Abstract: Colored markings such as a series of colored rings applied to an ampoule are read by causing the ampoule to move beneath an illuminating system which projects white light at the colored markings. Light reflected or scattered from the colored markings is directed at an aperture member arranged in the field of view of a color sensitive photoelectric detector arrangement and the image of the colored markings moves in a first direction across this aperture member due to relative movement of the object. The aperture member has a series of spaced apart optical apertures which are sequentially moved in a second direction transverse to the first direction and in front of the photoelectric detector arrangement. The photoelectric detector arrangement produces signals corresponding to the transmission of the image of the colored markings through the optical apertures.

Abstract: A flow velocity meter is described suitable for measuring the mean flow velocity of a medium flowing along a duct using optical means which generates first and second beams of light each in the form of a relatively shallow wide band which traverse the duct across first and second spaced apart transverse planes which are arranged substantially at right angles to the mean flow direction. Light beams emerging from the duct are received on respective photoelectric detectors the output signals of which are essentially identical but relatively displaced because of the time required for the medium to flow between the two planes. By processing the signals in a correlation circuit this time is established and is used to produce an output proportional to the mean flow velocity of the medium between the two planes. The correlation circuit used is based on digital techniques.

Abstract: An optical apparatus for use in conjunction with spherically shaped concave mirrors for substantially eliminating aberrations in the reflections from such mirror. The mirror cooperates with a light source or a light receiver placed in the vicinity of but off-set relative to the natural focal point of the mirror. A plane parallel, transparent plate is placed between the mirror and the light source or receiver and it has a size so as to intercept light rays between the mirror and the light source or receiver and which respectively result in or are caused by light beams oriented parallel to the optical axis of the mirror. Use of the invention for additionally correcting astigmatism and chromatic aberrations caused by spherical mirrors is disclosed. Also disclosed is the use of the invention in connection with large spherical mirrors forming part of light curtain arrangements.

Abstract: A light conducting rod in which light incident on the surface of the rod is conducted along the rod to its end faces for subsequent detection. The light entering the rod is incident on three neighboring linear arrays of individual mirrors formed along the diametrically opposite surface of the rod; each individual mirror is inclined towards the axis of the rod and cylindrically curved so that the light is reflected back onto the internal surface of the rod at an angle which ensures total internal reflection.

Abstract: A monitoring system for detecting the presence of folds, creases, etc., in the surface of a moving web of material such as paper. The system utilizes a laser light beam arranged parallel to the surface of the web and transversely to the direction of movement thereof. A light detector such as a differential photo electric detector senses changes in the light beam caused by impingement on a fold or crease.

Abstract: A light smoothing device for rendering a non uniform distribution of light more uniform especially suited for use in line scanning in combination with a light conducting rod which transmits light incident on its surface to its end faces for subsequent detection. The smoothing device has an optical passage with a reflecting interior surface an inlet to the passage and a detector at the other end of the passage. The passage ensures at least part of the light entering the inlet is reflected prior to incidence on the detector.A number of forms of optical passage are disclosed having various reflecting segments of convex, plain or concave curvature.

Abstract: A photo electric light detection device comprising an array of photodiodes is disposed at an end face of a light conducting rod in order to produce an output signal proportional to light incident on the surface of the rod and transmitted to the end face by total internal reflection. The array of photodiodes is subdivided into high and low pass frequency sub-arrays and the output signals from the sub-arrays are summed and processed to compensate for stray light. The device is useful in connection with a line scanner for detecting anomalies in a moving band.

Abstract: A light barrier system for monitoring the presence or absence of an obstacle in the monitored area and for simultaneously monitoring itself to detect contamination of the system. A photo-converter emits signals indicative of the light intensity of a light barrier beam and the signal is applied to a first, obstacle switch which is normally open but which closes at a relatively high level of darkness, i.e. when an obstacle is present. A converter signal is also applied to a second, contamination switch which is normally open but which closes at a lesser degree of darkness than the first switch so that both switches can be simultaneously closed. The outputs of the switches when closed are applied to relays to switch the relays between alternative position to indicate (a) the presence of an obstacle in the light curtain area and (b) the contamination of the light curtain system irrespective of whether or not an obstacle is present.

Abstract: A photoelectric detection system which has two sequential photoelectric receivers to determine the precise moment at which the boundary between two contrasting fields passes beneath the detectors irrespective of the relative contrast between the two fields. The signals from the two photoelectric detectors which change as the boundary progressively obscures their respective fields of view are firstly subtracted to produce a difference signal. The difference signal is then passed to a gated maximum value store which is operative during each difference pulse to store the maximum value of the difference occurring during that pulse. A fraction of this maximum value is then taken and compared with the instantaneous value of the difference as this value reduces, when these two values are equal an output pulse is generated and this output pulse always occurs at the same position of the boundary relative to the photoelectric receivers irrespective of the respective levels of contrast on either side of the boundary.

