Photogrammetric camera and method for the two-dimensional measurement of objects

A method for a two-dimensional measurement of objects with a photogrammetric camera, the photogrammetric camera including an object-side telecentric lens which has a pupil plane and a numerical aperture (NA), and which images a surface of an object onto an image sensor, a variable pupil filter which includes a micromirror device arranged in the pupil plane and which has a plurality of micromirrors, each of which is transferable into a first and into a second stable tilted position, an illumination system which produces light and directs the latter at the object with the aid of the micromirror device, a micromirror in the first stable tilted position reflecting light produced by the illumination system such that the light cannot reach the object and reflecting light reflected at the object such that the light can reach the image sensor, a micromirror in the second stable tilted position reflecting light produced by the illumination system such that the light can reach the object and reflects light reflected at the object such that said light cannot reach the image sensor, the method comprising:

• producing and directing light at the object with the micromirror device;
• to implement a recording of an image with coaxial dark field illumination or coaxial reflected light illumination, controlling the micromirror device such that the light produced by the illumination system is incident on the surface at different angles within an angular range of at least arcsin (NA)/10, wherein the angular range is between 70° and 90°;
• storing an image of the surface of the object recorded by the image sensor;
• calculating dimensions of structures on the surface based on the stored image of the surface;
• and
• to record an image with coaxial dark field illumination, controlling the micromirror device such that all micromirrors within a first region in the pupil plane are in the second stable tilted position and all micromirrors within a second region surrounding the first region are in the first stable tilted position, wherein the first region is not point symmetric.

A non-transitory computer-readable storage medium on which a computer program comprising program code is stored, which, when executed on a processor causes the processor to:

• produce light with an illumination system and direct the light at an object with a micromirror device;
• to implement a recording of an image with coaxial dark field illumination or coaxial reflected light illumination, control the micromirror device such that the light produced with the illumination system is incident on a surface of the object at different angles within an angular range of at least arcsin (NA)/10, wherein the angular range is between 70° and 90°, and wherein NA is a numerical aperture of an object-side telecentric lens;
• store an image of the surface of the object recorded by an image sensor;
• calculate dimensions of structures on the surface based on the stored image of the surface of the object;
• and
• to record an image with coaxial dark field illumination, control the micromirror device such that all micromirrors within a first region in the pupil plane are in a second stable tilted position and all micromirrors within a second region surrounding the first region are in a first stable tilted position,
• wherein the first region is not point symmetric,
• wherein a micromirror in the first stable tilted position reflects light produced by the illumination system such that the light cannot reach the object and reflecting light reflected at the object such that the light can reach the image sensor, and
• wherein the micromirror in the second stable tilted position reflects light produced by the illumination system such that the light can reach the object and reflects light reflected at the object such that said light cannot reach the image sensor.