The maximum number of degrees of freedom of an image, which is usually derived by a
rough application of the sampling theorem, has a precise mathematical meaning. This is …

Enlarged and updated in 1983, this is the second edition of Dr Steel's popular textbook on
interferometry. The text has been revised throughout and major additions have been made …

A new method is developed for obtaining images of high quality with an annular aperture.
The principle is of general application to all forms of optics but has special application to the …

Images from high aspect ratio annulus apertures are spatially filtered in a coherent optical
processor for equalization of the modulation transfer function. The imagery is relatively …

It was shown in a previous analysis that a mosaic of piezoelectric acoustic detectors would
be sensitive enough to image tissue structures deep within the body and would be able to …

Paul Wild stands tall among the founding fathers of modern radio astronomy. His early work
became the foundation for all future research on solar radio bursts. He established the …

Publisher Summary This chapter discusses two-beam interferometry, which is a major
method of experimental optics that has considerably progressed both in techniques and in …

The problem of imaging cross sections of opaque bodies by means of ultrasonic
transmissions is considered. Images are computed from measurements of ultrasonic …

It has recently been suggested that microwave antennas may be simulated at optical
frequencies using the neon-helium continuous gas laser. The present paper discusses …

Publisher Summary This chapter discusses the quasi-optical techniques of radio astronomy.
This review of radio astronomical instrumentation has attempted to concentrate on those …