Abstract: The invention relates to an apparatus for the quality control of a print produced by a printing machine. The apparatus includes a CCD camera and a measuring girder, extending substantially across the width of a printing surface to be controlled. A path of light coming from a printing surface to the camera is provided with mirrors arranged in a manner such that the light of said path reflects from the mirrors several times, whereby the distance covered by the light coming from a printing surface to camera is a multiple when compared to the distance between the camera and the printing surface. The mirrors can be used for "packing" the control apparatus into a compact size, and yet it is possible to employ a standard CCD line camera as the measuring head. The apparatus is particularly suitable for the quality control of newspaper printing.

Abstract: Apparatus and method for optically testing products such as condoms, gloves or any number of similar objects without contact and non-destructively. In testing for holes, a light source having a wavelength at which the product to be tested is relatively opaque is used to illuminate either the inner or outer wall of the product and a photo sensor sensitive to the particular wavelength is located to sense the amount of light passing through the wall of the product. In testing for embedded particles, a light source of visible light is used to illuminate the product to be tested and a photosensor senses any variation in the amount of light passing through the walls of the product.In the testing of products, such as condoms, for the presence of holes, the condom is mounted on a transparent mandrel or distended by inflating the condom with a jet of air.

Abstract: An on-line laser triangulation position sensing system provides measurements of the surface features of a moving sheet such as paper. The measurements are correlatable with measurements made with standard laboratory surface smoothness testers and provide predictions of the printability of paper during its fabrication. The sensing system includes a segmented balance detector having a high frequency response. The sensing system further includes signal processing circuitry comprising a plurality of channels, each channel including a filter. The various filters have different cutoff frequencies for passing different frequency spectra representing ranges of surface feature scale sizes. The cutoff frequency of each filter is varied in response to variations in sheet speed. The sheet sensing system further includes a sheet stabilizer to minimize flutter in the measurement region and a standardizing member permitting performance verification of the sensor system at at least one scale size spectrum.

Abstract: The invention aims to optimize a given parameter of a process of coating a support with a liquid composition. The device comprises: a) means (9, 10) for varying the parameter according to a predetermined profile; b) first detection means (11) for producing a first density profile for the support (6) across the width of the support, as the parameter varies; c) second detection means (13) for producing a second density profile for the support (6) parallel to the longitudinal axis, as the parameter varies; and d) means (15, 10) for determining a range of values for the said parameter for which the first and second profiles are satisfactory.

Abstract: Disclosed is an apparatus for measuring on-line the color and color-related properties of a moving sheet. Contrast ratio reflectance measurements are made for providing opacity corrections substantially in real time for a full color spectrum. An optical color sensor in accordance with the invention includes a pair of synchronized spectrometers, the first spectrometer being aligned to view a region of the sheet backed with a highly reflective ("white") material and the second spectrometer being aligned to view a region of the sheet backed with a highly absorptive ("black") material. The use of two spectrometers permits substantially simultaneous "black" and "white" measurements for a full color spectrum. The optical color sensing system further includes two light sources, a flashlamp and a continuously energized tungsten filament lamp. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile.

Abstract: On-line measurement of fiber orientation and anisotropy in a non-woven web of material is performed by directing three light sources toward a sensing region of the web. Reflectively scattered light from each light source is detected by a pair of light sensors positioned on either side of an incidence plane including the beam of incident light. Back scattered light from each light source is also detected by at least one light sensor positioned generally above the sensing region. Preferably two back scattered light sensors are provided for each light source, one common light sensor and one dedicated light sensor. The signals from the light sensors for each of the light sources are combined to generate resultant fiber orientation signals which are used to compute a fiber orientation angle relative to the machine direction and an anisotropy characteristic for the web.

Abstract: A device is provided whereby, when measuring yarn which has hairs, it is possible to detect data for the hairy part and data for the core part individually. The yarn measuring device is provided with a means which forms a Fourier transformation pattern, including a yarn core part pattern and a surface projection pattern, on a spectrum plane, by performing a Fourier transformation on diffracted laser light which has intersected and passed through traveling yarn; a first light detecting means which receives only one of the core part pattern and the surface projection pattern; and a second light detecting means which receives only the other pattern.

