AU693887B2 - Methods and apparatus for determining a first parameter(s) of an object - Google Patents

Description

WO 95/29396 PCT/AU95/00250 METHODS AND APPARATUS FOR DETERMINING A FIRST PARAMETER(S) OF AN OBJECT TECHNICAL FIELD The present invention relates to methods for determining a first parameter(s) of an object, apparatus for determining a first parameter(s) of an object, methods for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, and apparatus for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn.

BACKGROUND ART There is a need for a method and apparatus which can detect faults, contamination and/or variations in objects especially in a fibre(s) or yarn(s).

OBJECTS OF THE INVENTION Objects of the present invention are to provide methods for determining a first parameter(s) of an object, apparatus for determining a first parameter(s) of an object, methods for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, and apparatus for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn.

SDISCLOSURE OF THE INVENTION According to a first embodiment of this invention there is provided a method for determining a first parameter(s) of an object, comprising: locating the object in a measurement interaction volume(s) having a light absorbing background;

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passing a measurement light beam(s) through the measurement interaction volume(s), said measurement light beam(s) comprising at least two spectrally different wavelengths of light; interacting the measurement light beam(s) with the object to produce measurement outgoing light; filtering the measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions; detecting the at least two measurement spectrally different outgoing light portions and generating signals therefrom whereby the signals are a function of the first lo parameter(s); and determining the first parameter(s) from the signals.

q, Step may be performed before, at the same time or after step Typically the light absorbing background is a black background which may be a flat '7 r matt black background.

0' 15 Typically, the measurement outgoing light in step is light reflected from said object in said measurement interaction.

"."3Typically the object is selected from the group consisting of a yarn and a fibrous object, wherein: S 9* step comprises locating the object in a measurement interaction volume(s) having a 0o light absorbing background which is a black background; step comprises interacting the measurement light beam(s) with the object to produce measurement outgoing light reflected from the object; and ,step comprises filtering the reflected measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions.

Alternatively: step comprises filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands; step comprises detecting the at least two measurement spectrally different wavelength S 30 bands, each band being detected by a different detector at the same time or SWO 95/29396 PCT/AU95/00250 3 at different times or by the same detector at different times, and generating signals therefrom whereby ne signals are a function of the first parameter(s).

In another alternative: step comprises filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands; and step comprises detecting the at least two measurement spectrally different wavelength bands, each band being detected by a different detector at the same time or at different times or by the same detector at different times, and generating signals therefrom whereby the signals are a function of the first parameter(s).

Advantageously: step comprises locating the object in a measurement interaction volume(s) having a light absorbing background.

The filtering is typically selected from the group consisting of spectral filtering and temporal filtering.

The method of the invention may further comprise: outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

In one form of the invention: step comprises detecting at least two measurement spectrally different outgoing light portions and generating signals therefrom which are related to the respective intensities of the at least two measurement spectrally different outgoing light portions whereby the signals are a function of the first parameter(s); and step comprises determining the first parameter(s) from the signals by comparing the signals with reference signals or reference values.

The method of the invention may further comprise: determining from the first parameter whether the object is an acceptable object or an unacceptable object, According to a further embodiment of this invention there is provided a method for determining a first parameter(s) of an object, comprising: SWO 95/29396 PCT/AU95/00250 4 locating the object in a measurement interaction volume(s) having a light absorbing background; passing a measurement light beam(s) through the measurement interaction volume(s); interacting the measurement light beam(s) with the object to produce measurement outgoing light; filtering the measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions; detecting the at least two measurement spectrally different outgoing light portions and generating signals therefrom whereby the signals are a function of the first parameter(s); and determining the first parameter(s) from the signals.

Step can be performed before, at the same time or after step According to another embodiment of this inventidn there is provided a method for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, comprising: locating the fibre in a measurement interaction volume(s) having a black light absorbing background; passing a measurement light beam(s) through the measurement interaction volume(s); interacting the measurement light beam(s) with the object to produce measurement outgoing light reflected from the fibre; filtering the reflected measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions; detecting the at least two measurement spectrally different outgoing light portions and generating signals therefrom whereby the signals are a function of at least Sone parameter(s) selected from the group consisting of the diameter of the fibre and the colour of the fibre; and

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WO 95/29396 PCT/AU95/00250 j determining from the signals a first parameter(s) which is a function of the at least one parameter(s).

This embodiment may further include: outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

According to another embodiment of this invention there is provided a method for determining a first parameter(s) of an object, comprising: j locating the object in a measurement interaction volume(s) having a light absorbing background; passing a measurement light beam(s) through the measurement interaction volume(s); 4 interacting the measurement light beam(s) with the object to produce measurement outgoing light; detecting the measurement outgoing light from the measurement interaction 15 volume(s) and generating at least two different measurement signals therefrom, each of said signals corresponding to a spectrally different portion of the measurement outgoing light, whereby the signals are a function of the first parameter(s); determining the first parameter(s) from the signals.

Step can be performed before, at the same time or after step According to another embodiment of this invention there is provided a method for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, comprising: locating the fibre in a measurement interaction volume(s) having a black light absorbing background; passing a measurement light beam(s) through the measurement interaction volume(s); interacting the measurement light beam(s) with the object to produce measurement outgoing light reflected from the fibre;

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WO 95129396 PCTAU95/00250 6 detecting the measurement outgoing light from the measurement interaction volume(s) and generating at least two different measurement signals therefrom, each of said signals corresponding to a spectrally different portion of the measurement outgoing light, whereby the signals are a function of at least one parameter(s) selected from the group consisting of the diameter of the fibre and the colour of the fibre; and determining from the signals a first parameter(s) which is a function of the at least one parameter(s).

The latter method may further include: outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

According to a second embodiment of this invention there is provided an apparatus for determining a first parameter(s) of an object, comprising: means for locating thile object in a measurement interaction volume(s); a light absorbing background operatively, associated with the measurement interaction volume(s); at least one light source for passing a measurement light beam(s) through the measurement interaction volume(s) to interact with the object to produce mrneasurement outgoing light, the measurement light beam(s) comprising at least two spectrally different wavelengths of light; at least one detector to detect the at least two measurement spectrally different outgoing light portions and to generate signals therefrom, whereby the signals are a function of the first parameter(s), the detector(s) being operatively associated with the light source; mrneans for filtering the measurement outgoing light from tile measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions, the means for filtering being operatively associated with the light source(s) and/or the at least one detector; and means for determining the first parameter(s) from the signals, thile means for determining being operatively associated with the detector.

7 Typically the light absorbing background is a black background which may be a flat matt black background.

Typically: there are at least two detectors, to enable each measurement spectrally different outgoing light portion to be detected by a different detector at the same time or at different times, and generating signals therefrom whereby the signals are a function of the first parameter(s).

Typically the means for filtering is selected from the group consisting of means for spectral filtering and means for temporal filtering.

Typically the measurement outgoing light is light reflected from said object in said measurement interaction.

The apparatus may further comprise: means for outputting a first parameter(s) signal(s) which is a function of' the first 4:44 parameter(s) the means for outputting being operatively associated with means for is determining the first parameter(s).

The apparatus may further comprise: means for determining from the first parameter whether the object is an acceptable object or an unacceptable object, the means for determining being operative associated with the means for determining the first parameter(s).

20 According to another embodiment of this invention there is provided an apparatus S: for determining a first parameter(s) of an object, comprising: means for locating the object in a measurement interaction volume(s); a light absorbing background operatively associated with the measurement interaction volume(s); a light source(s) for passing a measurement light beam(s) through the measurement interaction volume(s) to interact with the object to produce measurement outgoing light; means for filtering the measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions, the means for filtering being operatively associated with the light source(s);

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WO 95/29396 PCT/AU95/00250 a detector(s) to detect the at least two measurement spectrally different outgoing light portions and to generate signals therefrom, whereby the signals are a function of the first parameter(s), the detector(s) being operatively associated with the means for filtering; and means for determining the first parameter(s) from the signals, the means for determining being operatively associated with the detector(s).

The measurement light beam may be focused or unfocused.

