Abstract: A light wave distance-measuring system, comprising a projection optical system having an optical axis of outgoing light and for projecting a measuring light, and a photodetection optical system having an optical axis of a returning light and for receiving a reflection light, wherein the photodetection optical system comprises a light receiving lens for receiving and for converging the reflection light, a light receiving surface where the reflection light enters, and a ring-like perforated multi-focal optical member arranged between the light receiving surface and the light receiving lens and for converging the light to the light receiving surface.

Abstract: Structures and methods for three-dimensional image sensing using high frequency modulation includes CMOS-implementable sensor structures using differential charge transfer, including such sensors enabling rapid horizontal and slower vertical dimension local charge collection. Wavelength response of such sensors can be altered dynamically by varying gate potentials. Methods for producing such sensor structures on conventional CMOS fabrication facilities include use of “rich” instructions to command the fabrication process to optimize image sensor rather than digital or analog ICs. One detector structure has closely spaced-apart, elongated finger-like structures that rapidly collect charge in the spaced-apart direction and then move collected charge less rapidly in the elongated direction. Detector response is substantially independent of the collection rate in the elongated direction.

Abstract: A forward electromagnetic wave is generated in accordance with a succession of pseudo random noise code signals. An echo electromagnetic wave caused by reflection of the forward electromagnetic wave at an object is converted into a received signal. Direct-current and low-frequency components are removed from the received signal to generate a filtering-resultant signal. The filtering-resultant signal is compared with a preset decision reference voltage to generate a binary signal. The binary signal is sampled into received data. Calculation is made as to a correlation between the received data and the pseudo random noise code signal. The distance to the object is computed on the basis of the calculated correlation. The pseudo random noise code signal is repetitively generated to produce a succession of the pseudo random noise code signals during a surplus time covering a stabilization time taken by the received signal to stabilize in direct-current voltage level.

Abstract: In a spatially resolving range-finding system, an object is illuminated in a pixelwise fashion by illuminating beams emanating from an array of light sources with returned imaging beams striking a corresponding array of solid state receiving elements. The particular arrangement of the light sources and the receiving elements may be varied. The laser light sources and receiving elements may be selectively operated such that one light source may illuminate one or more receiving elements or several light sources may illuminate a single receiving element. The light sources are driven serially, allowing limits of laser protection regulations to be reliably complied with. An advantage is a substantially better signal quality at the receiving elements.

Abstract: A system and method of efficiently obtaining distance measurements of a target by scanning the target. An optical beam is provided by a light source and modulated by a frequency source. The modulated optical beam is transmitted to an acousto-optical deflector capable of changing the angle of the optical beam in a predetermined manner to produce an output for scanning the target. In operation, reflected or diffused light from the target may be received by a detector and transmitted to a controller configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

Abstract: In geodetic measuring systems and measuring devices (14) there exists a need to find and detect, rapidly and automatically, marker points to be measured that are provided with a marker (retro reflector) (2a). For the rapid detection, identification and determination of the horizontal angles of such a marker, even at greater distances, electromagnetic radiation in the form of a vertical fan (17) is transmitted by a transmitter unit (1) whose radiation is received, after reflection from the marker, by a receiving unit with a view field in the form of a vertical fan. By analyzing the signal strength and the apparent object size, a plausibility test and a reliable suppression of foreign or interference markers can be achieved. Such a marker searching device is marked by a selective analysis of specific characteristics of a marker detected. On the basis of the plausibility test, a rapid, certain and robust location of markers is possible.

Abstract: A surveying instrument having a sighting optical system and a phase-difference detection type focus detection device which detects a focus state of the sighting optical system from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas on an objective lens of the sighting optical system, the phase-difference detection type focus detection device includes a pair of line sensors, a condenser lens group for condensing the two light bundles which are respectively passed through the two different pupil areas, and a pair of separator lens groups for forming two images of the two light bundles which are passed through the condenser lens group on the pair of line sensors, respectively. The condenser lens group includes more than one sub lens group.

