Abstract: The method herein images an object repeatedly moving about an axis. The mod uses signals to track the object's position with respect to the axis while a camera views the object. A reflection is cast from the object toward the camera in such a way that the camera scans both the reflection and the object. The camera outputs representations of video lines, which depict parts of the object and the reflection. These video lines have known positions relative to a reference plane, which passes through the image plane of the camera. Certain of the video lines are selected. The selected lines come from a chosen position relative to the reference plane and occur within a chosen time of the position signals. The selected video lines are arrayed according to their particular position signals and are used to compile a planar composite image representing the object's outer periphery. The composite image is conformed to a shape resembling the periphery, thereby creating a three dimensional representation of the object.

Abstract: A passive maser wherein control of the cavity and control of the oscillator on the line of stimulated emission operate in a shared-time mode. A control circuit acts on the injected signal by way of a programmable synthesizer, the injected signal then assuming the successive values .omega..sub.L.sup.+, .omega..sub.H, .omega..sub.H and .omega..sub.C.sup.+, .omega..sub.H and .omega..sub.C.sup.-, .omega..sub.L.sup.-, .omega..sub.L.sup.+, etc. in stages. .omega..sub.H is centered at the line of stimulated emission; .omega..sub.L.sup.+ and .omega..sub.L.sup.- which are symmetrically shifted interrogate the sides of the emission line; and .omega..sub.C.sup.+ and .omega..sub.C.sup.- which are further symmetrically shifted interrogate the sides of the cavity resonance. The control circuit periodically inhibits the detection action used for controlling the oscillator, and the detection action used for controlling the cavity is carried out only during the inhibition period.