Hyper-acuity through inverse filtering: Application to Terahertz cameras

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 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 about a high quality imaging cameras with a quite high number of detectors. Complexity of Terahertz detector technology pushes designers to find a simpler solution that 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 document we introduce a technique to recover a high resolution version of a signal which has been digitally captured or sampled in low-resolution. This technique implies the introduction of a known distortion before the detection, which is applied by using a direct low pass filter, and an inverse in order to recover the original data and be as well able to recover non-sampled data between samples, increasing the resolution of the final image.