Towards Detecting Changes in Underwater Image Sequences

Detecting changes between images of the same scene taken at different times is of great interest for monitoring and understanding the environment. It is widely used for on-land application but suffers from different constraints. Unfortunately, Change detection algorithms require highly accurate geometric and photometric registration. This requirement has precluded their use in underwater imagery in the past. In this paper, the change detection techniques available nowadays for on-land application were analyzed and a method to automatically detect the changes in sequences of underwater images is proposed. Target application scenarios are habitat restoration sites, or area monitoring after sudden impacts from hurricanes or ship groundings. The method is based on the creation of a 3D terrain model from one image sequence over an area of interest. This model allows for synthesizing textured views that correspond to the same viewpoints of a second image sequence. The generated views are photometrically matched and corrected against the corresponding frames from the second sequence. Standard change detection techniques are then applied to find areas of difference. Additionally, the paper shows that it is possible to detect false positives, resulting from non-rigid objects, by applying the same change detection method to the first sequence exclusively. The developed method was able to correctly find the changes between two challenging sequences of images from a coral reef taken one year apart and acquired with two different cameras

El cant coral infantil i juvenil educa en valors, hàbits i competències

This doctoral thesis is the result of the experience, continuous practice and day to day work as head of infant and youth choirs that the candidate has developed for over more than thirty years. The motivation, the concerns and the questions formulated with regards to choral singing, have underpinned this research. The thesis has focused on the learning of values, habits and competences in order to demonstrate that singing in an infant or youth choir is educational and goes far beyond the mere act of singing in a choir. We can therefore state that education is continuous, it never comes to an end and, furthermore, it unfolds in divergent ways. In summary to show that singing in an infant or youth choir is educational in the widest possible sense.