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Abstract: An optical setup is proposed for the implementation of compressive sensing with coherent images. This setup specifically exploits the natural multiplicative action of speckle noise occurring with coherent light, in order to optically realize the essential step in compressive sensing which is the multiplication with known random patterns of the image to be acquired. In the test of the implementation, we specifically examine the impact of several departures, that exist in practice, from the ideal conditions of a pure multiplicative action of the speckle. In such practical realistic conditions, we assess the feasibility, performance and robustness of the optical scheme of compressive sensing. [Copyright &y& Elsevier]

Spatial characteristics of thermal infrared (TIR) images are generally described by image-derived point spread function (IDPSF) for sampled imaging system. Most investigators working on IDPSF on-orbit evaluation focus on visible and near-infrared images and pay little attention on TIR ones, the reason of which lies on the fact that the assumption of an observed target with an ideal step profile is not suitable for TIR band. A new approach for TIR images is proposed here based on a more common slope-profile model, where the transition features, i.e., the sample number (Nslope) and the beginning position of slope interval, are extracted from the observed signals. Simulation results show that the estimation performance will be increased, with lower noise level as well as higher system modulation transfer function value at half of normalized spatial frequency (MTF0.5) or smaller Nslope. For a good performance system with noise squared-root variance (SRV) nomore than 1.0 count and MTF0.5 between 0.3 and 0.4, the relative error between simulated and estimated MTF0.5's is less than 20%. The IDPSF of FY-2C satellite TIR band is estimated, and the derived MTF0.5 is properly close to on-ground testing results. The image quality of FY-2C TIR band has been improved by using Wiener filtering and the estimated IDPSF, which eventually benefits the cloud detection product with more detectable low fractus and increased detection accuracy by about 1% in winter. Considering a step-profile target as a special case of this model, the proposed approach is also suitable for visible and near-infrared images. [ABSTRACT FROM AUTHOR]

Abstract: A digital holography interference pattern generated by a computer calculation (computer generated hologram, CGH) is one of the most expensive contents and its usage is being expanded. Thus, it is highly necessary to protect the ownership of a digital hologram. This paper introduces a watermarking scheme, a method to protect the ownership of digital holograms using the DCT domain data as the ones to be watermarked. This scheme shows very high imperceptibility and strong robustness against the anticipated attacks. We expect that the conclusions of this paper will be a very useful basis for further work in the area of electronic watermarking schemes for the digital holograms. [Copyright &y& Elsevier]

Abstract: The tendency today is to replace high-dynamic light modulators by high-speed binary ones (of which the micromirror is the best example). This kind of spatial light modulators (SLM) fulfils all the present needs in displays. They are used in optical communications as binary systems and also in display applications (video projectors) with temporal multiplexing, in order to generate greyscale or colour images. In optical processing, and in the majority of coherent applications, temporal dithering introduces some distortions. In this paper, this point is studied with simulations. We point out that temporal multiplexing cannot be used in the Fourier plane. In the imaging plane, the distortion is weak if the filter has a positive impulse response. [Copyright &y& Elsevier]

The article reports on all-optical multifunctional logic gates for image information using photorefractive two-wave mixing. The optical setup is simply configured compared with other all-optical logic gates for image information. The logic operations can be switched by means of the on-off control of the signal and the pump beam illumination. The spatial distribution of beam intensity in the logic gates are analyzed using a finite difference beam propagation method.

Abstract: A method for omnidirectional real-time optical edge extraction is proposed. The method consists on the design of a complex filter that is implemented in a Vander Lugt like optical processor. It is emphasized the rotation invariance of the technique, as its equivalence with the Canny edge detector. Numerical simulations have been performed to compare the proposed implementation with some frequently used edge detectors and enhancers. Experimental results are presented to show the very good performance of the method. [Copyright &y& Elsevier]

In vivo fluorescence molecular imaging and tomography has facilitated monitoring of genomics and proteomics over time and on the same animal. A highly important issue, however, has been the robust registration of animals imaged at different time points to obtain accurate description of activity and location. This paper presents a method for aligning temporal data of small animals based on surface anatomical features and improving the accuracy of monitoring fluorophore distribution. The method can account for differences in the positioning and compression of small animals and can be extended to three-dimensional as well as to other imaging modalities. [ABSTRACT FROM AUTHOR]