In the present radio frequency device, a radio frequency circuit part and a transmission line are disposed on the top surface of a circuit board on the surface of which a ground pattern is provided, and a metal shielding cap is fixed to the circuit board so as to cover the radio frequency circuit part and the transmission path. The image generator is configured to generate a first pair of images with a difference in visual field for an operational object. The fern plants remove pollutants from the water-containing sites, and can be harvested and readily disposed of, or can be treated to recover the pollutant. Besides, a contrast enlarging process, a saturation highlighting process and an edge highlighting process, which are suitable for application to a natural picture on the basis of the results of such judgment, can be selected automatically while changing the respective highlighting degrees. With the projection type display apparatus, a system can be configured with a simple processing circuit, and cost reduction can be realized.