I. Introduction to Human-Computer Interface
A Human Machine Interface (HMI), also known as a user interface or interface, is the medium and dialogue interface for the transmission and exchange of information between humans and computers, and is an important component of a computer system. It serves as the medium for interaction and information exchange between the system and the user, realizing the conversion between the internal form of information and a form that humans can understand. HMIs exist in any field involving human-computer information exchange.
II. The Development History of Human-Computer Interfaces
1. Command Language User Interface
Early human-computer interfaces (HCIs) used command-language interfaces, and human-computer dialogue was entirely in machine language. Interaction was limited to commands and queries, with communication conducted entirely in text format through user commands and user queries to the system. This required an astonishing amount of memorization and extensive training, demanding a high level of expertise from the operator. For the average user, command-language user interfaces were error-prone, unfriendly, difficult to learn, and had weak error handling capabilities. Therefore, this period is considered the era of human-computer confrontation.
2. Graphical User Interface
With the development of hardware technology and the advancement of software technologies such as computer graphics, software engineering, and windowing systems, graphical user interfaces (GUIs) have emerged and become widely used, becoming the mainstream human-computer interface. Relatively mature commercial systems include Apple's Macintosh, IBM's Presentation Manager (PM), Microsoft's Windows, and X2 Window running in Unix environments. GUIs are also known as WIMP interfaces, where windows, icons, menus, and positioning devices form a unified desktop. Windows are the basic interactive area, mainly including a title bar, elements that support movement and resizing, a menu bar, toolbars, and an operation area. Windows are typically rectangular, but many software programs now use irregular shapes for a more dynamic and personalized look. Icons are graphic symbols used to identify objects. Many are derived from technical terms and need to be memorized upon first encounter, such as minimize and close; others are derived from everyday life, being more pictographic and requiring less memorization, such as a speaker for volume control, a house for home, and an envelope for mail. Menus are action commands that users can select; all user commands in a software program are contained within menus. Menus are usually displayed through windows, and common types include toolbars (including graphical toolbars), drop-down menus, pop-up menus (right-click menus), and cascading menus (multi-level menus). A pointer is a graphic used to visually describe the position of a pointing device (mouse or trackball) input into the system. Common graphical interface pointers include arrows, crosshairs, text input "I", and hourglasses. Graphical user interfaces can display different types of information simultaneously, allowing users to switch between several environments without losing connection between tasks. Users can conveniently perform tasks through drop-down menus, greatly improving interaction efficiency while reducing keyboard input. This period is considered the human-computer coordination period.
3. Multimedia User Interface
The rapid development of multimedia technology has provided an opportunity for the advancement of human-computer interfaces. Multimedia technology has introduced dynamic media such as animation, audio, and video into user interfaces that previously only used static media. In particular, the introduction of audio media has greatly enriched the forms in which computers present information and broadened the bandwidth of computer output. At the same time, the introduction of multimedia technology has also improved people's ability to select and control information presentation formats, enhanced the integration of information presentation with human logic and creativity, and expanded human information processing capabilities. With the help of multimedia, users can improve the efficiency of information reception; therefore, multimedia information is more attractive than single-media information and is more conducive to people's active exploration of information.
Unfortunately, while multimedia user interfaces have become richer in terms of information output, they still force users to use conventional input devices (keyboard, mouse, and touchscreen) for information input. This means input is single-channel, resulting in a significant imbalance between input and output, which limits its application. Although the combination of multimedia and artificial intelligence technologies will change this situation, today's multimedia user interfaces are still in the exploratory and improvement stage. At this juncture, the rise of research into multi-channel user interfaces undoubtedly brings greater hope for solving the input-output imbalance in human-computer interfaces.
4. Multi-channel user interface
Since the late 1980s, multi-channel user interfaces (MCAs) have emerged as a new field of research in human-computer interaction (HCI) technology, attracting significant international attention. Research on MCAs arose to address the shortcomings of current graphical user interfaces (GUIs)—such as WIMP/GUI and multimedia user interfaces—due to unbalanced communication bandwidth. MCAs integrate new interaction channels, devices, and technologies, including eye contact, voice, and gestures, enabling users to engage in natural, parallel, and collaborative human-computer dialogue using multiple channels. The machine, in turn, captures the user's interactive intent by integrating precise and imprecise inputs from multiple channels, thus improving the naturalness and efficiency of the interaction. Research on input channels other than keyboards and mice primarily focuses on voice and natural language, gestures, writing, and eye movements, with a particular emphasis on specific system-level studies.
Multi-channel user interfaces, along with multimedia user interfaces, jointly improve the naturalness and efficiency of human-computer interaction. Multimedia user interfaces primarily focus on the efficiency of users' understanding and acceptance of computer-output information, while multi-channel user interfaces primarily focus on the methods of user input and the computer's understanding of that input. The goals of the multi-channel human-computer interfaces studied today can be summarized as follows: enabling users to interact with computers using their existing everyday skills as much as possible; increasing the throughput and variety of human-computer communication information, leveraging the different cognitive potentials of humans and computers; and incorporating the achievements of existing human-computer interaction technologies, ensuring compatibility with traditional user interfaces, especially the widely popular GUIs, so that the knowledge and skills of experienced and expert users can be utilized.
In the process of human-computer interaction, people are no longer satisfied with simply displaying or printing information on a screen; they further demand interaction through senses such as sight and hearing, leading to the development of multimedia user interfaces. People are also no longer satisfied with single-channel input, wanting to utilize more of their senses of smell, touch, and body language, gestures, or verbal commands, resulting in multi-channel user interfaces. Furthermore, people want to more naturally "enter" the environmental space, forming a "direct dialogue" between humans and computers and achieving an "immersive" experience; for this purpose, virtual reality human-computer interfaces have emerged.