Abstract: An apparatus and method for scanning a carpet is used for detecting tuft defects in the carpet during manufacture. The apparatus or system incorporates a light source for providing light along a width of the carpet; a scanning array for detecting light from the light source passing through the carpet; and control circuit means for controlling the sensor array to scan the carpet and for receiving the output signals from the first and second sensor cells detecting tuft defects in the carpet based on the light passing through the carpet. The scanning array has at least one pair of first and second sensor cells, and is positioned opposite the light source with the carpet passing transversely therebetween. Each of the first and second sensor cells includes first and second sets of sensor elements, and an output node between the first and second sets of sensor elements. The output node outputs a signal detecting tuft defects in the carpet based on an amount of light passing through the carpet.

Abstract: A system for electronically comparing yarn lengths to assist in grading yarn appearance quality in which the yarn diameter at a number of locations along the total length of the yarn is determined, and representations of the diameters of the yarn are displayed to allow comparison of portions of the yarn.

Abstract: An apparatus and method are provided for detecting a formation or change in the consistency of a moving sheet material. The apparatus includes a radiation source, a radiation receiver, a support base for the sheet material, and a signal processor for producing a signal in response to the detection of a formation in the material. The apparatus may be modified to include moving or stationary support bases, and may be further modified to include structure for automatically positioning the source and receiver to optimize the detection of formations.

Abstract: A system for adjusting the marker in preparation for cutting that is adapted for use with fabrics having a stripe or plaid design is characterized by computer assisted design matching that provides for automatic alignment of the fabric web with the cutting apparatus as well as matching fabrics whose designs vary in contrast. The present system also provides for coordinate matching between an image obtained by the system's camera and the actual fabric.

Abstract: A method and apparatus for rapidly and accurately determining fiber orientation of paper which is at a standstill or moving in a paper machine employs a projector which projects a light beam perpendicularly to an incident surface of the paper to be tested. The light beam reflected by the incident paper surface is caught by eight or more light receivers distributed on a circumference of a circle on the incident surface side of the paper. The circle is defined in a plane extending in parallel to the paper surface and having an axis at the point where the above-mentioned parallel plane intersects an axis of the incident light beam. A light information signal output from the light receivers are subjected to a processing to obtain the fiber orientation characteristics, such as fiber orientation index value and fiber orientation angle.

Abstract: A method and apparatus for identifying a moving web in a paper making machine are disclosed. The method includes of the steps of illuminating the web with the light from a transmitter, reflecting the transmitted light off the web, receiving the reflected light with a light transducer to produce an electrical signal corresponding to the intensity of the received light, and identifying the moving web based on the received signal. The intensity of the transmitted light is adjusted so that the received light signal from the transducer is normalized with respect to an optimum value. The apparatus includes a light transmitter, a light receiver, and a control and identification circuit which identifies the web based on a signal from the light receiver, and which adjusts the intensity of the light transmitter to optimize the reception of the signal from the light receiver in order to minimize the effects of environmental interference.

Abstract: A focused light beam instrument measures characteristics of webs of sheet material. The instrument and a reference surface, a backing tile in a carousel, are on opposite sides of the web which is maintained a fixed distance from the reference surface by a Bernoulli hold down device such that variations in the gap affect the beam focus. The instrument and reference surface scan the web via a scanning frame. The instrument is calibrated-standardized in an off sheet position where a first surface, a carousel backing tile, is moved opposite to the instrument and in the plane of the web. The instrument measures the first surface and a second surface, another carousel backing tile, which is moved opposite to the instrument but spaced farther from or closer thereto than the first surface. The distance of the instrument from the web is calculated from the difference between the measurements of the first and second surfaces.

