Recently terahertz imaging using two-dimensional E-O sampling has attracted much interest because it can acquire real-time terahertz images unlike a conventional raster scan method. We are applying this technique to the non-destructive measurement of opaque materials in a visible range. We acquired 10-fps consecutive terahertz transmission images: dripping water in a plastic pipe and metal included in a piece of gum. Since the obtained images were confirmed to be proportional to the electric field of the terahertz waves, the images in the present paper are useful for quantitative analysis. We also showed the signal-to-noise ratio of the terahertz images.