Abstract: A technique for developing an inspection program for a circuit board to be run on an AOI system includes determining a characteristic, such as average gray level, of each window of the circuit board. The positions of the windows are varied slightly to simulate expected errors in the placement of the windows relative to the circuit board. After varying the positions of the windows, the characteristic of each window is determined again. Different values of the characteristic corresponding to slightly different positions are compared for each window. Values that substantially change for a window indicate a strong sensitivity to position. These windows may be reported to a programmer for corrective action.

Abstract: An inspection system includes a plurality of models are applied in a way that enhances the effectiveness of each type of model. In one embodiment, a printed circuit board inspection system includes an image model, a structural model and a geometric model to inspect objects. The image model is first applied to an object being inspected to identify objects which look alike. After the image model is applied, a structural model is applied to determine whether the object exists in the image that has the same structure and is used to decide if the image model has truly found a part in the image. Lastly, a geometric model is applied and uses the approximate positional data provided by the previous two models to determine precisely the location of the object being inspected. Also described are techniques for learning and updating the plurality of models.

Abstract: An automated optical inspection system includes a plurality of asynchronously triggerable cameras for providing image data of an object, such as a printed circuit board. The circuit board is divided into fields of view that are to be imaged in one or more cameras in one or more lighting modes. Each location on the board can be imaged by each camera in a plurality of lighting modes in a single pass across the board. The image data for each of the cameras can be concurrently transferred directly to main memory for opportunistic analysis by the main computer. The system allows the full bandwidth of the cameras to be utilized for reducing the inspection time of the board.

Abstract: An automated optical inspection system with improved accuracy achieved by reducing the negative effects of extraneous light. The system includes a light trap behind a two-way mirror.