Abstract: The invention relates to a method for measuring distances, based on the phase measurement of an optical measuring beam that is reflected or scattered by an object, on which the beam is sighted. According to said method, the measurement object is exposed to an optical measuring beam of modulated intensity emitted by a measuring device and is converted into electrical measurement signals. The signals are then compared with a reference signal that is generated from the detection and conversion of a portion of measuring light that has been guided on a known reference trajectory, in order to determine the distance between the measuring device and the measurement objet, based on the phase difference that has been determined. The emitted measuring beam is modulated in bursts and the measurement signal of the receiver is only evaluated during the active burst period. The invention also relates to devices for carrying out said method.

Abstract: A method and system are provided for measuring water current direction and magnitude. A plurality of beams of radiation are transmitted radially outward from a location above a body of water. Each beam is incident on the water's surface at an angle with respect thereto. Each beam experiences a Doppler shift as a result of being incident on the water's surface such that a plurality of Doppler shifts are generated. Each Doppler shift is measured with the largest one thereof being indicative of water current direction and magnitude.

Abstract: A three-dimensional time-of-flight (TOF) system includes a low power optical emitter whose idealized output S1=cos(&ohgr;·t) is reflected by a target distance z away as S2=A·cos(&ohgr;·t+&PHgr;), for detection by a two-dimensional array of pixel detectors and associated narrow bandwidth detector electronics and processing circuitry preferably fabricated on a common CMOS IC. Phase shift &PHgr; is proportional to TOF or z, z=&PHgr;·C/2·&ohgr;=&PHgr;·C/{2·(2·&pgr;·f)}, and A is brightness. &PHgr;, z, and A are determined by homodyne-mixing S2 with an internally generated phase-delayed version of S1, whose phase is dynamically forced to match the phase of S2 by closed-loop feedback. Idealized mixer output per each pixel detector is 0.5·A·{cos(2&ohgr;·t+&PHgr;)+cos(&PHgr;)}.

Abstract: A light emitting diode (LED) illumination device for generating modulated light for a scannerless range imaging system includes circuitry for generating a drive signal having a given phase and frequency characteristic; a plurality of light emitting diodes arranged in a plurality of LED banks, wherein each LED bank comprises a plurality of light emitting diodes connected in series to the circuitry to receive the drive signal; and a switching stage for simultaneously activating the plurality of LED banks such that the LED banks generate the modulated light according to the phase and frequency characteristics of the drive signal.

Abstract: A surveying instrument includes a sighting for sighting an object; a beam-splitting optical system positioned between an objective lens and an eyepiece, and having a wavelength selection mirror which reflects light with specific wavelengths while allowing light having wavelengths other than the specific wavelengths to pass therethrough; an optical distance meter which includes a light-transmitting optical system for transmitting measuring light toward the object, and a light-receiving optical system for receiving light reflected by the object; and a phase-difference detection type focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are passed through two different pupil areas on the objective lens and the wavelength selection mirror. The two different pupil areas are positioned so that the two light bundles are incident on the wavelength selection mirror at the same incident angle.

Abstract: A preferably CMOS-implementable system measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S1=cos(&ohgr;·t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency.

Abstract: A system and method of efficiently obtaining distance measurements of a target. A modulated optical beam may be used to determine the distance to the target. A first beam splitter may be used to split the optical beam and a second beam splitter may be used to recombine a reference beam with a return ranging beam. An optical mixing detector may be used in a receiver to efficiently detect distance measurement information.

Abstract: A robot sentry with a scanning laser observes the sky just above the geographic skyline looking for a vertical airflow pattern characteristic of the rotor inflow to a helicopter rotor. The presence of this vertical airflow pattern indicates the probable presence of a reconnaissance helicopter that is using terrain masking.

Abstract: A preferably CMOS-implementable system measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S1=cos(&ohgr;·t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency.

Abstract: A surveying machine that automatically adjusts an optical axis includes a sighting optical system for sighting an object, a light-transmitting optical system that transmits a beam for surveying, radiated from a light source, to the object, a deviation detector, and an optical axis adjuster. The deviation detector detects a deviation between a first optical axis corresponding to the sighting optical system and a second optical axis corresponding to the light-transmitting optical system. The optical axis adjuster automatically adjusts at least one of the first optical axis and the second optical axis so as to correct the deviation.

Abstract: A preferably CMOS-implementable method measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S1=cos(&ohgr;·t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency.