According to a further embodiment of the invention there is provided an apparatus for determining a first parameter(s) which ;s a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, comprising: means for locating the fibre in a measurement interaction volume(s) having a black light absorbing background; a light source(s) for passing a measurement light beam(s) through the measurement interaction volume(s) to interact with the fibre to produce measurement outgoing light reflected from the fibre; means for filtering the reflected measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions, the means for filtering being operatively associated with the light source(s); a detector(s) to detect the at least two measurement spectrally different outgoing light portions and to generate signals therefrom whereby the signals are a function of at least one parameter(s) selected from the group consisting of the diameter of the fibre and the colour of the fibre the detector(s) being operatively associated with

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the means for filtering; and means for determining from the signals a first parameter(s) which is a function of at least one parameter(s), the means for determining being operatively associated with the detector(s).

This apparatus may further include: PCT/AU95/00250 WO 95'29396 9 means for outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

According to another embodiment of this invention there is provided an apparatus for determining a first parameter(s) of an object, comprising: means for locating the object in a measurement interaction volume(s); a light absorbing background operatively associated with the measurement 4 interaction volume(s); a light source(s) for passing a measurement light beam(s) through the measurement interaction volume(s) to interact with the object to produce measurement outgoing light; a detector(s) to detect the measurement outgoing light from tile measurement interaction volume(s) and for generating at least two different measurement signals therefrom, each of said signals corresponding to a spectrally different portion of the measurement outgoing light, whereby the signals are a function of the first parameter(s), the detector(s) being operatively associated with the light source(s); and means for determining the first parameter(s) from the signals, the means for determining being operatively associated with the detector(s).

According to a further embodiment of the invention there is provided an apparatus for determining a first parameter(s) which is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn, comprising: k means for locating the fibre in a measurement interaction volume(s) having a black light absorbing background; a light source(s) for passing a measurement light beam(s) through the measurement interaction volume(s) to interact with the fibre to produce measurement outgoing light reflected from the fibre; a detector(s) to detect the measurement outgoing light from the measurement interaction volume(s) and for generating at least two different measurement signals therefrom, each of said signals corresponding to a spectrally different portion of the measurement outgoing light, whereby the signals are a function of at least one WO 95/29396 PCT/AU95/00250 parameter(s) selected from the group consisting of the diameter of the fibre and the colour of the fibre, the detector(s) being operatively associated with the light source(s); and means for determining from the signals a first parameter(s) which is a function of the at least one parameter(s), the means for determining being operatively associated with the detector(s).

Ti his apparatus may further include: means for outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

The measurement light beam may be focused or unfocused.

I 'i Typically the first parameter(s) is or is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn.

S The object may be a fluid or solid or other form 'of matter. Typically the object is a yarn. Examples of objects include mineral objects, such as diamonds and other crystals, organic and inorganic contaminants, fibrous objects, randomly shaped objects, spherical objects or cylindrical objects. Typically the objects are fibrous objects including woven or twisted fibrous objects. The fibrous objects may be synthetic fibres or natural fibres, particularly dyed fibres, a textile product such as a strand, filament or yarn. The fibres or strands may be fibreglass fibres or strands hessian fibres or Sstrands nylon fibres or strands glass fibres or strands polnosic and polyester fibres Sor strands alpaca fibres or strands silk fibres or strands jute fibres or strands flax y and cellulose fibres or strands (including paper, recycled paper, corn stalks, sugar cane, wood, wood shavings, bagasse, wood chips), string, regenerated fibres or strands such as viscose, rayon, cuprammonium rayon and cellulose acetate, sisal fibres or strands carbon fibres or strands stainless steel fibres or strands vegetable fibrous material, polyolefin fibres or strands such as polyethylenes and polypropylene, steel fibres or strands boron fibres or strands copper fibres or strands brass fibres or strands other metal fibres or strands teflon fibres or stands dacron fibres or strands mylar fibres or strands aluminium fibres or strands aluminium alloy fibres or strands polyamide fibres or strands polyacrylic fibres or strands or absorbent 11 m ni a z i a 11 fibres or strands such as nylon 66, polyacrylonitrile, or polyvinyl alcohol and absorbent types of polyesters or polyacrylics, edible vegetable fibres or strands, such as wheat fibres or strands, or inedible vegetable fibres or strands, such as wood pulp or cotton fibres or strands, animal fibres or strands, such as meat fibres or strands, wool fibres or strands B such as wool fibres or strands from sheep, hairs, such as human hairs, goat hairs, cattle hairs, or feathers, yarns including wool and cotton yarns (especially dyed wool, rabbit hair, kangaroo fur, mohair and cotton yarns), string, wire, optical fibres or strands for example. f Typically the object is selected from the group consisting of a fibre and a yarn, and the first parameter(s) is selected from the group consisting of the diameter of the fibre, the difference between the diameter of the fibre and the diameter of a reference fibre, a ratio 0: of the instantaneous diameter of the fibre divided by a running average diameter of the fibre, the colour of the fibre, the difference between the colour of the fibre and the colour o of a reference fibre, a ratio of the instantaneous colour of the fibre divided by a running average colour of the fibre, the diameter of the yarn, the difference between the diameter of the yarn and the diameter of a reference yarn, the colour of the yarn, a ratio of the Sm instantaneous colour of the yarn divided by a running average colour of the yarn, and the difference between the colour of the yarn and the colour of a reference yarn.

More typically the object is selected from the group consisting of a wool fibre and a 20 wool yarn, and the first parameter(s) is selected from the group consisting of the diameter of the wool fibre, the difference between the diameter of the wool fibre and the diameter of a reference fibre, a ratio of the instantaneous diameter of the wool fibre divided by a running average diameter of the wool fibre, the colour of the wool fibre, the difference between the colour of the wool fibre and the colour of a reference fibre, a ratio of the instantaneous colour of the wool fibre divided by a running average colour of the wool fibre, the diameter of the wool yarn, the difference between the diameter of the wool yarn and the diameter of a reference yarn, a ratio of the instantaneous diameter of the wool yarn divided by a running average diameter of the wool yarn, the colour of the wool yarn, a ratio of the instantaneous colour of the wool yarn divided by a running average colour of the wool yarn, and the difference between the colour of the wool yarn and the colour of a reference yarn.

Typically in the apparatus of the invention the means for determining the first parameter(s) is selected from the group consists of means for determining the diameter of the fibre, means for determining the difference between the diameter of the fibre and the diameter of a reference fibre, means for determining a ratio of the instantaneous diameter of the fibre divided by a running average diameter of the fibre, means for determining the colour of the fibre, means for determining the difference between the colour of the fibre and the colour of a reference fibre, means for determining a ratio of the instantaneous olour of the fibre divided by a running average colour of the fibre, means for etermining the diameter of the yarn, means for determining the difference between the IRlUil n.no 12 diameter of the yarn and the diameter of a reference yarn, means for determining the colour of the yarn, means for determining a ratio of the instantaneous colour of the yarn divided by a running average colour of the yarn, and means for determining the difference between the colour of the yearn and the colour of a reference yarn.

Typically in the apparatus of the invention the means for determining the first parameter(s) is selected from the group consists of means for determining the diameter of the wool fibre, means for determining the difference between the diameter of the wool fibre and the diameter of a reference fibre, means for determining a ratio of the instantaneous diameter of the wool fibre divided by a running average diameter of the lo1 wool fibre, means for determining the colour of the wool fibre, means for determining the difference between the colour of the wool fibre and the colour of a reference fibre, means f or determining a ratio of the instantaneous colour of the wool fibre divided by a running average colour of the wool fibre- means for determining the diameter of the wool yarn, means for determining the difference between the diameter of the wool yarn and the 1ir diameter of a reference yarn, means for determining a ratio of the instantaneous diameter of the wool yarn divided by a running average diameter of the wool yarn, the colour of the wool yarn, means for determining a ratio of the instantaneous colour of the wool yarn divided by a running average colour of the wool yarn, and means for determining the differece between the colour of the wool yarn and the colour of a referec an z The first parameter(s) may be shape, diameter, area, chemical composition, colour, 9 number of parts, thickness, width, absorptivity, reflectivity, fluorescence, surface INALIBH100138HRB WO 95/29396 PCT/AU95/00250 texture or other surface detail, or surface roughness, or a change in any one of the foregoing, for example. In the case of a fibrous object for example the first parameter may be diameter and/or colour or change therein, for example.

