ABSTRACT
Over the past few decades, with the rapid development of digital cameras and various mobile devices equipped with cameras, which are convenient to use anywhere and anytime, we have witnessed the magnitude of visual data (images, photos, and videos), produced by humans in their daily lives, increasing explosively beyond expectations. In 2012, Facebook announced that the number of photos uploaded by its users had exceeded 220 billion [1]. Furthermore, the amount is still increasing at an average rate of several hundred million per day. Additionally, the magnitude of visual data has increased due to increasing resolution. The resolution of images and photos has been increased from several hundred thousand pixels to several million pixels. Video resolution has been increasing from early quarter common intermediate format (QCIF) to current high definition (HD).
