# Deep-cARe: Projection-Based Home Care Augmented Reality System with Deep Learning for Elderly
## 2 Related Work  
Recently, there is increasing interest in developing support systems that slow aging or continuously monitor the health conditions of the elderly rather than developing treatment methods. Studies on the development of systems that monitor the current condition of an elderly person include a study concerned with the determination of falling using vision information and deep-learning technology [8] and a study on behavior recognition in daily life [9]. Furthermore, a recent study proposed a system that monitors the current emotional state of an elderly person through emotion recognition. The system then conveys the emotional state information to the caregiver or hospital and accordingly provides treatment and mental assistance [10]. Furthermore, a guideline for diet therapy by recognizing foods and drinks using deep learning was proposed in [11]. In addition to monitoring systems, AR systems that allow the elderly to access a wide range of media information and content are currently being developed so that physical and mental deterioration may be mitigated. The display type of AR systems may be either a head mounted display (HMD), a mobile device providing virtual information, or a projector (in PAR). Research on therapeutic systems that employ HMD AR for patients with dementia and Alzheimer's disease is underway. A study that focuses on elderlies with dementia is currently underway. In [12], dementia patients are assisted in their daily activities by virtual information so that their physical and cognitive functions may improve by repeated use. Furthermore, an educational system was developed to assist those with Alzheimer's disease by improving their short-term and spatial memory and mitigating mental decline [13]. A HMD AR game was developed for Alzheimer's diagnosis [14]. In addition, a system for providing advice information on medicine through HMD was developed [15]. Few studies have been concerned with elderly care systems that use an HMD AR system and deep-learning technology. In the case of HMD, the range of information delivery is limited because the field of view is approximately 30\({}^{\circ}\) (Microsoft, HoloLens). An HMD system can also be inconvenient because the user should continuously wear it for consistently receiving information. HoloLens is fast and accurate spatial mapping, via an IR depth camera and visible light cameras, and dual HD translucent display [16]. Although HoloLens supports visual and tactile interactions with virtual objects, this interaction method can be difficult for the elderly to use [13]. A mobile AR system is relatively easy to develop and can provide a friendly user interface (UI) because it uses mobile devices. For example, applications have been developed that employ a mobile device's camera and provide related information through the device's display when the user uses a medicine case [17; 18]. Developed for mobile AR games for health promotion through the user-friendly mobile devices [19]. Furthermore, there exists a mobile AR system that recommends the best location for installing safety bars to prevent accidents [20]. However, mobile AR systems can increase fatigue because they are hand-held, and the user should continuously hold a smart device. Furthermore, these devices are less realistic than AR headsets because virtual objects and information are received through mobile device displays. A PAR system can mitigate the problems of existing studies and deliver information to a large number of users as well as ensure high realism by projecting virtual information directly onto the real world; thus, the system can naturally assist users. In [21], a PAR table-top system that provides daily care to patients with memory problems was studied. In [22], a system was developed that employs image and text recognition to control a smart home using PAR. A home-care system that enables the elderly to exercise and enhance their physical abilities through projections was investigated in [23]. Most PAR systems are either fixed mount or table-top [21; 22].