The light source(s) may be coherent, partially coherent or incoherent and can provide a UV light, visible light, infrared light or far infrared light. Generally the light source(s) is polychromatic and emits light of at least two different wavelengths in the range of and including far UV to far IR. Alternatively, at least two different narrow band light sources may be used each narrow band light source emitting light of a wavelength in the range of and including far UV to far IR the wavelength emitted by one of the S 10 source(s) being different from the wavelength emitted by the other source(s).

Examples of light sources include incandescent sources, such as tungsten filament source, vapour lamps such as halogen lamps including sodium and iodine vapour lamps, discharge lamps such as xenon arc lamp and Hg arc lamp, solid state light sources such as photo diodes, super radiant diodes, light emitting diodes (LEDs), laser diodes, electroluminescent light sources, frequency, doubled lasers, laser light sources including rare gas lasers such as an argon laser, argon/krypton laser, neon laser, helium neon laser, xenon laser and krypton laser, carbon monoxide and carbon dioxide lasers, metal ion lasers such as cadmium, zinc, mercury or selenium ion lasers, lead salt lasers, metal vapour lasers such as copper and gold vapour lasers, nitrogen lasers, ruby lasers, iodine lasers, neodymium glass and neodymium YAG lasers, dye lasers such as a dye laser employing rhodamine 640, Kiton Red 620 or rhodamine 590 dye, and a doped fibre laser. The light source may be a pinhole light source. The light SV source may comprise an optical fibre, the exit end of which may effectively act as a pinhole source.

S 25 Typically light in the wavelength range 390nm to 800nm is used as the measurement light beam(s). The measurement light beam(s) contains least two different wavelengths (typically 2-5 different wavelength bands) of light either simultaneously or sequentially. For example, the measurement light beam(s) may be white light or broad band light or light having several different wavelength bands. Typically, light having at least three wavelength bands (the measurement light beam(s) typically is provided by a single light source or multiple light sources), typically three different wavelength bands selected from the group consisting of a red band, an orange band, a green band, a if WO 95129396 PCT/AU95/00250 14 yellow band, a purple band and a blue band, more typically a red band, a green band and a blue band.

The light beam(s) may be collimated, diverging or converging. The optical fibres may include glass or plastic elements or a combination of these. The light guide can be a single mode or multimode optical fibre. The light guide may be a fibre bundle.

Portions of the source and detector light guides may be portions of the same light guide.

The detector(s) may comprise a single detecting element or an array of detecting elements. The detector(s) may comprise an optical fibre(s) coupled to a detecting element(s).

Examples of the measurement of the outgoing light include: filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands each band being detected by a different detector at the same time or at different times or by che same detector at different times; filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands each band being detected by the same detector at different times.

Examples of light source/filter/detector configurations include: A single white light source 3 different colour band filters 3 different detectors, each detector detecting a different colour band; (ii) Three different colour band light sources (eg red, green and blue LEDs) 3 different colour band filters (red, green and blue filters) 3 different detectors, each detector detecting a different colour band; (iii) Three different colour band light sources in time sequence (eg red, green and blue LEDs) 1 detector time multiplexed to detect the different colour bands; (iv) Three different colour band light sources operating at three different frequencies (eg red, green and blue LEDs) 1 detector 3 frequency filters to spectrally filter each different colour band and to output signals related thereto at least one detector to detect the outputted signals.

j- PICT/AU95/00250) WO 95/29396U95/0250 A single white light source n different colour band filters n different detectors, each detector detecting a different colour band, where n is typically 2 more typically 2-10 and even more typically (vi) N different colour band light sources (eg red, green and blue LEDs) n different colour band filters (red, green and blue filters) 4- different detectors, each detector detecting a different colour band, where n is typically 2 -20, more typically 2and even more typically (vii) N different colour band light sources in time sequence (eg red, green and blue LEDs) 1 detector time multiplexed to detect the different colour bands, where n is typically 2 -20, more typically 2-10 and even more typically 2-5; and (viii) N different colour band light sources operating at n different frequencies (eg red, green and blue LEDs) 1 detector n frequency filters to spectrally filter each different colour band and to output signals related thereto at least one detector to detect the outputted signals, where n is typically 2 -20, more typically 2-10 and even more typically The apparatus may include means to pass the object through the interaction volume(s), the means to pass being operatively associated with the means for locating. The means to pass may be a fibre winder such as a yarn (especially wool based yarn) or cotton winder, a sample carrier such as a light absorbing (eg black) conveyer strip, a sample holder on a linear stage. The apparatus may comprise a scanner operatively associated with the light source(s) and/or the object and/or the sample carrier to scan the light beam relative to the object in the interaction volume(s). Alternatively, the object may be scanned relative to the light beam or both the object and light beam may be scanned simultaneously (the measurement may also be one in which neither the object or light beam is scanned relative to one another). The scanner may be a piezo-electric stack, a magnetic core/magnetic coil combination, a mechanical vibrator, an electromechanical vibrator, a mechanical or electromechanical scanning mechanism such as a servomotor, an acoustic coupler electrooptic scanning means or any other suitable means.

The light source(s) may include a light dellector(s) located between the source and the interaction volume(s) wherein a portion of the light beam(s) passes through the deflector(s) and whereby the detlector(s) is operatively associated with the source to y WO 95/29396 PCT/AU95/00250 16 alter the shape, size, wavelength, intensity, polarisation, phase, direction of travel or focus of at least a portion of the light beam(s) in the interaction volume(s).

There may be disposed in the path of the outgoing light between the interaction volume(s) and/or the detector(s), a second light deflector wherein the outgoing light passes through the second deflector which alters the size, shape, intensity, polarisation, phase, direction of travel, focus for example, The first and second light deflectors may include light focusers or light reflectors. The focuser may be refractive lenses, including microscope objectives, reflective lenses, and/or holographic optical elements. If the light is of a frequency other than in the range of UV to near infrared light or other types of energies, analogous focusing elements are used in place of the optical focusing elements. The reflector may be a mirror or partially silvered mirror, a beam splitter including a polarisation dependent beam splitter, light waveguide splitter (eg an optical fibre coupler) or a wavelength dependent beam splitter, for example. The optical fibre coupler may be a fused biconical taper coupler, a polished block coupler, -a bottled and etched coupler or a bulk optics type coupler with fibre entrance and exit pigtails, a planar waveguide device based on photolithographic or ion-diffusion fabrication techniques or other like coupler. The interaction is typically one or a combination of refraction, diffraction, reflection, scattering, fluorescence, stimulated emission, incandescence, shadowing, polarisation rotation, phase retardation and other polarisation effects, occlusion, optical absorption, interference effects, sum frequency generation, one giving rise to a diffraction pattern, refraction, phase alteration, second, third or fourth harmonic generation, difference frequency generation, optical bistability, self bleaching, Raman scattering or Brillouin scattering. A nonlinear reaction can be involved as a result of heating, refractive index change, charge build-up or charge migration.

The measurement outgoing light may be intensity modulated (including spatially or temporally dependent intensity modulation such as intensity peaks or troughs as or not as a function of time), amplitude, wavelength or frequency modulation, phase, polarisation, wavelength, direction of travel, for example. The detector(s), the means for determining the first parameter(s), and/or the means for locating may comprise a calculator which may include optical, electrical, optoelectronic, mechanical or magnetic elements, for example, or may include such techniques as optical and/or 4 WO 95/29396 i1IAU/O2) electrical hieterodynn, (luadl ritnre operation, multi area detectors or phase lock loop techniques, for examrpke. 'Uho mleans fr (leermifling the, first, parame-ter(s) may log., andl arats a signal(s) Irom thv. (etwcor(s) or may log and anialyse thle first paramleter(s).

The dletector(s) maiy comprise ain array of detecting elements and/or apertures, An 1 aperture in the aray may he, a light entrance portion of an lighit pwl toclect portion of the, outgoing lighlt, and go iide it to the detector(s).

