Information security display system based on Spatial Psychovisual Modulation
Privacy protection is of increasing importance in this era of information explosion. This paper introduces an information security display system based on the idea of Spatial Psycho-visual Modulation (SPVM). With the rapid advance of modern manufacturing techniques, display devices now support very high pixel density (e.g. the retina display of Apple). Meanwhile the human visual system (HVS) cannot distinguish image signals with spatial frequency above a threshold, as predicted by the contrast sensitivity function (CSF). Therefore, it is now possible for us to devise a type of information security display using the mismatch between resolutions of modern display devices and the HVS. Given the desired visual stimuli for both the bystanders and the authorized users, we propose a method to design display signals accordingly. We select polarization as a way to effectively differentiate the bystanders and the authorized users. Operationally, applying complementary polarization to light emitted from different spatial sections of the display could in itself be a challenge. Fortunately, the development of stereoscopic display technologies has made available a lot of polarization based spatial multiplexing type of display devices. Hardware of the information security display system is based on a polarization based stereoscopic screen made by LG. Software of the information security display system is written in C++ with SDKs of DirectX and etc. Kinect is also included into our system to enhance the experience of human-computer interaction. Extended experimental results will be given in this paper to justify the effectiveness and robustness of the system. The developed system serves both as a proof-of-concept of the SPVM method, as well as a test bed for future research of SPVM based display technology.