Inside a two-dimensional model of the louvered Dorfan Impingo panel with transparent front and rear walls, the flow regions of filter granules without gas cross flow were observed. The white PE beads with diameter of 6 mm were used as filter granules. The red colored PE beads were used as tracers. The filter bed was filled with beads continuously and gently levelled above. Then the layer of colored beads was poured on the horizontal top surface. Filter granules were discharged and circulated to the bed. The flow rate of granules was controlled by the belt conveyer. The image processing system including a frame grabber and a JVC videocamera was used to record the granular flow. Every image of motion was digitized and stored in a computer file. Four different flow regions in moving granular bed were observed: a) a quasi-stagnant zone adjacent to the louver wall; b) a transition region - a shear zone in which large velocity changes occurred at each horizontal level; c) a central flowing core of near uniform velocity distribution with a plug flow pattern; and d) the left and right free surface regions where gas flows in and out. The velocity field of filter granules was evaluated and analyzed. The velocity profiles of the vertical and horizontal velocity components were investigated.