~detecting element in the array may phiotodiodo, lphotomlt ti p1 ir, part of ccd array or the like. The! array may he a one or two dIimensionalI array or- a planar array.

The meastiremen on tgoi ng i gh t is not occlt led light. Tlyp~icallIy the0 measu rement.

t0 outgoing light is lighit reflected frmt thle object.

Where the firs~t Pariamewtr to he me1aSU edT (lda mleter, tLhe Itt ocuon me~aSttred is a chiange in amplitude of 1,1 lenire Sped,111 01' in C of te tasutrement, outgoingp light. Where teF stlal'mei toh'eaord is colonur, thle Iunction measuirel is a, change in thle shape of thle sptrI. on lrerrl lrtns of' the method and apparatsoh 11 invention rel y onl the facet that the viI e of thle first parameloter(s) of the ob~ect. beingp examine is mo t adeired or within a desired range of' values so that the frequency of tunacceptable fi rst, parameter(s) values does nlot, significantly alter thle average first paramleter(s) Vaitne That, is when the dianmeter of a (libre, strand, yarn, etc. is being measutred, for' example, thle houlk of* the fibres arc thle desired (diameter and colour andl thle major pat of each fibres length is the (desired diameter or within an acceptable diameter range, The mleanls for dletermining thle first, parameter(s) typically includes digital and/or analogue processtng, The mieans for locating may comprise aI timer and/or a cotunter, Met h odology The method and apparatus of thie invention may determine thle fIrst parameter by comparison with a ktnowni rference or dliscri miniatiotn may be (lone onl a relaitive basis.

The basis for determining parameter variation iti an object is as follows.

3u An object 0 will typically have a number of measturtable paranieters prI where n 2, i, k, Taie, for example, the case where it is desired to mecasure whether WO 95/29396 PCT/AU95/00250 there is a variation in at least one of parameters pn. For parameter pn the intensity of light Ir for a given wavelength or band of wavelengths, Xn reflected from 0 at position x along its length is a function Fn of 0 and x thus: 1,i, W= &Ox) 1.1 In the case of no variation in p)n along thre length x of 0 we have: dx a 1.2 Where the average over length of function F is denoted by F and there is no variation in pn the following obtains: 1.3

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Hence for no variation in pn: 1.4 j Where there is variation in pn: d0 I 0 1.6

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1( 0 )1.7 Where the object 0 is being moved through the measurement volume the variable t for time may be substituted for the variable x for position.

It is apparent from equations that a conditional test or tests can be applied, if required at this stage, to determine variation in a particular pn, namely, Apn such as, for example, a test to ascertain whether Apn is within a desired range or not. One such test may be conducted by comparing lr(Xn) for a given measurement with a reference value which may advantageously be a running average based on a temporal average 19 measurement. Alternatively this reference may be based on a spatial average or a fixed reference.

There are a number of advantages in using a running average based on a temporal measurement namely: One detector assembly gets signals to set up a reference and measure an instantaneous or point value. There is no need for dual assemblies adaptation and measurement of parameters.

The reference signal generated from a running average will adapt to the parameters normal to the object being measured.

The parameter pn may be a combination of effects at several different wavelengths or bands thus: Pn 1.8 where the factors kn, j are specific to this parameter. The average value of pn is denoted S by Pn 2By comparing pn with P17~ a conditional test(s) may be applied 'to ascertain whether Ani is within adsrdrange or not, 2 One particularly advantageous way of determining an average value of F(O,x) is to significant length of that object.

One particular embodiment of this invention provides an apparatus to provide a number of signals from an object(s) such as fibre(s), for example. These signals are generated by illuminating the fibre(s) and sensing the reflected energy at particular bands of the visible spectrum. These signals may be generated by using light sources of different wavelengths or wavelength bands switched on repeatedly at separate times or in aknown pattern of times and detecting the signals with a single detector. This method gives a time series signal that contains the relevant information. This time series signal is then repeatedly sampled and stored at the appropriate times to give a parallel form of :3o data.

INALUBHI1a138:RRB WO 95/29396 PCT/AU95/00250 An alternative method is to illuminate an object(s), such as a fibre(s), with white light or light containing several wavelength bands, from one or more light sources, and sense the energy reflected in the different bands by using a number of detectors with selected filters in front of each detector. This method gives the relevant information in a parallel form.

Given the signal(s) in their parallel form, the following relationships can be seen. Let Bl,B2...Bn represent the light energy detected in the visible bands 1 to n. Diameter of fibre(s) is proportional to the sum total of energy sensed in each band if colour is constant or there is not a significant shift in overall colour: Fibre(s) (diameter) reflectivity 1.9 By integrating equation 1.9 over a significant area (or period of time tl...t2) of fibre(s) one can obtain an average value for the fibre which will be related to the "normal" diameter of the fibre(s). By dividing this normal (average) value into the instantaneous value we obtain a signal which is independent of the illumination intensity and fibre(s) diameter If the current area being measured is of "normal" diameter then this ratio approximates unity and is stable. If we get an "evenness" variation this ratio will vary from unity by an amount proportional to the size of the diameter variation.

F 1 I r I (Diameter) Reflectivity Variation L 1 J- 1.10 By comparison of this variation to a settable reference an output can be generated that will indicate if an "evenness" fault exists.

In a practical embodiment of this invention there will typically be a finite number of bands used. In a particular application the required sensitivity to detection of colour WO 95/29396

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PCTAU95/00250 1. 5 defects will determine the number of bands the higher the resolution of colour that is required the larger the number of different coloured bands that are detected).

By comparing the proportional energy in each band to that in other bands a "signature" of the present colour can be obtained. One example of this is shown in the following relationship for a three band system: B 3 B, Colour B, B 1.11 By integrating equation 1.11 over a significant area (period of time tI...t2) of fibre(s) one can obtain a value of the "normal" colour of the fibre(s). By dividing this normal value into the instantaneous value one can obtain a signal which is independent of the illumination intensity and fibre(s) diameter. If the current area being measured is "normal" colour then this ratio approximates unity is stable. If one gets a colour variation this ratio will vary from unity by an amount proportional to the size of the colo,.r variation: Fibre(s) (diameter) reflectivity Li 1.12 By comparison of this variation to a settable reference, an output signal can be generated that will indicate if an colour fault exists, Another method for analysis of these signals for colour analysis may be done by examination of the ratio of energy in each band to the average or finite int 'al of the total energy reflected, denoted BRi. For a system using n bands we can get n normalised signals that can be compared to a reference learnt from a running time or space average. For a system using n bands the following equation for BRi can be used: F 1 81,a I 1.13 After each of these ratios are produced, comparisons can be made to a reference value, which may be a fixed value or a settable proportion of the learnt average. The output of these comparators are combined so a change in any one or more bands will produce a digital signal that can be passed to another apparatus.

SWO 95129 PCT/AU95/00250 WO 95/29396 22 When the diameter and colour of a fibre are being measured each of the resultant signals from the detector(s) has the following components embedded in it: Incident light colour temperature intensity (undesirable component); Sa* Incident light angle, (undesirable component) diameter of the fibre(s) being examined; colour of the fibre(s) being examined.

The signals are ratioed in such a way as to eliminate the undeirable components of the signals and the diameter, This ratio technique allows for a more robust design of the system. Doing spectral analysis gives the potential for greater sensitivity hence more i 10 effective detection of colour faults, This method and apparatus of the invention may incorporate the ability to learn the colour and/or diameter signatures of the fibre and adapt to slow variations to the normal colour and/or diameter.

Particular embodiments of the method and apparatus of this invention can determine if the current section of fibre(s) within the apparatus is within tolerance for the following parameters on undyed fibre(s) or dyed fibre(s): Fibre(s) diameter for determining 'evenness' or linear density variations.

Visible presence of fibre(s) or other material that has not absorbed the dye or is pigmented or stained to a different colour to that of the undyed fibre(s) and as such is determined to be a contaminant.

