Method and apparatus for ascertaining the absolute coordinates of an object

A method for ascertaining the absolute coordinates of an object,

• wherein the object is irradiated with light through a projection grating,
• wherein the light reflected from the object is received by a sensor
• and wherein the signal from the sensor is evaluated, comprising the steps of irradiating the object with light of a first color through a first projection grating,
• irradiating the object with light of a second color through a second projection grating
• rotating the second projection grating through a predetermined angle with respect to the first projection grating,
• receiving the light reflected from the object is received by sensor means sensitive to said two colors,
• evaluating the signals from the sensor means, and
• ascertaining the absolute coordinates of the object on the basis of said evaluations.

An apparatus for ascertaining the absolute coordinates of an object comprising

• a light source,
• a projection optics, in particular a projection objective,
• a projection grating an image of which is formed on the object by means of the projection optics,
• a sensor for receiving the light reflected from the object and for generating a signal in response thereto,
• and an object which projects the light reflected from the object to form an image on the sensor,
• wherein the projection grating and the sensor can be rotated relative to each other, and an evaluation unit to evaluate the sensor signal at the least two different rotation angle positions of the projection grating and the sensor and which determines the absolute coordinates of the object therefrom.

An apparatus for ascertaining the absolute coordinates of an object comprising,

• a light source,
• projection optics, including, a projection objective,
• a projection grating, an image of which is formed on the object by means of the projection optics,
• a sensor for receiving the light reflected from the object,
• and an objective which projects the light reflected from the object to form an image on the sensor,
• a first projection grating for light of a first color,
• a second projection grating for light of a second color, which is rotated through a certain angle
• relative to the first projection grating,
• sensor means sensitive to said two colors for producing signal in response thereto,
• and an evaluation unit for evaluating the sensor means signal and determining therefrom the absolute coordinates of the object.