AU593544B2

AU593544B2 - Information transfer from spectrometric apparatus

Info

Publication number: AU593544B2
Application number: AU54899/86A
Authority: AU
Inventors: Timothy John Finney
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-03-19
Filing date: 1986-03-19
Publication date: 1990-02-15
Anticipated expiration: 2006-03-19
Also published as: AU5489986A

Description

!Z~iIj 59544 Form PATENTS ACT 1952 COMPLETE

SPECIFICATION

(ORIGINAL)

FOR OFFICE USE PATENT OFFICI Short Title: Int. Cl: Application Number: Lodged: Er' ?g PG' 990.3 190's Clnipiete Specification-Lodged: Accepted: Lapsed: OS.Published: ft~rity: *S 0 Related Art: This document contains the amendments made under Section 49 and is correct for printing.

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00 TO BE COMPLETED BY APPLICANT *Nene of Applicant: FJ- w **Ad~ress of Applicant: 5-g Hev 6 0 Cveevi 4 2 MCL j Ij Vj 6 15_ 7 Actual Inventor- -F1 VVL4 'jC Ik C-rce 4 Address for Service: S9 14 v, I ,_5 M 0yl I)z 6is-z Complete Specificatio,. for the invention entitled: 0~ifOV VLi Po F Trcu -N The olloing t ent~s;,a~fuII-description of this inivention, ihlCluding-the-ibe,,t ,method of performing it known1 to me:-* Note: The description is to be typed in double spacing, pica type face, in an area not exceeding 250 mm in depth and 160 mm in width, on tough white paper of good quality and it is to be inserted inside this form.

141 66/77-L Printed by C. J1. THOMNt, Acting Commtonwealth Ge ,drnmncnt Printer, Canberra -2- INFORMATION TRANSFER FROM SPECTROMETRIC APPARATAS This invention relates to transfer of information concerning a system being investigated by a spectrometric apparatus, from the apparatus to an investigator.

Spectrometric apparatus, hereafter called spectrometers, accumulate a spectrum or distribution representing the variation of a property of the investigated system with respect to some parameter. For example, an infra-red spectrometer accumulates a distribution of intensity versus wavelength of infra-red light. Similarly visible and ultra-violet spectrophotometers scan through respective wavelength ranges of electromagnetic radiation in such a way as to eventually accumulate a distribution of intensity versus wavelength. There are many other types of spectrometers including X-ray, gamma-ray, mass- and time of flight- spectrometers. A storage medium containing a frequency distribution of a variable and spectrographic devices may also be considered as spectrometric apparatus. These examples are in no way intended to limit the scope of applicability of the following novel invention to be fully described herein.

STraditionally a visual or graphical means has been used to show an investigator the accumulated information in a spectrometer such as is represented by display 14 in figure 1, or figure 2 of the appended drawings.

This is not always satisfactory or desirable, especially in the case of the Svisually impaired or field situations.

When God created the human hearing system he made a remarkably good frequency analyser. It is able to differentiate the sound of a single musical instrument from amongst the sound of an orchestra and a piano tuner is able I to differentiate a change in pitch of a quarter of the difference between consecutive notes easily. This invention makes use of this gift in such a way as to continuously inform an investigator of the distribution of a property of a system with respect to a particular parameter, as determined by a S spectrometer.

This is achieved by separately varying a characteristic of each of a set of distinguishable sounds in accordance with the distribution of a property of an investigated system with respect to som-' parameter and communicating a resultant sound synthesised from the set of sounds to an investigator. The S• characteristic which is varied is chosen to allow 'real-time' communication of time varying spectrometric information. Variation of the durations of each of the set of distinguishable sounds does not fall within the scope of this invention because it takes at least as long as the longest sound duration to S 40 communicate the system's spectral features. On the other hand, any means of S•variation of a characteristic of the distinguishable sounds which allows continuous information transfer i.e. allows information transfer in a time comparable with the accumulation time of the spectrometer is consistent with this invention. Some examples are, inter alia, amplitude-, frequency- or power spectrum- modulation of the distinguishable sounds.

The best method of performing this invention known to me will now be described with reference to the accompanying drawings where: figure 1 is a schematic representation of a diagnostic instrument incorporating this invention; figure 2 is a representation of a typical gamma-ray energy distribution as

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Ii 1-1 i IFF- _l~-i -3ps00 o o o o o 0 0o o e o 0 00* 0 0 oole 0o 0 o 0000 o 00 D r r oo 0 00 4r o r 0600 0 00« 0 0 0 or o n or 0 0 0 o 0 00 00 0°l 0 determined by a 64 channel pulse height analyser and a NaI(TI) scintillation crystal/photomultiplier detector combination; figure 3 shows a voltage controlled gain or modulator circuit; figure 4 shows a logarithmic amplifier circuit; and figure 5 shows a 'sample/hold' circuit.

