Patent US 5,307,153

A three-dimensional measuring apparatus including a multi-slit projector has an actuator for displacing at least one of first and second diffraction gratings by only a minute distance in a direction perpendicular to the slit lights. An image recognizing apparatus includes an image arithmetic unit for changing, each time a coded multi-slit light pattern is changed, weights assigned to the binarized image signals, and for summing up the last weighted binarized image signals or the image signals of the last added results read out from an image memory with newly weighted binarized image signals. This improves the image resolution reduces the memory capacity and increases the processing speed.