This invention concerns the testing of surveillance camera installations. In particular, the invention involves an automatic testing system for surveillance camera installations, and a method for testing. The invention involves receiving test or “probe” images from at least one camera in the installations. Storing a reference image from at least the one camera. Comparison of the probe image with a reference image from the same camera, and production of an output when maintenance is required for that camera. The comparison involves the steps of: Extracting salient features from both the probe and reference images. Calculating matching factors between the salient features extracted from both images. And, computing a decision about whether maintenance is required from the matching factors.