Referring to figure 1, a set of selectable filters is shown at 1 which serve to filter whatever is being detected by one of a set of selectable detectors 3 shown at 2. The signal from the selected detector passes through a noise discriminator 4 to a multi-channel analyser, hereafter referred to as a 5. This sorts the detected signal by incrementing one of a set of registers, hereafter called M.C.A. registers, whenever the signal's value falls within a corresponding interval of the parameter against which the signal is being analysed. Alternatively, the amplitude of the signal for monotonically increasing values of the analysing parameter may be stored in consecutive registers as in scanning spectrophotometers. The register contents are usually in the form of a digital number, so converters 7 change the contents into suitable converted signals which feed into the 'sample/ hold' circuits 8.

Control circuitry 12, upon registering that a sufficient accumulation has 20 occured in the registers 6, operates corresponding 'sample/hold' circuits 8 to sample the contents of the associated register via the associated converter, and hold this value of the converted signal in communication with its associated modulator. In this diagram associated registers 6, converters 7, 'sample/hold' circuits 8 and modulators 10, lie in a vertical line. Use may be made of a modulator circuit which is digitally programmed, in which case there is no need for the conver.',rs 7.

A set of distinguishable sound generators 9, selectable from an array of sound generators 15, is shown. The outputs from each of the selected set communicates with a corresponding analyser register content controlled modulator 10. The individually modulated distinguishable sounds are then combined and amplified at 11 to produce a resulting total sound indicative of the spectral features of the investigated system. This sound is maintained until control circuitry 12 registers that another sufficient accumulation has occured in the M.C.A. 5, which was reset at the same time as the 'sariple/hold' circuits were previously operated.

Conventional circuitry at 13 which may incorporate a microprocessor and memory storage, stores and processes data communicated via the data path from M.C.A. 5. Under the supervision of control circuitry 12, data is fed to display 14 to be depicted visually.

40 Control circuitry 12, which may also incorporate a microprocessor, also controls filter selection at 1, detector selection at 2, 'sample/hold' circuit operation and sound generator set selection at 15. The selections are performed according to both operator input and data fed into the control circuitry via data paths from the filters, detectors, 'sample/hold' circuits, array of sound generators, combining and amplifying section and conventional circuitry.

The purpose of this control is to: select filter/detector combinations suitable for particular applications and environments and to prevent analyser pile-up or overload or inefficient operation of the device;

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-4- A (ii) select a set of distinguishable sounds appropriate to the operator's B preferance or the instrument's state of operation or environment; (iii) control data transfer between M.C.A. 5 and conventional circuitry 13; (iv) control combining and amplifying section 11; and operate 'sample/hold' circuits 8 when sufficient accumulation has occured in registers 6.

With respect to item (iii), data from the conventional circuitry 13 can be loaded into the registers 6 and thereby give an audible indication of the data. This is highly desirable because the instrument may then be used to indicate the transient spectral features of a system and those accumulated over a long time. The operating sequence is that spectral data from conventional circuitry 13 is loaded into corresponding registers 6 under the influence of control circuitry 12. Peaks and troughs in the loaded spectrum respectively translate to high and low register counts, from left to right as the value range of the analysing parameter which corresponds to a particular register increases register by register. Control circuitry 12 then simultaneously operates 'sample/hold' circuits 8 and the resulting sound is immediately indicative of the loaded spectrum's features, and may have a duration which is convenient with regard to the operator or is dependant upon i 20 the instrument's state of operation.

Combining and amplifying section 11 can either sum or produce a weighted sum t of the individually modulated distinguishable sounds. Moreover, the amplification of the resulting sound can be varied to suit conditions even when the distinguishable sounds are amplitude modulated because relative variations between the amplitudes of the distinguishable sounds will be equally apparent. Once the amplification is set, variations in the overall loudness of the resulting sound are indicative of the amount of the analysed property being detected.

Often the amount of the property detected moment by moment is insufficient to accumulate a statistically significant distribution in the M.C.A. quickly enough to continuously provide a true representation of the spectral features of the investigated system.

