The presence of different constituents that possess specific material properties in fiber-reinforced polymers result with complex damage phenomena. When these materials are subjected to mechanical loading, a large number of cracks may occur accompanied with different damage mechanisms that initiate and propagate at different scales (micro-, meso- and macroscale). Therefore, the detection of damage in fiber reinforced polymers demands the use of advanced non-destructive testing methods. In recent years, Digital Volume Correlation combined with computed tomography is increasingly being used to detect and monitor damage initiation and growth in composite materials. In this way, it is possible to detect and analyze damage on the surface and in the bulk of the monitored object. In this work, the test specimen subjected to in-situ cyclic tensile loading was analysed. The material studied herein is a glass fiber mat reinforced epoxy composite. The test specimen was scanned in the unloaded state, as well as during different loading regimes. Finally, two scans of the specimen after failure were acquired. Damage analysis was performed on scans acquired during the experimental protocol. The analysis was performed using global Digital Volume Correlation method over the entire specimen. The maximum principal strain fields and the correlation residual map were obtained from the correlation analysis. Based on the proposed correlation procedure, damage mechanisms were identified, and the critical region of the specimen was determined. Within the critical region, a small sub-volume was chosen for implementation of heterogenous mechanical regularization and detailed damage analysis. Furthermore, segmentation of the selected sub-volume with respect to the corresponding microstructure was performed. From the segmented image, microscale finite element mesh accounting for morphology of the investigated material was generated. Microscale mesh was used to perform damage analysis in the observed sub-volume. The measurement protocol was performed employing the global Digital Volume Correlation approach with homogeneous and heterogeneous mechanical regularization. Homogeneous regularization was performed by using unique material properties for all constituents. In the correlation analysis with homogeneous regularization, the influence of different regularization lengths was studied. Furthermore, identification of crack initiation and propagation was performed. Such analysis was performed by observing the maps of correlation residuals and the main principal strain fields. Additionally, the microstructure of the initial and deformed scans was compared to identify the nature of the damage mechanism. Heterogeneous regularization was implemented by introducing different material properties for the constituents of the proposed composite material. In addition, the influence of different regularization lengths and different material parameters on the results of correlation analysis was investigated. Furthermore, in the case of heterogeneous regularization, the damage mechanisms identification in the observed sub-volume was performed and the strain fields and correlation residuals were analyzed. Finally, the scans acquired over the entire loading history was analyzed with heterogeneous regularization. In the latter analysis, changes in correlation residuals and strain fields were investigated throughout the sample loading history to monitor damage initiation and growth.