Through wall imaging: Historical perspective and future directions

Through wall imaging is highly desirable for police, fire and rescue, first responder, and military applications. The ultimate desire of such system is to provide detailed information in areas that cannot be seen using conventional measures. Borrowing from successes in geological and medical imaging environments, researchers are applying radio frequency (RF) and other sensing modes to penetrate wall materials and make intelligent decisions about the contents of rooms and buildings. For this application, they are many propagation differences that provide unique challenges that must be addressed to make through wall penetration sensors operationally viable. This paper outlines the historical context of early research as well as providing new directions for future research in this exciting interplay between electromagnetic propagation, signal processing, and knowledge-based reasoning algorithms.