The role of the hub is to transform the data presented by the camera modules into an estimate of the pose of the system so that it can be used by other software. The hub consists of two parts; a physical component and a software component. The physical component is an enclosure that holds three camera modules in a rigid fibre glass frame and is referred to as the ‘hub enclosure’. These camera modules are positioned so that their FOVs span a larger FOV. The software component is referred to as the ‘Soft Hub’. This is software written in C# that runs on a PC. This software is a prototype and the intention is for it to be implemented on an embedded system in the future. In this chapter, the hardware component is described in Section 7.1 followed by the software in the remaining sections.
The name Soft Hub reflects that the majority of the hub’s functionality is implemented in software. However, there is a physical aspect to the hub and this is the hub enclosure that contains the Black Spot modules. This is constructed from fibre glass and contains three cut-out sections for mounting the modules. The enclosure is designed so that there is a con- stant interior angle of 150 degrees between the modules providing a slight overlap between the camera modules FOVs. n overlap means markers at the edge of the middle camera’s FOV can be observed by the adjacent cameras simultaneously. This creates redundant data and allows for experimentation that would not be possible without this redundancy. For example, this small overlap in FOV essentially provides a small region of stereo vision that could potentially be used for camera self-calibration . Figure 7.1 shows the three Black Spot modules mounted in this housing. This configuration is an initial prototype and the intention is to extend the concept to incorporate more cameras into the hub enclosure in