Advanced weaponry is providing an exponential increase in intelligence data collection capabilities and the Intelligence Community (IC) is not properly positioned for the influx of intelligence supportabilitiy requirements the defense acquisition community is developing for it. The Air Force Material Command (AFMC) has initiated the Intelligence Supportability Analysis (ISA) process to allow the IC to triage programs for intelligence sensitivities as well as begin preparations within the IC for the transition of future programs to operational status. The ISA process is accomplished through system decomposition, allowing analysts to identify intelligence requirements and deficiencies. Early collaboration and engagement by program managers and intelligence analysts is crucial to the success of intelligence sensitive programs through the utilization of a repeatable analytical framework for evaluating and making cognizant trade-offs between cost, schedule and performance. Addressing intelligence supportability early in the acquisition process will also influence system design and provide the necessary lead time for intelligence community to react and resource new requirements.

In coded aperture imaging, adaptive masks provide significant benefit, notably for their role in supporting the image recovery process. Each discrete mask pattern produces a unique point spread function on the detector array, which can be used to enhance the resolution of imagery and indeed to enable tracking on a sub-pixel basis. The choice of adaptive mask technology is very dependent on both the spectral region of interest and the configuration of the coded aperture camera. Transmissive masks can be based on liquid crystal, micro-machined air-spaced Fabry-Perot cavities or even phase-change materials, whilst reflective masks can be based on liquid crystal on silicon (LCOS) or MEMS tip-tilt mirrors. Such components can also provide the basis for discriminative imaging. This paper provides a review of the various technologies and assesses performance levels in relation to different applications.

We introduce the linear system transfer matrix H as a means to interpret classical optical sensing, such as imaging and spectroscopy, and new computational sensing. This representation allows us to identify PSF engineering and multiplexed measurements as duals of each other. We also consider several new computational sensing systems and identify the corresponding system matrix.

The design and implementation of adaptive coded apertures (diffraction) has advanced significantly since the first SPIE conference on Adaptive Coded Aperture Imaging and Non-Imaging Sensors held in 2007. Core algorithmic concepts relating to coding and decoding techniques remain steeply based in its non-diffractive design origins. We discuss adaptive coded aperture imaging's current capabilities in light of recent advances as well as methods of improvement for future systems design. The advantages of implementing reconfigurable mask patterns compared to fixed ones will also be discussed, as well as potential improvement in angular resolution by means of reconfigurable masks.

Adaptive coded aperture imaging (ACAI) has the potential to enhance greatly the performance of sensing systems by allowing sub detector pixel image and tracking resolution. A small experimental system has been set up to allow the practical demonstration of these benefits in the mid infrared, as well as investigating the calibration and stability of the system. The system can also be used to test modeling of similar ACAI systems in the infrared. The demonstrator can use either a set of fixed masks or a novel MOEMS adaptive transmissive spatial light modulator. This paper discusses the design and testing of the system including the development of novel decoding algorithms and some initial imaging results are presented.

Coded aperture imagery poses a challenge for traditional image tracking algorithms because of the highly distributed nature of the coded imagery. Traditional algorithms would require this imagery to undergo a computationally expensive decoding operation before subsequent processing and tracking. In this paper, a novel tracking algorithm is described that can track point-source targets at sub-pixel accuracy without requiring the coded aperture imagery to be decoded. Furthermore, it is shown that the algorithm is robust to changes in the coded aperture mask pattern, and so is suitable for use in adaptive coded aperture imaging systems. Some results of the algorithm on synthetic and initial MWIR experimental data will be given.

Static Feature-specific imaging (SFSI) employing a fixed/static measurement basis has been shown to achieve superior reconstruction performance to conventional imaging under certain conditions.^1-5 In this paper, we describe an adaptive FSI system in which past measurements inform the choice of measurement basis for future measurements so as to maximize the reconstruction fidelity while employing the fewest measurements. An algorithm to implement an adaptive FSI system for principle component (PC) measurement basis is described. The resulting system is referred to as a PC-based adaptive FSI (AFSI) system. A simulation study employing the root mean squared error (RMSE) metric to quantify the reconstruction fidelity is used to analyze the performance of the PC-based AFSI system. We observe that the AFSI system achieves as much as 30% lower RMSE compared to a SFSI system.

