Abstract: The present invention provides a method and apparatus for identifying deformation of a moving sheet. In the present invention, the periodicity of original periodic or nearly periodic markings initially caused on the sheet is determined. Thereafter, a Fourier image of periodic markings of the sheet as it is moved along a path is produced with an imaging device using a Fourier transform optical element. The appropriate peaks of the Fourier image corresponding to the markings of the sheet are located, and the deformation of the sheet is calculated by comparing the measured peaks of the Fourier image to the known initial periodicity of the markings.

Abstract: The invention relates to a method and an apparatus for controlling a coloring process. In the coloring process, at least one fluorescent or non-fluorescent ingredient is added and the color of the substrate is determined by using a coloring model which describes the effect of said ingredient on the radiance transfer factor for the substrate to be colored.

Abstract: The invention relates to method for identifying plural relations in a sheet manufacturing process. Sheet properties are deduced from a response in a pseudo-property profile to a cyclic stimulation. A pseudo-property profile is calculated using a phase lag equal to half the stimulation cycle time, with and without stimulation. The properties of the sheet are deduced from the difference between an excited pseudo-property profile and a reference pseudo-property profile.

Abstract: The invention relates to a method and apparatus for determining the color and/or composition of a material. A sample of the material is illuminated with at least three separate illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range. The light reflected or transmitted by the sample is measured with at least four light detector elements responsive to light in wavelength bands which substantially span the visible range when the sample is illuminated. The width of the illumination bands differs in such a manner that the illumination bands are narrowest near the expected fluorescence absorption bands.

Abstract: The invention relates to a method and apparatus for determining the color and/or composition of a material. A sample of the material is illuminated with at least three illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range. The light reflected or transmitted by the sample is measured with at least four light detector elements responsive to light in wavelength bands which substantially span the visible range when the sample is illuminated. The measured reflected or transmitted light is compared to the light reflected or transmitted by a reference material of known apparent emissivity or transmissivity and the apparent emissivity or transmissivity of the sample is calculated therefrom.

Abstract: Method and apparatus for controlling moving paper web during manufacture or subsequent processing, wherein a web elongation profile and a moisture profile are measured. The web elongation is governed by at least two CD moisture actuators, which are situated at different stages in the web manufacturing process or subsequent processing. Means for measuring the web elongation profile and the moisture profile are situated after the CD actuators.

Abstract: The invention relates to a method and apparatus for measuring properties of a moving web. A stimulus is directed onto the moving web by an excitation element and the effect of the web on the stimulus is measured with a detection element. At the measuring point the web is supported by a measurement support sheet. The measurement support sheet comprises at least two regions having different but known responsiveness to one or more forms of stimulus or causing different but known transformation to one or more forms of stimulus.

Abstract: The invention relates to a method and apparatus for measuring and controlling optical properties of a moving web. Sensor heads are installed in the same location on the opposite sides of the web to be measured so that there is at least one means of illuminating the web and at least one means of detecting radiances on both sides of the web. At least one means of illuminating the web of at least one side is controlled so as to provide at least two different lighting states. Measuring the values in different lighting states with both means of detecting radiances simultaneously allows determination the optical properties of the web on its both sides.

Abstract: Method for operating a traversing sensor apparatus, wherein the properties of a paper web are measured through traversing such that a measuring head is moved during the measurement in the cross-machine direction. The movement of the measuring head in the cross-machine direction is stopped above the paper web and data is collected for a certain period through measurement from an area narrower than the width of the paper web, whereafter the movement of the measuring head in the cross-machine direction is continued. The data collected from an area narrower than the width of the paper web is used to calculate MD and CD values and to determine the effect of harmonic variations.

Abstract: The invention relates to a method and an equipment for defining the cross-directional properties of a sheet in a continuous sheet making process. According to the invention, the set point profile of the actuators affecting the cross-directional properties of the sheet is defined, high frequencies are filtered from the defined profile, and shrinkage nonlinearity is deduced from the filtered profile without modulating or stimulating the actuators.