Abstract: A method and device (1) are proposed for accurately measuring in a reliable manner the distance of an object (99). The method comprises the steps of emitting a signal (such as a laser light beam), directing the signal to an object (99), detecting the signal diffused by the object (99), and comparing the detected signal with the emitted signal to obtain a comparison signal representing the distances travelled by the emitted signal and the signal diffused by the object (99) (for example, by sending modulated laser light and then measuring the phase difference between the emitted and received signals). The method of the invention is characterized by a step of setting the measuring device in order to define a reference operational configuration within the device.

Abstract: A scannerless range imaging system includes an illumination system and an electromechanical light modulator. The illumination system illuminates objects in the scene with modulated illumination of a predetermined modulation frequency, and the modulated illumination reflected from objects in the scene incorporates a phase delay corresponding to the distance of the objects from the range imaging system. The electromechanical light modulator, which is positioned in an optical path of the reflected illumination, operates at a reference frequency that corresponds to the predetermined modulation frequency and accordingly modulates the modulated illumination reflected from the object, thereby generating a phase image from the interference between the reference frequency and the reflected modulated illumination.

Abstract: A tacheometer telescope, i.e.

Abstract: A surveying instrument includes a sighting telescope for sighting an object; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light toward the object via the sighting telescope, a light-receiving optical system for receiving light reflected by the object, and a light-receiving element which receives the measuring light reflected by the object and received by the light-receiving optical system; and a light shield mask positioned on an optical axis between the eyepiece and the light-receiving element to cut off incoming rays from the eyepiece.

Abstract: An electronic distance meter includes a sighting telescope having an objective lens for sighting an object; a reflection member positioned behind the objective lens; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light via the reflection member and the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object, passed through the objective lens and not obstructed by the reflection member; a focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas on the objective lens; and at least one optical element, positioned outside the two different pupil areas, to deflect the portion of the measuring light toward an optical axis of the light-receiving optical system.

Abstract: A scanner for scanning three-dimensional objects, wherein the distance between the scanner and the object for each measured location is derived by determining the phase difference between a generated light beam, and light received off of the object being scanned. The phase difference is determined by mixing the modulation signal for the generated light with a second modulation signal, and also mixing the received light signal with the second modulation signal. Additionally, an approximation of the amplitude of the mixed received light signal and the second modulation signal is used in conjunction with the received light signal to generate a correction for delay inherent in a photoreceiver used in the scanner. The approximation and raw receiver signal may also be used to obtain texture information from a surface being scanned. The distance between two points may also determined by the apparatus and method of this invention.

Abstract: Apparatus for determining a distance of a target, the apparatus comprising a pulse transmitter, a gatable beam detector, and a comparator, the gatable beam detector being operable to obtain gated and calibration beam energy information of a pulse transmitted by the beam pulse transmitter for reflection from the target, and to pass the beam energy information to the comparator, thereby to obtain a ratio between the gated and the calibration beam energy, the ratio being inversely proportional to the distance. Also an array thereof for simultaneously obtaining distances of a multiplicity of points of a three-dimensional object in real time, in particular to obtain movement information of the target.

Abstract: An autofocus distance-measuring optical system includes a sighting telescope having an objective lens for sighting an object; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light via the, and a light-receiving optical system for receiving light reflected by the object; a focus detecting device for detecting a focus state of the sighting telescope; and a controller for controlling the sighting telescope to automatically focus on the object in accordance with the focus state detected by the focus detecting device. The focus detecting device is a phase-difference detection type which detects an in-focus state from a pair of images respectively formed by two light bundles which are passed through two different pupil areas. The two different pupil areas are positioned so as not to interfere with any optical elements of the optical distance meter.

Abstract: A system and method of efficiently obtaining distance measurements of a target. A modulated optical beam may be used to determine the distance to the target. A first beam splitter may be used to split the optical beam and a second beam splitter may be used to recombine a reference beam with a return ranging beam. An optical mixing detector may be used in a receiver to efficiently detect distance measurement information.

Abstract: A surveying instrument includes a distance-measuring optical system having an objective lens via which a distance from the surveying instrument to an object is measured; and an optical distance meter which includes a reflection member positioned behind the objective lens, a light-transmitting optical system for transmitting a measuring light toward the object via the reflection member and the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object, subsequently passed through the objective lens, and not interrupted by the reflection member. The light-receiving optical system includes a plurality of light-guiding optical systems, so that the measuring light which is reflected by the object is selectively incident on an end of one of the plurality of light-guiding optical systems in accordance with the distance from the surveying instrument to the object.