Coded Aperture Imaging (CAI) is a new approach to system design whereby the optics are simplified in a controlled way so that system performance can be recovered using appropriate computer based algorithms. Adopting Coded Aperture approaches to sensor designs opens up possibilities of increasing the system design trade-space thereby giving the system designer greater degrees of freedom to optimise the system. A comparison has been made between a system adopting CA in its optical train with systems based on conventional optics approaches. These comparisons show that CA based systems can provide significant benefits to the user in some applications.

The use of hybrid optical-digital techniques facilitates improved optimisation of imaging systems. It involves the combined use of optical coding of an image using pupil-plane phase-modulation of the transmitted wavefront and postdetection digital decoding. Previous research in hybrid imaging tends to emphasize constancy of the modulation transfer function with aberrations and ignore the significant variations in the phase transfer function. We show that the restoration artefacts introduced by phase mismatch effects can also be used to deduce the defocus PSF, and when this is achieved, an overall improvement in image quality can be attained. Both numerical simulations and experimental images of hybrid imaging systems are presented.

We have previously reported the use of coded aperture for the design of wide area imaging sensors. Such sensors can allow the rate and resolution of the sensed information to be controlled by varying the sequence of codes used to acquire and reconstruct the data. However, since sensor resources are finite, it is essential to develop a framework for optimizing their allocation with respect to dynamic scene content over a large area. In this paper, we discuss an approach for achieving this using the principle of highly optimized tolerance (H.O.T) [1] which provides a theoretical basis for allocating resources in response to events to minimize a user defined loss function. Some results of initial simulations are presented to illustrate the concept.

For many years, the basic goal of sparse aperture design has been to maximize the support of the modulation transfer function (MTF). Golay apertures and related nonredundant arrays are typically used to achieve this objective. Unfortunately, maximizing the support of the MTF has the necessary effect of decreasing the magnitude of the MTF at mid-band spatial frequencies. Fienup has shown that the decreased magnitude of the MTF for nonredundant arrays contributes as much as reduced throughput to the loss of SNR in sparse apertures relative to full aperture systems. This paper considers the use of periodic sparse arrays to improve the mid-band MTF at the cost of reduced spatial frequency coverage. We further consider methods to recover lost spatial frequencies using multispectral and multiframe sampling and decompressive inference.

Adaptive coded aperture (diffraction) sensing, an emerging technology enabling real-time, wide-area IR/visible sensing and imaging, could benefit from new high performance biologically inspired image processing architectures. The memristor, a novel two terminal passive device can enable significantly powerful biologically inspired processing architectures. This device was first theorized by Dr. Leon Chua in 1971. In 2008, HP Labs successfully fabricated the first memristor devices. Due to its unique properties, the memristor can be used to implement neuromorphic functions as its dynamics closely model those of a synapse, and can thus be utilized in biologically inspired processing architectures. This paper uses existing device models to determine how device parameters can be tuned for the memristor to be used in neuromorphic circuit design. Specifically, the relation between the different models and the number of states the device can hold are examined.

Two major missions of Surveillance systems are imaging and ground moving target indication (GMTI). Recent advances in coded aperture electro optical systems have enabled persistent surveillance systems with extremely large fields of regard. The areas of interest for these surveillance systems are typically urban, with spatial topologies having a very definite structure. We incorporate aspects of a priori information on this structure in our aperture code designs to enable optimized dealiasing operations for undersampled focal plane arrays. Our framework enables us to design aperture codes to minimize mean square error for image reconstruction or to maximize signal to clutter ratio for GMTI detection. In this paper we present a technical overview of our code design methodology and show the results of our designed codes on simulated DIRSIG mega-scene data.

