Abstract: A system for analyzing smoke has a plurality of units, wherein each unit includes an optical emitter for alternately directing horizontally and vertically polarized light along a beam path, and into a smoke cloud, to generate scattered light. A horizontally polarized detector and a vertically polarized detector are positioned at different locations, but at a same distance and scattering angle relative to the beam path. Each unit has a different wavelength. A computer receives signals from the detectors of all units, in response to each emitter, for analysis of the smoke.

Abstract: A method for determining optical density is disclosed. A first measurement is taken on a white area of a substrate (402). A second measurement is taken on an area of the substrate printed with ink (404). A relative optical density of the ink is determined using the first and second measurements (406).

Abstract: The present invention provides a method and apparatus for determining intensities and peak wavelengths of light. The apparatus comprises one or more pairs of sensing units for sensing the light, a first sensing unit of a pair configured to sense a first intensity of the light in a first predetermined wavelength range with a first predetermined spectral responsivity and a second sensing unit of a pair configured to sense a second intensity of the light in the first predetermined wavelength range with a second predetermined spectral responsivity. The apparatus further comprises a processing system operatively connected to the one or more pairs of sensing units; the processing system configured to determine the intensity and peak wavelength for each of the one or more predetermined wavelength ranges of the light according to one or more predetermined functional relationships between each of the first intensity and second intensity.

Abstract: An optical power meter is provided which can measure with high accuracy a power of a light-to-be-measured containing a plurality of wavelength of light and light-to-be-measured having a broad wavelength region without incurring cost rise and without the necessity for the user to input an wavelength of a light-to-be-measured. In an optical power meter for measuring a power of a light-to-be-measured, there are provided a photodiode having a sensitivity characteristic that sensitivity changes in accordance with a wavelength of a light incident on a light-receiving surface and a dielectric multi-layered film filter arranged on a side of the light-receiving surface of the photodiode and having a wavelength characteristic substantially reverse to the sensitivity characteristic of the photodiode.

Abstract: A range selection circuit (13), including a logarithmic amplifier (23) and output circuitry (25) associated therewith, is configured to directly drive linear ranging circuitry for measurement circuitry (12) in an optical power meter (10) to measure signals that vary over a wide range of, for example, from about -7dB to about -45dB. This allows the optical power meter to change ranges as fast as one (1) times the hardware settling time. The range selection circuitry is in parallel with the measurement circuitry, which allows ranging to happen in real time.

Abstract: A method for describing pattern repetitiveness which may exist within an image, is provided. The method of describing pattern repetitiveness of an image comprises: (a) projecting an image on a predetermined axis having a predetermined direction, (b) decomposing the projected image down one level, (c) increasing a threshold value until a pattern quantizing value is retained, and denoising the decomposed data, and (d) describing pattern repetitiveness of the image using the pattern quantizing value of the denoised data and the threshold value used for denoising. Because the method of describing pattern repetitiveness of an image effectively denoises the original image without damaging the pattern repetitiveness of the original image, and the pattern repetitiveness is described using the denoised data, it is possible to describe more definite pattern repetitiveness.

Abstract: An electro-optical apparatus particularly suitable for exposing a sample of light sensitive material to provide a graded series of exposures of different intensity levels. The apparatus includes a light source, beam shaping optics, and a rotatable polarizer. The light source provides a Gaussian beam of light directed along an optical axis. The beam shaping optics are disposed in the optical path and are adapted to expand the Gaussian beam of light into an elongated beam of light and to project the elongated beam of light along the optical axis toward a sample. The rotatable polarizer, disposed in the optical path intermediate the light source and the beam shaping optics, is rotated to vary the intensity level of the beam of light.

Abstract: A method for manufacturing a thin film AMA is disclosed. The second sacrificial layer is formed by using amorphous silicon, poly silicon or a material having fluidity and the first sacrificial layer is formed by using amorphous silicon or poly silicon. The light efficiency is enhanced by the reflecting member having an even surface after the first and the second sacrificial layers are formed in order to have even surfaces. In addition, the active matrix, the active layer and the reflecting member have no damages because the second sacrificial layer is removed by using the oxygen plasma or the vapor of bromine fluoride or xenon fluoride and the first sacrificial layer is removed by using the vapor of bromine fluoride or xenon fluoride.