A statistically significant distribution is one where the random component is small compared with the magnitude of each register's contents. For example, in a distribution with gaussian statistics, over 99% of the trial results will have a value within 3 standard deviations of the mean value of the results. Where data has a Poisson distribution, as in radiation counting experiments, the standard deviation is the square root of the mean value of i the results. The random component is then small when the square root of the 40 total is small compared with the total. In a M.C.A. where the total is distributed between a number of channels, the square root of the total must i be small compared with the total divided by the number of channels: ,N 0.5 «<N/n N=Sum of register contents; n=Number of registers.

For example, where there are 64 channels and the degree of significance requires the square root to be one tenth of the total divided by the number of channels, N 050.1xN/64.

Therefore N=640 2 L Some spectrometers take time to accumulate a sample distribution because they sweep through monotonically varying values of the analysing parameter. In summary, the time taken to accumulate a truly representative spectrum, depends on the analysing method and the quantity and statistical distribution of the analysed property, and is consequently highly variable. This highlights one of the advantages of this invention which is that the i accumulated information can be communicated immediately with a continuously time-varying spectral distribution. Therefore bottle-necking of spectra to be communicated, which is a serious problem with systems which use sequential or duration-modulated distinguishable sounds, is eliminated.

Returning to figure 1, control circuitry 12 operates 'sample/hold' circuits 8 whenever the M.C.A. contains a complete or significant distribution, as determined by control circuitry 12 from M.C.A. data. Conventional circuitry 13 may have interface facilities for external apparatus, and a line to combining and amplifying section 11 whereby a single tone may be used to indicate the presence or absence of a detected signal. Also, the instantaneous value of the analysed property may be indicated by simultaneous variation of a parameter of a single sound. This would be the case where a voltage controlled oscillator was connected to the output of an energy 20 sensitive detector, such an arrangement being within the scope of this invention.

One preferred embodiment of this invention takes the form of a radiation survey instrument. Detectors 3 are energy sensitive (dispersive), and different ones of the detectors are suited to different types of radiation such as alpha, beta, X-ray, gamma-ray, proton and neutron radiation. They may be semiconductor, scintillation, or proportional counter detectors. In association with apparatus well known to those skilled in the art, a signal with an amplitude corresponding to the energy deposited in the detector results. Discriminator 4 eliminates pulses of low amplitude and M.C.A. accumulates a pulse height spectrum. The contents of groups of M.C.A.

registers are summed to form the contents of registers 6. In another embodiment some of the M.C.A. registers may be used for storing elapsed time or the mean values of respective groups of analysing M.C.A. registers accumulated over a suitable desired time interval. In figure 1 contents of groups of 8 analysing channels are summed to produce the contents of registers 6, with channel zero storing the accumulation time. Other instrument architectures will be obvious to those skilled in the relevant arts. The number of modulators, distinguishable sound generators and registers 6 may be any number greater than or equal to one. An upper limit is set by the least number that would cause confusion to the hearing system given a particular set of distinguishable sounds and method of modulating them. M.C.A.s with up to 4096 channels are readily obtainable.

Register contents 6 are converted to control voltages by D to A converters 7.

These voltages are present at 'sample/hold' circuits 8, an example of which is shown in figure 5. These are triggered by control circuitry 12 which can simply consist of a monostable multi-vibrator sent into its unstable state (which produces a logic high 'sample' pulse on the 'sample/hold' line) upon registration that a sufficient number of pulses have been counted. This may be achieved by triggering the monostable from a diode pump and fixed reference comparator circuit operating as a pulse number threshold detector.

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P 4 C o ci *0 *P 4 4 4* 4 4CC CCC 4, 1 -6 The 'sample.' pulse operates analog switch 21 which allows capacitor 22, isolated by high input impedance buffer 23, to charge up to the converted voltage via amplifier 20. The trailing edge of the 'sample' pulse resets the register contents 6 to zero. The converted voltage is held constant on the outward control line to associated modulator 10 until the next 'sample' pulse occurs.

Modulators 10 in this preferred embodiment consist of gain controlled amplifiers, a suitable circuit for which is shown in figure 3. The control voltage from the associated 'sample/hold' circuit 8 alters the drairn-source impedance: of FET 10, which may be a MOS device, to control the amplification of the signal from associated distinguishable sound generator 9 of figure 1.

Many modulators -and mixers are known and may be used instead of this particular circuit.

The combining and amplifying section 11 may consist of a single operational amplifier with the modulated distinguishable sound generator signals combined at its summing node. Alternatively, an array of amplifiers with various gains or a weighted sum output resistive network may be used to mix the modulated distinguishable sounds in a desired manner.

Sound generator array 15 can simply consist of an electronic organ type tone 20 generator which produces a scale of separate notes such as a chromatic scale.

