We present an interpolation scheme for deformable block motion compensation based on a pseudo-perspective mapping model. The motion compensation method based on this model is targeted for coding aerial surveillance video sequences. In aerial video sequences, distortion occurs as the perspective of the surveillance camera relative to the scene changes. The traditional motion compensation method based on translational model is inadequate to compensate for this perspective distortion. One solution to overcome this problem is to use a deformable block motion compensation method with a more sophisticated model. Polynomial approximations of the perspective motion model, such as the affine and bilinear models, have been reported in the literature. Nevertheless, the affine model lacks the correct degree of freedom required to capture the effect of perspective distortion between frames. Though the bilinear model has the correct degrees of freedom, it still cannot accurately model the perspective distortion, especially near the boundaries of an image block.
In this paper we propose to apply an eight-parameter pseudo-perspective mapping model for deformable block motion compensation. We developed an efficient interpolation scheme for this model based on finite element shape functions. We tested our interpolation scheme on aerial video frames in the NTSC format (720 x 480 pixels). The proposed interpolation scheme, motion-compensation algorithm, and simulation results are described. The motion compensation scheme based on the proposed mapping model yields an improvement of 1.5dB to 2.3dB in peak signal-to-noise ratio compared to a bilinear model based scheme.
In this paper the experimental results of a study conducted to investigate dependence of low-frequency noise on the geometrical shape of VLSI interconnect are discussed. The metal thin films are most commonly used in fabrication of these metallic interconnects. The interconnection lines of modern ICs have effective cross sections in the range of 1-5 square μm. Therefore, the operating currents of a few milliamps results in current densities in the range of MA/square cm. Under these conditions, the phenomenon of electromigration arises, which may lead to the failure of the interconnection lines in a time ranging from a few several hours to several years, depending on the subjected current density J and thermal stress T. To study the effect of subjected current densities and temperatures, low-frequency noise measurements were performed on a group of ten metal thin film VLSI interconnects. These measurements were carried out under stressing current densities between 1.0x10<sup>5</sup> <i>A/cm<sup>2</sup></i> and 2.2 x10<sup>6</sup> <i>A/cm<sup>2</sup></i> at different heating temperatures up to 280 <sup>°</sup> C. We used a sophisticated noise measurement system based on dual-channel dynamic signal analyzer and ultra low-noise amplifier to monitor and capture the noise spectra exhibited by the samples when subjected to electrical and thermal stress. The low-frequency noise measurement system and measurement technique, metal thin film sample design, and the behavior of these samples under subjected stressing conditions are discussed in the paper.