Abstract: Apparatus for measuring power in a laser-beam includes a transmissive diffuser for diffusely expanding the laser-beam and a photon detector for receiving the diffusely-expanded laser-beam and generating an electrical signal in response thereto. Electronic circuitry including a microprocessor is provided for interpreting the electrical signal as a measure of power in the laser-beam. A display device is provided for displaying the interpreted signal.

Abstract: A measurement circuit having high dynamic range includes high-gain and low-gain amplifiers connected in parallel. A shunt feedback circuit is activated to prevent the high-gain amplifier from saturating when the magnitude of an input signal exceeds its dynamic range. The output of the high-gain amplifier is utilized to measure small input signals and the output of the low-gain amplifier is utilized to measure large input signals.

Abstract: Apparatus for measuring power in a laser-beam includes a transmissive diffuser for diffusely expanding the laser-beam and a photon detector for receiving the diffusely-expanded laser-beam and generating an electrical signal in response thereto. Electronic circuitry including a microprocessor is provided for interpreting the electrical signal as a measure of power in the laser-beam. A display device is provided for displaying the interpreted signal.

Abstract: An optical power meter which is capable of performing power range switchover operations in short periods of time and are capable of performing optical power measurements over a wide range in short periods of time. The invention comprises a photodiode 101 which outputs an electrical current proportional to the input optical power, an I/V amp 102 which converts this electrical current into voltage, a variable-gain amp 103 for amplifying this voltage, an A/D converter 107 which converts the output voltage from this variable-gain amp into a digital signal, a CPU 110 which processes the digital signal outputted from this A/D converter 107, and saturation detecting comparators 108 and 109 which detect saturation of the I/V amp and the variable-gain amp. The CPU 110 switches the gains of the I/V amp and the variable-gain amp based on the output signals from the saturation detecting comparators.

Abstract: A high speed, automatic calibration system of laser (or other light source) sensitometers capable of a wide range of power measurements, of densitometers and of other optical power measuring systems, and particularly to an automatic gain scaling circuit for use in the same. The system measures optical power incident on a photodiode detector in the course of calibrating or using a sensitometer and automatically and rapidly selects the appropriate gain for the operational amplifier. An automatic gain scaling function performed in gain scale logic rapidly selects the proper gain of a transimpedance operation amplifier operating as a current to voltage converter and delivers an analog voltage signal within a range between an upper limit and a lower limit. An over range error signal is generated in response to an upper out of limit signal generated at the minimum gain set by said gain scale logic.

Abstract: A light metering device incorporates a light dependent resistor as a light sensing element, a network including a plurality of circuit elements, and a selection mechanism for selectively connecting the light dependent resistor to one of the plurality of circuit elements in the network. The selection mechanism is controlled to set a voltage measured at an output terminal of the light dependent resistor within a predetermined threshold level. The light metering device can be readily incorporated in both photographic and electronic cameras.

Abstract: An illuminant discriminator distinguishes a range of separate illuminants, including high efficiency fluorescent lighting, by modifying the frequency response of a signal output from a photodetector. A switchable high pass filter coupled to the photodetector has a first filter section with a first cutoff characteristic selected to pass signal components due to various types of lighting including high efficiency lighting, and a second section with second cutoff characteristic that separates out the high efficiency components. The high pass output is processed by a log amplifier to develop flicker frequency harmonics that are distinguished as to source illuminant by comparator stages. Undersampling artifacts due to high efficiency lighting are present in the mixed illuminant spectrum when the first filter section is operative, and positively identified as high efficiency lighting when the second section is operative.

Abstract: A wide dynamic range optical receiver has low and high sensitivity signal channels for converting first and second portions of an optical input signal into voltage values representative of the various portions of the optical input signal. The voltage signals are converted into digital values by a converting means and a reconstruction is performed in a combining means to produce a digital output representative of the optical input signal. The wide dynamic range optical receiver may be used in an optical signal measurement instrument, such as an optical time domain reflectometer, where the optical return signal from a fiber under test is coupled to the wide dynamic range optical receiver in first and second portions with the first portion having an optical power level substantially less than the second portion.

Abstract: The present invention relates to a chemical luminescence-detecting apparatus that is provided with a plurality of optical detectors different in sensitivity in the vicinity of a photometric cell. A ratio of outputs from the optical detectors based on intensity of luminescence is previously determined and stored. Signal processing can multiply an output of a low sensitivity optical detector by a factor determined by the stored ratio to measure the intensity of luminescence so that a conversion value corresponding to an equivalent output from a high sensitivity optical detector may be obtained when the output from the high sensitivity optical detector has become saturated.

