Abstract: A method includes illuminating a material with first light along an optical path. The method also includes capturing an image of second light transmitted through the material using a first detector, where a first portion of the second light follows the optical path of the first light and a second portion of the second light diverges from the optical path. The method further includes capturing one or more measurements of third light using a second detector. The third light diverges from the optical path by a larger amount than the second portion of the second light, and the second detector is spaced apart from the first detector. In addition, the method includes determining one or more haze values associated with the material based on the image and the one or more measurements and at least one of storing and outputting the one or more haze values.

Abstract: A method includes receiving multiple biased measurements associated with a property of a sheet of material, where the biased measurements correspond to multiple known sheet geometries. The method also includes determining an unbiased measurement associated with the property of the sheet using the biased measurements, where the unbiased measurement corresponds to a nominal sheet geometry. The method further includes storing and/or outputting the unbiased measurement. Determining the unbiased measurement could include performing regression using the biased measurements and their corresponding sheet geometries to identify an estimated value of the property of the sheet at the nominal sheet geometry. The biased measurements can be generated using one or more sensors, and the sheet may not be stabilized during the biased measurement generation. Additional sheet geometries can also be created, such as by varying a tilt angle, a curvature, and/or a position of the sheet.

Abstract: A method includes passing a web of material over a deflector having a backstep, where the backstep causes the web to deflect towards the deflector. The method also includes capturing measurements of one or more characteristics associated with the web at one or more locations downstream of the backstep. In addition, the method includes identifying a cross direction (CD) profile of machine direction (MD) tension on the web using the measurements. The method could further include generating a Coanda airflow between the web and the deflector. The measurements could include pressure measurements identifying air pressures in a space between the web and the deflector and/or deflection distance measurements identifying distances by which the web is deflected towards the deflector.

Abstract: A system includes multiple light emitting diodes (LEDs) and a light pipe configured to mix light from the LEDs and produce collimated light. The light pipe includes multiple reflective optical devices configured to reflect the collimated light at different angles. The light pipe also includes multiple outlet optical devices configured to selectively control exit of the reflected collimated light from the light pipe. The reflected collimated light has one or more controllable spectral characteristics and/or one or more controllable geometries of illumination.

Abstract: A system, apparatus and method are provided for adjusting an on-line appearance sensor system (OnLASS) for color and other appearance characteristic(s) of a web product produced during a production run of a web production system. The OnLASS is calibrated and its setting(s) are sent to a color error minimizer (CEM). The OnLASS measures a first appearance characteristic of the web product during the production run and the on-line measurement is sent to the CEM. After the production run, a second appearance characteristic of the web product is measured with an off-line appearance sensor system (OffLASS) and the off-line measurement is sent to the CEM. The CEM compares the on-line and off-line appearance measurements and adjusts at least one setting based on the comparison. The adjusted setting(s) are sent to the OnLASS.

Abstract: A system includes multiple light emitting diodes (LEDs) and a light pipe configured to mix light from the LEDs and produce collimated light. The light pipe includes multiple reflective optical devices configured to reflect the collimated light at different angles. The light pipe also includes multiple outlet optical devices configured to selectively control exit of the reflected collimated light from the light pipe. The reflected collimated light has one or more controllable spectral characteristics and/or one or more controllable geometries of illumination.

Abstract: A method includes illuminating a material with first light and capturing an image of second light transmitted through the material. The method also includes analyzing multiple regions of the image and determining one or more haze measurements associated with the material based on the analyzing. The method further includes storing and/or outputting the one or more haze measurements. Analyzing the multiple regions of the image may include summing pixel values in each region to produce a total pixel value for that region. The multiple regions of the image may include (i) a first region forming a first disc, (ii) a second region forming either a first annular region around the first region or a second disc larger than and including the first disc, and (iii) a third region forming either a second annular region around the second region or a third disc larger than and including the first and second discs.

