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It is generally believed that spatial domain watermarking methods are not robust against common image processing attacks. In this paper, a novel application of an unsharp mask is proposed to increase the performance of watermark recovery in correlation based watermarking. Commonly, unsharp mask is used to improve quality of the image by emphasizing its high frequency contents to enhance the edge and details information in it. Dissimilarity between different parts of image is increased by this filter. Thus, the watermark could recover more correctly from the watermarked image. This filter is applied before running watermark recovery procedure. To show efficiency of proposed filter on the spatial domain watermarking, it is applied on a typical correlation based method. Several experiments are done to evaluate the performance of proposed method is improved by applying this filter before watermark extraction procedure.

In this study the graphitization characteristics were studied in the test bars produced by the inmold lost foam (IMLF) process. Polystyrene patterns were prepared, and the test bars were produced in three different diameters. In this paper, only the microstructure of the test bars, having 10 mm diameter and 200 mm height, cast at two temperatures of 1410 and 1440 °C, and 1 wt% of spheroidizing material (FeSiMg), have been investigated. For this purpose, 10 mm bars were cut from two sections, the middle and the end part (the furthest distance from the gate) and then, these sections were examined using optical microscope. The results show that, the melt temperature and fluid flow affect the graphite morphology as well as the distribution, shape, size and type of graphite. In the central part of the test bar, cast at 1410 °C, non-spheroidal graphite is formed which are different from other areas, but at 1440 °C, the graphite in the whole section is uniform and spherical, from the center to edge. The high nodule count (above 700 pcs. per unit surface) and above 80 percent nodularity, in both cases, are worth mentioning.

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