Coded aperture imaging has been used for astronomical applications for several years. Typical implementations used a fixed mask pattern and are designed to operate in the X-Ray or gamma ray bands. Recently applications have emerged in the visible and infra red bands for low cost lens-less imaging systems and system studies have shown that considerable advantages in image resolution may accrue from the use of multiple different images of the same scene - requiring a reconfigurable mask. Previously reported work focused on realising a 2x2cm single chip mask in the mid-IR based on polysilicon micro-optoelectro- mechanical systems (MOEMS) technology and its integration with ASIC drive electronics using conventional wire bonding. It employs interference effects to modulate incident light - achieved by tuning a large array of asymmetric Fabry-Perot optical cavities via an applied voltage and uses a hysteretic row/column scheme for addressing. In this paper we report on the latest results in the mid-IR for the single chip reconfigurable MOEMS mask, trials in scaling up to a mask based on a 2x2 multi-chip array and report on progress towards realising a large format mask comprising 44 MOEMS chips. We also explore the potential of such large, transmissive IR spatial light modulator arrays for other applications and in the current and alternative architectures.

Adaptive coded aperture imaging systems can resolve objects that are smaller than the pixel-limited resolution of the detector focal plane array. This is done by combining multiple frames of data, where different frames are taken with different coding patterns on the coded-aperture mask. In the mid-wave infrared the required signal to noise ratio necessitates some form of light concentration. Optical design software has been used to model candidate optical systems with the aim of achieving up to four times resolution enhancement along each linear dimension. As in some other computational imaging systems, the requirements on the optical system are found to be different to those that are normally used in more classical optical designs. The basic needs are a point-spread function of suitable extent that changes gradually with angle and does not vary significantly with the expected changes in input spectra or system temperature. Novel metrics have been derived and used to inform the optical design. The modeling and design trade-offs and resulting performance are discussed.

Coded aperture imaging technology have been utilized [1] for imaging in various space missions primary associated with X-Ray and Gamma ray sources. The need to extend the coded aperture technique into Visible/IR is pushing the technology and so geometrical features become smaller [2,3]. As the geometrical feature become smaller, second order effect such as diffraction become noticeable. The effects are typically isolated in order to improve Signal-to- Noise Ratio (SNR). In this paper we are exploiting diffraction and interference to use as a coding approach. We propose a coded aperture transmitter/receiver system capable of hiding information (bits) inside the diffraction nulls.

The memristor, experimentally verified for the first time in 2008, is one of four fundamental passive circuit elements (the others being resistors, capacitors, and inductors). Development and characterization of memristor devices and the design of novel computing architectures based on these devices can potentially provide significant advances in intelligence processing systems for a variety of applications including image processing, robotics, and machine learning. In particular, adaptive coded aperture (diffraction) sensing, an emerging technology enabling real-time, wide-area IR/visible sensing and imaging, could benefit from new high performance biologically inspired image processing architectures based on memristors. In this paper, we present results from the fabrication and characterization of memristor devices utilizing titanium oxide dielectric layers in a parallel plate conuration. Two versions of memristor devices have been fabricated at the University of Dayton and the Air Force Research Laboratory utilizing varying thicknesses of the TiO₂ dielectric layers. Our results show that the devices do exhibit the characteristic hysteresis loop in their I-V plots.

In this paper we investigate coded apertures as a function of mask damage, cross talk (on the focal plane arrays), and combinations of the two. We apply a Monte Carlo simulation to extract the probability of the scene reconstruction vs SNR as a performance metric. In addition we calculate the mean time between failures of the system as function damage to the mask.

