1. A method for determining a defect during sample inspection involving charged particle beam imaging, comprising: providing an image group including a target image, a first reference image and a second reference image of a sample obtained from charged particle beam imaging; transforming said target image into a plurality n of target feature images using a set of n image transformation operators; transforming said first reference image and said second reference image using said image transformation operators into n first reference feature images and n second reference feature images, respectively; evaluating a distance between said target image and said first reference image according to a distance between each said target feature image and corresponding said first reference feature image using a distance evaluation operator to obtain a first distance; evaluating a distance between said target image and said second reference image according to a distance between each said target feature image and corresponding said second reference feature image using said distance evaluation operator to obtain a second distance; and comparing said evaluated first and second distances to a predefined threshold distance to determine a presence of said defect within said target image.