No time in human history has ever witnessed such explosive influence and impact image processing on modern society, sciences, and technologies. From nanotechnologies, astronomy, medicine, vision psychology, remote sensoring, security screening, and entertainment industry to the digital communication technologies, images have helped mankind to see objects in various environments and scales, to sense and communicate
distinct spatial or temporal patterns of the physical world, as well as to make optimal decisions and take right actions. Image processing and understanding are therefore turning into a critical component in contemporary sciences and technologies with many important applications.