ÐWe study implementation issues for spatial convolution filters and their Fourier alternative, with the aim to optimize the accuracy of filter output. We focus on Gaussian scale-space filters and show that there exists a trade-off scale that subdivides the available scale range into two subintervals of equal length. Below this trade-off scale Fourier filtering yields more accurate results than ...

Fast data links require a low phase noise reference clock. An alternative is to reduce the noise of a low cost clock part using the band pass filtering inherent to the clocking architecture in the link. This study has a two-fold objective: to verify clock noise filtering in a 16 Gbps data link, and to prove the degree of filtering is adjustable. Two measured band pass filters are presented. Clo...

The new generation of space borne sensors like TerraSAR-X and TanDEM-X is very attractive for 3D information extraction because of their high resolution and their possibility to achieve repeat-pass and since short single-pass data. Moreover, they can cover a huge area and especially their interferometric constellations allow recovering the height of objects like buildings. Nevertheless, the det...

Graph convolutional networks (GCNs) have achieved great success on graph-structured data. Many GCNs can be considered low-pass filters for graph signals. In this paper, we propose a more powerful GCN, named BiGCN, that extends to bidirectional filtering. Specifically, consider the original structure information and latent correlation between features. Thus BiGCN filter signals along with both f...

Digital watermarking is a method of copyright protection of audio, images, video and text. We propose a new robust watermarking technique based on contourlet transform and singular value decomposition. The paper also proposes a novel encryption algorithm to store a signed double matrix as an RGB image. The entropy of the watermarked image and correlation coefficient of extracted watermark image...

Through pixel-wise optical coding of images during exposure time, it is possible to extract sub-exposure images from a single capture. Such a capability can be used for different purposes, including high-speed imaging, high-dynamic-range imaging and compressed sensing. In this paper, we demonstrate a sub-exposure image extraction method, where the exposure coding pattern is inspired from freque...

Online social networks (OSNs) are threatened by Sybil attacks, which create fake accounts (also called Sybils) on OSNs and use them for various malicious activities. Therefore, detection is a fundamental task OSN security. Most existing methods based the graph structure of OSNs, have been proposed recently. However, although almost all compared experimentally in terms performance noise robustne...