Application-Specific Design

Historically, the function that a camera performed was simple and straightforward. A lens collected light from a scene and refocused it to form an image on a piece of film. Somewhat later, electronic imagers were developed in which the film was replaced by an array of light-sensitive "pixels." Each pixel detects the light, converting it to an electrical signal that indicates the brightness of the corresponding point in the scene. In one common type of imager, the charge-coupled device (CCD), invented in 1969 by Boyle and Smith at Bell Telephone Laboratories, each pixel converts the light to a packet of electrons. At the end of the exposure time, these electron packets are shifted to the periphery of the CCD in order to be sensed and converted to digital image data.

In many military and scientific applications, the camera does very specialized tasks. It does not just take pictures; it enables the user to extract information that is hard to get for various reasons. The event of interest may be faintly illuminated and therefore hard to distinguish from its background or from noise in the electronics of the camera system, or the image may be moving quickly or jumping around on the device imaging surface. In some applications, the information sought might include more than just brightness, such as spectral signatures or scene depth. In other applications, the sheer amount of image data can be challenging; astronomers surveying large portions of the night sky desire billions of pixels. Electronic imagers, unlike film, can be designed to enhance their performance in delivering the desired output.

The Advanced Imager Technology program area at Lincoln Laboratory develops imagers that are customized to solve many specific and difficult problems. Some of these imagers have an extremely large number of pixels. Others are exquisitely sensitive photon-counting devices and are able to capture images in near darkness. Many imagers perform information extraction functions that reduce the need for high-speed data transfers and off-chip computations. Sometimes this information extraction is not done by conventional computer circuits. Rather, it may involve manipulations that are convenient to do in the pixel, so that "processing" is done that is inherent in the way the light is being detected.

Please visit our pages on Digital Pixel Focal Plane Arrays, On-Focal-Plane Embedded Processing, High-Speed Imagers (particularly multisample CCDs and sub-1-ns imagers) and Orthogonal-Transfer Arrays to understand the breadth of our experience in building innovative imagers.














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