Abstract: An apparatus and method for monitoring and regulating the amount of multiple coating materials containing different compositions applied to a substrate, such as paperboard. The coating measurement is insensitive to changes in both the amount of substrate as well as in the amount of an interfering component associated with the substrate.

Abstract: A light source casts light on a transparent sheet through a slit plate. A camera which is focused at a distance nearer than the transparent sheet or remoter than the slit plate, receives the light transmitted through the transparent sheet and picks up an image of a defect of the transparent sheet. An image processing unit inspects the image for a defect of the transparent sheet as "knots", "cords", etc.

Abstract: The present invention relates to a detector for measuring the characteristics of a linear product of very great length relative to its other dimensions, on a production machine or the like. The detector operates without contact with the linear product and is provided with at least one means (1) having zones (2 and 3) for measurement relative to a mean position of the moving filament (4) and measuring the variation of the complex morpho-dimensional and/or positional characteristics of the filament (4), this latter varying, either by vibrating movement, or by displacement induced by the mean position of the axis of movement. The invention is applicable to the field of the measurement of the characteristics of linear products of very great length.

Abstract: A motion indicating device used especially to monitor the movement of sheets of paper, which are moved via conveyor paths. A scanning device has a rotatably mounted scanning member, which lies on the scannable surfaces of the moving sheet of paper and is set into rotation by same, and which is provided with signal elements, which generate motion signals in a stationary electronic signal transmitter by their rotary movements. The scanning member is a ball (8) with uneven weight distribution or a hollow ball (81, 82). The ball is guided freely rotatably in a guide cage (7) and has at least one signal element. A signal transmitter is arranged on a side located diametrically opposite the contact point (19) of the ball (8) and is directed in this plane of rotation toward the ball (8).

Abstract: The present invention relates to an apparatus for optical monitoring of whether a thread is in motion or not in a determined direction in a region illuminated by one or more light sources, the region being a part, illuminated by the light source (5), of a channel (2) with light-reflecting walls (4, 6, 7, 10, 11, 12), through which the thread extends, and at least one light-sensitive element (8, 9) is placed in said part of the channel (2) in such a manner that the optical axes (13, 14, 15) of the light source (5) and the light-sensitive element (8, 9) make an angle with each other, whereby the optical coupling between the light source (5) and the light-sensitive element (8, 9) is influenced by the vibrations occurring in the thread during its motion, e.g. the microvibrations, the changes in the optical coupling being reflected in amplitude variations of a signal from the light-sensitive element (8, 9).

Abstract: To order to determine a distortion angle in a textile material fed in a specific feeding direction, the textile material is monitored by means of a first detection means, the output signal of which depends on an angular position of said means with respect to the feeding direction and to the distortion angle. This first output signal is filtered so that signal components that are at least statistically independent of the distortion angle are filtered out. The filtering means used comprise a band-pass filter which is adjustable with respect to its center band-pass frequency, its bandwidth and/or the shape of its filter-curve shape by means of a second output signal from a second detection means. The second output signal is dependent on the frequency characteristic of those signal components in the first output signal that are at least statistically dependent on the distortion angle.

Abstract: A print paper detecting circuit for installation on a printer, to detect whether a print paper is supplied at a predetermined position along a paper path by using an optical sensor composed of a light emitting diode and phototransistor. The circuit detects the existence of the print paper according to the detection of light which is emitted from the light emitting diode, which is reflected from the print paper, and which arrives at the phototransistor. According to one embodiment, circuit has a current amplifier and a gain reducing circuit. The current amplifier feeds a pulse current which is greater than the normal constant current to the light emitting diode while the gain reducing circuit reduces the output of the output voltage.

Abstract: An optical fiber evaluation test station (20) includes optical fiber supply (26), translation, and rewinding mechanisms (52), and at least one module performing a test of optical fiber quality through which the optical fiber (22) continuously passes. The test station (20) includes a supply section wherein the optical fiber (22) is paid out from a supply spool (24) and cleaned by a cleaning and static discharging unit (30). There is a high tension test section wherein tests such as a buffer cure test (46) and a bend proof test (48) are performed. In a low tension test section, tests such as an optical fiber diameter test (58), a buffer flaw test ( 60 ), and a visual observation test (64) are performed. Tension-isolating capstans (40, 44) separate the various sections, optical fiber guides (62) direct the optical fiber (22) and stabilize its movement, and spring-mounted dancers (36, 42) measure the tension in the optical fiber (22) in the tension-isolated sections.

