Abstract: A rotating optical joint has two organs which are able to rotate independently of one other on a common axis (14). Collimators (18, 20) are mounted directly opposite one another on the organs, in an arrangement such that they permanently provide a variation of the power of the transmitted signal of less than 25%, during relative rotation of the said organs. The total number of collimators (18, 20) is preferably less than or equal to eight. Advantageously, three collimators (20) are mounted on one of the organs and four collimators (18) are mounted on the other organ.

Abstract: A detector of stains on a transparent plate surface is arranged on an internal surface of the plate and includes an emitter for emitting a modulated light signal towards the inside of the plate and a receiver for receiving the signal after it has been reflected on an external surface of the plate. An optical unit made with a material having an index substantially higher than the plate, is arranged on the internal surface of the plate. The optical unit is made up of at least three faces returning the light signal and an interface with the internal surface of the plate through an optical coupler. A deflector deflects the signal from the emitter toward the plate and from the optical unit towards the receiver. At least two reflections on the external surface of the plate are produced through the optical coupler without reflection on the internal surface of the plate.

Abstract: A process and device for continuously measuring the quantity of particles spended in a liquid, which exist in at least two different physical states, such as detached or attached within the paper pulp. A separation assembly separates the particles into divisions depending on their size, and the separation assembly is continuously fed with liquid via an input pipe. A measuring and processing assembly has two channels or ducts coming from the separation assembly and are provided with translucent windows. A measurement and capture unit illuminates the windows, and at least two cameras located opposite each of the respective windows are synchronized with the illumination unit to capture, at regular intervals, an image of the windows. A system for digitizing the captured images and processing them to determine the quantity of particles for each physical states is forwarded to an output unit in a digital or analog form.

Abstract: Apparatus for measuring the relief profile of a score line mode in a subste such as a paper board. A hand-held measuring head containing a light source illuminates the score line and the back-scattered light reflected therefrom is recorded by a CCD imager. The digital output of the imager is sent to a processor to determine one or more physical characteristics of the score line.

Abstract: A device for contactless detection of glass sheets in movement in glass installations, using a reflective photoelectric barrier, includes an emitter and a receiver (3) of light beams (4). The light beams follow a path in a channel (6) of heat-resistant material whose walls delimit a homogeneous isothermal environment, the channel emerging in the vicinity of sheet (11) to be detected.

Abstract: A device for the continuous determination of a surface state index for a ing sheet, creped in the form of undulations, comprising a light source, a first optical system, a cell intended to receive the back-scattered beam and a system for processing the beam, wherein: the light source is a laser source; the first optical system is an astigmatic system, intended to adapt the size of the laser beam at the point where it meets the sheet to the average pitch of the said undulations in the moving creped sheet; the cell is an optoelectronic cell whose sensitive surface receives at least part of the back-scattered light, concentrated by a second convergent optical system; and the processing system comprises a means for determining a surface state index for the sheet from the electrical signals.

Abstract: A device for calibrating an apparatus for measuring the formation index of a sheet of paper in which an emitted light beam is directed through the sheet of paper and detected and electronically processed into a modulated output signal. The device has a frosted glass for diffusing the measuring beam of light and an opaque rod mounted for rotation in and out of the beam of light so as to provide a modulation of the detected light of a known amount which can then be used to calibrate the measuring apparatus by adjusting the various parameters of the apparatus to yield the desired known output modulation.

Abstract: Device for detecting insipient cracks or tears on the edges (4) of a moving heet (5), of the type comprising:a light source (6),and a receiving cell for picking up the light transmitted by the source (6) through the sheet (5) moving between the source (6) and the cell,characterized in that:on the one hand, the light source (6) is a laser source;and on the other hand, the receiving cell (17) is an optoelectronic cell placed in such a way that the solid angle under which the serviceable surface of said cell (17) or of its image by an optical system, can be seen from the sheet, is less than 0.01 steradian.

Abstract: This invention relates to an apparatus for continuously measuring the state of formation of a sheet of paper which comprises: --means for moving a sheet of paper at a predetermined speed; --a light source directing a laser beam through said sheet; --a means for picking up the laser light transmitted, then for converting it into an electrical signal; --electronic processing means for separating this electrical signal into two components; --means for calculating from these components the index I representative of the state of formation; --a means for displaying the value of this index I; wherein the laser beam is polarized, and the apparatus further comprises, between the sheet and the means for picking up the laser light transmitted, a polarizer of which the axis of polarization is perpendicular to the axis of polarization of the laser beam transmitted.

Abstract: For continuous measurement of the linear speed of relative travel of an object 11 in front of a measuring device 10 two fixed zones 21,22 in the path of the object are illuminated by means of two parallel laser beams emitted by a single source 15, images of the two zones illuminated are formed upon one and the same transducer 17 the output signal from which is processed electronically by autocorrelation in order to determine the time of travel of a point on the object in going from one illuminated zone to the other.