An Approach to Explain the Human Hyper-acuity: Applied to THz Imaging

Abstract

Hyper-acuity of the human eye is the capability to see beyond the understandable acuity defined by the number and size of the photoreceptors of the human eye. Surprisingly, in other words, we could say that the human eye is able to see small details at very long distances that never could be detected by a CCD camera of equal number of detectors [1] [2]. On the other hand, the emerging topic of Terahertz imaging cameras is getting more and more relevance for the multiple applications that could be used for: security in airports and borders, medicine, support to vision under hard conditions, etc. Nowadays, the technology used to detect these frequencies is still expensive and quite complex to think in a high quality imaging cameras with a quite high number of detectors. The complexity of the Terahertz detector technology pushes the designers to find a simpler solution that it could be found in the human eye strategy to create the Hyper-acuity, that is, create high resolution images from a significantly reduced number of detectors. In this paper, we discuss about this human high resolution capability and its principles applied to THz antenna systems. Firstly, human eye paradigm is explained and shown by examples and formulae. Secondly, optical basis and explained principles are studied and discussed for THz imaging systems. We propose a method that significantly reduces the number of detectors needed for achieving a certain resolution by means of diffraction that paradoxically is the resolution limiting factor in current imaging devices.