Abstract: A system, apparatus and method are provided for adjusting an on-line appearance sensor system (OnLASS) for color and other appearance characteristic(s) of a web product produced during a production run of a web production system. The OnLASS is calibrated and its setting(s) are sent to a color error minimizer (CEM). The OnLASS measures a first appearance characteristic of the web product during the production run and the on-line measurement is sent to the CEM. After the production run, a second appearance characteristic of the web product is measured with an off-line appearance sensor system (OffLASS) and the off-line measurement is sent to the CEM. The CEM compares the on-line and off-line appearance measurements and adjusts at least one setting based on the comparison. The adjusted setting(s) are sent to the OnLASS.

Abstract: A method includes receiving light from a material at a digital imaging device. The method also includes filtering the light into at least three spectral bands using a filter, where different regions of the filter pass different spectral bands. The method further includes measuring the light in each of the spectral bands and determining at least one color associated with the material using the measured light in the spectral bands. The different regions of the filter could include multiple masks (where each mask passes one of the spectral bands), different areas of a linear variable filter, and/or individual filters (where each individual filter passes one of the spectral bands). The digital imaging device could include a digital camera. The filter could be formed on a detector in the digital camera, and/or a component of the digital camera could be replaced with the filter.

Abstract: A method includes receiving a sheet of material at a sensor assembly. The sensor assembly includes a sensor configured to measure a property of the sheet. The method also includes stabilizing the sheet with respect to the sensor using a guide roller. Stabilizing the sheet includes using the guide roller to remove at least a portion of a first boundary layer of air moving towards the guide roller and to reform at least a portion of a second boundary layer of air moving away from the guide roller. For example, the guide roller could include a plurality of grooves or openings in a surface of the guide roller, or the guide roller could include a plurality of rings spaced apart from one another. Air could move from one side of the guide roller to another side of the guide roller through the grooves, through the openings, or between the rings.

Abstract: An apparatus includes at least one scanner. Each scanner includes a plurality of sensors, and each sensor is capable of measuring one or more characteristics associated with a portion of a substrate. The substrate has printing produced by a printing system. The apparatus also includes a controller capable of receiving at least some of the measurements from the plurality of sensors and determining a quality of the printing on the substrate using the received measurements. The substrate could represent paper, and the printing system could represent an offset printing system. At least one of the sensors may be in a fixed position and/or at least one of the sensors may be movable over part of a surface of the substrate. The determined quality of the printing could involve density, dot area, dot gain, contour sharpness, doubling, mottling, ghosting, misregister of different colored inks, slur, or improper positioning of the printing.

Abstract: A method includes generating at least one first light beam and generating at least one second light beam and at least one third light beam using the at least one first light beam. The at least one first light beam has a plurality of first regions, the at least one second light beam has a plurality of second regions, and the at least one third light beam has a plurality of third regions. Each of the first, second, and third light beams has at least two regions that are spectrally different. The method also includes measuring a spectrum in each of a plurality of first wavelength bands for each of the second regions. The method further includes illuminating at least part of an object with the at least one third light beam to produce at least one fourth light beam. The at least one fourth light beam has a plurality of fourth regions, where at least two of the fourth regions are spectrally different.

Abstract: A method includes illuminating a material using first light. The first light is associated with one or more ultraviolet wavelengths/wavelength bands, and the material includes pulp fibers. The method also includes measuring second light from the material, where the second light is based on the first light. The method further includes determining an amount of lignin in the material using the measured second light. The ultraviolet wavelengths/wavelength bands could include at least one wavelength between 260 nanometers and 300 nanometers, inclusive (such as 280 nm). The one or more ultraviolet wavelengths/wavelength bands could additionally include 205 nanometers, 250 nanometers, 300 nanometers, and/or 360 nanometers. The method could also include illuminating the material using third light and measuring fourth light from the material, where the fourth light is based on the third light.

Abstract: A method includes receiving multiple biased measurements associated with a property of a sheet of material, where the biased measurements correspond to multiple known sheet geometries. The method also includes determining an unbiased measurement associated with the property of the sheet using the biased measurements, where the unbiased measurement corresponds to a nominal sheet geometry. The method further includes storing and/or outputting the unbiased measurement. Determining the unbiased measurement could include performing regression using the biased measurements and their corresponding sheet geometries to identify an estimated value of the property of the sheet at the nominal sheet geometry. The biased measurements can be generated using one or more sensors, and the sheet may not be stabilized during the biased measurement generation. Additional sheet geometries can also be created, such as by varying a tilt angle, a curvature, and/or a position of the sheet.