Abstract: A system for aligning control zones with measurement zones in a sheetmaking system having a plurality of actuators arranged in the cross-direction, comprising the steps of: a) bumping at least one of the actuators; b) measuring a profile of the sheet at a substantial distance from the bumped actuators; and c) determining a location of the effect of each of the bumped actuators on the sheet.

Abstract: A method for determining the tendency of a non-woven web to curl, where the web has a machine direction (MD), a cross-machine direction (CD) and the web includes a wire side and a felt side. The method comprises determining a wire ratio which is the ratio of the number of fibers oriented in the MD to the number of fibers oriented in the CD, where the fibers are associated with the wire side of the web, a felt ratio which is the ratio of the number of fibers oriented in the MD to the number of fibers oriented in the CD, where the fibers are associated with the felt side of the web, and determining the wire to felt ratio which is a measure of the tendency of the web to curl.

Abstract: A beam of light is transmitted from a transmitter (30) which is broken as the moving fiber (22) passes through the beam. A receiver (32) receives the light and generates a signal in response thereto. The signal is processed to determine the status of the pattern generated by the moving fiber (22) of material. In response to changes in the status of the pattern, the rate at which the fiber is dispensed and/or the movement of the pattern can be adjusted as well as alarm conditions noted.

Abstract: An apparatus, and a method for its use, for measuring particulate contamination on a web (10) in a web-cleaning system having means for contacting and removing particles from the web (12). The means for contacting and removing particles has a particle-collecting surface (14). A light source (16) is positioned to direct a light beam against the particle-collecting surface. A sensor (18) senses the intensity of light reflected from the particle collecting surface and generates a signal R.sub.0 representative of the initial reflected light intensity prior to particle collection by the particle collecting surface and a signal R.sub.f representative of the reflected light intensity after particle collection by the particle collecting surface, the difference between R.sub.0 and R.sub.f being a measure of the particulate contamination level on the web.

Abstract: In the case of an optical sensor, which is used for a thread (Y) moving approximately transversely to the longitudinal direction thereof, in particular for the thread supply (V) which consists of non-separated thread windings in a thread storage and feed device (F) having provided therein a light source (2) directed towards a predetermined passage area (P) for the thread (Y) and a receiver (3) oriented such that scattered light (6) reflected by the thread in said passage area will fall onto it, a shield element (9), (10) is arranged in the passage area (P) below the thread (Y) on the side of the thread which faces away from the light source (2), said shield element being arranged and/or constructed in such a way that it will not reflect light (4), which comes from the light source (2), to the receiver (3) and that it will not allow light, which is reflected by surfaces or objects (L) located on the other side of the shield element (9) with respect to the light source (2), to pass to the receiver (3).

Abstract: A luster detector arranged such that an output light beam of an LED is applied to a surface through a light projecting lens as an irradiating light beam having a predetermined width. Rays of light reflected from the surface are applied through a condenser lens to a line sensor. Of the rays of light reflected from the surface, the rays of light reflected regularly form a light spot on a light detecting section extending in the longitudinal direction of the light detecting section. Hence, even if the light receiving position is shifted, the light detecting operation is positively achieved. A detecting circuit determines the light reception distribution of the sensor to detect the luster of the surface.

Abstract: Registration inspection of composite products during the fabrication of a series of such products is accomplished by making a two-dimensional image of a product and analyzing the image to determine the location of at least one component in the machine direction and the location of at least one component in the transverse direction. The thus determined locations are compared to the desired locations for the respective components in the composite article, and feedback control signals are utilized to adjust the fabrication process so that the components will be at the desired locations in subsequent products. When a component is outside of its acceptable position, the article can be removed from the fabrication line without further processing. The invention is particularly useful with fabrication lines for the production of absorbent articles, such as disposable diapers, incontinence devices, sanitary napkins, and the like.

