The Denver Universal Microspectroradiometer (DUM): II. Computer configuration and modular programming for radiometry

Abstract

This paper describes and discusses for microscopists and spectroscopists the choice of computer equipment and the design of programs used in the Denver Universal Microspectroradiometer (DUM). This instrument is an accurate computerized photon-counting microspectrophotometer, microspectrofluorimeter and microrefractometer. The computer is used to control the operation of the system, to acquire radiometric data of various kinds, and to reduce, analyse and output the data in a readily usable form. Since the radiometer was designed to carry out many kinds of measurements in a variety of micro- and macroscopic specimens, and since different methods of microscopy or spectroscopy have to be combined in various ways fro the study of any one specimen, no single master-program could fulfill efficiently all foreseeable requirements. Therefore, the programming developed is interactive, modular, hierarchical and hybrid. Modular interactive programming makes it possible for almost any kind of main program, applicable to almost any kind of measurement, to be assembled quickly from a collection of hierarchical subroutines. Main programs are short and composed mainly of Fortran statements calling subroutines; subroutines, in turn, automatically call other subroutines over many levels. The subroutines are independently written and optimized for maximum operational efficiency in the computer system used, or for maximum ease of transfer to other systems. This approach to programming enables someone unfamiliar with computer languages to operate the radiometric system from the console of the CRT terminal. The writing of new main programs, by linking groups of existing subroutines, requires only a minimum acquaintance with Fortran; only the writing and revision of subroutines requires programming experience. Differences and similarities in the method of computer operation between the present system and other computerized radiometers are briefly discussed.

Microspectrophotometric studies of Romanowsky stained blood cells

“…Spectral measurements. Spectra were measured by photon counting, using the Denver Universal Microspectroradiometer (DUM) Galbraith et al, 1975). A stabilized 450 W xenon arc was used, and further stabilization was introduced by diverting a fraction of the light beam near the source to a 'monitor' photon counter, attenuating to 1 million photons s-1, and using the resulting signal as the 1 MHz external clock signal to the photon counting electronics .…”

An aid to understanding differential interference contrast microscopy: computer simulation

“…The program was written using the modular, hierarchical hybrid programming described by Galbraith et al (1975). The highest levels of subroutines are not used since these relate to the microscope functions and in this program only the interactive CRT, light-pen and x-y plotter are involved.…”

“…It is possible to show very quickly how the image changes as instrumental parameters, such as phase-bias, amplitude-ratio, extinction factor, and beam-splitter shear are altered.Simulation was found useful as a tool to learn DICM and as an aid to the interpretation of complicated images obtained with real objects. Examples of common errors in adjusting the microscope and interpreting images are given in this paper.The simulation program was developed for the computer of the Denver Universal Microspectroradiometer Galbraith et al, 1975), but it can be used on a number of compatible computing systems. The program construction is explained to enable comparable programs to be written for different computers.…”

“…The simulation program was developed for the computer of the Denver Universal Microspectroradiometer Galbraith et al, 1975), but it can be used on a number of compatible computing systems. The program construction is explained to enable comparable programs to be written for different computers.…”

“…The construction of the program is described in the Appendix. The program is based on the computer hardware of the Denver Universal Microspectroradiometer Galbraith et al, 1975), but it could be run without modifications on other DEC PDP 11 computers fitted with a GT40 interactive CRT system and an x-y plotter. We could make the full program available at cost to users having access to such computers.…”