse

When the Crop Image tool is active in a figure, the pointer changes to cross hairs when you move it over the target image. Using the mouse, you specify the crop rectangle by clicking and dragging the mouse. You can move or resize the crop rectangle using the mouse. When you are finished sizing and positioning the crop rectangle, create the cropped image by double-clicking the left mouse button. You can also choose Crop Image from the context menu. The figure illustrates the Crop Image tool with the context menu displayed.

Answer 2

[Image Analyst]

See my attached lung segmentation demo.

It should be easy for you to adapt even though your images are in a different orientation.

Once you have the mask, you can crop your image to the bounding box of just the lungs like this

[r, c] = find(mask);
row1 = min(r);
row2 = max(r);
col1 = min(c);
col2 = max(c);
croppedImage = maskedImage(row1:row2, col1:col2);