In this paper, we propose a system that presents a virtual window using curtains and projection. A screen and curtains are installed on the wall, and images are projected as they are opened and closed. By using curtains, which are commonly used in life, this system replaces the role of windows in everyday life by projecting images naturally onto our living environment. We propose applications that focus on spatial presentations and communication provided by the window and discuss there potential of this system.
The living environment is important for people to lead comfortable daily lives. For a more comfortable life, it is desirable to live in a place with suficient space, windows connecting the inside to the outside world, and no feeling of being blocked in. However, because of design problems caused by the density of buildings or financial issues, many people live in places with little space, in underground places with no windows, or in small rooms.
Solutions to these problems include to arrange furniture to improve openness, or the use of mirrors in interior design to create the impression of ampler. However, these spatial presentations lack flexibility and ease of use. It requires personal sense and knowledge to make an efective interior design. Since mirrors reflect what actually exists in the environment, skill is required to successfully create a spatial presentation with a sense of openness. Therefore, neither approach can easily eliminate the sense of being blocked.
Therefore, this study proposes a method of creating a virtual window using curtains and projection to produce a spatial presentation. A screen and curtains are installed on a wall, and images are projected as the curtains are opened and closed. Using a projector, the appearance the window and the size of the window can easily be changed, making this system more flexible. Moreover, using curtains, which are commonly used everyday items, the window is presented in such a way that it blends in with the living environment. Furthermore, the presence of the curtains gives depth to the flat projected image, and makes the system three-dimensional.
This virtual window substitutes for the window’s original role of connecting to the outside world, presenting information and connecting to the space behind it, thus producing a spatial presentation. Once the position of the curtains and screen for the system is determined, the projector, PC, and webcam necessary for projection can be installed in any position, provided that simple conditions are satisfied. This makes it easy to design the environment in which the system is used.
nication between people, which provides virtual shared
drawers that connect family members who are located at
a distance. Homma et al. proposed a method of
presenting information using a shade and windows as screens,
which can be projected from inside a room to create a
display that can be seen from both inside and outside [
daily life. Tsuchida et al. propose a practice-support
system for performing the formation using the two-axis to the PC. First, the screen area is extracted by the PC.
movable curtain rail, whose movement direction does Next, the open area of the curtain is calculated based on
not drift and the material used for projection is soft [
an empty wall, and a projector is used to project images onto the open areas of the curtains, presenting the entire system as a window. The projected area changes according to the opening and closing of the curtains.
late the open area of the curtains from the screen image acquired by the camera. The background image taken at first is an image of the screen without curtains, and the input image is an image of the curtains on the screen. The luminance diference between these images is compared to compute the areas where the curtains are open. The final binary image is used as a mask image and is combined with the image of the window to create the projected image. This research used a gray curtain and a white screen. 3.2.2. Camera image processing
cluded in the webcam’s angle of view. Only the screen area to be projected is extracted from the camera image.
The image of the extracted screen area is transformed
using projective transformation and treated as if it were
taken from the front. The resulting image is used as a earlier, SwitchBot Curtains [
User interfaces are implemented to extract the screen The system calculates and projects the open area of the area. As shown in Figure 3(a), clicking four points on the window in real time so that the window always appears camera image displayed on the PC, the user can crop the between the curtains. The system presents windows in image onto a rectangle. By specifying the four corners response to the opening and closing of the curtains and of the screen area to be projected, only the screen area is to random movement of the curtains in everyday life. extracted. The size of the window can be easily changed because the system uses projection to present the window. The 3.2.3. Projection using a projector appropriate window can be presented according to the type of curtains, the location where it is projected, and the design. Figure 4(b) shows windows whose sizes change according to the curtains.
The system can be used if the entire screen area is included in the projection range of the projector. The image of the window between the curtains, created from the mask image obtained using background subtraction and the original window image, is projected onto the screen 4.1. External Window area. The projector can be positioned at any desired The system can be used as an external window that serves location provided that suficient projection distance is as a boundary between the inside and the outside. A maintained. screen and curtains are installed on the wall facing the
User interfaces are implemented to project images ac- outside of the room, and any view can be projected withcording to the screen area. First, a black image is pro- out depending on time or location. The projected imjected over the entire projection area. As shown in Fig- ages and videos can be changed according to the users’ ure 3(b), by clicking on the four points in the corners of preferences. This system presents a view of the outside the screen area while viewing the projected black image. regardless of the location of the indoor space or the local The window image is transformed using projective trans- time. formation and displayed inside the rectangle. Thus, the Another possible application is projecting a view that projector’s output is projected only onto the screen area. changes according to the actual environment. As shown in Figure 4(c), it is possible to present the current time of day or weather to people indoors by gradually changing the projected image.
proposed system. The actual appearance of the projection The system is used to create an indoor window between is shown in Figure 1. rooms. Two webcams are used to project other locations
The system was implemented in the environment in real time. shown in Figure 4(a). In addition to the devices described
A screen and curtains are installed on a wall facing accurately if the luminances of the two images are similar. another room, and images of the room behind the screen It is necessary to use curtains that are not too bright are projected in real time (Figure 4(d)). In this application, because the color of screen is white. a space that is behind a wall and therefore invisible can In addition, there is also the problem of occlusion in be viewed without noticing the existence of the wall. For daily life. Since there are few restrictions on the position example, when children are in another room, their par- of the camera and projector, there are not many opportuents can keep an eye on them by looking in the direction nities for occlusion to occur. However, the presence of in which they are originally located. objects or people in positions that block the direction of
Another possible application is installing two systems the projector and camera will afect the appearance of on a wall separating adjacent spaces. This allows users in the window. both rooms to see each other. The users can communicate with each other from their own spaces and feel as if they 5.3. Expansion of functions were in the same room.
4.3. Remote communication tools amples, further work is needed to extend the system’s functions to make it easier to use and more efective.
This work proposes a method that uses curtains as a The user can actually touch the curtains, which are
remote communication tool based on the SmoothCur- commonly used everyday items. This makes the system
tain [
People in remote areas will be able to communicate information. with each other through windows provided by the system. If the user want to use a certain image or video of Taking advantage of curtains as a boundary between the the scenery, they need to manually paste the window inside and outside of a room, it requests a connection by frame. Therefore, a tool that automatically creates winopening the curtains and ends it by closing the curtains. dow frames on images can be implemented to allow users Since it uses the opening and closing of curtains, which to use their preferred materials to be projected. is closely related to privacy management, the communi- We also demonstrated a remote communication tool as cation is more familiar to our daily lives than video calls an application example. To make the system realistic, it using PCs or smartphones. is necessary to add its functionality such as the ability to integrate a video call function and the ability to produce sound.
The system is flexible in terms of space because the cam- This research developed a system that uses projection to era and projector are not limited in terms of positioning present a virtual window by installing a screen and curand the size of the window can be changed by adjust- tains on a wall. The efectiveness of spatial presentation ing the projection. However, curtains would need to be was demonstrated through examples of applications, such installed. Furthermore, the efectiveness of the spatial as external windows, indoor windows between rooms, presentation in this study has not been evaluated by ac- and remote communication tools. In the future, we will tual users. It is necessary to evaluate the system with conduct user surveys to assess the efectiveness of the actual users in terms of efectiveness and implementation system. costs.
calculate the open area of curtains, and the curtains are detected by comparing the luminance diference between the background image and the input image. Therefore, the area between the open curtains cannot be calculated