Computer vision systems are important for capturing environments, for facial recognition and as a way to scan objects for documenting and for manufacturing. One of the current challenges is to scan objects that change dynamically, whether rigid transformations or shape deformations. This paper presents a new system based on an RGB-D camera array, an array which is calibrated by means of a set of equations that relate the distance, angles and resolution of the cameras. The Iterative Closest Point algorithm is proposed for a fine alignment, as well with a process of reconstruction and elimination of noise by means of a Poisson distribution function. The system was exhaustively validated using two forms with different properties. When comparing the obtained result of the scan versus the real models by means of the distance of Hausdorff, errors of no more than 0.0045 mm were obtained. In addition, an experiment is performed by scanning the palm of the hand under deformations and movements. These results show that the system can scan static and non-static and dynamic forms, thereby demonstrating its usefulness for the reconstruction, analysis and manufacture of objects of different classes.
Lower limb prosthesis has the purpose of recovering mobility in amputees, giving autonomy to patients to do several activities. Mobility degree quantification and correct use of the prosthesis is necessary to reduce the risk of desertion. An adequate measurement of movements when patients are walking can help the physiotherapists evaluate the performance. For that reason, this work presents a new tracking method based on the extraction of texture and shape features that feed the retraining Random Forest classifier. The aim is to use a depth camera to track people with lower limb prosthesis when walking between parallel bars. Two experiments were performed with the proposed system: the first one under three patients with lower limb prostheses in order to apply the tracking algorithm. The second was carried out in three healthy control subjects with the purpose of validating the proposed algorithm and comparing the results with a motion capture system (MoCap). In this test the participants carried out two different activities; the results present errors from 3.3 to 4.9 mm according to the root mean square error. This suggests that the system can be used to track human joints under different conditions; however, it is necessary to solve the problem of occlusion artifacts by using human body models or by employing several depth cameras.
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