Pre-Blurred Spatial Sampling can Lead to Hyperacuity

While it may be counterintuitive to some, pre-blurring an image prior to spatial sampling can result in an increased ability to localize certain image features or to detect minute motions of such features. This does not produce better acuity in the traditional sense (e.g., the ability to resolve line pairs), but for certain classes of applications this technique can be quite useful and the resulting effect has, for better or for worse, been given the name "hyperacuity" in the literature. While observations of hyperacuity in animal vision tests have been reported in various journals, a signal processing based explanation of the effect has been lacking. In this paper, we explain how, in the process of developing a biomimetic imaging sensor based on the compound eye of the common housefly (Musca domestica), we have been able to mathematically model and explain in well-known signal processing terms how this hyperacuity effect comes about.