Abstract: A method for the formation of a comparison square wave signal having a reference edge in a curve control device in which a scanning head periodically transversely scans a line to be tracked and transmits a base comparison square wave signal and a measurement square wave signal whose phase position is a criterion for the divergence of the scanning head from the desired value, and is determined by comparison with the position of the base comparison square wave signal, whereby a follow-up signal is formed which is dependent on the direction of the divergence. The method comprises forming by frequency halving, integration and threshold means, needle pulses from the base comparison square wave signal produced by the scanning head, each successive pair of the needle pulses being completely symmetrical to the reference edge and wherein the comparison square wave signal is formed from the needle pulses and the reference edge.

Abstract: Optical apparatus for extending a light curtain, using a light beam shifted periodically laterally parallel to itself onto an array of plane mirrors at an angle to the beam, the span of the array normal to the emergent reflected beam being greater than its span normal to the incident beam.

Abstract: A curve follower device having an optical scanner head circularly scanning a guide region containing a guide line and a separate code region provided at least on one side of the guide region, the measurement point of the head being a predetermined distance from its pivot point in the direction towards the guide line, and the head being movable along the guide region at a speed considerably slower than the scanning speed and being connected to a control device which forms from the signals delivered by the scanner head, control signals for the movement of the scanner head along the guide line. In the code region marks associated with the guide line as detected by the scanner head are provided in order to initiate further control commands in the control device, the length of the marks being greater than the width of the guide line.

Abstract: A line scanning device for detecting defects in webs of material, wherein a laser light source throws a light spot by way of an objective, a light deflector device, and a cylindrical lens onto a web of material moving parallel to its surface, the light spot periodically scanning the web at right angles to the direction of its movement and parallel to its surface, and wherein a light receiving arrangement comprising a rod light guide and at least one photoreceiver is disposed parallel to the web of material and to the direction of scanning. The rod light guide carries a step mirror arrangement on that side of its periphery lying opposite the light inlet, and a light-scattering cylindrical lens grid, the axes of whose lenses extend in the scanning direction, is disposed between the light source and the objective.

Abstract: An apparatus for concentrating light from a linear field on to a relatively small receiver disposed at the end of a rod light guide on the peripheral surface of which light emanating from the linear field is directed. The linear field is arranged substantially at the focal distance from a first concave strip mirror which is disposed so as to extend optically parallel to the field and reflects the incident light from the field to a second concave strip mirror which is optically parallel with the first mirror and forms therewith a substantially telecentric system and which, in turn, reflects the incident light to the peripheral surface of the rod light guide.

Abstract: Apparatus for combining light emanating from a linear scanning field on a relatively small receiver via an optical arrangement producing a scanning light spot with a light ray scanning device onto which a light beam impinges, the arrangement further having optical elements of the transmitting beam of rays located in front of the light ray scanning device, a transmitting concave mirror and a receiving concave mirror extending in the scanning direction, and a cylindrical lens parallel to the scanning field and extending in the vicinity of the latter, the transmitting and receiving beams of rays being separated by pupil separation.

Abstract: A light curtain for scanning rectangular openings with an oscillating light beam originating in a corner of the opening. A photo-detector is placed in the same corner. Retroreflectors, such as triple reflectors are placed on adjacent sides of the opening which are opposite the light source for reflecting light back to the photo-sensor. Above a critical reflection angle for the retroreflector, a plane mirror is provided which directs light from the source to the retroreflector on the adjacent side so that light impinging on the mirror at an angle exceeding the critical angle is received by the adjacent retroreflector at an angle that is within the critical angle. Consequently, such light is reflected via the plane mirror back to the photo-sensor. The light can be modulated to facilitate the monitoring of the area encompassed by the opening.

Abstract: A door securing light barrier with a plurality of optically active devices, between which the light barrier beam extends through at least part of the door opening and whereof one emits an electrical signal when the light barrier beam is broken, the angle of the light beam of the light beam emitting device being adjustable relative to a fixed casing.

Abstract: Optical apparatus for determining the angle at which light is reflected by a surface being scanned by light spot, wherein in the area of the light beams emanating from the surface is provided a lamellar stepped mirror arrangement which extends in the scanning direction and whose individual planar mirrors are arranged parallel to one another and deflect the light which strikes them to an optical system on whose focal plane is arranged a photo detector array extending at right angles to the optical axis.A particular application occurs in conjunction with monitoring webs of fabric or paper for surface irregularities faults or errors.

Abstract: Bottle color identification apparatus with a light beam passing through the bottle, in which the light beam passing through the bottle is supplied to a spectral decomposition arrangement which emits a signal characteristic of the bottle color.A special application of the invention is the sorting of returnable bottles having the same size and shape but different colors.