New Approach for Photogrammetric Rock Slope Premonitory Movements Monitoring

An automated, fixed-location, continuous time-lapse camera system was developed to analyze the existence of rockfall precursory movements and quantify volume changes after detachments. It implemented monitor basaltic formation on which Castellfollit de la Roca village is built. Due geometrical conditions area, consists three digital cameras managed by a control unit that contains Raspberry Pi 4 microprocessor. Images taken every day are sent server for processing. A workflow has been work with set images an irregular time interval detect precursor movement. The first step matching reference master image filtering vegetation improve process using mask obtained green leaf index (GLI) index. Then, adjusted used forward-backward correlation carried out movements. If movement detected, 3D model built structure from motion (SfM) working since September 2021. During this period, 0.01 0.5 m several rockfalls small have detected.