This particular method and apparatus can work regardless of the colour of the dye used on the fibre(s), When a fibre(s)'s parameters are determined to be outside tolerance a signal is typically passed to another apparatus which will enable that apparatus to take appropriate action, Typically the tolerance is variable can be set by external means, Particular embodiments of the method and apparatus of this invention can determine if the current section of fibre(s)/yarn contains the following: Differently coloured contaminants and/or foreign bodies in the fibre(s) or yarn including differently coloured foreign fibres, Differently coloured fibres or yarn in fibre(s) and yarn including differently coloured foreign fibres or foreign yarn.

WO 95/29396 PCT/AU95/00250 O 23 In the apparatus employing this method the functions are designed to be the energy levels reflected by the yarn in each of the spectral bands of interest. These signals are summed to generate a signal proportional to the diameter of the fibre(s) being measured. By employing a lowpass filter which approximates an definite integral function, a signal proportional to the running average of the fibre(s) being measured is generated. If the assumption is made that the fibre(s) are mostly the correct colour the this running average will learn the correct diameter. By dividing this learnt diameter into the instantaneous measured value of diameter variations of diameter or linear density can be detected.

Using the functions Ir(%n) and comparing the proportional contribution to the sum a measure of intensity in each band is obtained. This measurement is independent of the diameter. By employing a lowpass filter which approximates an definite integral tunction, a signal proportional to the running average of the proportional contribution of each band can be obtained. If the assumption is made that the fibre(s) are mostly the correct colour the this running average will learn the correct colour. By dividing this learnt colour into the instantaneous measured value of colour variations of colour can be detected.

By logical comparison of these variations of instantaneous measured diameter and colour to the learnt running average of diameter and colour variation or diameter variation can be measured.

BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a block diagram of a first apparatus for determining a change in diameter Sand change in colour of a yarn; Figure 2 is a block diagram of a second apparatus for determining a change in diameter and change in colour of a yarn; Figure 3 is a plot of the signal taken from line 124 (of the apparatus of Figure 1); Figure 4 is a plot of the signal taken from line 124 (of the apparatus of Figure 1) after temporal filtering; Figures 5, 6 and 7 are plots of the signals taken from lines ll, 112 and 113 (of the apparatus of Figure 1) respectively; I W s/29396 PCT/AU95/00250 24 Figures 5a, 6a and 7a are unscaled plots showing the proportion of signal that each of the detected red, blue and green bands contributed to the total signal depicted in Figure S3 or 4; and Figures 8, 9 and 10 are plots of the signals taken from line 213 (which carries the signal corresponding to the temporal sequence of reflected light energy) in an experiment using the configuration of Figure 2 showing the sequence of colour variation on red, yellow and blue yarns respectively.

iBEST MODE AND OTHER MODES FOR CARRYING OUT THE INVENTION Referring to Figure I an apparatus 1000 for determining a change in diameter and S 10 change in colour of a yarn 101 is depicted. Apparatus 1000 includes a light absorbing background 100 which generally comprises a flat black surface (or a flat matt black surface) to substantially uniformly absorb light falling thereon. Yarn guides 150 and 151 are adjacent to one another but are located a distance defining the measurement interaction volume, apart from yarn guides 152 and 153. Both sets of yarn guides 150 and 151 and 152 and 153 are disposed in close proximity to background 100 to locate and guide yarn 101 in such a way that when yarn 101 passes there between it does so in a direction which is substantially parallel to background 100 with the result that the distance between yarn 101 and background 100 is substantially constant. Light source 120 is located so as to direct a measurement light beam(s) through the measurement interaction volume(s) to interact with yarn 101 and thence to produce measurement outgoing light reflected from yarn 101.

Broad band width light source 120 is typically an incandescent tungsten filament globe.

SFilters 102, 103 and 104 are located relative to source 120 so as to spectral filter the reflected measurement outgoing light from the measurement interaction volume(s) after interaction with yarn 101 into three measurement spectrally different wavelength bands 105, 106 and 107 respectively (for example filter 102 may pass 400-500nm light, filter 103 may pass 500-650nm light and filter 101 may pass 650-800nm light).

Photodetectors 108, 109 and 110 are located behind filters 102, 103 and 104 respectively to respectively detect measurement spectrally different wavelength bands 105, 106 and 107 and to generate signals therefrom whereby the signals are a function of at least the diameter of the yarn and the colour of the yarn. Apparatus 1000 includes means for determining from the signals from photodetectors 108, 109 and 110

I,'

parameters which are functions of the diameter of yarn 101 and the colour of yarn 101.

The means for determining includes temporal filters 114, 115 and 116, which are respectively coupled to photodetectors 108, 109 and 110 via lines 111, 112 and 113, signal processing unit 125 which is coupled to photodetectors 108, 109 and 110 via lines 111 and lila, 112 and 112a, and 113 and 113a respectively, summing amplifier 123 which is coupled to photodetectors 108, 109 and 110 via lines 111, Illa and 111b, 112, 112a and 112b, and 113, 113a and 113b respectively and which is coupled to output lin- 124, reference voltage generator 121 which is coupled to summing amplifier 123 via line 122, and difference discriminator 126 having output lines 129 and 130 and which is lo coupled to signal processing unit 125 via lines 127 and 128. Line 124 is coupled to signal processing unit 125 via line 124a. Temporal filters 114, 115 and 116 are coupled to S signal processing unit 125 via lines 117, 118 and 119 respectively. Lines 117, 118 and S 119, lines 112, 112a and 112b, and lines 113, 113a, and 113b respectively carry electrical signals proportional to the current energy resulting from photodetection wavelength bands 1o 5 105, 106 and 107 Lines 117, 118 and 119, respectively carry electrical signals i corresponding to the running average energy resulting of wavelength bands 105, 106 and 107. Line 122 carries a reference voltage signal from reference voltage generator 121 to summing amplifier 123. Lines 124 and 124a carry an electrical signal proportional to the diameter of yarn 101. Line 127 carries an electrical signal corresponding to the colour 20 variation in yarn 101. Line 128 carries an electrical signal corresponding to the diameter i: variation in yarn 101. Line 129 carries a digital electrical signal which is indicative of whether the measured colour variation of yarn 101 is acceptable or not. Line 130 carries a digital electrical signal which is indicative of whether the measured diameter variation of yarn 101 is acceptable or not. These digital electrical signals are passed to item 131 which is an external device to initiate the removal contaminate or colour faults.

In use yarn 101 is guided under tension by yarn guides 150 and 151 and 152 and S153 in a direction substantially parallel to background 100 such that the distance between yarn 101 and background 100 is substantially constant. Yarn guides 150, 151, 152 and 153 define the measurement interaction volume in this embodiment of the invention.

During the measurement, light source 120, filters 102, 103 and 104 and photodetectors 108, 109 and 110 are in fixed positions relative to background 100. Broad band light 400-800nm) emitted from source 120 is directed to yarn 101. Typically during the measurement, yarn 101 is moving so the measurement is a progressive one along its axis.

The majority of light :L21 (N:LIBH100138:RR B 4" PCT/AU95/00250 WO 95/29396 26 energy from souivce 120 is absorbed by background 100. A small part of the light energy from source 120 interacts with fibre 101 and is reflected back to the spectral filters 102, 103 and 104. Filter 102 passes a band of 400-500nm light, filter 103 passes a band of 500-650nm light and filter 104 passes a band of 650-800nm light.

Photodetectors 108, 109, 110 respectively create electrical signals that are proportional to the energy reflected by yarn 101 in the respective bands. These three signals are sent to summing amplifier 123 via lines 111, 11 la and 11 lb, 112, 112a and 112b, and 113, 113a and 113b, respectively. Tile three signals and a reference signal from reference voltage generator 121 via line 122 are summed by summing amplifier 123 to produce an electrical signal proportional to the measured diameter of yarn 101 in accordance with equation 1.9 which is output to lines 124 and 124a. The three signals are also passed to temporal filters 114, 115, 116 via lines 111, 112 and 113 respectively. These,, temporal filters approximate the definite integral used in the denominator of equation 1.10. Each of these filters output a signal corresponding to the running average of the energy reflected by yarn 101 in the respective bands. These latter signals are carried respectively on lines 117, 118, 119 to signal processing unit 125.

