A plurality of images of a plurality of fields is acquired using an image sensor under varying conditions associated with a defect. Defect pixels in a test image in the plurality of images are identified using a standard image to provide a defect tolerance level. The standard image has no defects. Clustering analysis is performed on the identified defect pixels based on the defect tolerance level to obtain defect clusters. A process window is generated based on the defect clusters. An imprint process is created according to the process window.