Masayuki Yokota

TL;DR: In this article, a phase-shifting digital holography method for surface contouring is proposed and verified by experiments and numerical simulations, which does not need the removal of the tilt component and is free from the shadowing effect.

TL;DR: It is shown that reduction of the bit depth of the phase data does not seriously damage the image even down to 1 bit, and the procedure for smoothing the images that result from the data-compression methods is shown to be effective.

Abstract: Phase-shifting digital holography has been used for the study of vibrating objects. The time-averaged complex amplitude of Fresnel diffracted field due to a vibrating object was obtained by using a three-step phase-shifting algorithm. Taking the inverse Fresnel transform of the complex amplitude resulted in an image of the object superimposed with Bessel fringes. The Bessel fringes are contour map of the vibration amplitude. By sinusoidally modulating the phase of the reference beam at the vibration frequency, the brightest fringe could be shifted to points of interest, thus extending the measurable range of vibration amplitude.

TL;DR: In this paper, the state of drying paint is monitored from the dynamic behaviors of the speckle pattern arising from laser illumination of the region inspected, and the temporal variation of the peak height of the cross-correlation function between successive frames taken with a fixed interval is plotted until the peak maintains a stationary maximum value.

TL;DR: In this article, a compact optical sensor based on photometric detection of soil nutrients is developed, which consists of three light emitting diodes and a simple data I/O circuit using a PIC (peripheral interface controller) device.