ABSTRACT
A Wiener filter-based deconvolution algorithm is developed to restore vibration-degraded video imagery from an intensified CCD camera. The method is based on the use of azimuth and elevation angular optical line-of-sight data recorded from external sensors to estimate a two-dimensional vibration-blur impulse response on a per frame basis. Flight conditions are reproduced in the laboratory by use of prerecorded in-flight vibration data. The performance of the algorithm varies from frame to frame, following the time-varying characteristics of the vibration-blur impulse response. However, real-time display of the restored video minimizes these effects because of eye integration, and near-full restoration of the original uncorrupted imagery is observed for both high-light- and low-light-level conditions with minimal amplification of noise.
ABSTRACT
In many imaging systems, the detector array is not sufficiently dense to adequately sample the scene with the desired field of view. This is particularly true for many infrared focal plane arrays. Thus, the resulting images may be severely aliased. This paper examines a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled frames. Several approaches to this problem have been investigated previously. However, in this paper a maximum a posteriori (MAP) framework for jointly estimating image registration parameters and the high-resolution image is presented. Several previous approaches have relied on knowing the registration parameters a priori or have utilized registration techniques not specifically designed to treat severely aliased images. In the proposed method, the registration parameters are iteratively updated along with the high-resolution image in a cyclic coordinate-descent optimization procedure. Experimental results are provided to illustrate the performance of the proposed MAP algorithm using both visible and infrared images. Quantitative error analysis is provided and several images are shown for subjective evaluation.
ABSTRACT
A method is presented for measuring the modulation transfer function of signal processing in the element (SPRITE) detectors with a HgCdTe composition optimized for the 3-5-microm band. This method incorporates a 3.39-microm He-Ne laser to generate Young's fringes of varying spatial frequency, which are scanned across the detector elements. The results are consistent with theoretical models for these devices and indicate a limited resolution capability for SPRITE detectors used for the 3-5-microm band.
