Patent ID: 6847910
Filing Date: 2005-01-25
Classification: G01B,G01D,H04N

Abstract:
1. A lensless apparatus for measuring the amount which an object to be measured has moved in a plane and back and forth using a granular speck pattern generated by a reflecting laser beam, said apparatus comprising: a laser projector to generate a granular speck pattern corresponding to a rough surface of an object to be measured; a line sensor to directly pick up without a lens said granular speck pattern used as an index; an A/D converter coupled to said line sensor to convert an analog signal supplied from said line sensor to a digital signal; a processing unit coupled to the A/D converter to calculate the amount of movement of said object toward and away from said sensor on the basis of movement of the granular speck in said pattern with respect to a change in the pixel interval of said granular speck pattern picked up by said line sensor and represented by said A/D converted signal; a display coupled to said processing unit to display the amount of movement calculated by said processing unit; and a light shield positioned in front of said line sensor; wherein said light shield comprises a tube.