# Smart Interactive Technologies in the Human-Centric Factory 5.0: A Survey
## 2 Smart Interactive Technologies in the Human-Centric Smart Factory
### Large Displays
#### 2.2.1 Touch and Touchless Interaction  
Touch and touchless interaction modes can affect the type of applications to be used on large displays and have different pros and cons [37].  
**Touch interaction.** [PERSON] and [PERSON] [38] carried out a study where they asked participants to perform a series of tasks where they had to select one or more elements through different interaction modes. Touch interaction was very precise and had a low margin of error. This positive result is probably partly due to the familiarity users have with touch interaction, albeit to a lesser extent than with mouse-based interaction, which proved to guarantee the highest level of precision. This primacy may depend on various factors, such as the size of the screen with which one interacts, the size of the icons or objects to be selected, or the problem of \"fat fingers\", whereby users with large fingers may encounter difficulty in using small screens.  
It should be emphasized how touch interaction has evolved over time, passing from the simple touch of a single hand to multitouch, which allows the use of multiple fingers for actions such as zoom-in and zoom-out and moving elements on the screen and gives the possibility of using the human touch in combination with other interactive tools.  
However, touch interaction can be uncomfortable in some occasions, especially in the business and industrial sectors and in cases where users need to wear gloves [23], or when there are other disturbing elements. Touchless interaction, where users do not have to touch any interface, can be used as an alternative to touch interaction on such occasions.  
**Touchless interaction.** Different interaction styles can be classified under the \"touchless\" umbrella term, ranging from hand-based gestures recognized by a tracking device to the detection of the posture, position, or presence of the user's body to gaze tracking and facial expression recognition. The best known examples of touchless interaction are often associated with the gaming and entertainment domain, where both the tracking of body movements (e.g., using Kinect ([[https://developer.microsoft.com/en-us/windows/kinct/](https://developer.microsoft.com/en-us/windows/kinct/)]([https://developer.microsoft.com/en-us/windows/kinct/](https://developer.microsoft.com/en-us/windows/kinct/)), accessed on 29 July 2022)) and the detection of gestures executed via an external, dedicated device (e.g., PlayStation Move) are used. Other dedicated devices, such as the Myo proxelect, can be worn by users. Touchless interaction exploits the natural language of the body, which is why it could significantly reduce the distance between the user and the interface, especially if used in the business context. However, it is essential to design the interface and user experience (UX) so that they are as fluid and engaging as possible, in order to accompany the user in the interactive process and not cause frustration. In this regard, the UX design will also have to take into account the effort that repeating actions with gestural interfaces can determine, much higher than when approaching a touch- or mouse-based interface. In addition, designers will have to make sure that the interface layout allows a precise execution of actions, also considering the fact that many potential users are not very familiar with this type of interaction. For this reason, it is also necessary to ensure that the interface returns clear feedback and makes any error reversible, including those caused by involuntary body movements and incorrectly detected gestures (_immersion syndrome_).