It is not advisable to use harmonics of a fundamental tone as the distinguishable sounds because the ear does not readily differentiate these.

Alternatively, a scale of notes may be synthesised from a particular sound or noise as is done in the 'Fairlight' musical computer developed by the University of Sydney, Australia.

Logarithmic amplifiers such as is shown in figure 4, may be used in the detected signal input line to the M.C.A. 5 and in the control lines (the vertical lines between the registers 6 and modulators of figure 1) to extend the range of indication with respect to both the energy bandwidth and the 30 intensities (peak heights) of radiations of particular energies. For example the loft hand register 6 could accumulate pulses corresponding to energies of 10-1OkeV, the next one energies of 100-iQO0keY, and so on up to the right most register with energies of 100-1000MeV.

There are many other embodiments for this invention. One is particularly useful for the visually impaired who wish to know what colour an object is. A prism or diffraction grating disperse s incoming light from the object into constituent colours. The spectrum then falls on to an array of photocells or a CCD. The respective intensities of the constituent colours then produce corresponding voltages from separate sensing regions of the array or CCD.

40 These voltages are then used to modulate a set of distinguishable sounds such that each distinguishable sound corresponds to a particular colour (i.e.

wavelength interval) as is illustrated in figure 6.

The hereinbefore described inventive concept is not intended to be limited by the preferred embodiments and many variations will be obvious to those who may work this invention. Any system which involves storage, retrieval and communication of a spectrum, distribution or graphical representation of the values of a property of an investigated system with respect to a particular parameter may be improved by the teaching of this specification.

Finally I would like to thank God for the part He has played in making this invention possible.

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Claims

1. A method for informing an investigator of the distribution of a property of a system with respect to a parameter as measured by a spectrometric apparatus wherein a characteristic of separate ones of a set of distinguishable sounds is varied in accordance with the measured amount of the property in respective intervals of the parameter associated with the separate ones of the set by a known correspondence and a resultant sound is synthesised from the set of varied sounds.

2. A method as claimed in claim 1 wherein the characteristic which is varied is chosen to allow ":eal-time" communication of time varying spectrometric information. ''t r r C I t CC C C I I 1* tC t.511t CtI t V t I C r C C C~

3. A method as claimed in claims 1 or 2 wherein there is a one to one correspondence between consecutive ones of the set of distinguishable sounds and consecutive ones of the intervals of the parameter.

4. A method as claimed in claims 1, 2 or 3 wherein the varied characteristic is the amplitude. A method as claimed in claims 1, 2 or 3 wherein the varied characteristic is the frequency.

6. A method as claimed in claims 1, 2 or 3 wherein the varied characteristic is the power spectrum.

7. A method as claimed in any one of claims 1 to 6 wherein the spectrometric apparatus is an X-ray or gamma-ray spectrometer.

8. A method as claimed in any one of claims 1 to 6 wherein the spectrometric apparatus is a mass-spectrometer or time o- flight spectrometer.

9. A method as claimed in any one of claims 1 to 6 wherein 40 the spectrometric apparatus is an infra-red, visible or ultra-violet spectrophotometer.

10. A method as claimed in any one of claims 1 to 9 wherein the parameter is a physical quantity.

11. A method as claimed in claim 10 wherein the physical quantity is wavelength, frequency or energy of ionising or non-ionising electro-magnetic radiation.

12. A method as claimed in any one of claims 1 to 11 wherein the set of distinguishable sounds is a chromatic scale.

13. A method as claimed in any one of claims 1 to 11 wherein the set of distinguishable sounds is a chromatic scale of notes synthesised from a particular sound or noise as is done in the "Fairlight" musical computer J I I I i developed by the University of Sydney, Australia.

14. An apparatus comprising spectrometric analyser means adapted to spectrometrically analyse a property of a measured system with respect t- a particular parameter, means for generating a set of uistinguishable sounds, a corresponding set of modulator means, and synthesising means, wherein a characteristic of separate ones of the set of distinguishable sound generating means is varied by the corresponding modulator means in accordance with the measured amount of the property in respective intervals of the parameter, and respective intervals of the parameter are associated with the separate ones of the set of distinguishable sound generating means by a known correspondence, and a resultant sound is synthesised from the output of the set of varied sound generating means. 4441 *oe' @414 o eq o o e9o #08 o1 t 4 o T 44f I t4t1 4 4 *It gt 44,4 til 4114 t 4 t t 1 An apparatus as claimed in claim 14 wherein the characteristic which is varied is chosen to allow 20 "real-time" communication of time varying spectrometric information.

