Abstract: A holographic optical element transforms a spectral distribution of light to image points. The element comprises areas, each of which acts as a separate lens to image the light incident in its area to an image point. Each area contains the recorded hologram of a point source object. The image points can be made to lie in a line in the same focal plane so as to align with a linear array detector. A version of the element has been developed that has concentric equal areas to match the circular fringe pattern of a Fabry-Perot interferometer. The element has high transmission efficiency, and when coupled with high quantum efficiency solid state detectors, provides an efficient photon-collecting detection system. The element may be used as part of the detection system in a direct detection Doppler lidar system or multiple field of view lidar system.

Abstract: A vehicle alignment sensor system includes a first sensor assembly for measuring at least a first angle with respect to a fixed reference, that angle being related in a predetermined manner to an alignment angle of a vehicle whose alignment is to be measured, and a second sensor assembly for mounting in a known geometrical relationship to a wheel of a vehicle whose alignment is to be measured. The first sensor assembly has at least one detector, and the second sensor assembly has at least a pair of emitters in fixed geometrical relationship with respect to each other. The detector is capable of measuring the apparent geometrical relationship of the pair of emitters to determine a relative alignment angle of the vehicle, so that a true alignment angle of the vehicle is determinable from the first angle and the relative alignment angle. A calibration method using the present system is also disclosed.

Abstract: The actual value of a parameter from a laser range finder to a target is determined by adjusting the measured parameter by a measurement error. The error adjustment is based on the relationship between the intensity of the detected pulse and the expected parameter error. The laser range finder has a laser diode for emitting a laser pulse to a target to produce a reflected pulse, and a detector for receiving the reflected pulse. A measurement circuit is coupled to the detector for determining a measured parameter based on the reflected pulse. An integrator is coupled to the detector for determining the pulse area, and therefore, the intensity of the reflected pulse. A processor is coupled to the measurement circuit and the integrator for adjusting the measured parameter based on the pulse area of the reflected pulse, to provide the actual value of the parameter.

Abstract: A method and a system for detecting and ranging objects utilize summed and difference signals to determine whether a target is present at a predetermined distance from the system. The summed and difference signals represent corresponding points on two discriminator functions that are derived by summing and subtracting two autocorrelation functions. The two autocorrelation functions are identical functions, except that one has been shifted by a one-bit period. By analyzing the summed and difference signals, the system is able to detect objects that cross a boundary zone located at the predetermined distance from the system. In the preferred embodiment, an optical signal is transmitted by a transmitter of the system to detect a target. Preferably, the optical signal is modulated in accordance with a double concatenated eleventh order Barker-based code. The optical signal is received by an associated photodiode after being reflected by the target.

Abstract: A device for harmonizing a laser beam path with an observation path for a target includes a laser that generates a laser beam; a first optical element that directs a first part of the laser beam toward the target along the laser beam path while directing a second part of the laser beam toward a conversion device; and a second optical element that directs a converted beam from the conversion device to a sensor that receives the converted beam and an image from the target. The conversion device includes a photoluminescent material that converts the second part of the laser beam into a converted radiation having a wavelength within a spectral band of the sensor, and an optical assembly that focuses the second part of the laser beam into the photoluminescent material and that collects at least a portion of the converted radiation to form the converted beam. The photoluminescent material can include photoluminescent ions such as erbium ions, or a semiconductor material such as indium arsenide.

Abstract: Variable shear A.C. interferometer based on a rotating radial grating. Light is passed through the rotating radial grating to produce multiple sidebands diffracted at various angles. These multiple sidebands produce overlapping (sheared) images of the input wavefront at a detector plane causing intensity variations proportional to the phase difference between the sheared wavefronts. An array of detectors is positioned to monitor the images on the detector plane and the outputs of each are processed to obtain the local slope of the wavefront averaged over each detector. From this data, complete wavefront slope information in one direction (X) can be obtained. By providing a second interferometer to make slope measurements in the Y direction, complete information can be obtained from which the entire input wavefront can be reconstructed.

Abstract: An optical distance measuring apparatus is provided which is designed to transmit a laser beam in a cycle to scan a two-dimensional detection zone and to receive a return of the laser beam from a target through a light sensitive unit to determine data on the distance to the target. The light sensitive unit is made of a matrix of cells which are selectively activated in each scan cycle of the laser beam for minimizing optical interference with incoming light other than the return of the laser beam from the target in determining the data on the distance to the target.

Abstract: A three-axis, non-scanning, self-referenced laser air data sensing system comprises a support having three separate laser diodes providing beams of coherent light, which beams are directed toward separate beam expander mirrors. The expander mirrors reflect an expanding beam back toward a focusing mirror that focuses the beams along three diverging axes at known angles to each other at three separate locations in space. The focused beams form small detection cell regions through which particles in the fluid pass and reflect light. The reflected light is received back along the same paths as the transmission of the source light, and is directed back toward detectors on the base. The reflected light undergoes a Doppler shift, and this reflected light is combined with a reference signal tapped from one of the other of the three coherent light sources for heterodyning the signals for determining the Doppler shift and thus the relative velocity.

Abstract: In the rangefinder apparatus in accordance with the present invention, an infrared emitting diode (IRED) having four light-emitting areas projects a first correction beam when only a first light-emitting area emits light, a reference beam when the first and second light-emitting areas emit light, and a second correction beam when all of the first to fourth light-emitting areas emit light. These three kinds of beams have emission light intensity distributions different from each other and an identical emission center-of-gravity position with respect to the base-length direction. The three kinds of beams are successively projected to an object at a distance to be measured, to yield respective distance information items, according to which a beam eclipse correction is carried out.

