I can't do region of interest sharping of image why ?

I have a mammogram image. In Left side image, I used roipoly command and drawed that polygon .

and then I sharpened that polygon inside region but image blurred instead of sharpen

What's my mistake in my codes ?

I need that polygon inside region sharpened.

img=imread('image.jpg');
if(size(img,3)>1)
img=rgb2gray(img);
end

mask=roipoly(img);   
filt=fspecial('unsharp');
filt_img=roifilt2(filt,img,mask);
figure, imshow(filt_img);

Answer 1

[Nitin Kapgate]

You can use the imsharpen function to sharpen a ROI in your image as illustrated here.

[Ali Zulfikaroglu]

I tried but I got still same image.

My code is in here which is applied your solution way with imsharpen.

I drawed my circle with roipoly function

and then filtered. But it looks crystallized which is showen above ,not sharpened.

img=imread('image.jpg');
if(size(img,3)>1)
img=rgb2gray(img);
end

mask=roipoly(img);   
f = @(x)imsharpen(x,'Amount',3)
filt_img=roifilt2(img,mask,f);
figure, imshow(filt_img);