An image of an object is formed on a matrix detector consisting of pixels and a property dependent on at least one dimension is measured by means of a value related to the object and proportional to the intensity of the optical radiation detected by at least one pixel.

The invention relates to a method and apparatus for measuring the caliper of paper substantially continuously during papermaking. A sensor (3a, 3b) is arranged above and/or under the paper (2), the sensor (3a, 3b) measuring the caliper of the paper (2) at least on one side of the paper (2) mainly without contacting the surface of the paper (2). At given intervals the sensor (3a, 3b) measuring mainly without contact is brought into momentary contact with the surface of the paper (2).

The invention relates to a method and apparatus for measuring paper color. Paper color is measured from the surface of a paper roll on a winder. As the size of the paper roll grows, a measuring device is moved in such a way that the angle between the measuring device and the surface of the paper roll is kept substantially constant and, at the same time, the distance of the measuring device from the surface of the paper roll remains substantially constant

The invention relates to a method and equipment for controlling properties of paper, which method comprises modelling the effect of the flow of retention agent (F.sub.ra) both on the amount of filler in the white water and on the paper ash content (ASH), and the effect of the flow of filler (F.sub.fi) both on the paper ash content (ASH) and on the amount of filler in the white water. The fulfilled modelling is used to adjust the amount of filler in the white water and the paper ash content (ASH)...

A method and arrangement for controlling short circulation in a paper machine, in which the control of at least one property of the diluted fiber-containing pulp conducted to the headbox is based on consistency measurement or determination in high-consistency fiber-containing pulp, diluted pulp and/or white water. The amount of fiber-based fines in high-consistency fiber-based pulp, diluted fiber-based pulp and/or white water is determined, and the result obtained is used for controlling at leas...

A method and an apparatus for measuring the amount (CW) of a coating (2) on a paper web (1). The amount (CA) of at least one component in the coating (2) on the paper web (1) is measured and the composition (CC) of the coating (2) to be transferred to the paper web (1) is determined. The amount (CW) of the coating (2) on the paper web (1) is determined on the basis of the amount (CA) of at least one component in the coating (2) on the paper web (1) and the composition (CC) of the coating (2) to ...

The invention relates to a method for measuring and analyzing the performance of a control circuit in an industrial process. Different parameters (indices) illustrating the state of the control circuit are combined in an intelligent manner such that each combination of index (VI, IAE, CTI, OI) values represents a specific example state of the control circuit. The indices and combinations of their values are selected in advance on the basis of expert knowledge and process research. A momentary st...

The invention relates to a method and a system for determining hysteresis of a process device in a process environment. The process comprises collecting (50) second-level sample data ys and us from control and measurement signals u and y of a control circuit. Minute mean values y(min) and u(min), which are stored in a database (52), are calculated from these second-level measurement values. The pairs suitable for hysteresis calculation are selected from the minute-level sample pairs um and ym ac...

Adjusting the operation of a wire section, in which the development of the consistency of stock on the wire section (2) is determined and the effect of the consistency determined above on the formation and/or porosity of a paper web (3) is determined. The consistency developed on the wire section is adjusted based on a quality property of paper and/or by optimising a cost function, the quality property of paper comprising the formation and/or the porosity and/or a combination defined by means of...

The invention relates to a method in the control of the quality or the condition of a fibre web (21) on the basis of optical imaging diagnostics, wherein the fibre web (21) under examination and/or means (22, 23) relating to the processing of the fibre web are monitored with at least one optical imaging measuring device (1 to N). According to the method, the scale of the observation area of said at least one imaging measuring device (1 to N) is calibrated, when said measuring device is taken int...