Increasing the Resolution of CCD Line Sensors by Image Matching

Abstract

The CCD image line sensors have very good mechanical and electrical properties to apply them as position sensor of high stability. Their only disadvantage is the low resolution arising from the distance between two adjacent pixels (7–13 μm) determined by the manufacturing technology. Because of it, they cannot be used directly for measurements of very small linear and angular displacements needed in geodynamics and engineering geodesy. In the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences a CCD displacement transducer of subpixel accuracy was developed. A microprocessor is built into the new transducer which determines the displacement by fitting the dark-bright transfer functions of the CCD sensor at different positions by means of the least squares method. The accuracy of the displacement transducer is±0.02 pixel.