We determined the performance of an optical correlator that used input images of N x N pixels to examine larger images of LN x LN pixels. The larger images were examined in parallel using a pyramid technique. We used morphological processing to approximate a low-pass filter to generate an image pyramid for a binary correlator. In correlation experiments we found that the discrimination between objects and SNR dropped with increasing L. Although the discrimination may remain useful, the more rapidly decreasing SNR limited the value of L that could be used. In addition, we showed by simulation the processing of a 512 x 512 pixel image from an infrared sensor with a 128 x 128 pixel binary optical correlator.