16. An apparatus as claimed in claims 14 or 15 wherein there is a one to one correspondence between consecutive ones of the set of distinguishable sound generating means and consecutive ones of the intervals of the parameter.

17. An apparatus as claimed in claims 14, 15 or 16 wherein the varied characteristic is the amplitude.

18. An apparatus as claimed in claims 14, 15 or 16 wherein the varied characteristic is the frequency.

19. An apparatus as claimed in claims 14, 15 or 16 wherein the varied characteristic is the power spectrum. An apparatus as claimed in any one of claims 14 to 19 wherein the spectrometric apparatus is an X-ray or gamma-ray spectrometer.

21. An apparatus as claimed in any one of claims 14 to 19 wherein the spectrometric apparatus is a mass-spectrometer or time of flight spectrometer.

22. An apparatus as claimed in any one of claims 14 to 19 wherein the spectrometric apparatus is an infra-red, visible or ultra-violet spectrophotometer.

23. An apparatus as claimed in any one of claims 14 to 19 wherein the parameter is a physical quantity.

24. An apparatus as claimed in claim 23 wherein the physical quantity is wavelength, frequency or energy of ionising or non-ionising electro-magnetic radiation. An apparatus as claimed in any one of claims 14 to 24 1 a i ii I t C ;X C 9 wherein each one of the set of distinguishable sound generating means generates an individual note of a chromatic scale.

26. An apparatus as claimed in any one of claims 14 to 24 wherein the set of distinguishable sound generator means generate a chromatic scale of notes synthesised from a particular sound or noise as is done in the "Fairlight" musical computer developed by the University of Sydney, Australia.

27. An apparatus consisting of a dispersive detector, a multi-channel analyser, an array of modulators, an array of distinguishable sound generators, control circuitry, memory storage circuitry, an array of "sample-hold" circuits and summing and audio amplifying circuitry wherein the contents of consecutive groups of the multi-channel analyser's channels representing the distribution of a property of an investigated system with respect to a dispersive parameter are summed to produce consecutive control signals communicated to respective modulators of associated distinguishable sound generators upon operation of the array of "sample-hold" circuits and the modulated distinguishable sounds are synthesised into a resultant sound which is continuously indicative of the distribution accumulated in the multi-channel analyser under the control of the control circuitry.

28. An apparatus consisting of a dispersive detector, a multi-channel analyser, an array of modulators, an array of distinguishable sound generators, control circuitry, memory storage circuitry, an array of "sample-hold" circuits and summing and audio amplifying circuitry wherein the contents of consecutive groups of the multi-channel analyser's channels representing the distribution of a property of an investigated system with respect to a dispersive parameter are summed to produce consecutive control digital words communicated to respective modulators of associated distinguishable sound generators upon operation of the array of "sample-hold" circuits and the modulated distinguishable sounds are synthesised into a resultant sound which is continuously indicative of the distribution accumulated in the multi-channel analyser under the control of the control circuitry.

29. An apparatus as claimed in claims 27 or 28 wherein the control circuitry operates the array of "sample-hold" circuits when a distribution with a desired statistical significance has accumulated in the multi-channel analyser. An apparatus as claimed in claims 27, 28 or 29 wherein the dispersive detector is a scintillation, semiconductor or proportional counter radiation detector.

31. An apparatus wherein a prism or diffraction grating disperses incoming light from an object into constituent colours which spectrum then falls on to an array of photocells or a CCD and the respective intensities of the constituent colours then produce correspording voltages from the respective sensing regions of the array or CCD which corresponding voltages modulate a set of associated distinguishable sounds wherein each distinguishable sound is associated L.ith a particular wavelength interval by a known correspondence. An apparatus as claimed in any one of claims 14 to 31 wherein the resultant sound is synthesised from the st of varied sounds by summing the varied sounds.

33. An apparatus as claimed in any one of claims 14 to 31 wherein the resultant sound is synthesised from the set of varied sounds by preparing a weighted mean of the varied sounds.

34. A metlod as claimed in any one of claims 1 to 13 w"w. herein the resultant sound is synthesised from the set of varied sounds by suming the varied sounds.

35. A method as claimed in any one of claims 1 to 13 wherein the resultant sound is synthesised from the set of varied sounds by preparing a weighted mean of the varied H sounds.

36. A method for informing an investigator of the distribution of a property of a system with respect to a parameter as hereinbefore described with reference to the description, claims and drawings.

37. An apparatus for informing an investigator of the I distribution of a property of a system with respect to a parameter as hereinbefore described with reference to the S .description, claims and drawings. S I I I I I