MACHINE VISION INSPECTION SYSTEM AND METHOD FOR ACQUIRING IMAGES HAVING EXTENDED DEPTH OF FIELD

摘要

PROBLEM TO BE SOLVED: To acquire images that have an extended depth of field.SOLUTION: A method for providing an extended depth of field image comprises: periodically changing an imaging system focal position at a high frequency; using an image exposure that includes a discrete image exposure increment acquired at a discrete focal position during an image integration time including a plurality of change periods of the focal position; and using a strobe action that has a controlled timing configured so as to define a set of equally spaced focus positions for the image exposure increment. The controlled timing is configured to be acquired at a point of time when adjacent focus positions within the set are separated by at least one inversion of a focus position change direction during the periodic change. Accordingly, a problem of a practical timing is solved that is likely to prevent an acquisition of close discrete image exposure increments during the high frequency focus change. Use of a deconvolution operation can improve sharpness of the EDOF image to be obtained.SELECTED DRAWING: Figure 1