| Research Abstract |
To acquire spatial information, most laser-based position measurement systems, such as rangefinders and the motion capture system, are utilized so as to receive the reflected light after light has been projected onto an object, or to directly receive the light from a light source attached to the object. A laser is often used for such a system because it has the advantage of high intensity, high directivity, and monochromaticity [1]. In measuring systems, the high directivity of the laser is useful from two points of view : the transmission of the energy of the light and the maintenance of the optical path. The transmission of the energy of the light is often used for the measurement. In comparison, the maintenance of the optical path has seen less use. Since information on the optical path includes information on the position or orientation of objects, utilization of the information on the optical path in measurements has great potential for development in laser-based measurement syste
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In order to acquire information on the optical path, it is necessary to use a sensor that is able to detect both the position and the incident angle of the light. A sensor exclusively for detecting the position of alight spot and a sensor exclusively for detecting the incident angle have already been developed. The sensor typically used for the former is a CCD (charge coupled device) [2]. or a PSD (position sensitive device) [3]. An example of the latter has been marketed by the Hamamatsu Photonics Co [4]. However, a sensor which can simultaneously detect the position and the angle of a light spot has not yet been developed, and up to now, conventional sensors such as the CCD or PSD have been used. Ordinary laser-based position measurement techniques using a CCD or PSD have, as a result, employed algorithms exclusively using the light spot's pixel position.
if an image sensor can detect both the incident angle of a light and its position, this image sensor could be effectively applied to a number of situations. Thus, we have previously proposed a one-dimensional sensor type [5]. which can measure a one-dimensional position and one-dimensional incident angle onto the sensor at a given position of a y-direction.
In this project, we describe the development of the extended version of the previous sensor, consisting of a two dimensional type sensor which can measure a two-dimensional position and two-dimensional incident angle.
We have designed and built a prototype of this two-dimensional sensor system in which the proposed principle is implemented. We first examined its accuracy by measuring the position and the incident angle of the prototype sensor system. Next, we tested the usefulness of the sensor by applying it to a two-dimensional position measurement.
Experimental results demonstrate the practicable accuracy of the proposed position sensors. Less
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