## 3 Equal Baseline Camera Array  
The array described in this paper is called Equal Baseline Camera Array (EBCA) [1,2]. In previous papers the author of this paper called it Equal Baseline Multiple Camera Set (EBMCS), however the name was changed because the current one is more adequate [3, 4, 5]. A real camera set mounted in the form of Equal Baseline Camera Array (EBCA) is presented in Figure 3. The figure presents the set consisting of MS LifeCam Studio cameras with the 1080p HD sensor.  
[PERSON] and [PERSON] were the first to research the possibilities of using a camera set arranged in the form of Equal Baseline Camera Array with five cameras [1]. Research concerning such a set was also conducted by [PERSON] and [PERSON] who were in possession of a larger camera array but they selected from their array a five camera subset [60,61]. The author of this paper is further developing this technology [2, 3, 4, 5, 62].  
EBCA consists of up to five cameras placed in such a way that there is a central camera and up to four side cameras. The distance between every side camera and a central camera is the same. Such a distance is called a baseline. In real devices there are some inaccuracies causing that baselines are not equal to each other. However, distortions occurring in images caused by these imperfections are corrected in the calibration process. Side cameras are placed on opposite sides of a central camera in vertical and horizontal dimensions.  
The set with five cameras has a function of combined four stereo cameras created by a central camera paired with different side cameras. These stereo cameras will be marked with \(C_{1}\) (right pair), \(C_{2}\) (up pair), \(C_{3}\) (left pair), and \(C_{4}\) (down pair).  
The central camera is a reference one in each considered pair of cameras. Algorithms processing images from stereo cameras distinguish between a reference camera or a side one. A reference camera is a point of view of a stereo camera. Side cameras are used to acquire disparity maps for points visible from the reference camera.  
In EBCA, every considered stereo camera shares the same reference camera which is the central camera in the set. It is an important benefit of this kind of a camera set because 3D data acquired from each constituent stereo cameras can be easily merged together in order to acquire data which is more precise than those based on a single stereo camera.  
Figure 3: The camera set consisting of MS LifeCam Studio mounted in the form of Equal Baseline Camera Array.  
EBCA resembles a linear camera array. However, in general, pairs of cameras which can be selected from a linear stereo array may have a different reference camera or differ in sides of baselines. The problem with inequality of baselines is such that it influences the disparity. The increase in the size of a baseline cause that disparities became greater. It is more problematic to merge data from stereo cameras with different baselines. [PERSON] and [PERSON] addressed this problem which is particularly significant in leaner camera arrays [19]. Moreover, stereo cameras selected from a leaner camera array may have different reference cameras. The problem with merging data from such stereo cameras is also complicated because of the necessity to unify points of view of camera pairs. This problem does not occur when EBCA is used.