## 4 Results and Discussion  
The method described has been evaluated over a number of selected pages extracted from the [PERSON] book. The evaluation requires manual creation of ground truth data since due to the specificity of the task there are no other pieces of software known to the authors adapted to the tracking and reconstruction of such type of tetragram data. In the selected pages, the staff lines were carefully marked, linking the missing parts following the staff-slope trend and observing the limits (start and end points) of the staff lines, which are considered to run from the left side to the right side of each page. In order to perform the evaluation, it must be taken into account that the ground truth creation task is a very tedious, eye-straining, prone-to-error and time-consuming one that requires much attention in order to create the best ground truth possible at the working resolution. This fact needs to  
Figure 8: Reconstructed staff lines drawn over the original image analyzed. Detail of folic 4r. Figure 7: Illustration of the performance of the smoothing procedure. (**a**) Detail of the first staff of the original binary image corresponding to folio 2r. (**b**) Detail of the lowest staff line of (**a**). (**c**) Detail of the tracked and interpolated staff line for the image in (**b**). (**d**) Detail of the smooth reconstructed staff line for the image in (**b**). be mentioned because, as a consequence, the ground truth has been observed to commonly deviate from the column-wise center of the images' staff lines as it is shown in the sample excerpt in Figure 9. This will be taken into account in order to perform a fair evaluation. Data describing the ground truth created are shown in Table 1. In order to create the staff line ground truth, control points are set on the images obtained after the Pixelwise scheme with the aim that the spline curve passing through such points run through the vertical center of gravity of the corresponding staff line. The difference in the number of control points for different staff lines relies on the length of each staff line and the necessity of more or less control points so that the splines employed to characterize the staff lines actually lay on the real staff lines. The control points are employed to create a set of ground truth staff lines by using spline curves running through them, the staff lines created are formed by a total number of 664,425 pixels. The locations of these pixels are employed to perform the evaluation and obtain the evaluation scores that will be described. The evaluation is done by measuring the scores described in Table 2. The meaning of the scores is as follows:  
* Detection of staff line: at a certain pixel location, the scheme presented marked the pixel as corresponding to a staff line, the binary image presented a level corresponding to the image foreground and a pixel of a ground truth staff line is found at a close vertical position (this idea will be defined later). This indicates a valid staff line detection/tracking at the pixel location. * Interpolation of staff line: at a certain pixel location, the scheme presented marked the pixel as corresponding to a staff line, the binary image presented a level corresponding to the image background and a pixel of a ground truth staff line is found at a close vertical position. This indicates a valid staff line interpolation at the pixel location. * Missed detection: at a certain location, a pixel of a ground truth staff line is found, the binary image presented a level corresponding to the image foreground and the scheme presented did not mark a pixel as corresponding to a staff line at any close vertical position. This indicates that a detection is missed. * Missed interpolation: at a certain location, a pixel of a ground truth staff line is found, the binary image presented a level corresponding to the image background and the scheme presented did not mark a pixel as corresponding to a staff line at any close vertical position.