1. A method for removing an undesired feature in an image, the method comprising: converting the image from a spatial domain to a frequency domain to form a transformed image; applying a filter to the transformed image to form a filtered image in the frequency domain; converting the filtered image from the frequency domain back into the spatial domain to form a modified image, wherein an intensity of the undesired feature in the modified image is increased as compared to the intensity of the undesired feature in the image; and removing the undesired feature from the image, wherein removing the undesired feature comprises: applying a threshold to the modified image in which pixels in the modified image having values greater than the threshold are retained to form a thresholded image; convolving the modified image with a point spread function for the image to form a convolved image, wherein the convolved image indicates a first location for the undesired feature in the convolved image that corresponds to a second location for the undesired feature in the image; and subtracting the convolved image from the image to form a processed image, wherein a portion of the image at the second location for the undesired feature in the image is removed from the image to remove the undesired feature.