Recent Advances in Computer Vision

Computer vision is the branch of artificial intelligence that focuses on providing computers with the functions typical of human vision. To date, computer vision has produced important applications in fields such as industrial automation, robotics, biomedicine, and satellite observation of Earth. In the field of industrial automation alone, its applications include guidance for robots to correctly pick up and place manufactured parts, nondestructive quality and integrity inspection, and on-line measurements. Until a few years ago, chronic problems affected computer-vision systems and prevented their widespread adoption. Since its start, computer vision has appeared as a computationally intensive and almost intractable field because its algorithms require a minimum of hundreds of MIPS (millions of instructions per second) to be executed in acceptable real time. Even the input–output of high-resolution images at video rate was traditionally a bottleneck for common computing platforms such as personal computers and workstations. To solve these problems, the research community has produced an impressive number of dedicated computer-vision systems. One such famous system was the Massively Parallel Processor (MPP), designed at the Goddard Space Flight Center in 1983 and operated there until 1991. The MPP used an array of 16,384 single-bit processors and was capable at peak performance of 250 million floating-point operations/s—an impressive feat at the time. Dedicated computers such as the MMP have always received a cold reception from industry because they were expensive, cumbersome, and difficult to program. In recent years, however, increased performance at the system level—faster microprocessors, faster and larger memories, and faster and wider buses—has made computer vision affordable on a wide scale. Fast microprocessors and digital-signal processors are now available as off-the-shelf solutions, and some of them can execute calculations at rates of thousands of MIPS. The Texas Instruments C6414 processor, for example, runs at 600 MHz and can achieve a peak performance of 4,800 MIPS. Highspeed serial buses such as the IEEE 1394 and USB 2.0 are capable of transferring hundreds of megabits per second, a rate that greatly exceeds the requirements of any common high-resolution video camera. These buses are already integrated into the most recent personal computer chipsets or are available as inexpensive daughterboards. Moreover, video cameras have gone almost completely to digital, and they come in several price ranges and types. Consumer camcorders are based on standards such as the Digital Video (DV), which provides videos with 720 × 480 pixels/frame at a rate of 30 frames/s. Even Webcams can now provide images of satisfactory quality at prices starting as low as $25. The availability of affordable hardware and software has opened the way for new, pervasive applications of computer vision. These applications have one factor in common. They tend to be human-centered; that is, either humans are the targets of the vision system or they wander about wearing small cameras, or sometimes both. Vision systems have become the central sensor in applications such as • human-computer interfaces (HCIs), the links between computers and their users; • augmented perception, tools that increase normal perception capabilities of humans; • automatic media interpretation, which provides an understanding of the content of modern digital media, such as videos and movies, without the need for human intervention or annotation; and • video surveillance and biometrics.