Method and apparatus for picking up 2d image of an object to be sensed

Abstract

A method and apparatus for sensing by a linear image sensor a two-dimensional image of an object to be sensed includes detecting a position of the object by a position sensor having a first resolution, picking up an image of the object being projected in a direction (V-scan direction) generally perpendicular to an internal scan (H-scan) direction of the linear image sensor in synchronism with relative movement between the object and the linear image sensor, periodically switching a pixel size along the V-scan direction between a plurality of predefined pixel sizes during the relative movement between the object and the linear image sensor in accordance with information of the relative movement detected by the position sensor, and producing from an output of the linear image sensor a two-dimensional image of the projected image having a second resolution of the object to be sensed. The second resolution is a higher resolution than the first resolution.