Abstract: A videophone system having an electronically controlled shutter to vary the amount of light falling onto the target by a shutter, e.g., for a greater or lesser length of time during a short exposure time rather than b y means of a controlled mechanical aperture. Data reduction is used for the transmitted signal, a control circuit is used for the exposure time, and the mains power supply, which produces ambient light, are coupled by means of a PLL circuit so that the exposure time occurs at the same phase of the mains voltage. In this way, interference occurring when data reduction is used for the signal to be transmitted is avoided and macroblocks are not formed when no difference signal is present.

Abstract: A video camera which is convertable into a projector includes a detachable view finder having an eye-piece for viewing a scene to be recorded and an opto-electrical converter which converts the scene into an electronic image. A coupling supports the view finder during use as a camera or a light source during use as a projector. A display screen receives the electronic image and converts the electronic image into a visible image. A switch selectively connects the display screen to input terminals during use as a camera and to output terminals during use as a projector. The opto-electronic converter is pivotable away from the display screen when the camera is used as a projector.