Abstract: To ensure that on-line measurements performed at a moving or stationary fiber structure, such as a fiber composite or a sliver, deliver useful and reproducible measuring values, the fiber structure, whether such be fiber composites or fiber slivers, must be compressed at the location where they pass a measuring location or site where there is accomplished the measurement with a commercially available measuring instrument or apparatus. According to the invention, there is selected as the measuring location or site a location of the fiber processing process where the fiber structure is compressed any way by virtue of the undergoing fiber processing process.

Abstract: A system for sensing breakage of one or more of a plurality of strands of material that are being fed in unison along a circular array of separate feed paths while the array of feed paths is being rotated about an imaginary axis that extends substantially centrally among the array of feed paths utilizes separate indicator assemblies positioned along each of the separate feed paths, with the indicator assemblies being arranged in a substantially circular array for rotation along a circular path of movement that extends substantially concentrically about the axis of rotation. At least one optical detector is positioned alongside the substantially circular path of movement that is followed by the indicator assemblies as they rotate, whereby, at least once during each revolution, each of the indicator assemblies is caused to move past an optical detector.

Abstract: An optical scanner includes a light source (39) which directs a beam of light at a web of moving paper whereby the beam of light is transmitted through the web of moving paper. The transmitted beam (43) is split by a beam splitter (19) to provide a first split beam (44) travelling in a machine direction and a second split beam (45) travelling in a cross-machine direction. The split beams are received by charge-coupled device linear arrays (15, 19) which provide analog signals having magnitudes proportional to the magnitude of light intensity of the split beams. The analog signals are fed to analog-to-digital converters which provide digital data at the output. The digital data is then used to compute paper formation descriptors including paper mass variation, floc size statistics and histogram, Fourier power spectra and paper anisotropy.

Abstract: As an optical fiber (12) is being drawn, air (14) is directed at a portion of the fiber as a succession of air pulses, the pulses having a frequency near the natural frequency of the fiber portion. The frequency of the air pulses is then varied over a range of frequencies that includes the natural frequency of the fiber portion. When the air pulse frequency equals the natural frequency of the fiber portion, a resonance occurs which greatly amplifies the amplitude of the vibration of the fiber portion. The large deflection of the fiber that occurs at resonance is easy to detect, and the air pulse frequency which causes such maximum deflection is taken as being equal to the resonant frequency and therefore to the natural frequency of the fiber portion. Changes of the detected resonant frequency can be interpreted in a straightforward manner as changes in optical fiber tension which, in turn, are used to make compensatory changes of the temperature of the furnace (10).

Abstract: Method and apparatus for inspecting the surface of a moving web of homogeneous material for anomalies, the apparatus including a light source for illuminating the web surface and a light sensitive detector for receiving data from the web surface. The data is representative of the light reflected from the surface, as the light is affected by surface anomalies and background information. Computational means are provided for receiving output data from the detector in response to the data the detector receives from the web surface, and for processing the output data in a manner that determines the presence of surface anomalies. The computation means includes a plurality of filters for transforming the surface data in a manner that effects substantial elimination of the background information, and means for establishing threshold levels for background information.

Abstract: A process is disclosed for sampling textile fiber skeins. A fiber skein (2) continuously moved in the longitudinal direction (23) is intermittently brought to a stop within a defined section (4, 28). The profile of the immobilized section (4, 28) of the fiber skein (2) is flattened at least in partial region (24) and the textile analysis is carried out on this temporarily immobilized, flattened partial region (24) of the fiber skein.

Abstract: An in situ traveling paper machine web is stabilized from flutter and vibration for the purpose of formation and optical property measurement by an air flow system by which a boundary layer air stream between a sole plate and the adjacent web surface secures the web in a stable position.

