| 摘要 |
PURPOSE:To make it possible to measure a distance with high resolving power by a miniaturized light wt. distance measuring apparatus, by excluding the relation of the spot size of laser beam at an irradiation position and a distance to be measured from proportional relation. CONSTITUTION:The spot size D of laser beam is constant regardless of a distance. Herein, the intensity distribution of speckle by diffused beam from the irradiation point of laser beam is at first detected by a beam detector 6 (a unidimensional photodiode array is used). A speckle average paricle size DSP becomes large with the increase of a distance L0 to be measured. That is, by using parallel beam, the particle size DSP can have the proportional relation with the distance L0. Next, the particle size DSP is calculated from the self-correlation of the speckle intensity distribution obtained by the beam detector 6 and, as the width of correlation at a point lowered by a certain value from the peak value of the calculated correlation function, the distance DSP is calculated. Therefore, the operation content of an operation apparatus 7 is constituted of three stages, that is, correlation operation, peak value detection and correration calculation. |
