Abstract: Methods and apparatuses to image particles are described. A plurality of illuminating light beams propagating on multiple optical paths through a particle field are generated. The plurality of illuminating light beams converge at a measurement volume. A shadow image of a particle passing through a portion of the measurement volume at a focal plane of a digital camera is imaged. Shadow images of other particles in the particle field are removed using the plurality of illuminating light beams.

Abstract: An apparatus to detect contaminants in a fuel comprises an input to receive a fuel flow. A light scattering system is coupled to the input. An imaging system is coupled to the light scattering system. A memory is coupled to the imaging system. A processor is coupled to the memory. Output signals from the imaging and light scattering systems are transferred to the processor. The processor is configured to cause the light scattering system to monitor the light scattering intensity from the contaminants in the fuel flow. The processor is configured to cause the light scattering system to measure a light scattering intensity signal from the contaminants in the fuel flow. The processor is configured to generate a trigger signal to turn on the imaging system when the light scattering intensity is greater than a predetermined threshold.

Abstract: Methods and apparatuses to detect particles in dense particle fields are described. A time varying signal is partitioned into a plurality of segments. Parameters are determined from the segments. The time varying signal is parsed into a plurality of individual particle signal components based on the plurality of parameters.

Abstract: An apparatus to provide multi-beam imaging of particles includes a plurality of vertical cavity surface emitting lasers (VCSELs) configured to generate a plurality of light beams that converge with each other to form a measurement volume within a particle field. The plurality of the VCSELs are configured to provide uniformity in a background illumination of the measurement volume. An imaging optics is coupled to at least one of the plurality of VCSELs. A digital camera is coupled to the imaging optics to obtain a shadow image of a particle passing through the measurement volume at a focal plane of the digital camera. A processor is coupled to the digital camera.

Abstract: Methods and apparatuses to image particles are described. A plurality of illuminating light beams propagating on multiple optical paths through a particle field are generated. The plurality of illuminating light beams converge at a measurement volume. A shadow image of a particle passing through a portion of the measurement volume at a focal plane of a digital camera is imaged. Shadow images of other particles in the particle field are removed using the plurality of illuminating light beams.

Abstract: Machine-implemented methods and apparatuses to automatically set-up a signal processing system are described. The signal processing system is set to a first bandwidth. A sampling frequency of the signal processing system is set to a first sampling frequency. Next, first samples of first signals are received at the first bandwidth and the first sampling frequency. First parameters of the first signals based on the first samples are determined. Next, a second sampling frequency is determined based on the first parameters to sample second samples. The first parameters of the first signals may be a mean transit time, a minimum transit time, a mean frequency of the signals, and a standard deviation of the frequency of the signals. Next, a mixer frequency is determined based on the first parameters. A low pass filter is set based on the mixer frequency.

Abstract: Machine-implemented methods and apparatuses to automatically set-up a signal processing system are described. The signal processing system is set to a first bandwidth. A sampling frequency of the signal processing system is set to a first sampling frequency. Next, first samples of first signals are received at the first bandwidth and the first sampling frequency. First parameters of the first signals based on the first samples are determined. Next, a second sampling frequency is determined based on the first parameters to sample second samples. The first parameters of the first signals may be a mean transit time, a minimum transit time, a mean frequency of the signals, and a standard deviation of the frequency of the signals. Next, a mixer frequency is determined based on the first parameters. A low pass filter is set based on the mixer frequency.

Abstract: Machine-implemented methods and apparatuses to automatically set-up a signal processing system are described. The signal processing system is set to a first bandwidth. A sampling frequency of the signal processing system is set to a first sampling frequency. Next, first samples of first signals are received at the first bandwidth and the first sampling frequency. First parameters of the first signals based on the first samples are determined. Next, a second sampling frequency is determined based on the first parameters to sample second samples. The first parameters of the first signals may be a mean transit time, a minimum transit time, a mean frequency of the signals, and a standard deviation of the frequency of the signals. Next, a mixer frequency is determined based on the first parameters. A low pass filter is set based on the mixer frequency.

Abstract: Methods and apparatuses for validating signals to determine sizes and velocities of spherical objects are described. Light is scattered from a spherical object to form an interference fringe pattern. Portions of the interference fringe pattern are received by photodetectors. In response, the photodetectors generate time varying electrical signals. At least one of the time varying signals is partitioned into timing segments. The timing segments are processed to determine one or more timing parameters. A timing parameter consistency between at least two of the timing segments is verified. At least one of the time varying signals is validated based on the timing parameter consistency. The time varying electrical signal is accepted if a timing parameter difference is less or equal to a predetermined timing parameter error threshold. The time varying electrical signal is rejected if the timing parameter difference is larger than the predetermined timing parameter error threshold.

Abstract: Machine-implemented methods and apparatuses to automatically set-up a signal processing system are described. The signal processing system is set to a first bandwidth. A sampling frequency of the signal processing system is set to a first sampling frequency. Next, first samples of first signals are received at the first bandwidth and the first sampling frequency. First parameters of the first signals based on the first samples are determined. Next, a second sampling frequency is determined based on the first parameters to sample second samples. The first parameters of the first signals may be a mean transit time, a minimum transit time, a mean frequency of the signals, and a standard deviation of the frequency of the signals. Next, a mixer frequency is determined based on the first parameters. A low pass filter is set based on the mixer frequency.

Abstract: A compact computer-controlled fully-packaged apparatus providing reliable multi-dimensional characterization of spherical objects in a field environment is disclosed. The apparatus has a rugged, free-space, integrated optical system with up to three lasers that generate at a laser-specific wavelength the coherent light with substantially high pointing stability. The apparatus also has a receiver. Each laser generates a pair of beams crossing each other at a predetermined laser specific angle to form a sample volume such that beams from all lasers coincide in the same spot. The receiver has photodetectors to sense the light scattered from a spherical object. Three photodetectors measure a size and one of the three photodetectors measures a first velocity component, a fourth photodetector measures a second velocity component, and a fifth photodetector measures a third velocity component of the spherical object. The velocity components are orthogonal to each other.