Signal processing unit 125 is composed of operational amplifiers and analogue dividers connected in such a fashion as to perform the functions described by equations 1.10, 1.11 and 1.12. Alternatively signal processing unit 125 may be connected to perform the functions described by equations 1.10, 1.12 and 1.13. Signal processing unit 125 takes the input signals from lines I I1 and II Ia, 112 and 112a, and 113 and 113a and running average signals from lines 117, 118 and 119 and combines these with the signal from line 124a to produce output signals via lines 127 and 128 which are respectively proportional to the difference between current and mean values of colour (line 127) and diameter (line 128). The processing to produce difference between current and mean values of diameter is done in accordance with equation 1.10 to produce a diameter variation signal which is output via line 128. The processing to produce difference between current and mean values of colour is done in accordance with equation 1.12 or 1.13 to produce a colour variation signal which is output via line 127.

Difference discriminator 126 consists of operational amplifiers and comparators and reference generators connected in such a manner so as to perform test described by La-i -WO 95/29396 *I WO 95/29396 PCT/AU95100250 equations 1.3 to 1.7. Difference discriminator 126 which processes the signals from lines 127 and 128 by comparison with the references, to output a digital electrical signal to line 129 which is indicative of whether the measured colour variation of yam 101 is acceptable or not and output a digital electrical signal to line 130 which is indicative of whether the measured diameter variation of yarn 101 is acceptable or not.

These digital electrical signals are passed to external device 131 to initiate corrective action.

Referring to Figure 2 an apparatus 2000 for determining a change in diameter and change in colour of a yarn 201 is depicted. Apparatus 2000 includes a light absorbing background 200 which generally comprises a flat black surface to substantially uniformly absorb light falling thereon. Yarn guides 250 and 251 are adjacent to one another but are located a distance defining the measurement interaction volume, apart from yarn guides 252 and 253. Both sets of yarn guides 250 and 25 1 and 252 and 253 are disposed in close proximity to background 200 to locate and guide yarn 201 in such a way that when yarn 201 passes there between it does so in a direction which is substantially parallel to background 200 with the result that the distance between yarn 201 and background 200 is substantially constant. Light source 220 is located so as to direct a measurement light beam(s) through the measurement interaction volume(s) to interact with yarn 201 and thence to produce measurement outgoing light reflected from yarn 201.

The light sources 202, 203 and 204 are typically light emitting diodes with differing predominant wavelengths in the visible spectrum. Their spectral bandwidth is such that the visible spectrum is covered with minimum overlap. These light sources are illuminated sequentially by sequencer 206 controlled by line 208 from oscillator 207.

Line 209 connects to demodulating unit 220.

Detector 205 is located relative to sources 202, 203 and 204 so the reflected measurement outgoing light from the measurement interaction volume(s) after interaction with yarn 201 is converted to an electrical signal carried on line 213. Line 213 connects sample and hold units 210, 211 and 212. Sample and hold units 210, 211 and 212 are controlled by lines 215, 217 and 219 respectively. Sample and hold units 210, 211 and 212 hold the detected signal on lines 214, 216 and 218 respectively.

610.V I WO 95/29396 PCT/AU95/00250 28 Demodulation unit 220 controls sample and hold units 210, 211 and 212 via lines 215, 217 and 219 respectively. Demodulation unit 220 outputs lines 225, 221 and 222 to low pass filters 223, 224 and 225 respectively. Demodulation unit 220 also outputs lines 225a, 221a and 222a connected to signal processing unit 229. Signal processing unit 229 accepts signals on lines 225a, 221a and 222a from demodulation unit 220.

Signal processing unit 229 accepts signa' lines 226, a, 227 and 228 from low pass filters 223, 224 and 236 respectively., ignal processing unit outputs signal on lines 230, and 231 to discriminator 232. Discriminator unit 232 accepts signals on lines 230 and 231 from signal processing unit 229. External unit 235 accepts signal on lines 233 and 234 from discriminator unit 232 and signal on line 233 from signal processing unit 229 respectively.

In use yarn 201 is guided under tension by yarn guides 250 and 251 and 252 and 253 in a direction substantially parallel to background 200 such that the distance between yarn 201 and background 200 is substantially constant. During the measurement, light sources 202, 203 and 204 sequentially illuminate yarn 201 with light from different bands of the visible spectrum. During measurement light sources 202, 203 and 204, detector 205 are in fixed positions relative to background 200. Typically during measurement yarn 201 is moving so the measurement is a progressive one along its axis. The majority of light energy from light sources 202, 203 and 204 is absorbed by background 200. A small part of the light energy from sources 202, 203 and 204 interacts with yarn 201 and is reflected back to detector 205.

Typically oscillator 207 is running it a frequency fast enough with respect to the speed of axial movement of yarn 201 so the samples of reflected light from each of the bands are essentially spatially coii~cident. Sequencer 206 is composed of a counter and decoder to give three discrete outputs that are mutually exclusive in time. These outputs typically drive three switches to sequence light sources 202, 203 and 204.

Because the illumination of yarn 201 from light sources 202, 203 and 204 is sequential ie. only one source is turned on for a fixed time before the next source is turned on, detector 205 converts the reflected spectral time series to an electrical time series on line 213. Sample and hold units 210, 211 and 212 sample this electrical time series and store a signal proportional to the reflected energy in a particular band. These signal for each band are available on lines 214, 216 and 218. Demodulator 220 under the control WO 95/29396 PCT/AU95/00250 29 of sync signal on line 209, controls sample and hold 210, 211 and 212 on lines 215, 217 and 219 respectively. Demodulation unit 220 also contains operational amplifiers to compensate for signal and sensitivity at different parts of the visible spectrum. The signal outputs of demodulation unit 220 proportional to the energy reflected in each of the spectral band from yarn 201 are passed to low pass filters 223, 224 and 236 on lines 225, 221 and 222 respectively. These signals are also passed to signal processing unit 229 on lines 225,a 221a and 22a respectively.

Low pass filters 223, 224 and 236 approximate the definite integral function used in the denominator of equation 1.13. Signal processing unit 229 is composed of operational amplifiers and analogue dividers connected in such a fashion as to perform the functions described by equations 1.9, 1.10, 1.11 and 1.12. Alternatively signal processing unit 229 may be connected to perform thile functions described by equations 1.9, 1.10, 1.12 and 1.13. The signals l)roportional to parameters of colour and diameter are passed from signal processing unit 229 to discriminator unit 232 on lines 230 and 231 respectively.

Difference discriminator 232 consists of operational amplifiers and comparators and reference generators connected in such a manner so as to perform test described by equations 1.3 to 1.7. Difference discriminator 232 which processes the signals from lines 230 and 231 by comparison with the references, to output a digital electrical signal to line 233 which is indicative of whether the measured colour variation of yarn 201 is acceptable or not and output a digital electrical signal to line 234 which is indicative of whether the measured diameter variation of yarn 201 is acceptable or not.

These digital electrical signals are passed to external device 131 to initiate corrective action.

EXAMPLE 1 An experiment using the configuration of Figure 1 was conducted on a white yarn (yarn formed from natural wool fibres) with diameter variation at various positions along the yarn and having fibres of various non white colours twisted through thile white yarn at various positions along the yarn. Figure 3 is a plot of the signal taken from line 124 (of the apparatus of Figure I) which signal corresponds to thile sum of reflected light detected. Figure 4 is a plot of the signal taken from line 124 (of the apparatus of Figure 1) after temporal filtering, which temporally filtered signal corresponds to the sum of WO 95-29396 PCT/AU95/00250 reflected light detected. Figures 5, 6 and 7 are plots of the signals taken from lines 111, 112 and 113 (of the apparatus of Figure 1) respectively. Typically, these signals respectively correspond to the detected light after spectral filtering to give signals corresponding to detected red, detected green and detected blue light bands respectively.

