Sikulli screen.click() how to give the region where to click

Hi

I am trying to perform the click() through sikulli. I have captured the image and I am doing it like below

Pattern image1 = new Pattern("C:\\Users\\KHANDELA1\\Pictures\\DAM_Username.PNG");
screen.click(image1)

But the image has radio button and some text and I only want to click on the radio button. I want to know how to click on particular area or pixels on the image.