Crop with imfreehand?

I dont know if my question has an answer.I have an image and crop a ROI with imcrop

[cropped_image,rect]=imcrop(original_image);

I work with cicular regions so this rectangular is not working very well.I want to draw freehand the ROI i want..

I tried this but doesnt work.(I want to get similar image such as cropped_image)

cropped_image=imfreehand();

and then extract this cropped_image and continue to my analysis

Answer 1

[Satoshi Kobayashi]

I = imread('corn.tif',2);
imshow(I)
h = imfreehand; % Place a closed ROI by dragging and double-click on the region.
position = round(wait(h));
min_values = min(position,[],1);
max_values = max(position,[],1);
Inew = I(min_values(2):max_values(2),min_values(1):max_values(1),:);
[X1,X2] = meshgrid(1:size(Inew,2),1:size(Inew,1));
in = inpolygon(X1,X2,position(:,1)-min_values(1)+1,position(:,2)-min_values(2)+1);
in =repmat(in,1,1,size(I,3));
Inew(~in) = 0; % If I is uint

Now Inew is the rectangular cropped image. Out of ROI has been blacked out.

[DIMITRIOS THEODOROPOULOS]

This is very good but i need only the extracted image without the black....Black creates problems for further segmentation...

[Satoshi Kobayashi]

Using only the extracted image may be difficult.

The measures to be taken depend on what you would like to do (further segmentation) and what type of image (grayscale or not) you use.

You can use any color instead of black.

[DIMITRIOS THEODOROPOULOS]

ok thank you very much for support!

[sinjini ghosh]

Could you comment on what each of the command is doing, the code works, but I didnot understand the operations you used

Answer 2

[Image Analyst]

See my attached demo. I think you'll like it a lot better than the other answer. It gives you drawing instructions, it doesn't ask you to "confirm" the shape after you draw it, it does a variety of masking options, and it does the cropping you want. Adapt as needed.

[DIMITRIOS THEODOROPOULOS]

Of course!!!!

You are a master!!!

[Warid Islam]

Hi @ImageAnalyst,

I tried to draw a boundary using the freehand() above. Below is the image.

However, problem arises when I try to crop that specific portion of the image defined by the boundary and save it in a different file. The following error message is displayed.

Unrecognized method, property, or field 'getPosition' for class 'images.roi.Freehand'.

Error in freehand_masking_demo (line 49)

xy = hFH.getPosition;

Any suggestions would be very much appreciated. Thank you.

[Image Analyst]

Warid, what version do you have?

[Warid Islam]

Hi,

I use MATLAB 2019a.