Figures 5a, 6a and 7a are unscaled plots showing the proportion of signal that each of the detected latter bands contributed to the total signal depicted in Figure 3 or 4. By comparing the proportional energy in each band at a particular point along the yarn, where a white yarn is being measured, to that in other bands, at the same particular point, a "signature" of the white colour can be obtained. One example of this has been i) given in Equation 1. 11. By integrating equation 1.11 over a significant area (period of time tl...t2) of fibre(s) one can obtain a value of the "normal" colour of the fibre(s). By dividing this normal value into the instantaneous value one can obtain a signal which is independent of the illumination intensity and fibre(s) diameter. If the current area being measured is "normal" white colour then this ratio approximates unity is stable. If one gets a colour variation this ratio will vary from unity by an amount proportional to the size of the colour variation.

By comparison of this variation to a settable reference, an output signal can be generated that will indicate if an colour fault exists.

EXAMPLE 2 An experiment using the configuration of Figure 2 was conducted on red, yellow and blue yarns respectively. Figures 8, 9 and 10 are plots of the signals taken froin line 213 (which carries the signal corresponding to the temporal sequence of reflected light 4 energy) showing the sequence of colour variation on red, yellow and blue yarns respectively.

4 'Ir

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Claims (24)

1. A method for determining a first parameter(s) of an object, comprising: locating the object in a measurement interaction volume(s) having a light absorbing background; passing a measurement light beam(s) through the measurement interaction volume(s), said measurement light beam(s) comprising at least two spectrally different wavelengths of light; interacting the measurement light beam(s) with the object to produce measurement outgoing light; lu filtering the measurement outgoing light from the measurement interaction volume(s) into at least two meastrement spectrally different outgoing light portions; detecting the at least two measurement spectrally different outgoing light portions and generating signals therefrom whereby the signals are a function of the first parameter(s); and determining the first parameter(s) from the signals.

2. A method according to claim 1 wherein the object is selected from the group consisting of a yarn and a fibrous object, wherein: step comprises locating the object in a measurement interaction volume(s) having a light absorbing background which is a black background; step comprises interacting the measurement light beam(s) with the object to produce measurement outgoing light reflected from the object; and step comprises filtering the reflected measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions.

3. A method according to claim I wherein: step comprises filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands; step comprises detecting the at least two measurement spectrally different wavelength bands, each band being detected by a different detector at the same time or 32 at different times or by the same detector at different times, and generating signals therefrom whereby the signals are a function of the first parameter(s).

4. A method according to claim 1 wherein: step comprises filtering at least two different portions of the measurement outgoing light into at least two spectrally different wavelength bands; step comprises detecting the at least two measurement spectrally different wavelength bands, each band being detected by a different detector at the same time or at different times or by the same detector at different times, and generating signals therefrom whereby the signals are a function of the first parameter(s).

5. A method according to claim 1 wherein: step comprises locating the object in a measurement interaction volume(s) having a light absorbing background.

6. A method according to claim 1 wherein said measurement outgoing light of step is light reflected from said object in said measurement interaction volume.

7. The method of claim 2 wherein said filtering is selected from the group consisting of spectral filtering and temporal filtering.

8. The method of claim 1 further comprising: outputting a first parameter(s) signal(s) which is a function of the first parameter(s).

9. The method of claim 2 further comprising: outputting a first parameter(s) signal(s) which is a function of the first parameter(s). The method of claim 1 wherein step comprises detecting at least two measurement spectrally different outgoing light portions and generating signals therefrom which are related to the respective intensities of the at least two measurement spectrally different outgoing light portions whereby the signals are a function of the first parameter(s); and step comprises determining the first parameter(s) from the signals by comparing the signals with reference signals or reference values.

11. The method of any one of claims 1 to 10 further comprising: determining from the first parameter whether the object is an acceptable object or an unacceptable object.

12. The method of any one of claims 1 to 10 wherein the first parameter(s) is or is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn.

13. The method of any one of claims 1 to 10 wherein the object is selected from the group consisting of a fibre and a yarn, and the first parameter(s) is selected from the group consisting of the diameter of the fibre, the difference between the diameter of the fibre and the diameter of a reference fibre, a ratio of the instantaneous diameter of the P,4 fibre divided by a running average diameter of the fibre, the colour of the fibre, the ifference between the colour of the fibre and the colour of a reference fibre, a ratio of [N:\UBHIOO138:RRB V/ f~EEiiT~~d~~~ 33 the instantaneous colour of the fibre divided by a running average colour of the fibre, the diameter of the yarn, the difference between the diameter of the yarn and the diameter of a reference yarn, the colour of the yarn, a ratio of the instantaneous colour of the yarn divided by a running average colour of the yarn, and the difference between the colour of the yarn the colour of a reference yarn.

14. The method of any one of claims 1 to 10 wherein the object is selected from the group consisting of a wool fibre and a wool yarn, and the first parameter(s) is selected from the group consisting of the diameter of the wool fibre, the difference between the diameter of the wool fibre and the diameter of a reference fibre, a ratio of the instantaneous diameter of the wool fibre divided by a running average diameter of the wool fibre, the colour of the wool fibre, dhe difference between the colour of the wool fibre and the colour of a reference fibre, a ratio of the instantaneous colour of the wool fibre divided by a running average colour of the wool fibre, the diameter of the wool yarn, the difference between the diameter of the wool yarn and the diameter of a reference yarn, a ratio of the instantaneous diameter of the wool yarn divided by a running average diameter of the wool yarn, the colour of the wool yarn, a ratio of the instantaneous colour I of the wool yarn divided by a running average colour of the wool yarn, and the difference between the colour of the wool yarn and the colour of a reference yarn. An apparatus for determining a first parameter(s) of an object, comprising: means for locating the object in a measurement interaction volume(s); a light absorbing backgroind operatively associated with the measurement interaction volume(s); at least one light source for passing a measurement light beam(s) through the S measurement interaction volume(s) to interact with the object to produce measurement outgoing light, the measurement light beam(s) comprising at least two spectrally differetU wavelengths of light; at least one detector to detect the at least two measurement spectrally different outgoing light portions and to generate signals therefrom, whereby the signals are a function of the first parameter(s), the detector(s) being operatively associated with the light source; means for filtering the measurement outgoing light from the measurement interaction volume(s) into at least two measurement spectrally different outgoing light portions, the means for filtering being operatively associated with the light source(s) and/or the at least one detector; and means for determining the first parameter(s) from the signals, the means for determining being operatively associated with the detector.

16. An apparatus according to claim 15 wherein the measurement outgoing light of step is light reflected from said object in said measurement interaction volume.

17. An apparatus according to claim 15 wherein the light absorbing background is black background. -N IN:\LIBH 1001 3B:RRB m- 34

18. The apparatus according to claim 15 wherein: said apparatus includes at least two detectors, said at least two detectors permitting each measurement spectrally different outgoing light portion to be detected by a different detector at the same time or at different times, and generating signals therefrom whereby the signals are a function of the first parameter(s).

19. The apparatus of claim 15 wherein said means for filtering is selected from the group consisting of means for spectral filtering and means for temporal filtering. The apparatus of claim 15 further comprising: means for outputting a first parameter(s) signal(s) which is a function of the first parameter(s) the means for outputting being operatively associated with means for determining the first parameter(s).

21. The apparatus of claim 18 further comprising: means for outputting a first parameter(s) signal(s) which is a function of the first parameter(s) the means for outputting being operatively associated with means for determining the first parameter(s).

22. The apparatus of any one of claims 15 to 21 further comprising: means for determining from the first parameter whether the object is an acceptable object or an unacceptable object, the means for determining being operatively associated with the means for determining the first parameter(s).

23. The apparatus of any one of claims 15 to 21 wherein the first parameter(s) is or is a function of at least one parameter(s) selected from the group consisting of the diameter of a yarn, the diameter of a fibrous object, the colour of a fibrous object and the colour of a yarn.

24. The apparatus of any one of claims 15 to 21 wherein the object is selected from the group consisting of a fibre and a yarn, and the first parameter(s) is selected from 4 1the group consisting of the diameter of the fibre, the difference between the diameter of the fibre and the diameter of a reference fibre, a ratio of the instantaneous diameter of the fibre divided by a running average diameter of the fibre, the colour of the fibre, the difference between the colour of the fibre and the colour of a reference fibre, a ratio of the instantaneous colour of the fibre divided by a running average colour of the fibre, the diameter of the yarn, the difference between the diameter of the yarn and the diameter of a reference yarn, the colour of the yarn, a ratio of the instantaneous colour of the yarn divided by a running average colour of the yarn, and the difference between the colour of the yarn and the colour of a reference yarn.