Abstract: A color scannerless range imaging system includes an illumination system for illuminating the scene with modulated illumination of a predetermined modulation frequency and an image capture section positioned in an optical path of the reflected illumination from the scene for capturing a plurality of images including (a) at least one range image corresponding to the reflected modulated illumination and including a phase delay corresponding to the distance of objects in the scene from the range imaging system, and (b) at least one other image of reflected unmodulated illumination corresponding to color in the scene.

Abstract: In a shift clock signal generating apparatus, a delay line includes a plurality of unit delay elements connected in cascade. A reference clock signal propagates in the delay line while being successively delayed by the unit delay elements. Switches have first ends connected with output terminals of the unit delay elements respectively, and second ends connected with a shift clock signal output path. When specified one among the switches is in its on position, a delayed clock signal which results from delaying the reference clock signal by a prescribed time interval is transmitted via the specified switch to the shift clock signal output path as a shift clock signal. The specified one among the switches is determined on the basis of data representing a phase difference of the shift clock signal from the reference clock signal. The specified switch is set in its on position.

Abstract: Measuring method and device providing a traveling path of light beam. The traveling path includes a front portion between a target and a prism unit, a refraction portion entering the prism unit and extending inside the prism unit and a first and a second rear portions positioned outside the prism unit and corresponding to the front portion. A visible light beam and an invisible light beam at the same time travel along the front portion. The visible light beam comes from the surface of the target while the invisible light beam is a laser beam coming from a laser transmitter. The laser beam travels along the same path as the visible light beam to reach the surface of the target. Therefore, very long parts of the traveling paths of the visible light beam and the invisible light beam coincide with each other and are commonly directed to a specific portion of the target.

Abstract: An alignment method is provided for a color scannerless range imaging system whereby the separate optical paths of colored texture and monochromatic range images may be precisely aligned. The range imaging system includes an illumination system for illuminating a scene with modulated infrared illumination, image forming optics for forming an image of the scene, optical means for forming first and second optical paths between the image forming optics and an image sensor, a transponder subject to modulation located in the first optical path for amplifying and converting infrared light to visible light to form a range image on the image sensor.

Abstract: The invention relates to a device for optical distance measurement in geodetic and industrial surveying. It comprises a transmitter unit (1) having one or two optical radiation sources (2, 3) which emit a diffraction-limited, visible radiation and a divergent visible or infrared radiation. The radiation of the two radiation sources (2, 3) is passed through a common lens (5) and directed toward a target object (6). The radiation reflected or scattered by the target object (6) is received by the same lens (5). Selection means (10; 10a, 10b, 10c; 11; 12a, 12b) for selecting the radiation or the radiation sources (2, 3) are provided. Consequently, the distance to cooperative and noncooperative target objects (6) can be measured at short and long distances with high positional resolution. When used in a theodolite, the three-dimensional coordinates of the target object (6) can be determined with very high accuracy.

Abstract: A portable type distance measuring apparatus which comprises an apparatus main body 11 having a distance measuring unit for measuring a distance by projecting a distance measuring light 30, a control unit for controlling the distance measuring unit and for processing measurement data from the distance measuring unit and a transmitting unit to emit a communication light including the measurement data to a distance measuring direction, and a target unit having a display unit 13, an operation unit 14 and a photodetection unit 15 for receiving the communication light, wherein the target unit is removably mounted on the apparatus main body so that the target unit may be used as an object to be measured for distance measurement when necessary.

Abstract: Two-photon absorption measurements are made at various points remote from monitoring apparatus by apparatus which includes two lasers that produce counter-propagating beams through the earth's atmosphere. The lasers are tuned such that the sum of the energies of the photons in each of the laser beams equals that associated with a predetermined transition of a gas in the earth's atmosphere. In one embodiment, a pulsed laser and a CW laser are used. The pulse from the pulsed laser propagates along the CW beam produced by the CW laser and overlaps the CW beam at positions determined by a range gating technique, which makes possible the measurement of the two photon absorption at the various positions of overlap or coincidence. In one embodiment, the subject apparatus is utilized for pollution monitoring, in which the frequencies of the lasers are tuned such that the energies of the photons from these lasers add up to a transition of a predetermined pollutant.

