For me and, probably, many readers, each issue of IEEE Signal Processing Magazine ( SPM ) is the opportunity and pleasure to learn something new in the area of signal and image processing. In addition to lecture notes, tips-and-tricks articles, special reports, and so on, which propose interesting and clever solutions to typical signal or image processing problems, the feature articles and special issue provide tutorial-like articles on various mature or fast-developing domains.

A window function is a mathematical function that is zero valued outside some chosen interval [1] , [2] . For applications like filtering, detection, and estimation, the window functions take the form of limited time functions, which are in general real and even functions [3] , [4] , while for applications like beamforming and image processing, they are limited spatial functions. A spatial window can be a complex function for optimizing the beams in magnitude as well as in phase, as in the case of certain antenna arrays, where the phasor currents in the array are complex numbers [5].

The IEEE Signal Processing Society (SPS) is an international organization whose purpose is to advance and disseminate state-of-the-art scientific information and resources, educate the SP community, and provide a venue where people can interact and exchange ideas. To achieve its mission, the SPS relies heavily on volunteers working in the area of SP, governed by collaborative organizational practices in decision making that are transparent and fair. By bringing volunteers together, the SPS catalyzes advances in the field of SP in its pursuit of excellence.

Robots are rapidly becoming an integral part of daily life. The mechanizing of routine tasks has been underway for decades, with development making particularly remarkable progress over the past several years. Now, with the development robots that can closely interact with humans, sensing users’ needs and often relieving people of dangerous tasks, robotic technology is entering a new phase of intimacy and practicality.

Multiscale 3D characterization is widely used by materials scientists to further their understanding of the relationships between microscopic structure and macroscopic function. Scientific computed tomography (SCT) instruments are one of the most popular choices for 3D nondestructive characterization of materials at length scales ranging from the angstrom scale to the micron scale. These instruments typically have a source of radiation (such as electrons, X-rays, or neutrons) that interacts with the sample to be studied and a detector assembly to capture the result of this interaction (see Figure 1 ).