A method to extract the synchronous characters in the electromagnetic information leaked by a computer
Xiang Changbo, Jianhua Xu · 2011
Receiving and recovering of computer video-leaking information is an important part in TEMPEST which is essential for information interception and safety. The pick - up of synchronous signal is predetermination of this technology. In this paper, a similar Harr Wavelet method and Hough transform technology are used to extract the tilt angle of the image recovered from video-leaking information. Based on the tilt angle, direction of the synchronizing deviation can be automatically recognized. The synchronizing deviation is used to adjust the frequency of the synchronous signal and reduce the synchronizing deviation gradually until the synchronal accuracy is enough for steady display.