Abstract: The invention is directed to an optoelectronic mixer for demodulating a high-frequency light signal amplitude modulated at a signal frequency (fsig) The optoelectronic mixer includes a light sensor for receiving and converting the light signal into free charge carriers. The light sensor has at least two individually drivable sensor electrodes and a reference frequency generator supplies an alternating-current voltage at a reference frequency (fref). The reference frequency generator is connected to the sensor electrodes to alternately conduct the charge carriers to the one or the other of the sensor electrodes at the reference frequency (fref).

Abstract: The invention particularly relates to a mixing apparatus using an eccentric phase plate, and an optical rangefinder using the mixing apparatus. In the optical rangefinder, an external distance measurement optical path leads light from the light source to a light receiving part passing through an article to be measured, an internal distance measurement optical path leads the light from the light source to the light receiving part not passing through the article to be measured, and processing means calculates the distance to the article to be measured from the difference between the distance value obtained by the external distance measurement optical path and the distance value obtained by the internal distance measurement optical path. In the mixing apparatus, driving means drives the phase plate.

Abstract: A color scannerless range imaging system includes an illumination system for controllably illuminating a scene with modulated illumination and an image responsive element for capturing image light from the scene, including the modulated image light. The system establishes a primary optical path for directly image light toward the image responsive element. A beamsplitter located in the primary optical path separates the image light into two channels, a first channel including an infrared component and a second channel including a color texture component, whereby one of the channels traverses a secondary optical path distinct from the primary path. A modulating element is operative in the first channel to receive the infrared component and a modulating signal, and to generate a processed infrared component with phase data indicative of range information.

Abstract: A portable type distance measuring apparatus which comprises an apparatus main body 11 having a distance measuring unit for measuring a distance by projecting a distance measuring light 30, a control unit for controlling the distance measuring unit and for processing measurement data from the distance measuring unit and a transmitting unit to emit a communication light including the measurement data to a distance measuring direction, and a target unit having a display unit 13, an operation unit 14 and a photodetection unit 15 for receiving the communication light, wherein the target unit is removably mounted on the apparatus main body so that the target unit may be used as an object to be measured for distance measurement when necessary.

Abstract: A laser beam transmitted from a laser diode is run for scanning laterally as a transmitted-beam elongated vertically with a lateral width thereof limited. A wave of the transmitted-beam reflected from an object is caught in a beam receiving area which is elongated laterally with a vertical width limited and scanned vertically, and is received by a photo-diode. Even if the vertical width of the transmitted-beam is set at a sufficient large value to absorb an error in the vertical mounting of a radar system, the period of time when the direct sun rays enter the beam receiving area to make the detection impossible can be shortened by vertically scanning the beam receiving area elongated laterally. Thus, the influence of the direct sun rays can be maintained to the minimum to reliably detect the object without need for a precise aiming, excluding the case where the height position of the sun corresponds to the level of the object.

Abstract: A surveying instrument includes a distance-measuring optical system having an objective lens via which a distance from the surveying instrument to an object is measured; and an optical distance meter which includes a reflection member positioned behind the objective lens, a light-transmitting optical system for transmitting a measuring light toward the object via the reflection member and the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object, subsequently passed through the objective lens, and not interrupted by the reflection member. The light-receiving optical system includes a plurality of light-guiding optical systems, so that the measuring light which is reflected by the object is selectively incident on an end of one of the plurality of light-guiding optical systems in accordance with the distance from the surveying instrument to the object.

Abstract: A surveying instrument includes a sighting for sighting an object; a beam-splitting optical system positioned between an objective lens and an eyepiece, and having a wavelength selection mirror which reflects light with specific wavelengths while allowing light having wavelengths other than the specific wavelengths to pass therethrough; an optical distance meter which includes a light-transmitting optical system for transmitting measuring light toward the object, and a light-receiving optical system for receiving light reflected by the object; and a phase-difference detection type focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are passed through two different pupil areas on the objective lens and the wavelength selection mirror. The two different pupil areas are positioned so that the two light bundles are incident on the wavelength selection mirror at the same incident angle.

