Coverslip detection locating all four coverslip edges. A field of view processor receives image data from a charge coupled device camera. The charge coupled device camera images a slide and coverslip that is mounted on a movable frame. The slide and coverslip are illuminated from below with a uniform light source. The moveable frame is under computer control and moves in response to the field of view processor. The field of view processor locates the coverslip by first positioning the movable frame to view a portion of the slide on a predetermined potion of the slide within a predetermined area of the slide. The slide is then re-imaged after the movable frame moves the slide toward a chosen edge of direction. Edge type objects are located and followed over multiple fields of view. If the edge object satisfies a set of predetermined criteria the coverslip edge has been found. The edge is extended to find all four corners of the coverslip. The edge objects are processed using morphological operators.