25. The apparatus of any one of claims 15 to 21 wherein the object is selected from the group consisting of a wool fibre and a wool yarn, and the first parameter(s) is selected from the group consisting of the diameter of the wool fibre, the difference between the diameter of the wool fibre and the diameter of a reference fibre, a ratio of the R instantaneous diameter of the wool fibre divided by a running average diameter of the Svool fibre, the colour of the wool fibre, the difference between the colour of the wool j 4' n WW^l I-C~r*l-rP~-r;Uu~tl=;-~LI-~I fibre and the colour of a reference fibre, a ratio of the instantaneous colour of the wool fibre divided by a running average colour of the wool fibre, the diameter of the wool yarn, the difference between the diameter of the wool yarn and the diameter of a reference yarn, a ratio of the instantaneous diameter of the wool yarn divided by a running average diameter of the wool yarn, the colour of the wool yarn, a ratio of the instantaneous colour of the wool yarn divided by a running average colour of the wool yarn, and the difference between the colour of the wool yarn and the colour of a reference yarn.

26. A method for determining a first parameter of an object, substantially as hereinbefore described with reference to any one of the Examples.

27. An apparatus for determining a first parameter of an object, substantially as hereinbefore described with reference to Figures 1 and 2. Dated 8 May, 1998 Commonwealth Scientific and Industrial Research Organisation Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON ~r L r i' 8. r f I .1.,4Wlul 1ipO1ipo38R; -II~Y-iYe~L?1F1I i~i~ RECEIVED 6 JUN 1995 13/13 APPAR'AT-US 1000 /120 r~, C-T co Ln7 F0S-! LOl) %CLjJ ~~:7i7iIjI272i&. Yj /2001 TO7AL REFLECTED SIGNAL (DIAMETER -f-COLouR) 800 600 400 Zo00 400 600 &800 lox D1l57rANCE- F/G. 3 c CX c-i LkCf/AUy~O JU RECEIVED -6 JN 1995 4/13 LQQ Rz I7 -4 0 -qL&,JJ dHHS H 3EMLSl t1 SIGNAL x /00 JIM I/s sm6 N nr 9 0 9 z 0 0 GAONJ kt~i'/AJ 2 5 0 RECEIVED -6 JUN 19 *1 6/13 U~Q) -LNNHPO SUBSTITUTE SHEET (Rule 26) 4/ RECEIVED 6 1995 7/13 0 0 00/ x 7VN~~/2 SUBSTTUTE SHEET (Rule 26) U GA'EE/V DATA/15IJM (GA/SCALED) 0.2S k I.u 0 K) j C cr rn 0200 400 600 800 /000 1 F/s. 6a I(C C.C Cc, '400-BLUE DATA UNPROCF8 z2oo 0 200 400 600 800 f000 DISTANCE cTI RECEIVED 1 10/13 u u~ u A! 6 JUN 1995 v u 4 J u 6 JUN 1995 I~ V) -4 (j -4 -1 -1N3/ ,cI/ O2? ;7fl7g SIJBS'TFIT q'Pp~r D,dt Iri U--illlll~i RECEIVED U U4 JU 6 JUN 1995 11/13 Q dz 4 SUBSTITUTE SHEET (Rule 2W) A-: YELLOWf/ YARN 00. -1.o RED IA! ER VAq L ,5000 OREEN BLULIE uvr~lq VA L- INJ-ER VAL- 2a C-M Flo'.9 RECEIVED -6 JUN 1995 13/13 LO0 4- 4+ SUBSTITUT SHEET (Rule 26) INTERNATIONAL SEAR Mzk~~~m~ cl xaa ~i~ :CH REPORT International application No. PCT/AU 95/00250 i A. CLASSIFICATION OF SUBJECT MATTER Int. C1. 6 G01N 21/27, 33/36 According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) IPC G01N 21/17, 21/25 to 21/39, 21/84 to 21/89, 33/36 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched AU IPC as above Electronic data base consulted during the international search (name of data base, and where practicable, search terms used) DERWENT IPC as above with Keywords: FIBER#, FIBR:, YARN#, FILAMENT#, STRAND#, AND WAVELENGTH# C. DOCUMENTS CONSIDERED TO BE RELEVANT Category Citation of document, with indication, where appropriate, of the relevant passages WO 82/03688 Al (A B BONNIERFORETAGEN) 28 October 1982 Fig 1, 6, Page 6-10 DE 3706056 Al (BACKMANN) 11 May 1988 Abstract, Fig 2 Derwent Abstract Accession No. 84-305894/49, Class S03, SU 1086371 A (AS UKR NUCLEAR PHYS) 15 April 1984 Abstract Relevant to Claim No. S Further documents are listed in the continuation of Box C. See patent family annex. I1 fi S Special categories of cited documents later document published after the international filing date or priority date and not in conflict document defining the general state of the art which is with the application but cited to understand the not considered to be ofparticular relevance principle or theory underlying the invention earlier document but ublished on or after the document of particular relevance; the claimed international filing date invention cannot be considered novel or cannot be document which may throw doubts on priority claim(s) considered to involve an inventive step when the or which is cited to establish the publication date of document is taken alone another citation or other special reason (as specified) document of particular relevance; the claimed document referring to an oral disclosure, use, invention cannot be considered to involve an exhibition or other means inventive step when the document is combined document published prior to the international filing date with one or more other such documents, such but later than the priority date claimed combination being obvious to a person skilled in the art document member of the same patent family Date of the actual completion of the international search Date of mailing of the international search report 8 June 1995 _2 E i95 t. o6. q) Name and mailing address of the ISA/AU Authorized officer AUSTRALIAN INDUSTRIAL PROPERTY ORGANISATION PO BOX 200 WODEN ACT 2606 AUSTRALIA P.F. GOTHAM/, Facsimile No. 06 2853929 Telephone No. (06) 2832165 S Form PCT.ISA/210 (continuation of first sheet (July 1992) cophin 4/ INTERNATIONAL SEARCH REPORT International application No. PCT/AU 95/00250 C(Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate of the relevant passages Relevant to Claim No. Derwent Abstract Accession No. 84-022317/04, Class S03, SU 1004878A, March 1983 Abstract WO 93/15389 Al (ABB STROMBERG DRIVES OY) 5 August 1993 Abstract, Fig 4 US 4577104 A (STURM) 18 March 1986 Abstract, Fig 1 US 4928013 A (HOWARTH) 22 May 1990 Abstract, Fig 1 US 5229841 A (TARANOWSKI) 20 July 1993 Abstract, Fig 1, 6 EP 553446 A2 (GEBRUDER LOEPFE AG) 4 August 1993 US 5383017 A (SCHURCH) viewed Abstract, Fig 1 1-10, 14-20 11-13, 21-23 1-10, 14-20 11-13, 21-23 1-10, 14-20 11-13, 21-23 1-10, 14-20 11-13, 21-23 1, 7, 9, 10, 14, 17, 18, 1-23 Ai -A Form PCT/ISA/210 (continuation of second sheet)(July 1992) cophin INTERNATIONAL SEARCH REPORT 117 International application No. PCT/AU 95/00250 This Annex lists the known publication level patent family members relating to the patent documents cited in the above-mentioned international search report. The Australian Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent Document Cited in Search Patent Family Member Report US 4577104 AU 38845/85 CA 1224643 DE 3570287 EP 171413 JP 61500931 WO 8503351 US '4928013 EP 279743 FI 880728 JP 63298030 WO 8203688 EP 76301 US 5383017 CH 683035 EP 553446 JP 5273152 WO 9315389 AU 33545/93 FI 920341 NO 942764 SE 9402547 DE 4390253 US 5229841 EP 522548 JP 5187919 4 Ai3; END OF ANNEX Form PCT/ISA/210(patent family annex)(July 1992) cophin