# Mixed Reality: A Reconsideration Based on Mixed Objects and Geospatial Modalities
## 3 MR: A Reconsideration Based on Mixed Objects and Geospatial Processes
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Figure 4: Mixed Object, as a result of the linkage between physical and digital properties. Figure 3: Microsoft’s approach for MR, as a result of the interactions between computers, humans, and environments. Adapted from [8]. Mapped Object is the digital form of a Real Object. Ideally, it is a 3D model produced with high resolution capturing equipment (object input device), such as Unmanned Aerial Vehicles (UAV) properly equipped for a high-precision mapping process, in conjunction with advanced surveying techniques such as photogrammetry or 3D scanning (object input language). In addition, a Mapped Object is spatially referenced (object input language) according to a coordinate reference system (georeferenced) and therefore it is identical to the existing real, in terms of location, orientation but also shape and texture. After being created, a Mapped Object may be further processed and rendered to the end-user visual display (object output device) through geovisualization frameworks (object output language) such as WebGL. As a result, the Real Object is still perceived by the end-user as a Real Object; however, it has technically been transformed into a Mixed Object. In fact, the Real Object is \"merged\" with an identical invisible digital object created by applying typical image processing techniques (blackening and additive blending). The physical properties of the Real Object are now connected with digital properties, therefore forming the Mixed Object. We are now ready to form our proposal by putting together Microsoft's approach to MR from the one side (Figure 3) and [PERSON] and [PERSON]'s approach to the Mixed Object as applied with our proposed Geospatial Linking Modalities on the other side (Figure 5). The result is shown in Figure 6 and the first impression is that there is a clear and explicit correspondence between the two approaches. One can tell that the Mixed Object approach is verified by Microsoft's MR representation. We have enhanced the whole schema by introducing Geospatial Input and Output Linking Modalities as two major groups of technologies capable of digitizing environmental input on the one side and enabling human-computer interaction on the other side. Object input devices are employed to capture environmental input. As such, we consider input that is related to real objects and is captured via high-resolution cameras; and also input related to the position of the end-user experiencing MR, which is captured via geospatial positioning technologies. The object input language may include 3D mapping methods, interpreting environmental input data, to provide DSM/DTM or 3D models of real objects; also, methods providing RGB-D data for object recognition. Object output languages such as geovisualization frameworks are employed to process acquired 3D mapped areas and 3D digital objects so that they may be visualized and rendered on object output devices such as simple visual displays. Figure 5: A Mixed Object generated by employing contemporary geospatial technologies. Based on the terms used in the generated diagram, we specify all involved types of Objects and the resulting Mixed Object as well as the contribution of Geospatial Linking Modalities on the above:  
* A Real Object containing physical properties is sourced from conventional reality, which is the common ground between humans and computers. * A Mapped Object is a 3D model of an acquired Real Object possessing shape, geolocation, texture, orientation and attributes, and is rendered in conjunction with the end-user positioning data and behavior (geolocation, direction of view, rotation and velocity). It is the result of the appliance of fundamental 3D mapping processes, such as photogrammetry, over Real Objects and represents the perception of the environment by computers. * A Rendered-Transparent Object is a Mapped Object participating in a 3D Scene by overlaying the Real one; however, being invisible.