We report a tentative interferometric detection of an earth-orbiting artificial satellite using optical interferometry. We targeted four geosynchronous communications satellites with the Navy Prototype Optical Interferometer (NPOI) near Flagstaff, AZ, and obtained interferometric fringes on one of them, DIRECTV-9S. We used an east-west 15.9-meter baseline of the NPOI and took data in 16 spectral channels covering the 500-850 nm wavelength range. Observations took place during the "glint season" of 28 February to 3 March 2008, when the geometry of the solar panel arrays and the Sun's position creates glints as bright as 2nd magnitude of a few minutes' duration each night. We detected fringes on the satellite at approximately the 2 σ level on 1 March at magnitude 4.5. Subsequent analysis shows that the fringe amplitudes are consistent with a size scale of 2 meters (50 nanoradians at geosynchronous orbit) in an east-west direction. This detection shows that interferometric detection of satellites at visual wavelengths is possible, and suggests that a multi-baseline interferometer array tailored to the angular size and brightness of geosynchronous satellites could lead to images of these satellites.

Intensity interferometry utilizes measurements of the squared-magnitude of the Fourier transform of an object using relatively simple, phase-insensitive hardware, and therefore holds the promise of extremely high spatial resolution in astronomy and various branches of physics. However, this promise has not been realized due to signal-noise-ratio (SNR) issues and due to the maturity of image recovery algorithms. To recover an image, the phase of the Fourier transform must be determined in addition to its magnitude. In a recent paper, relatively good one-dimensional (1-D) image recoveries were obtained with a fast non-iterative algorithm utilizing the Cauchy-Riemann relations and a mild constraint on the symmetry of the object. In this paper, the approach is extended to two spatial dimensions by combining multiple 1-D reconstructions, and ensuring mutual consistency between 1-D slices. Mutual consistency is enforced using several different approaches, including phase retrieval. This use of the Cauchy-Riemann approach combined with imposition of mutual consistency is found to reduce noise sensitivity significantly. Three approaches are evaluated for image quality for different objects using sparse Fourier-plane sampling, showing good reconstruction of images at SNR's as low as 7 at the origin in the Fourier plane (and thus even lower SNR's at higher angular frequencies).

The purpose of this paper is to develop adaptive optics system which estimates degrading factors using observed images and automatically compensates the distorted wavefronts using a spatial light modulator (SLM). The system estimates optical wavefront aberrations by phase diversity method. The SLM which is used for wavefront compensation applies multiple time-series known wavefronts as a priori information to the optical system. By using the SLM for the phase diversity generator, it is possible to select the optimal number and shape of phase diversities for various kinds of natural modes of wavefront aberrations which are represented by the Zernike polynomials. In laboratory test, wavefront aberrations were generated by optical misalignments, and they were estimated as the coefficients of Zernike polynomials for an extended scene. The suggested method was validated by numerical simulations and laboratory tests. The high estimation accuracy of the distorted wavefront was demonstrated, and nearly diffraction limited images were acquired by wavefront compensation.

In a coherent LADAR system, the spatial coherent performance of the return signal will be affected by the scattering of target object and atmospheric effect, which thus has influence on the mixing efficiency, Singal-to-noise ratio and receiving field of view. Since the practical wave front correlation of return signal beam is complex for coherent LADAR, here we will confine ourselves to a simple model that the return signal field has uniform distributed irradiance and is partially coherent, and the local oscillator beam adopts a Gauss mode. In this paper we research the variance of the mixing efficiency, signal-to-noise ratio and field of view with the influence of the signal spatial coherence width and collecting aperture radius, and give some guiding suggestions on the design of heterodyne receiver for coherent LADAR .

A demonstrator of synthetic aperture imaging ladar (SAIL) is constructed with the maximum aperture Ø300mm of antenna telescope. This demonstrator can be set with a rectangular aperture to produce a rectangular footprint suitable for scanning format with a high resolution and a wide strip. Particularly, the demonstrator is designed not only for the farfield application but also for the verifying and testing in the near-field in the laboratory space. And a 90 degree optical hybrid is used to mitigate the external phase errors caused by turbulence and vibration along line of sight direction and the internal phase errors caused by local fiber delay line. This paper gives the details of the systematic design, and the progresses of the experiment at a target distance around 130m.