Abstract: A method and device for determining the state of a movement or stoppage of a yarn fed to a textile machine in which a variation in the shape and/or position of the yarn relative to an optical sensor in front of which the yarn runs during its feed to the textile machine is determined. On the basis of this variation, an output electrical signal is generated and is used for operating an operating member of the textile machine such as an indicator for indicating the state of movement of the yarn, a machine control circuit or a similar operating member. The method is implemented by an optical sensor which generates at least one output which is a variable electrical signal on the basis of a variation in the shape and/or position of the yarn relative to the sensor. The signal is compared with a reference signal in order to operate a switch device which causes the output electrical signal to be generated.

Abstract: A surface defect detector for detecting a gentle wavy defect and a minute rough defect on a surface of an object. The detector has a conveyer to move the object in a linear direction, a laser beam generator to irradiate a laser beam onto the object in a direction perpendicular to the linear direction, two photoreceptors to generate two different signals in accordance with a reflection of the laser beam from the object, a separator to optically separate the photoreceptors, and a processor to process the signals from the photoreceptors to detect the gentle wavy defect and the minute rough defect.

Abstract: The apparatus comprises at least one light source (3) and a plurality of test channels with in each case one optoelectronic converter (4a, 4b). In the light path between the light source and the converter is provided at least one light channel (5a, 5b) and the test material (1). The light channels are constructed as optical elements for bounding or defining a light bundle. A plurality of light channels is juxtaposed in a common casing (6a, 6b) on at least part of the light path. In each light channel can be provided a beam splitter element (12) and together form a single beam splitter (12) removably arranged in the casing. The converters (4a) can be juxtaposed on the same casing as the beam splitter (12) and each is associated with a light channel (5a). Two casings (6a, 6b) can be provided, the light source (3) in the first casing (6a) and the converters (4b) in the second casing (6b) are juxtaposed and associated with in each case one light channel (5a, 5b).

Abstract: A device for characterizing the formation of a sheet material is described. The device comprises a formation sensor for measuring the basis weight of the sheet material as the material passes through the sensor, and signal processing circuitry which receives a basis weight signal from the formation sensor and which produces three types of outputs, which outputs characterize: (1) the magnitude of variation in the sheet basis weight; (2) the strength of the weakest portion or portions of the sheet; and (3) the size of the flocs comprising the sheet. The formation sensor includes a light pipe that is held against the sheet as the sheet moves through the sensor, and that directs a small spot of light transmitted through the sheet to a light detecting device. The magnitude of small-scale variation in the sheet basis weight is computed by determining the ratio between average value of the basis weight signal and the varying or AC component of the basis weight signal.

Abstract: The detection of abrupt changes in opacity of a moving sheet resulting from, for example, an overlap type splice is provided. The web material is fed between two identical light emitter/detector pairs such that its opacity is measured. An abrupt change in web thickness passing through one light emitter/detector pair is sensed as a change in web opacity. The difference and resulting imbalance with the opacity signal from the other light emitter/detector pair, not yet interrupted with the abrupt change, is utilized to indicate the presence of the defect which, in this application, could be an overlap splice. The disclosed invention, although adaptable to thicker textile webs, specifically relates to a device for the detection of overlap splices in a moving sheet representative of all the paper types required by the cigarette, printing, and labeling industries.

Abstract: The invention relates to an optical inspection apparatus comprising an illuminating means which has a linear light source (11) and a concave cylindrical mirror (10) which forms an image of the light source (11), with the cylindrical axis of the cylindrical mirror extending essentially parallel to the light source (11) in order to generate an illuminated strip (31) on a web (12) to be monitored, with the illuminated strip preferably extending over the entire width of the web (12). By means of an optical system (24) a light receiving means forms an image of an inspection line (32) extending on the material web (12) at the center of the illuminated strip (31) on a row-like photoreceiver arrangement (25), so that light emerging from the material web (12) is detected. The photoreceiver arrangement (25) is connected to an electronic processing circuit (26).

