Apparatus for measuring dimension of article and scale to be used in the same

摘要

A scale has marks of a point-symmetrical shape which are arranged in matrix. The scale and an article to be measured in dimension are positioned without any relative movement. An image sensor unit detects a predetermined portion of the article and the marks of the scale corresponding to the predetermined portion of the article selectively and successively, and the image sensor unit generates output signals in accordance with the detected results of the article and the scale. The output signals are processed to calculate the dimension of the article. An apparatus for measuring the dimension of an article is provided which can eliminate the occurrence of parallax, resulting in satisfactorily improved precision of the measurement. In the apparatus, an article and a marker are disposed so that the optical distance between the article and a reading unit is equal to the optical distance between the marker and the reading unit. <IMAGE>