A twofold modulation frequency laser range finder

Poujouly, Stephane; Journet, Bernard

doi:10.1088/1464-4258/4/6/380

Cited by 39 publications

(18 citation statements)

References 5 publications

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“…The technique adopted for the simultaneous collection of distance and color information is based on amplitude modulation [6][7][8] of three monochromatic laser sources (680 nm, 532 nm, and 460 nm), which operate as carrier waves. The distance and color information are extracted from modulating waves by phase-shift and reflectivity responses of the target at the three wavelengths.…”

Section: Methodsmentioning

confidence: 99%

Remote Colorimetric and Structural Diagnosis by RGB-ITR Color Laser Scanner Prototype

Guarneri

Collibus

Fornetti

et al. 2012

Advances in Optical Technologies

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Since several years ENEA's Artificial Vision laboratory is involved in electrooptics systems development. In the last period the efforts are concentrated on cultural heritage remote diagnosis, trying to develop instruments suitable for multiple purposes concerning restoration, cataloguing, and education. Since last five years a new 3D (three-dimensional) laser scanner prototype (RGB-ITR) based on three amplitude-modulated monochromatic laser sources mixed together by dichroic filters is under development. Five pieces of information per each sampled point (pixel) are collected by three avalanche photodiodes and dedicated electronics: two distances and three target reflectivity signals for each channel, red, green, and blue. The combination of these pieces of information opens new scenarios for remote colorimetry allowing diagnoses without the use of scaffolds. Results concerning the use of RGB-ITR as colorimeter are presented.

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Section: Methodsmentioning

confidence: 99%

Remote Colorimetric and Structural Diagnosis by RGB-ITR Color Laser Scanner Prototype

Guarneri

Collibus

Fornetti

et al. 2012

Advances in Optical Technologies

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“…An interesting approach is described in [23], where the phase-based method, implementing a double frequency modulation, is applied for wide-range and high-resolution ranging using undersampling. The pulse-based technique is suitable for long range applications, allowing safe high-power emissions due to the short duration of the pulses.…”

Section: Contextmentioning

confidence: 99%

SNR Degradation in Undersampled Phase Measurement Systems

Salido-Monzú

Meca

Martín-Gorostiza

et al. 2016

Sensors

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A wide range of measuring applications rely on phase estimation on sinusoidal signals. These systems, where the estimation is mainly implemented in the digital domain, can generally benefit from the use of undersampling to reduce the digitizer and subsequent digital processing requirements. This may be crucial when the application characteristics necessarily imply a simple and inexpensive sensor. However, practical limitations related to the phase stability of the band-pass filter prior digitization establish restrictions to the reduction of noise bandwidth. Due to this, the undersampling intensity is practically defined by noise aliasing, taking into account the amount of signal-to-noise ratio (SNR) reduction caused by it considering the application accuracy requirements. This work analyzes the relationship between undersampling frequency and SNR reduction, conditioned by the stability requirements of the filter that defines the noise bandwidth before digitization. The effect of undersampling is quantified in a practical situation where phase differences are measured by in-phase and quadrature (I/Q) demodulation for an infrared ranging application.

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“…Generally an extension of the nonambiguity range can be achieved by using two different modulation frequencies analog to the multiple wavelength interferometry technique [24]. In [25] it was shown that no additional phase-shift measurement stages are necessary in order to process a twofold modulation frequency for an increase of the nonambiguity range.…”

Section: Signal Processingmentioning

confidence: 99%

Large aperture at low cost three-dimensional time-of-flight range sensor using scanning micromirrors and synchronous detector switching

Bogatscher

Streck²,

Fox³

et al. 2014

Appl. Opt.

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In this article the problem of achieving fast scanning of a time-of-flight range sensor with a large optical receiver aperture at low system cost is targeted. The presented approach to solve this problem consists of a micromirror-based transmitter unit and a receiver unit consisting of a large aperture lens system with a small field of view and a detector array. A concept, which is called synchronous detector switching, is applied to the detector array. Thereby electronic steering of the small receiver field of view is possible. The overall approach is compared to alternative approaches, and the underlying concept of synchronous detector switching is demonstrated experimentally in an implementation of a three-dimensional time-of-flight range sensor. It is theoretically shown that the presented concept is potentially cheaper than the alternative approaches for applications with a field of view of less than 60×60°. After a discussion of the strengths and limitations of the approach, its effect on broader scientific issues is outlined.

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A twofold modulation frequency laser range finder

Cited by 39 publications

References 5 publications

Remote Colorimetric and Structural Diagnosis by RGB-ITR Color Laser Scanner Prototype

Remote Colorimetric and Structural Diagnosis by RGB-ITR Color Laser Scanner Prototype

SNR Degradation in Undersampled Phase Measurement Systems

Large aperture at low cost three-dimensional time-of-flight range sensor using scanning micromirrors and synchronous detector switching

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