The flow path structure includes a flow path introducing fluid from an inlet to an outlet, and a flow velocity control structure provided in a portion between the inlet and the outlet in the flow path to reduce difference in flow velocity that the fluid flowing into the flow path has in a direction intersecting with a flow direction of the fluid. In some implementations, only a data block containing evidence that is appended with a server-generated challenge and signed or encrypted by the sensor may validate that the evidence is responsive to a current request and belongs to a current session. In a second step a style is selected for applying to the media files. The full image scanner includes means for obtaining a full video image of said documents, means for obtaining a image of a selected area of said documents, and means for obtaining information contained in said selected area of said document.