Abstract: A printer has a light source and an objective which direct a light beam along a predetermined path, and a unit in the path for measuring the density of a master to be reproduced. The measuring unit includes a filter combination of at least two filters downstream of the objective and a light sensor downstream of the filter combination. The filter combination has a transmission pattern which shifts as the angle of incidence of the light beam on one or more of the filters changes. At least one of the filters is pivotable in order to vary the angle of incidence of the light beam on the same. This allows the transmission pattern to be shifted so as to adjust the measuring unit to the spectral sensitivity of the copy material used for reproduction of the master.

Abstract: An indicator circuit is provided for an apparatus that measures the concentration of a selected component in a test sample. The apparatus generates a test voltage that represents the concentration of the component in the test sample. The circuit generates a series of range voltages, each of which represents a respective one of a series of potential concentration ranges of the component in the test sample. A switching circuit selects an adjacent pair of range voltages immediately above and below the test voltage and applies the selected range voltages across an incremental voltage divider such that the voltage difference of the selected range voltages is divided into a series of incremental voltages, each of which represents a respective one of a series of potential incremental concentration levels of the component within each concentration range.

Abstract: A light detector which indicates decrease in the level of ambient light below a prescribed value. The light detector includes a light indicator for radiating light when the level of ambient light decreases below the prescribed value, a light sensor arranged parallel to the light indicator for receiving actual light including ambient light and light from the light indicator for outputting a detection signal corresponding to a level of actual light, and a control circuit for evading effect of the light from the light indicator for controlling the operation of the light indicator while ambient light is below the prescribed level even though the actual light received by the light sensor increases above the prescribed level.

Abstract: A device for measuring the intensity of light received by a photosensor comprises a photosensor for receiving light and producing a corresponding current and a circuit for integrating the current so that the intensity of the received light is indicated as the time required for the integration value of the integrating circuit to reach a predetermined value. If the intensity of the light is determined to be high at the start of the integration operation the integration value is set to the smaller of two predetermined values. If the intensity of the light is low, the integration value is set to a larger value.

Abstract: An apparatus for measuring a radiation characteristic of a laser diode. An AC signal and a step-like DC voltage are applied to the laser diode and the radiant power output thereof is received by a photodiode having an output to which a first amplifier, a transformer, a capacitor and an AC amplifier for extracting the AC signal. The apparatus further comprises a first switch connected between the input of the first amplifier and the capacitor, and a second switch connected between both ends of the transformer. Every time the step-like voltage is stepped up, the first and second switches are closed for a short time as compared with the duration of a step period to protect the measurement from the influence of the change in the DC voltage.

Abstract: An optical power meter system comprises a chopper with a semicircular total reflection mirror along an incident light path, two photo-detectors of different characteristics of wavelength sensitivity, and a comparator for comparing the levels of the photo-detection signals derived from the two photo-detectors and for outputting the optical detection signal of a higher level. The photo-detectors are positioned in a first path of the light passing through the chopper and a second path of the light reflected by the chopper, respectively. The comparator may be replaced by an adder for adding the photo-detection signals derived from the two photo-detectors.

Abstract: An improved optical endpoint detector is disclosed in which two photocells are used in conjunction with analog multipliers and variable voltage sources, all under microprocessor control. The combination enables one to measure the ratio of intensity of different emission lines, as well as their individual outputs and alternative process monitoring signals.

Abstract: Light induced current from a photodiode is converted into a voltage proportional to the integral with respect to time of the current using two serially connected integrating operational amplifiers. In each case the integrating capacitors are connected so that the photodiode is part of the charge current for the capacitors. The amplifiers operate in sequence.

Abstract: An image reader having a high sensitive detection system for detecting a variation in a first light quantity to generate a first output, a low sensitive detection system for detecting a variation in a second light quantity to generate a second output where the second light quantity is greater than the said first light quantity, and a signal composing circuit for receiving the outputs of the high and low sensitive detection systems, each of the detection systems being so disposed as to detect simultaneously or substantially simultaneously a ray bundle from a picture element of a picture, and the output of the signal composing circuit being (a) the output of the high sensitive detection system when the received light quantity is smaller than a threshold light quantity which can be detected with substantially the same degree of accuracy by both the detection systems or (b) the sum of (i) the output of the low sensitive detection system and (ii) the difference between the outputs of the detection systems at the t

Abstract: A light measuring device includes one or more photodiodes, which generate current in relation to the received light, and at least one capacitor for integrating the generated current. The amount of charge stored in the at least one capacitor at the completion of the integration is roughly detected by the number of capacitors used and/or the voltage across the capacitor. A current source capable of producing different levels of current in accordance with the detected amount of charge is provided for changing the amount of charge stored in the at least one capacitor. The time needed to change the amount of charge stored in the at least one capacitor is measured so as to obtain the value of total amount of the change in the charge stored in the at least one capacitor and to thus obtain the value of the received amount of light intensity.

