Sutanto

Bio: Sutanto is an academic researcher from Hokkaido University. The author has contributed to research in topics: Speckle pattern & Diffraction. The author has an hindex of 2, co-authored 2 publications receiving 43 citations.

Dynamic statistical properties of laser speckle due to longitudinal motion of a diffuse object under Gaussian beam illumination

Abstract: The dynamic statistical properties of laser speckle produced in the far-field diffraction region from a diffuse object moving longitudinally along the optical axis under illumination of a Gaussian beam are investigated theoretically and experimentally. Although the spatial structure of speckle patterns varies in time owing to the longitudinal motion of the object, the time-varying speckle intensity detected at the center of the far-field diffraction plane is found to follow a statistically stationary variation. The autocorrelation function and power spectral density of the speckle intensity variations are studied with relation to the illuminating condition of the Gaussian beam.

Laser Speckles Produced by the Longitudinal Motion of a Diffuse Object under Gaussian Beam Illumination

Abstract: The dynamic statistical properties of laser speckles produced in the far-field diffraction region by the longitudinal motion of a diffuse object under Gaussian beam illumination are experimentally investigated. A new phenomenon, the statistical stationarity of the time-varying speckle intensity detected at the center of the far-field diffraction plane, was observed, despite the fact that the spatial structure of corresponding speckle patterns, characterized, for example, by the average size, varies greatly in time due to changes in both the illuminated object area and the distance from the object to the receiving plane.

Dynamic Laser Speckles and their Application to Velocity Measurements of the Diffuse Object

Abstract: In connection with the parameters of the optical configuration used to produce speckles and under illumination of a Gaussian beam over a moving diffuse object, this paper discusses the statistical properties of dynamic speckles produced in the diffraction and image fields by the diffuse object moving in a plane with constant velocity. Especially, the space-time correlation function of the dynamic speckle intensity is examined in detail. Two typical speckle motions of translation and boiling are interpreted for various optical configurations in the diffraction and image fields. As one of the interesting applications of dynamic speckles to metrology, various methods for velocity measurements of the diffuse object are introduced.

Dynamic laser speckles and their application to velocity measurements of the diffuse object

Abstract: In connection with the parameters of the optical configuration used to produce speckles and under illumination of a Gaussian beam over a moving diffuse object, this paper discusses the statistical properties of dynamic speckles produced in the diffraction and image fields by the diffuse object moving in a plane with constant velocity. Especially, the space-time correlation function of the dynamic speckle intensity is examined in detail. Two typical speckle motions of translation and boiling are interpreted for various optical configurations in the diffraction and image fields. As one of the interesting applications of dynamic speckles to metrology, various methods for velocity measurements of the diffuse object are introduced.

Dimensional probe and methods of use

Abstract: Disclosed is a surface sensing apparatus, one embodiment having a source of coherent radiation capable of outputting wavelength emissions to create a first illumination state to illuminate a surface and create a first speckle pattern, an emission deviation facility capable of influencing the emission to illuminate the surface and create a second illumination state and a second speckle pattern, and a sensor capable of sensing a representation of the first and a second speckle intensity from the first and second speckle pattern. Also disclosed are methods of sensing properties of the surface, one embodiment comprising the steps of illuminating the surface having a first surface state with the source of coherent radiation emission, sensing a first speckle intensity from the surface, influencing a relationship of the surface to the emission to create a second surface state and sensing a second speckle intensity from the surface at the second surface state.

III: The Statistics of Dynamic Speckles

Abstract: Publisher Summary This chapter discusses the statistics of dynamic speckles. Dynamic speckle arises as a consequence of interference of the waves that are scattered from diffuse objects in motion or random media undergoing the temporal change of their structures. The chapter discusses the statistical properties of dynamic speckle patterns produced by moving diffuse objects. The fundamental properties of dynamic speckles formed in the free-space and imaging geometries are described. The spatial and temporal integration of intensity and the surface-roughness dependence are also considered. The chapter focuses on the speckles arising from various types of the object motion and also discusses the differences of their temporal behaviors. The effect of the wavelength distribution of the incident light on resultant intensity fluctuations is considered. The speckled-speckle patterns produced by illuminating a moving diffuser with static and dynamic speckle patterns are also discussed. Some salient features of doubly-scattered speckle patterns, as distinct from singly-scattered normal speckles are presented.

Detection of movement with laser speckle patterns: statistical properties

Abstract: We present an optical method for detection of in-plane movement of a diffusing object. The technique is based on spatial filtering of the laser speckle pattern, which is produced by illumination of the object with coherent light. Two interlaced differential comb photodetector arrays act as a periodic filter to the spatial-frequency spectrum of the speckle pattern intensity. The detector produces a zero-offset, periodic output signal versus displacement that permits measurement of the movement at arbitrarily low speed. The direction of the movement can be detected with the help of the quadrature signal, which is produced by a second pair of interlaced comb photodetector arrays. When speckle size and period of the comb photodetector arrays are matched, the output signal versus displacement is quasi-sinusoidal with statistical amplitude and phase. First- and second-order statistics of the signal are investigated. First the probability density function and the autocorrelation function of the complex Fourier transform of the speckle pattern intensity are determined. Then the statistical properties of the spectrum of the filtered signal and of the signal itself are calculated. It turns out that the amplitude of the signal is Rayleigh distributed. Both the autocorrelation function of the signal and the probability density function of the measured phase difference for a given displacement are calculated. The potential accuracy of displacement measurements is analyzed. In addition, the signal quality is investigated with respect to the geometry of the detector. The theoretical results are experimentally verified.