Abstract: An electronic distance meter includes a sighting telescope having an objective lens for sighting an object; a reflection member positioned behind the objective lens; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light via the reflection member and the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object, passed through the objective lens and not obstructed by the reflection member; a focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas on the objective lens; and at least one optical element, positioned outside the two different pupil areas, to deflect the portion of the measuring light toward an optical axis of the light-receiving optical system.

Abstract: A surveying instrument having a sighting optical system and a phase-difference detection type focus detection device which detects a focus state of the sighting optical system from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas on an objective lens of the sighting optical system, the phase-difference detection type focus detection device includes a pair of line sensors, a condenser lens group for condensing the two light bundles which are respectively passed through the two different pupil areas, and a pair of separator lens groups for forming two images of the two light bundles which are passed through the condenser lens group on the pair of line sensors, respectively. The condenser lens group includes more than one sub lens group.

Abstract: A three-dimensional time-of-flight (TOF) system includes a low power optical emitter whose idealized output S1=cos(&ohgr;·t) is reflected by a target distance z away, and is detected by a two-dimensional array of pixel detectors and associated narrow bandwidth detector electronics and associated processing circuitry preferably fabricated on a common CMOS IC. The idealized detected reflected energy S2=A·cos(&ohgr;·t+&PHgr;), where phase shift &PHgr; is proportional to TOF or z, and z=&PHgr;·C/2·&ohgr;=&PHgr;·C/{2·(2·&pgr;·f)} and is known modulo 2&pgr;C/(2·&ohgr;)=C/(2·f). Phase &PHgr;, distance z, and other information, is determined by homodyne-mixing S2 with the drive signal to the optical emitter. The idealized mixer output per each pixel detector is 0.5·A·{cos(&ohgr;·t+&PHgr;)+cos(&PHgr;)} and has average value 0.

Abstract: An autofocus distance-measuring optical system includes a sighting telescope having an objective lens for sighting an object; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light via the, and a light-receiving optical system for receiving light reflected by the object; a focus detecting device for detecting a focus state of the sighting telescope; and a controller for controlling the sighting telescope to automatically focus on the object in accordance with the focus state detected by the focus detecting device. The focus detecting device is a phase-difference detection type which detects an in-focus state from a pair of images respectively formed by two light bundles which are passed through two different pupil areas. The two different pupil areas are positioned so as not to interfere with any optical elements of the optical distance meter.

Abstract: A method of unambiguous range estimation is provided for use with a range imaging system that derives phase images from image pixels of a digital image. The method involves generating (a) a first phase image having one or more ambiguous phase intervals and (b) at least one additional phase image that is generated by shifting the phase intervals of the first phase image. Then at least one region of intersection between phase intervals in the two phase images is identified. Finally, the phase of at least one of the ambiguous phase intervals in the first phase image is adjusted based on values of the phase of the image pixels that belong to the region of intersection. As a result, the phase adjustment unwraps the phase ambiguity in the phase intervals of the first phase image.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instruments internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a “zero” value and a “cal” value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: The invention provides a method and apparatus for guiding a weapon to a target using an optical seeker having dual semi-active laser (SAL) and laser radar (LADAR) modes of operation. The dual mode seeker incorporates a laser light source, an optical package including a quadrant detector for operating in SAL mode and a LADAR receiver for operating in LADAR mode. The seeker further includes a high speed scanning mirror for switching between modes to guide the weapon to the target. The method for guiding a weapon to a target includes receiving radiation from the target and tracking the radiation to guide the weapon; monitoring the detected radiation such that if the radiation falls below a predetermined level, a laser system on-board the weapon continues guiding the weapon by generating a laser beam; reflecting the laser beam off the target so that the reflected laser radiation is received from the target to track the radiation and guide the weapon to the target.

Abstract: A self-mixing sensor usable for remotely measuring speed, vibrations, range, and length is provided in a manner making the device practical for economic implementation while retaining accuracy. In one embodiment, the device is configured to avoid mode hopping, such as by providing for relatively high loss for all modes other than the desired mode. Preferably this is accomplished by utilizing laser types that have a high degree of side mode supression, such as DFB lasers or through active or passive control of the amount of light permitted to reenter the laser.