Abstract: A method of visually inspecting the formation of a web of translucent material by means of a device it moves past. The device consists of a source of light on one side of the web generating a beam of light of a desired hue and intensity that penetrates the web, and a video camera on the side of the web away from the source of light, intercepting the beam and converting it into a video signal that is forwarded to a monitor. The source of light emits the beam in a flash of duration t.sub.1 that is too short for the web to advance far enough while illuminated to blur the image. The image on the monitor is accompanied by a reference image.

Abstract: An adaptor bracket for the mounting of a color sensor head and a support pad held in a specific orientation such that the light emitted from the color sensor head strikes the support pad in a manner that the reflected light is directed back towards the color sensor head while the support pad serves as a low friction surface over which a flexible translucent material can be passed for measurement of its color quality.

Abstract: A fluorescent lamp light output is maximized by cooling the cathode regions. Mercury vapor pressure is maintained at an optimum or desired level for light production by cooling the cathode areas of the lamp. The cooled cathode areas of the lamp collect cathode emissive material and mercury vapor condensates. Thus, the light output remains uniform and constant. The functional length of the lamp is not degraded by the deposition of either cathode material or mercury vapor condensates. Cooling can be effected by forcing cool air against the exterior of the lamp adjacent the cathodes or by using forced water heat exchangers. By cooling the respective cathode regions equally, the amount of deposition in the respective regions is substantially the same. Thus, gradations of deposition are avoided. The constant high output fluorescent lamp can be used with electronic inspection equipment and machine vision measurement devices.

Abstract: As an optical fiber (12) is being drawn, air (14) is directed at a portion of the fiber as a succession of air pulses, the pulses having a frequency near the natural frequency of the fiber portion. The frequency of the air pulses is then varied over a range of frequencies that includes the natural frequency of the fiber portion. When the air pulse frequency equals the natural frequency of the fiber portion, a resonance occurs which greatly amplifies the amplitude of the vibration of the fiber portion. The large deflection of the fiber that occurs at resonance is easy to detect, and the air pulse frequency which causes such maximum deflection is taken as being equal to the resonant frequency and therefore to the natural frequency of the fiber portion. Changes of the detected resonant frequency can be interpreted in a straightforward manner as changes in optical fiber tension which, in turn, are used to make compensatory changes of the temperature of the furnace (10).

Abstract: In an opto-electronic detector apparatus, particularly of a yarn storage and feeder apparatus, for detecting at least one yarn or yarn section moving transversely of its longitudinal direction in a detection field, said apparatus comprising a light source, a receiver surface, a photoelectric cell for generating an output signal, and an optical system, the optical system is an optical imaging system (A) having a focus depth defining a predetermined depth (T) of said detection field, and a field of vision of limited dimensions at least in the direction of its width (B), the receiver surface (16) being disposed in the vicinity of the focal plane of the optical imaging system (A), so that said imaging system (A) produced a clear image on the receiver surface (16).

Abstract: A device for scanning marks printed on workpieces travelling under a light source includes at least two parallel mark scanning channels emitting an electric impulse due to passage of a mark, each channel being sensitive to a particular color. The device incudes, moreover, electronics for selecting a most representative mark impulse among the electric impulses emitted by the channels.

Abstract: The present invention concerns a process and a device for optically measuring the twist of a textile yarn.The device comprises means (20) for lighting up the yarn (10) by a beam of light (11) to form a spot of light (12) which corresponds to the light diffracted by the surface fibres of the compact core of this yarn. The energy repartition of this spot is then analyzed by means such as a rotary analyzer (27) to define the angle of twist by determination of the maximum of energy in the said spot (12).

Abstract: A beam of light is transmitted from a transmitter (30) which is broken as the moving fiber (22) passes through the beam. A receiver (32) receives the light and generates a signal in response thereto. The signal is processed to determine the status of the pattern generated by the moving fiber (22) of material. In response to changes in the status of the pattern, the rate at which the fiber is dispensed and/or the movement of the pattern can be adjusted as well as alarm conditions noted.