Scattered lighting is used to inspect stamped characters on a curved surface. A certain part of direct light which is reflected in diverse directions is observed to detect the edge of the stamped character.
	Scattered lighting is used to inspect stamped characters on a piston head. A certain part of direct light which is reflected in diverse directions is observed to detect its polished surface in white colour and stamped characters in black colour.
	Filtering of light reflection removes a glare appearing on the light bulb surface and enables to inspect white-printed characters on the surface.