A consumer media content (e.g., a two dimension (2D)-content, a 3D content, and/or the like) has been evolved from a black content and a white content to a color content, a high definition (HD) content, a ultra high definition (UHD) content, and/or the like. Recently, the standardization for a high dynamic range (HDR) content has been established and promoted. Meanwhile, a virtual reality (VR) content has not been evolved before VR products were introduced.
A characteristic of a VR content is different from characteristics of existing 2D and 3D contents. The VR content may provide a user with a 360 degree-experience and thus completely immerse the user in the experience. However, if the user views many different views during short time, image mismatch may occur due to a change in a displayed view.
A virtual reality ecosystem (VR ecosystem) is a system which displays a space of an fictional world or a remote location using various videos or a computer graphic, and makes a user to feel as if the user exists at the space by converting the user's motion using a computer. The user is capable of interacting with the virtual reality ecosystem by adjusting a controller, and/or the like.
The virtual reality ecosystem may include a display device such as a head mounted display (HMD), cave automatic virtual environments (CAVE), a monitor, and/or the like, a control device for receiving a user's input such as haptics, and/or the like, a VR content to be displayed on the display device, an app store which will provide the VR content, and/or the like. The display device may perform a function of the control device. The virtual reality ecosystem may be used in various fields such as education, health care, real estate, construction, travel, and/or the like. In addition, there is a need for a technology such as an image processing technology such as image stitching, a 3D engine, and/or the like for supporting the virtual reality ecosystem.
In the virtual reality ecosystem, motion feedback that the user can input to the virtual reality ecosystem through the control device may be divided by a bearing (that is, rotation) and movement (that is, position change). The virtual reality ecosystem should provide a VR content according to the user's feedback.
In virtual reality experience, a field of view (FOV) provided to the user through the display device is also important. A human's general horizontal field of view (or an angle of field) is about 200 degrees. In the 200 degrees, 120 degrees overlap in three dimensions. The display device (for example, an HMD) has a field of view of 100 to 120 degrees. In the 120 degrees, 60 degrees correspond to tunnel vision. In the VR ecosystem, a field of regard (FOR) corresponds to the human's field of view. The FOR means a degree of spaces that surround the user in the VR ecosystem. For example, the HMD has 100% of FOR. The reason is that the HMD provides a continuously changed view even though the user moves. The FOR of CAVE is dependent on the number of walls used as virtual screens. In contrast, televisions or monitors have a very restricted FOR value. The reason is that VR exists only in the television or the monitor in front of the user and is abruptly discontinued outside the television or the monitor. Accordingly, it is difficult to show VR content through the television or the monitor.
Even if a size of the television or a size of the monitor becomes large for preventing sudden disconnection of a virtual world, it is difficult to provide a VR content which may allow a user to experience the virtual world. The reason is why a phenomenon that a plurality of images which compose an entire vision of the VR content are enlarged when part of the VR content is enlarged and the enlarged part is viewed, difference among the enlarged images is exaggerated, so the difference among the images is remarkable occurs, that is, image mismatch occurs. In addition, a phenomenon that the same image is differently viewed due to user's frequent movements in a case that an image showed in a VR content is changed may be an image mismatch-phenomenon. So, there is a post-processing operation for a VR content in order to display the VR content with relatively low resolution on a large monitor for providing the VR content for a virtual world on the large monitor.