Intelligent switching networks for selectively delivering satellite video signals. The external and internal portions are separated so the transparent filler material, when set, forms a smooth and featureless surface. In comparison to other traffic systems, the inventive system’s velocity, line capacity, safety and reliability, ability of resisting disasters and comfortableness are much increased while its consumption of energy, construction cost, occupied space, operating cost, noise and visual pollution are greatly reduced. A defect detecting unit detects a defect in the pattern formed on the mask from comparing the differential interference images with reference images, respectively. The apparatus also includes a sound source and thermal imaging camera that generates thermal images of the specimen along with a controller connected to the sound source and the imaging camera. The conveyor has been positioned outside the chamber during the functioning of the plant.