Method for the time-resolved measurement of the size and position of a moving particle using an image sensor

Parametric solution of the inverse light-scattering problem for individual spherical particles

We analyze the relation between spherical particle parameters (size parameter ? and relative refractive index m ) and light-scattering indicatrix parameters (fringe pitch and visibility) for ?and m ranging from 7 to 88 and from 1.025 to 1.2, respectively. We consider formation of the indicatrix structure under variation of size parameter ? and phase-shift parameter ? =2 ?(m - 1). We show that indicatrix visibility depends basically on the phase-shift parameter whereas fringe pitch depends on the size parameter. An analysis of these dependencies allows us to determine the region in the ? x ? map where particle parameters can be derived unambiguously from indicatrix parameters. We clarify errors in determination of particle characteristics on the basis of the approximating equations that relate particle size and phase shift to indicatrix parameters.

Spatial and temporal analysis of solid-state imaging systems

Temporal and spatial properties of the image that is stored in the digital memory of a frame grabber through a solid-state image sensor, which employs the X-Y addressing method for scanning the image, are analyzed in the space-time domain by using the mathematical expression that we have obtained. This expression includes not only the static effects of the finite picture-cell size of the sensor and the image sampling in both the sensor and the grabber but also the dynamic effects of the temporal response of photoelectric conversion in the sensor, a one-dimensional electrical filter of the camera controller, and the asynchronous sampling with regard to time in both the sensor and the grabber. Results of the experiment and the numerical simulations based on the mathematical expression are presented for a time-varying one-dimensional object with good agreement.