Any way to free hand crop an image?

Is there any way to free hand crop on an image? I have an organic shape I want to quickly crop not using the rectangular box that matlab has for cropping. Any way to go about this?

Answer 1

[Sean de Wolski]

How do you propose cropping a non-rectangular shape? Do you want to zero out parts that aren't within in your "cropped" region. An image always has to be rectangular.

doc imcrop
doc impoly
doc imfreehand

If you want to zero out the parts not in the free hand reason. use the createMask method of the freehand region to build a mask of the free hand region. Then negate it and zero everything in it out.

I = imread('cameraman.tif');
imshow(I);
h = imfreehand; %draw something 
M = ~h.createMask();
I(M) = 0;
imshow(I);

[Siddharth]

Perfect. Thank you.

[keshav satpute]

thank you so much

[Warid Islam]

Hi,

I have an image which I want to crop using the freehand(). Please find the image below:

The boundary is defined in the image above. I tried using the code above to crop the image and display it in a separate window. But I am getting a different result. Any suggestions would be appreciated.

[Image Analyst]

Use max and min() to get the limiting coordinates from imfreehand. Then just crop using those indexes:

row1 = min(y);
row2 = max(y);
col1 = min(x);
col2 = max(x);
maskedImage = rgbImage(row1:row2, col1:col2, :);

[Warid Islam]

Hi,

I tried the above code but I am getting the following error:

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

Error in freehand_masking_demo (line 49)

xy = hFH.getPosition;

[Image Analyst]

Try the drawfreehand function instead then.

[Warid Islam]

Hi,

I found tha MATLAB does not recommend getPosition method. They recommend to use ROI classes. I tried using the ROI.FREEHAND class but I get the following error:

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

Error in fh4 (line 6)

pos = images.roi.Freehand(); % get position for that ROI

[ali seraj]

thank you