In this paper, a concept of spotlight-mode incoherently-synthetic aperture imaging ladar (SAIL) is proposed on the basis of computer tomography (CT). This incoherent SAIL has three operations of conventional, inverse and CT spotlight-modes with two sensing techniques of range and Doppler resolutions, and supplies a variety of dimensional transformations for 2-D range- and Doppler-resolved imaging of 2-D objects and for 3-D range-resolved imaging or in the depth compressed 2-D range- and Doppler-resolved imaging of 3-D objects. Due to the simplification in both the construction and the algorithm the difficulties in the signal collection and data processing are importantly relaxed. The incoherent SAIL provides a great potential for applications in the extensive fields. The paper gives the detailed analysis.

Miniature inexpensive neon indicator lamp plasma glow discharge detectors (GDD) are excellent candidates to serve as room temperature, low cost, terahertz (THz) radiation detectors and as pixels in THz imaging systems. Heterodyne amplification of low power signals via higher power reference beams is very important for THz imaging systems because it permits detection of much lower object beam intensities. An experimental result of 300GHz heterodyne detection by a single commercial GDD device costing about 30 cents is presented here. In heterodyne image detection a picture is taken of interference fringes or a hologram deriving from a coherent reference wave and a coherent wave reflected from or transmitted through an object. Transmission with in-line or zero angles between those two waves is important to widen the fringes. The GDD detector is transparent, so that it's possible to receive radiation from both sides, at 0 and 180 degree. This permit receiving the wave reflected from or transmitted through an object at 0 degree and the reference wave from the opposite direction at 180 degree. Such interference fringe widening can permit heterodyne direct imaging of the object instead of imaging the interference pattern.

Correlography is a technique that allows image formation from non-imaged speckle patterns via their relationship to the autocorrelation of the scene. Algorithms designed to form images from this type of data represent a particular type of phase retrieval algorithm since the autocorrelation function is related to the Fourier magnitude of the scene but not the Fourier phase. Methods for forming 2-D images from far field intensity measurements have been explored previously, but no 3-D methods have been put forward for forming range images of a scene from this kind of measurement. Farfield intensity measurements are attractive large focusing optics are not required to form images. Pupil plane intensity imaging is also attractive due to the fact that the effects of atmospheric turbulence close to the imaging system are mitigated by the cancelation of phase errors in the intensity operation. This paper suggests a method for obtaining 3-D images of a scene through the use of successive 2-D pupil plane intensity measurements sampled with an APD (Avalanche Photo-Diode) array. The 2-D array samples the returning pulse from a laser at a fast enough rate to avoid aliasing of the pulse shape in time. The spatial pattern received by the array allows the Autocorrelation of the scene to be determined as a function of time. The temporal autocorrelation function contains range information to each point in the scene illuminated by the pulsed laser. The proposed algorithm uses a model for the LADAR pulse and its relation to the autocorrelation of the scene as a function of time to estimate the range to every point in the reconstructed scene assuming that all surfaces are opaque (meaning a second return from the same point in the scene is not anticipated). The method is demonstrated using a computer simulation.

A new method of high resolution laser imaging is developed in this paper, which is denoted as Fresnel telescopy. It creates Fresnel zone plate (FZP) fringe at the detected target, then makes relative motion between Fresnel zone plate and the target to accomplish the encoding process, namely, to achieve the convolution between target reflection function and the Fresnel zone plate intensity distribution function. The design scheme of the proposed system is presented. The proposed technique offers significant practical benefit for ground-based imaging of objects in many important military applications.

A control software experiment system of synthetic aperture imaging ladar is developed based on multithreading parallel mechanism of Labview8.6 and SCPI (standard commands for programmable instruments) protocol. Firstly, hardware composition and software function requirement of the system are analyzed. Then, the control module of the laser and stepper motor and the data communication module of oscillograph are developed separately and the three modules are integrated to realize the gather and compute of the return signal. Finally, by the result of experiment, the control software worked steady and real timely and it can operate the laser, stepper motor and oscillograph successfully.