Abstract: In a distance measurement mode, an autofocus integrated circuit is furnished with a power supply voltage and an integrating capacitor is preliminarily charged to a reference voltage VREF. During the preliminary charging, an external luminance measured by a photometer is input into a CPU, together with a temperature measured by a temperature sensor. The CPU also checks power supply voltage. After the completion of the preliminary charging, an infrared emitting diode emits infrared pulses under the control of the CPU and an integrating capacitor is discharged by a voltage corresponding to distance to an object, a distance that is to be measured.

Abstract: A distance measurement system for measuring a distance with a little time difference while maintaining high accuracy. An infrared emitting diode (IRED) emits a beam of light toward an object at a distance to be measured and a position sensitive detector (PSD) receives reflected light. Outputs from the PSD are processed by signal processing circuits, and an arithmetic circuit, which issues an output as distance information. An integrating circuit integrates the signal outputted by the arithmetic circuit and outputs a signal corresponding to the results of the integration. A CPU determines the distance to the object based on the signal outputted from the integrating circuit. In this distance measurement system, the integrating circuit starts integrating the signal outputted from the arithmetic circuit, immediately after the output, i.e., distance signal, from the arithmetic circuit is stabilized.

Abstract: A laser receiver is provided that is capable of providing an accurate indication of laser receiver tilt and correcting a generated elevation signal based upon the indicated laser receiver tilt. In accordance with one embodiment of the present invention, a laser receiver is provided comprising a laser beam detection unit, an inclination detection unit, and suitable laser receiver control circuitry. The laser beam detection unit is arranged to enable production of an elevation signal indicative of an elevation of a laser beam relative to the laser receiver. The inclination detection unit comprises a reference light source, an optical fiber, and an optical detector. The optical fiber defines a light input end and a light output end and is coupled to the reference light source such that light from the reference light source enters at the light input end and exits from the light output end as an output beam of light. The optical detector is arranged to receive the output beam of light.

Abstract: Secure computation environments are protected from bogus or rogue load modules, executables and other data elements through use of digital signatures, seals and certificates issued by a verifying authority. A verifying authority—which may be a trusted independent third party—tests the load modules or other executables to verify that their corresponding specifications are accurate and complete, and then digitally signs the load module or other executable based on tamper resistance work factor classification. Secure computation environments with different tamper resistance work factors use different verification digital signature authentication techniques (e.g., different signature algorithms and/or signature verification keys)—allowing one tamper resistance work factor environment to protect itself against load modules from another, different tamper resistance work factor environment. Several dissimilar digital signature algorithms may be used to reduce vulnerability from algorithm.

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 system and method for determining at least one physical quantity by means of a relation between a transmission signal and a reception signal, wherein a transmitter emits the transmission signal having a predetermined frequency through a signal path for reception as the reception signal by a receiver. A reference signal generator generates a reference signal having a frequency which has a predetermined fixed relation to the frequency of the transmission signal. The reception signal is mixed with the reference signal to produce an intermediate frequency signal, which is filtered to isolate a difference signal, converted to a digital signal and then processed digitally to determine a phase and/or amplitude relation of the respective physical quantity to be determined. The transmission signal, the reference signal and the digital signal are generated in phase-locked relation using a clock signal derived from a main clock pulse of a master oscillator.

Abstract: An infrared countermeasures system is provided by ganging a plurality of modulators each of which modulates the output of a radiant source to generate at least one collimated beam of radiation. The modulators are so disposed with respect to each other that the beams generated the reby are staggered in angular phase. When the modulators are rotated together they will provide at a point in space remote therefrom a signal comprising a burst of pulses followed by a dead time when no signal is present.

Abstract: A distance measuring device using markers and capable of accurately measuring distance irrespective of the distance to an object. An optical system converges light from markers affixed to an object on the light receiving surface of a light receiving section. The light receiving section generates an image signal by photoelectric conversion and outputs the generated signal. First marker image acquiring means acquires images of markers, and second marker image acquiring means also acquires images of markers. Selecting means selects the output of the first marker image acquiring means if the distance to the object is short, and selects the images acquired by the second marker image acquiring means if the distance to the object is large. Based on the distance between the marker images selected by the selecting means, computing means computes the distance to the object by trigonometry.

Abstract: A lightwave distance measuring apparatus having a coaxial light-transmitting/receiving type optical system is provided with light-transmitting means for transmitting pulsed light toward an object, light-receiving means for receiving reflected pulsed light reflected by the object, a time measuring section for measuring a period of time from when the pulsed light is transmitted until the light is received, a distance measuring section for determining a distance to the object from the measured period of time, and a pulse number detecting section for detecting whether the number of received pulses of reflected light in response to one transmitting pulsed light is one or more; while the value measured when only one pulse of the reflected light is detected by the pulse number detecting section in response to the transmission of pulsed light is made effective.

Abstract: A method for determining the lift and drag coefficients of a golf ball includes launching the ball along a flight path, measuring the velocity at two positions along the flight path, using the measured velocities to determine the coefficients of lift and drag. The step of measuring the velocity includes taking two images of the ball at the two positions, where the time interval between images at each position is less than about 0.01 seconds.

Abstract: A system for airborne detection of fires and transmission of fire location and characteristic data to the system ground station. The system includes an airborne pod and an associated ground station. The pod uses a passive infrared (IR) scanning system which employs a rotating and nutating mirror within an air slipstream driven propeller/spinner and is optically coupled to an infrared detector. A computer in the pod receives fire pod GPS position, IR detector fire spot detection pulse or ‘hit’ plus fire spot characteristics, spinner/mirror rotation and nutation angle at the ‘hit’ time and pod platform attitude relative to North-East-down using an on board Inertial Measurement Unit (IMU). The computer then calculates the firespot GPS location, and processes associated firespot characteristic data and downlinks this data to the ground station. Onboard pod video scene cameras also provide operational video that is also downlinked to the ground station.