A Highly Miniaturized, Battery Operated, Commandable, Digital Wireless Camera

This paper discusses the design, development, testing, and demonstration of a highly miniaturized, battery operated, digital wireless camera. The miniature wireless camera receives commands transmittedfrom a remote base station requesting it to take one or more frames of data, and broadcasts the digital image data to the base station receiver for display. The camera uses a complementary metal-oxide-semiconductor (CMOS) active pixel image sensor (APS) that achieves noise performance comparable to a charge-coupled device (CCD) with orders of magnitude better power consumption performance. The image sensor is integrated with a wireless communications transceiver, antennas and batteries into a stand alone miniature package, The results of a three year development efort are described. The miniature wireless camera will be delivered Advanced Research Projects Agency 1998. INTRODUCTION to the Defense (DARPA) in July The objective of this effort is to develop and demonstrate a small wireless digital camera based on JPL’s CMOS active pixel sensor (APS) technology with 1 km range, 2.5 Mbps image transmission rate, and a long battery life. This effort was motivated by the invention of the APS imaging technology, coupled with the proliferation of miniature, low power wireless communications integrated circuits. The highly integrated APS with its ultra low power consumption lends itself to miniature battery operated designs that are impractical for CCD based irnagers. Applications of the miniature wireless camera include surveillance in military (e.g., shell launched and hand placed) and civilian settings, perimeter monitoring, micro unmanned aerial vehicles, and remote baby monitoring. [1] The novel capabilities of the miniature wireless camera become apparent when compared to commercial wireless cameras that are on the market today. Table 1 provides a comparison of the DARPA/JPL wireless camera capabilities to two representative commercial wireless cameras. [2,3] The commercial cameras are typically used in applications where they are manually turned on, hand placed, and transmit continuously until the battery is completely discharged or they are manually turned off. The DARPA/JPL wireless camera differs from these cameras in that it has a command link that permits remote control. Additionally, it has sleep, receive, and transmit modes that are managed to conserve power. As is shown in this paper the wireless camera can have a lifetime of many days or weeks vs. hours for these commercial cameras. In addition to possessing “smart” camera capabilities the DARPA/JPL camera differs from commercial wireless cameras in that it is snap-shot oriented rather than video, uses digital vs. analog transmission, includes an APS vs. a CCD, and includes low profile, conformal antennas vs. non-conformal antennas. These features combine to provide a capability to the Department of Defense (DoD) that is not available with current wireless cameras.