Abstract: A method includes illuminating a material with first light and capturing an image of second light transmitted through the material. The method also includes analyzing multiple regions of the image and determining one or more haze measurements associated with the material based on the analyzing. The method further includes storing and/or outputting the one or more haze measurements. Analyzing the multiple regions of the image may include summing pixel values in each region to produce a total pixel value for that region. The multiple regions of the image may include (i) a first region forming a first disc, (ii) a second region forming either a first annular region around the first region or a second disc larger than and including the first disc, and (iii) a third region forming either a second annular region around the second region or a third disc larger than and including the first and second discs.

Abstract: Devices, systems, and methods for measuring the color of a sample are disclosed. The exemplary device may have one or more light emitting diodes for directing a beam of ultraviolet light onto the sample and may also have one or more light emitting diodes for directing a beam of visible light onto the sample. The exemplary device may have a component for controlling the timing and power of operation of each light emitting diode. The exemplary device may also have at least one light detector for receiving the beam of light reflected from or transmitted through the sample and measuring at least one wavelength band of the received light. The exemplary device may further have a measurement analyzer for determining the color of the sample based on the measured light. The color may be determined for a specified illuminator incorporating effects of fluorescence.

Abstract: A method includes illuminating a mixture of materials in a wet-end of a paper process, where the mixture includes an ultraviolet-activated material. The method also includes measuring light from the mixture and determining a property of the ultraviolet-activated material based on the measured light. The method may further include adjusting an operation in the wet-end of the paper process based on the determined property of the ultraviolet-activated material. The determined property could include a quantity of fluorescent material in recycled material used to form stock for a paper machine and/or a quantity of fluorescent material in stock provided to a headbox in the paper process. Adjusting the operation in the wet-end could include adjusting an amount of one or more materials used to form stock provided to the headbox, such as a fluorescent whitening agent, fixative, fluorescent fiber, fluorescent pigment, fluorescent particle, fluorescent highlight, fluorescent planchette, or fluorescent quencher.

Abstract: A system and method for color measurements or other spectral measurements of a material are provided. An illuminating device generates light for illuminating a sample of material. A detector detects light that has interacted with the sample and provides a measurement of the light that has interacted with the sample. A controller adjusts a duty cycle of the illuminating device to control the illumination of the sample. The measurement could be used by an analyzer to determine a spectral characteristic of the sample (such as a color of the sample). The determination of the spectral characteristic could be done without using any measurement of light that has not interacted with the sample. One or multiple light emitting diodes (LEDs) could be used to illuminate the sample, and the duty cycle of individual LEDs or groups of LEDs could be adjusted.

Abstract: A method includes illuminating a material using first light. The first light is associated with one or more ultraviolet wavelengths/wavelength bands, and the material includes pulp fibers. The method also includes measuring second light from the material, where the second light is based on the first light. The method further includes determining an amount of lignin in the material using the measured second light. The ultraviolet wavelengths/wavelength bands could include at least one wavelength between 260 nanometers and 300 nanometers, inclusive (such as 280 nm). The one or more ultraviolet wavelengths/wavelength bands could additionally include 205 nanometers, 250 nanometers, 300 nanometers, and/or 360 nanometers. The method could also include illuminating the material using third light and measuring fourth light from the material, where the fourth light is based on the third light.

Abstract: A method includes receiving light from a material at a digital imaging device. The method also includes filtering the light into at least three spectral bands using a filter, where different regions of the filter pass different spectral bands. The method further includes measuring the light in each of the spectral bands and determining at least one color associated with the material using the measured light in the spectral bands. The different regions of the filter could include multiple masks (where each mask passes one of the spectral bands), different areas of a linear variable filter, and/or individual filters (where each individual filter passes one of the spectral bands). The digital imaging device could include a digital camera. The filter could be formed on a detector in the digital camera, and/or a component of the digital camera could be replaced with the filter.