No abstract

No abstract

Most of the problems involved in a measurement of the velocity of light by a microwave resonant cavity are discussed briefly on the basis of work reported elsewhere. A more nearly complete theoretical analysis of the effects of the cavity-surface impedance is given. In general, the surface reactance and resistance must both be known to relate the measured resonant frequency to the normal-mode frequency. This problem limits the accuracy of the experiment to an uncertainty of no less than about 2 parts in 10 6 . The formal requirements for reducing this uncertainty are stated, but no experiment is suggested.New and more accurate measurements were made of the volume change on melting of N2 up to 3500 kg/cm 2 . Liquid density and thermal expansion were also studied along the melting curve. A lowpressure metering system was used throughout. The AV m data were fitted to the empirical equation, AV m = A -B logio(.P+C), with success. Combination of this equation with our previously reported melting equation yields expressions for AS and AH of melting useful up to 3500 kg/cm 2 .

No abstract

The Los Alamos Scientific Laboratory (LASL) maintains an active and broad program of computerized image analysis. Initially begun as an image enhancement adjunct to a flash radiographic facility, the base of experience has now beer expanded to include medical and industrial radiography, astronomical observations, and high -speed framing camera images. In addition to classical image enhancement and restoration, there is now activity in precision high -speed data extraction, often as an end in itself without the need for the analyst to view the image once it is digitized and supplied to the computer. Examples of various applications are given. In order to support these activities LASL has developed a library of image analysis subroutines, and is now developing a useroriented command language. A substantial hardware installation has been developed. An active research program for development of new digital techniques of image restoration is maintained. IntroductionIt is now known throughout the popular press that many of the spectacular television images sent to earth from lunar and space probes were digitally restored by the Jet Propulsion Laboratory (JPL) prior to release by NASA. Though the principles applied by JPL were known in the last century (the Abbe theory of image formation in the microscope, for example), it was the impetus of the space program which stimulated modern work on a massive scale.1The Los Alamos Scientific Laboratory (LASL), noting the clear success of the JPL work, undertook a program of digital image restoration and enhancement in 1967. The LASL motive was the improvement of images taken by PHERMEX, a unique high energy flash x -ray facility used in high -explosives research.2 Early LASL image enhancement efforts were directed to both flash and standard industrial high-energy radiography. Thè success of these efforts has been previously reported.3,4 Applications Since the beginning LASL work on enhancement of highenergy radiographs, digital image processing and data extraction have been applied to images of all types. Selected examples are given here.