Shape measuring instrument
AssigneeNTT Technology Transfer Corporation
InventorsGiichi Ito, Kousaku Mukai, Yuichi Shimizu, Saiju Suzuki
Life of this patent
Estimating the term…
Abstract
A flat light beam is projected from a light projecting unit to an object to be measured, sweeping its surface with a bright line. The image of the bright line is focused on pluralities of photosensor arrays and line photosensors. A plurality of positions in the bright line are computed by triangular surveying, based on the direction of projection of the flat signal light beam and the positions of those photosensors in each array from which the signal light component is obtained. The position of a gap in the surface of the object is computed, using the detected positions of the photosensors and a signal which indicates a dropout of the signal light component from the output of a line photosensor.
Claims12
A shape measuring instrument comprising:
- a measuring head;
- a light projecting unit mounted on the measuring head, for projecting a flat signal light beam and oscillating it to sweep the surface of an object with a bright line;
- a light receiving unit mounted on the measuring head for focusing the bright light on the object surface into an image on a plurality of photosensor arrays by optical means;
- switching circuits each provided for each of the photosensor arrays, for sequentially switching output terminals of photosensors of each photosensor array at a speed higher than the oscillation speed of the signal light beam and picking up their outputs;
- detecting means operatively connected to each of the switching circuits, for detecting the signal light component from each output of the switching circuit;
- means for generating a signal indicating the direction of projection of the signal light beam;
- deciding means for deciding, for each array, the position of a photosensor from which the signal component has been detected;
- and
- computing means for computing the positions of a plurality of points in the bright line, based on the decided photosensors in the photosensor arrays and the direction of projection of the oscillating signal light beam;
- said light receiving unit including line photosensors of the same number as the photosensor arrays, the bright line being focused by said optical means into an image on the line photosensors, a dropout signal being generated which indicates the disappearance of the signal component from the output of each line photosensor, and said computing means including means for calculating the position of a gap in the surface of the object, using the detected positions of the photosensors and the dropout signal.
A shape measuring instrument comprising:
- a measuring head;
- a light projecting unit mounted on the measuring head, for projecting a signal light beam and oscillating it to sweep the surface of an object with a bright spot;
- a light receiving unit mounted on the measuring head, for focusing the bright spot, by optical means, into an image on a photosensor array and a line photosensor;
- deciding means for deciding the position of a photosensor in said array from which the signal light component has been detected;
- means for generating a dropout signal indicating disappearance of the signal component from the output of the line photosensor;
- means for generating a signal indicating the direction of projection of the signal light beam;
- and
- computing means for computing the position of the bright spot on the surface of the object, based on the signal indicating the direction of projection of the signal light beam and the decided photosensor position in the photosensor array, and computing the position of a gap in the object surface, using the computed position of the bright spot and the dropout signal.
Dependencies are inferred from the claim text.