Traditional methods of optical design trade optical system complexity for image quality. High quality imagers often require high system complexity. A new imaging methodology called Wavefront Coding uses aspheric optics and signal processing in order to reduce system complexity and deliver high quality imagery. An example in terms of a conformal IR imaging system is given.

Telescope performance is often limited by aberrations, and/or fabrication and alignment errors. Additionally, image formation in large space-based systems is sensitive to changes in physical form parameters such as temperature-related deformations, mirror structure, piston position and detector alignment. Changes in these parameters significantly degrade image quality and often limit the performance of the system. A fundamental new technology called Wavefront Coding has been successfully demonstrated via simulations for large space-based imaging systems that promise to surpass the performance attained by traditional optical designs. Wavefront Coding uses specialized aspheric optics and signal processing of the detected image to correct defocus-like aberrations thereby enabling a new paradigm in aberration balancing for telescope systems. Wavefront Coding can provide dramatic new mission capabilities by allowing space-based imaging systems that are simpler, lighter, and cheaper, while also providing high quality imagery in dynamic environments that are difficult or impossible to image in with traditional imaging systems. As an example two systems are presented that allow the telescope to repoint the boresight through the actuation of the primary segments or through the use of a scan mirror. Traditional systems with the same goal of repointing the boresight historically have not been feasible due to either the increased error space or due to constraints on system cost and complexity. BACKGROUNDTraditional spaced-based imaging systems produce high quality images by accurately controlling all parameters of the physical imaging system. This accurate control translates to traditional imaging systems that have very tight error budgets, are heavy and large, and are also expensive. Wavefront Coding provides dramatic new mission capabilities by allowing space-based imaging systems that are simpler, smaller, lighter, and cheaper, while also providing increased high quality imagery in dynamic environments that are difficult or impossible with traditional imaging systems. Our effort focused on large optics that allow fast repointing of the boresight of a battlestar-sized space vehicle through the actuation of mirror segments on the primary (Figure 1) or through the actuation of a small aft scan mirror. By bending individual mirrors to change boresight direction, a very large space vehicle does not need the ability to vary attitude to repoint the field of view. Scene dynamic invariance results by applying Wavefront Coding to optical systems with dynamic mirror forms. This leads to imaging system invariance to aberrations traditionally formed by such repointing. Bending of segmented mirrors in traditional designs leads to very difficult aberration error budgets. Our study concluded that Wavefront Coding can enable:• Fast repointing of large optical fields of view by controlled bending of optical elements or through the use of a small scan mirror rather than repointing the spacecraft • Solutions to problems that weren't previous...

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