Fractional correlator with real-time control of the space-invariance property

In pattern recognition, it happens that the amount of space variance should be controlled. This may be achieved by use of a partially space-variant correlator. We present a novel configuration for achieving a partially controlled space-variant correlator. In this configuration the lenses are fixed in their focal lengths and locations. The filter function is also fixed. To change the amount of space variance, we need change only the longitudinal location of the filter without reencoding it. It is also shown that this type of correlator provides improved correlation peaks according to correlation-sharpness criteria.