Abstract: An optical fiber evanescent wave fuel sensor, employing a light source with a wavelength selected to be at the strong infrared absorption lines of the fuel, typically hydrocarbons. The amount of light leaking from the optical fiber is an exponential function of the length of the fiber in the liquid, and is independent of the relative indices of refraction of the fuel and fiber cladding material.

Abstract: A method for measuring eccentricity uses two radial gratings, in annular areas of which elementary patterns are provided at equal intervals so that the patterns of one radial grating are opposite to those of the other radial grating rotated by 180.degree.. Reference lines are provided on a rotary axis having eccentricity to be measured, coordinate axes relative to a bisector of the patterns opposite to each other are provided parallel with the reference lines, and spaces between the coordinate axes and the reference lines are measured, thereby allowing the shift of the rotary axis to be found. Thus, the eccentricity of the rotary axis can be measured with high accuracy.

Abstract: An apparatus and electronic circuit for the measurement of fluid levels in containers. The circuit and apparatus constitute an instrument which measures fluid levels by optical means. Only light signals are used near the fluid itself. The instrument thus provides an intrinsically safe method of measuring fluid levels in the presence of explosive or flammable fluids, vapours or gasses, or in containers which must be electrically isolated.

Abstract: An optical device for sensing marks carried on an area to be sensed of a medium, especially printed and/or handwritten patterns, is disclosed. Sensing of marks is accomplished by inclined illumination of the area to be sensed by a light source (3) emitting shortwave light, especially in the green spectral area, and reception of reflected light by a photoreceptor (4).

Abstract: A light source which is stabilized in frequencies at uniform intervals comprises a light source 5 whose light frequency is varied with a signal from a reference signal source 4; a frequency detector 6 for detecting the frequency of the output of the light source 5, the cycles of the said frequency detector being the same as the uniform intervals; a comparator 2 for comparing the output of the frequency detector 6 and the output of the reference light source 1; and a switch 3 having as its input the output of the comparator 2 for inputting the output to the light source 5, said switch being so operated that when the frequency of the light source 5 is to be changed the switch is opened and the output of the reference signal source 4 is changed to set the output frequency of the light source 5 near the desired frequency and then the switch 3 is closed.

Abstract: A method and apparatus are provided for detecting bar-space and space-bar transitions in a bar code symbol. A sequence of sparsely sampled analog signals from a photodetector in a bar code scanner is representative of the reflectance pattern of a symbol.Following initialization, a threshold, representing the value of the analog signal at a transition point, is derived from observed samples of the bars and spaces in the bar code symbol. Sampled reflectance information is accumulated as the symbol is scanned, and a program driven microprocessor calculates and repeatedly updates this threshold, using observed maxima and minima in the analog samples, and also referencing a binary output to determine whether a bar or space is currently being viewed.When the values of two successive analog samples bracket this threshold, then a bar-space or space-bar transition has occurred. Linear interpolation is performed on the two samples to determine the transition point and an offset from the first of the two samples.

Abstract: A scanning confocal microscope scans a sample with an incident beam of radiation, in a raster scan pattern, causing the sample to fluoresce and emit visible radiation in at least two wavelengths. A portion of the fluorescent light retraces a portion of the path optical of incident beam, to a dichroic mirror that separates it from the incident beam for detection by a pair of photomultiplier tubes. A data processor accumulates digital data from the photomultiplier tubes to form a succession of image data frames of the sample being scanned, in the two wavelengths. Image data for a selected number of frames in each wavelength is averaged and then recorded on a single track of a recording system, in an alternating fashion with averaged data for the other wavelength. In addition, a ratio of the averaged data for the two wavelengths is delivered to a video display.

Abstract: In an edge detector process, a working plane (A) is scanned by a focussed light beam, e.g. a laser beam emitted by a light source (L) projected at an angle of typically 40.degree. to 45.degree. from the working plane. A first and a second detector (D1, D2) receive the scattered light from the working plane. The first detector (D1) is positioned behind a focussing imaging optics (0), such as an off-axis parabolic mirror, which is arranged coaxially, i.e. all round the laser beam, or is positioned below the emitted light beam relative to a main working plane (H). The second detector (D2) is positioned approximately over the light spot produced by the emitted light on the main working surface. The stray light measured by the first detector (D1) is therefore received at an angle to the main working plane, which is equal to or smaller than the angle between the emitted light and said plane.

Abstract: An object sensor and method using pulsed laser range imaging technology is adapted for controlling an agricultural spraying system. A single laser sensor employs a continuously scanned pulsed laser transmitter and optical receiver to determine the presence or absence of foliage in predetermined spray zones to selectively control spraying only in those spray zones where foliage has been sensed. Range and distance data are also collected and stored in a microprocessor for use in determining the appropriate zones requiring spraying.

Abstract: An optical sensor, having serviceable electronics, for monitoring the level of a liquid within a vessel having an exterior and an interior and for providing an electrical signal on the traverse of the liquid level past the sensor. The sensor comprises a fitting adapted to traverse the vessel wall, the fitting including a window having a prism shaped interior face and a planar exterior face sealed into the fitting and providing a fluid-tight optical path from the vessel interior to the vessel exterior. The fitting includes a chamber adjacent the planar face of the window and an electronic module shaped to fit the chamber. The module has an optical face. A light source and a light detector are positioned in the optical face to provide substantially zero clearance light communication between the window and both the source and the sensor, when the module is positioned within the chamber.

