Sensor device for measuring a surface, with: an illumination unit for emitting a light beam; an optical device which is designed to divide the light beam into a first partial light beam and a second partial light beam, whereby the optical device is designed to emit the first partial light beam in the direction of a first area of the surface and to emit the second partial light beam in the direction of a second area of the surface; a light sensor which is designed to receive a reflection of the first partial light beam on the first surface area and a reflection of the second partial light beam on the second surface area; and a processor which is designed to detect a distance of the first surface area and of the second surface area to the sensor device on the basis of the respective position of the reflection of the first partial light beam and the reflection of the second partial light beam on the light sensor; whereby the optical device comprises a first partially transparent mirror device, whereby the first partially transparent mirror device is designed to divide the light beam into the first partial light beam and the second partial light beam, whereby the first partially transparent mirror device is also designed to reflect the first partial light beam in the direction of the first surface area and to reflect the reflection of the first partial light beam on the first surface area in the direction of the light sensor; whereby the first partially transparent mirror device comprises a partially transparent mirror, and whereby the partially transparent mirror can be passed by the second partial light beam. an illumination unit for emitting a light beam; an optical device which is designed to divide the light beam into a first partial light beam and a second partial light beam, whereby the optical device is designed to emit the first partial light beam in the direction of a first area of the surface and to emit the second partial light beam in the direction of a second area of the surface; a light sensor which is designed to receive a reflection of the first partial light beam on the first surface area and a reflection of the second partial light beam on the second surface area; and a processor which is designed to detect a distance of the first surface area and of the second surface area to the sensor device on the basis of the respective position of the reflection of the first partial light beam and the reflection of the second partial light beam on the light sensor; whereby the optical device comprises a first partially transparent mirror device, whereby the first partially transparent mirror device is designed to divide the light beam into the first partial light beam and the second partial light beam, whereby the first partially transparent mirror device is also designed to reflect the first partial light beam in the direction of the first surface area and to reflect the reflection of the first partial light beam on the first surface area in the direction of the light sensor; whereby the first partially transparent mirror device comprises a partially transparent mirror, and whereby the partially transparent mirror can be passed by the second partial light beam.