Abstract: An arrangement for measuring exposure in which an adapter is attached to an electronic exposure meter. The adapter has at least three plugs mating with corresponding sockets on the exposure meter. The exposure meter has a circuit supplying a measured voltage which is a linear function of the logarithm of a measured magnitude. A defined constant voltage is taken from the exposure meter circuit and applied to two sockets. The adapter has a voltage divider whose external connections are formed by two plugs which apply a constant voltage upon plugging the adapter to the exposure meter through the sockets. The voltage divider has a tap which is connected to another plug that is, in turn, connected, through the associated socket in the exposure meter, to a point in the circuit where application of a correction voltage results in a change in measured voltage equivalent to an increase in the measured magnitude.

Abstract: The meter senses flashes of illumination, it converts the illumination to an electrical current whose magnitude is proportional to the intensity of the illumination; it integrates the current over a period of time corresponding to a selected shutter speed by charging a capacitor; it discharges the capacitor and measures the time required to do so; it converts the time required to discharge the capacitor into a corresponding signal representative of an appropriate camera aperture setting for a preselected film sensitivity and shutter speed via a microprocessor and a stored data program; and then displays the camera aperture setting on a multi-segment display. This process is repeated with each new flash of illumination automatically. The meter also measures multiple flashes and displays an accumulated camera aperture setting as well as the number of flashes needed to accumulate that setting.

Abstract: The sensing device is a light level indicator that comprises a light sensitive element such as a photo resistor, associated detection circuitry and "go" and "no go" indicator lights which determine whether the level of illumination is above or below a predetermined acceptable level for a given area being tested. The device may be constructed with two light sensitive elements one for sensing direct light and the other for sensing reflected light, or alternatively, the device may have only either element. A multi-position switch may also be provided which can be set at any one of a number of different threshold levels. An adapter is used with the device for checking the calibration of the device. This adapter comprises a radioactive source, holder and a mask which is periodically replaced for maintaining the source at a constant light output.

Abstract: A device is provided for controlling the sensitivity of a receiver of the type comprising a photosensitive element operative to convert radiant energy into electric signals and having an amplifier connected to the output of the photosensitive element and signal processing members for separating a useful signal from interfering background radiation. A sensor device is connected to the photosensitive element to sense the direct current which the element emits in response to radiation from the sun or other strong sources of disturbance, the sensor device being operative to emit a signal when the direct current exceeds a predetermined value, and a switching device responsive to said signal operates to switch the amplifier from a given fixed sensitivity level to a lower fixed level of sensitivity.

Abstract: In an exposure meter having a row of lighting elements, such as lamps or light-emitting diodes, which correspond to respective exposure values, an improvement is made in that by utilizing a capacitor-charging integrating circuit, a constant current circuit and a ring-counter, an exposure value between two neighboring steps of the above-mentioned exposure values can be indicated by lighting said two lighting elements, and in that ranges of exposure indication can be switched by shifting a dial plate, which is facing the lighting elements, in interlocking relation with a range-shifting switch for switching its circuit for range selection, thus enabling a doubling of the steps of exposure values to be indicated with a limited number of lighting elements.

Abstract: A laser power meter is described which enables the direct measurement of the output power of lasers over a full range of differing beam wavelengths. The laser power meter includes not only the photocell for intercepting a laser beam and the needle-scale meter conventionally provided, but also calibration means for simple adjustment of the meter to provide a correct power reading irrespective of the wavelength of the beam whose power is being measured. The calibration means includes first and second pluralities of resistors which are selectively connected in series between the photocell and the needle-scale meter by switches which are calibrated in nanometers. A user of the device is able to obtain a true reading of the power in a laser beam merely by "dialing in" the wavelength of the beam and selecting the proper power range for the needle-scale meter.