Abstract: A moisture sensor device for detecting the degree of wetting of a transparent pane by drop-shaped precipitation. The sensor device is provided with a beam guide element, which is affixed to the pane by an optical adhesive. A beam transmitter and a beam receiver are each associated with a lens. Such a sensor device solves the problem of guaranteeing optimum conditions for the generation and output of rays into and out of a beam guide element. Aspherical lenses are associated with and arranged at a short distance from the beam transmitter and the beam receiver. Each lens has a surface facing the beam transmitter or beam receiver which in outline is fashioned according to a polynomial selected to be equal to or greater than the third degree and is developed to form a body of rotation.

Abstract: A multichannel imaging spectrometer for airborne geological, geophysical and environmental surveys in a moving vehicle. An optical scanner employs a rotating polygon allowing reduced scan optics with increased data acquisition efficiency. Multiple spectrometers integrally registered allow channelization of the received signal to optimize noise performance in the range from ultraviolet through infrared. Output data is in a form for recording and real time display. A staring mode configuration provides enhanced sensitivity by using a two-dimensional detector array and adjustable mirror orientation. A scanning mode embodiment employs a two-dimensional detector array with time delay integration and three-dimensional storage of temporal spatial data and spectral wavelength and intensity. Thus, all channels are acquired simultaneously, resulting in perfect band-to-band registration with continuous spectral curves over the field of view.

Abstract: The invention relates to a method and an arrangement for selective driving of valves of small drive power by means of light. A control generates control signals which are modulated onto a light source which emits said control signals which are received by all the valves via solar cells. However only the addressed valve is switched. No cabling is necessary between the control and the valves.

Abstract: The present invention relates to a method and to an apparatus for detecting the presence of bark and for determining the barking degree of wood or chips. Accordingly, the apparatus includes a light source (12) which directs a concentrated light beam (14) onto the measurement object (16), for instance a log which is moved continuously in a transport chute (20). The shape and/or size of the light image obtained on the log (16) at the point (18) on which the light beam (14) impinges on the log is detected with the aid of a camera (10), preferably a CCD-camera. The shape and/or size of the light image is mutually different for wood and bark. The detection values obtained by the CCD-camera (10) are evaluated in a processing means.

Abstract: A device for detecting a specific liquid level, that can be mounted externally on a transparent or translucent vessel wall, and is insensitive to ambient light. This device utilizes a single light detector and a pair of AC activated light sources. The light sources produce reflected light signals which, when balanced at the detector, cancel. When liquid is absent the light signals are balanced, and no signal is detected. When liquid is present the extra signal reflected by the meniscus causes the light signals to become unbalanced, and a signal is detected.

Abstract: A rotary coupler comprises a rotary transformer which transfers power across an air gap and an infrared coupler that carries data across the air gap in duplex. The rotary transformer and the data coupler are built within an enclosure to withstand downhole conditions. Control circuitry comprising a pulse width modulator regulates the amount of power transferred across the air gap by the rotary transformer. The data coupler comprises two transmitter/receiver array pairs to transfer data across the air gap in duplex.

Abstract: An apparatus for imaging and analyzing particle components in a sample liquid flow containing particle components such as blood and urine, or fine particles of organic high polymer in suspension or the like. A conventional particle imaging flow cytometer is combined with a light source such as a lamp with small coherence, and an image intensifier with gate function of high response, so that a clear particle image without a deflection or interference fringe is obtained. Thus, in the apparatus having the still imaging function, by using the image intensifier with a high speed gate function, even with a light source of a long luminous time such as a lamp, a clear still image of a particle flowing at high speed is obtained.

Abstract: An optical beginning-of-tape detection device with automatic threshold adjustment. In a first embodiment, at two different locations on a tape, a comparator threshold is varied until the comparator switches states. The two locations are sufficiently far apart to guarantee that at least one measurement is not at the beginning-of-tape indication area. The greater of the two thresholds is used, with a predetermined offset for noise margin. In a second embodiment, the threshold is continuously adjusted through a diode across the comparator inputs. The threshold is initialized by moving the tape sufficiently far to guarantee that at some time during initialization the sensor is not at the beginning-of-tape indication area.

Abstract: A radiographic imaging system includes a quality control workstation for processing a digital radiographic image signal in either a pass-through mode or a manual mode. In the pass-through mode, the digital radiographic image signal is automatically processed according to preselected image parameter values to produce one or more versions of image processed digital radiographic images which are automatically routed to preselected destinations. In the manual mode, a preselected version of image processed digital radiographic image is displayed to be verified by a user. The user can also change image parameters to change the displayed radiographic image. The user then routes the image processed radiographic image signals to preselected destinations or user selected destinations. Preferably, the digital radiographic image signal is produced by a storage phosphor reader which converts a latent radiographic image stored on a storage phosphor into said digital radiographic image signal.

Abstract: The present invention is directed to a solid state image sensing device which can reduce a consumed amount of an electric power.During a horizontal blanking period, a vertical scanning pulse of 5 V is supplied to a vertical selection line (2A) from a vertical scanning circuit (3). In synchronism therewith, a voltage (.phi.I) is changed from 5 V to 0 V and a voltage (.phi.VGG) is changed from 0 V to 5 V. Thus, a source switch transistor (6) is turned off and a load transistor (9) is turned on, whereby a source follower circuit formed by a pixel transistor (12) and the load transistor (9) of a unit pixel (1) is set in the operable state to read an electrical signal accumulated in the unit pixel (1). According to the present invention, the load transistor (9) is turned on by the application of the voltage (.phi.VGG) only during the electrical signal read-out period and the dark signal read-out period of the unit pixel within the horizontal blanking period.